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Synthesis of Trishomocubane Amino Acid Derivatives | Govender ...
African Journals Online (AJOL)
The synthesis of four novel trishomocubane amino acid derivatives is described. The hydantoin precursor and bis-Boc protected hydantoin (>95% yield) were previously reported. A mild hydrolysis of the bis-Boc hydantoin with lithium hydroxide at room temperature quantitatively yielded the corresponding novel cage amino ...
Protein synthesis in the presence of carbamoyl-amino acids
International Nuclear Information System (INIS)
Kraus, L.M.; Stephens, M.C.
The role of exogenous carbamoyl-amino acids in protein biosynthesis has been examined in vitro using a mixture of 14 C amino acids to label newly synthesized protein in human reticulocyte rich (8-18%) peripheral blood. Aliquots of the radiolabeled newly synthesized protein were acid precipitated, washed and the radioactivity measured. Control samples which measured the synthetic capacity of the blood were aliquots of the same blood- 14 C amino acid mixture without added carbamoyl-amino acids or cyanate. N-carbamoyl leucine alone or a 3 N-carbamoyl amino acid mixture of leucine, aspartic acid and tyrosine were used to test inhibition of protein synthesis. Also carbamoyl-amino acids were synthesized using cyanate and Pierce hydrolyzate amino acid calibration standards or the mixture of 14 C amino acids. In this system the carbamoylation of endogenous amino acids by cyanate up to 8 μmol/100μl showed a linear decrease in protein synthesis with time which is inversely related to the cyanate concentration. At greater cyanate levels the inhibition of protein synthesis reaches a plateau. When N-carbamoyl-amino acids only are present there is about a 50% decrease in the 14 C protein at 30 minutes as compared to the synthesis of 14 C protein without N-carbamoyl-amino acids. These results indicate that the presence of carbamoyl-amino acids interferes with protein synthesis
Synthesis of some labelled non-proteinogenic amino acids
International Nuclear Information System (INIS)
Adrianens, P.; Vanderhaeghe, H.
The literature on the synthesis of labeled non-proteinogenic amino acids contains approximately 300 papers, whereas syntheses of labeled proteinogenic amino acids are dealt with in some 800-1000 publications. However, most of the methods described in this paper for the synthesis of non-proteinogenic amino acids are also used for the preparation of the essential amino acids addition, the first category also contains β, γ...amino acids, seleno amino acids, N-methyl and α-methyl amino acids and sometimes have atoms or groups which are not present in the protein building blocks. Furthermore the latter group is more easily available so that methods for synthesis of non-proteinogenic amino acids are more needed
Synthesis of L-2-amino-8-oxodecanoic acid: an amino acid component of apicidins
Linares de la Morena, María Lourdes; Agejas Chicharro, Francisco Javier; Alajarín Ferrández, Ramón; Vaquero López, Juan José; Álvarez-Builla Gómez, Julio
The synthesis Of L-2-amino-8-oxodecanoic acid (Aoda) is described. This is a rare amino acid component of apicidins, a family of new cyclic tetrapeptides, inhibitors of histone deacetylase. Aoda was synthesised in seven steps from L-glutamic acid along with some derivatives. Universidad de Alcalá Fundación General de la Universidad de Alcalá FEDER
Negishi cross-couplings in the synthesis of amino acids.
Brittain, W.D.G.; Cobb, S.L.
The Negishi cross-coupling is a powerful C–C bond-forming reaction widely utilised in many areas of organic synthesis. This review details the use of Negishi cross-couplings in the synthesis of unnatural amino acids. The application of this reaction in the preparation of aromatic, heteroaromatic, and, complex amino acid derivatives are reviewed and presented herein.
Rewiring protein synthesis: From natural to synthetic amino acids.
Fan, Yongqiang; Evans, Christopher R; Ling, Jiqiang
The protein synthesis machinery uses 22 natural amino acids as building blocks that faithfully decode the genetic information. Such fidelity is controlled at multiple steps and can be compromised in nature and in the laboratory to rewire protein synthesis with natural and synthetic amino acids. This review summarizes the major quality control mechanisms during protein synthesis, including aminoacyl-tRNA synthetases, elongation factors, and the ribosome. We will discuss evolution and engineering of such components that allow incorporation of natural and synthetic amino acids at positions that deviate from the standard genetic code. The protein synthesis machinery is highly selective, yet not fixed, for the correct amino acids that match the mRNA codons. Ambiguous translation of a codon with multiple amino acids or complete reassignment of a codon with a synthetic amino acid diversifies the proteome. Expanding the genetic code with synthetic amino acids through rewiring protein synthesis has broad applications in synthetic biology and chemical biology. Biochemical, structural, and genetic studies of the translational quality control mechanisms are not only crucial to understand the physiological role of translational fidelity and evolution of the genetic code, but also enable us to better design biological parts to expand the proteomes of synthetic organisms. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue. Copyright © 2017 Elsevier B.V. All rights reserved.
Stereoselective synthesis of stable-isotope-labeled amino acids
International Nuclear Information System (INIS)
Unkefer, C.J.; Martinez, R.A.; Silks, L.A. III; Lodwig, S.N.
For magnetic resonance and vibrational spectroscopies to reach their full potential, they must be used in combination with sophisticated site-specific stable isotope labeling of biological macromolecules. Labeled amino acids are required for the study of the structure and function of enzymes and proteins. Because there are 20 common amino acids, each with its own distinguishing chemistry, they remain a synthetic challenge. The Oppolzer chiral auxiliary provides a general tool with which to approach the synthesis of labeled amino acids. By using the Oppolzer auxiliary, amino acids can be constructed from several small molecules, which is ideal for stable isotope labeling. In addition to directing the stereochemistry at the α-carbon, the camphorsultam can be used for stereo-specific isotope labeling at prochiral centers in amino acids. By using the camphorsultam auxiliary we have the potential to synthesize virtually any isotopomer of all of the common amino acids
Synthesis and chirality of amino acids under interstellar conditions.
Giri, Chaitanya; Goesmann, Fred; Meinert, Cornelia; Evans, Amanda C; Meierhenrich, Uwe J
Amino acids are the fundamental building blocks of proteins, the biomolecules that provide cellular structure and function in all living organisms. A majority of amino acids utilized within living systems possess pre-specified orientation geometry (chirality); however the original source for this specific orientation remains uncertain. In order to trace the chemical evolution of life, an appreciation of the synthetic and evolutional origins of the first chiral amino acids must first be gained. Given that the amino acids in our universe are likely to have been synthesized in molecular clouds in interstellar space, it is necessary to understand where and how the first synthesis might have occurred. The asymmetry of the original amino acid synthesis was probably the result of exposure to chiral photons in the form of circularly polarized light (CPL), which has been detected in interstellar molecular clouds. This chirality transfer event, from photons to amino acids, has been successfully recreated experimentally and is likely a combination of both asymmetric synthesis and enantioselective photolysis. A series of innovative studies have reported successful simulation of these environments and afforded production of chiral amino acids under realistic circumstellar and interstellar conditions: irradiation of interstellar ice analogues (CO, CO2, NH3, CH3OH, and H2O) with circularly polarized ultraviolet photons at low temperatures does result in enantiomer enriched amino acid structures (up to 1.3% ee). This topical review summarizes current knowledge and recent discoveries about the simulated interstellar environments within which amino acids were probably formed. A synopsis of the COSAC experiment onboard the ESA cometary mission ROSETTA concludes this review: the ROSETTA mission will soft-land on the nucleus of the comet 67P/Churyumov-Gerasimenko in November 2014, anticipating the first in situ detection of asymmetric organic molecules in cometary ices.
Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids
DEFF Research Database (Denmark)
Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele
Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them...
Stereoselective synthesis of unsaturated α-amino acids.
Fanelli, Roberto; Jeanne-Julien, Louis; René, Adeline; Martinez, Jean; Cavelier, Florine
Stereoselective synthesis of unsaturated α-amino acids was performed by asymmetric alkylation. Two methods were investigated and their enantiomeric excess measured and compared. The first route consisted of an enantioselective approach induced by the Corey-Lygo catalyst under chiral phase transfer conditions while the second one involved the hydroxypinanone chiral auxiliary, both implicating Schiff bases as substrate. In all cases, the use of a prochiral Schiff base gave higher enantiomeric excess and yield in the final desired amino acid.
Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System
Directory of Open Access Journals (Sweden)
Akiyoshi Hoshino
Full Text Available Mars is a CO2-abundant planet, whereas early Earth is thought to be also CO2-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO2/liquid H2O (10:1 system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source and keto acids (oxylic acid sources. In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life's origin.
Synthesis of branched amino acids : isonorstatine, phenylisothreonine, lactacystin analogues, and amino polyols
Li, Feng
The 1,2-aminoalcohol fragment is found in many natural products and drugs, for example as a central moiety of non-proteinogenic amino acids. It is also an integral part of doxorubicin and daunomycin, which have been used for the treatment of human malignancies. There is, therefore, a particular interest in the synthesis of branched amino hydroxy acids such as isonorstatine, phenylisothreonine, amino polyols and lactacystin derivatives. Norstatine is part of amastatin, an inhibitor of leuc...
A novel synthesis of chromone based unnatural -amino acid ...
Indian Academy of Sciences (India)
bromomethyl chromone has been described. Using this method ... inal work on synthesis of unnatural amino acids has been done by O'Donnell22 and ... To a solution of compound 6a (20 g, 147.12 mmol) in DMF. (57 mL, 735.02 mmol) was added ...
Prebiotic Amino Acid Thioester Synthesis: Thiol-Dependent Amino Acid Synthesis from Formose substrates (Formaldehyde and Glycolaldehyde) and Ammonia
Weber, Arthur L.
Formaldehyde and glycolaldehyde (substrates of the formose autocatalytic cycle) were shown to react with ammonia yielding alanine and homoserine under mild aqueous conditions in the presence of thiol catalysts. Since similar reactions carried out without ammonia yielded alpha-hydroxy acid thioesters, the thiol-dependent synthesis of alanine and homoserine is presumed to occur via amino acid thioesters-intermediates capable of forming peptides. A pH 5.2 solution of 20 mM formaldehyde, 20 mM glycolaldehyde, 20 mM ammonium chloride, 23 mM 3-mercaptopropionic acid, and 23 mM acetic acid that reacted for 35 days at 40 C yielded (based on initial formaldehyde) 1.8% alanine and 0.08% homoserine. In the absence of thiol catalyst, the synthesis of alanine and homoserine was negligible. Alanine synthesis required both formaldehyde and glycolaldehyde, but homoserine synthesis required only glycolaldehyde. At 25 days the efficiency of alanine synthesis calculated from the ratio of alanine synthesized to formaldehyde reacted was 2.1%, and the yield (based on initial formaldehyde) of triose and tetrose intermediates involved in alanine and homoserine synthesis was 0.3 and 2.1%, respectively. Alanine synthesis was also seen in similar reactions containing only 10 mM each of aldehyde substrates, ammonia, and thiol. The prebiotic significance of these reactions that use the formose reaction to generate sugar intermediates that are converted to reactive amino acid thioesters is discussed.
Abc Amino Acids: Design, Synthesis, and Properties of New Photoelastic Amino Acids
Energy Technology Data Exchange (ETDEWEB)
Standaert, Robert F [ORNL; Park, Dr Seung Bum [Seoul National University
Photoisomerizable amino acids provide a direct avenue to the experimental manipulation of bioactive polypeptides, potentially allowing real-time, remote control of biological systems and enabling useful applications in nanobiotechnology. Herein, we report a new class of photoisomerizable amino acids intended to cause pronounced expansion and contraction in the polypeptide backbone, i.e., to be photoelastic. These compounds, termed Abc amino acids, employ a photoisomerizable azobiphenyl chromophore to control the relative disposition of aminomethyl and carboxyl substituents. Molecular modeling of nine Abc isomers led to the identification of one with particularly attractive properties, including the ability to induce contractions up to 13A in the backbone upon transa?cis photoisomerization. This isomer, designated mpAbc, has substituents at meta and para positions on the inner (azo-linked) and outer rings, respectively. An efficient synthesis of Fmoc-protected mpAbc was executed in which the biaryl components were formed via Suzuki couplings and the azo linkage was formed via amine/nitroso condensation; protected forms of three other Abc isomers were prepared similarly. A decapeptide incorporating mpAbc was synthesized by conventional solid-phase methods and displayed characteristic azobenzene photochemical behavior with optimal conversion to the cis isomer at 360 nm and a thermal cisa?trans half life of 100 min. at 80 AoC.
Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics
Directory of Open Access Journals (Sweden)
Matthias Wünsch
Full Text Available The amide moiety of peptides can be replaced for example by a triazole moiety, which is considered to be bioisosteric. Therefore, the carbonyl moiety of an amino acid has to be replaced by an alkyne in order to provide a precursor of such peptidomimetics. As most amino acids have a chiral center at Cα, such amide bond surrogates need a chiral moiety. Here the asymmetric synthesis of a set of 24 N-sulfinyl propargylamines is presented. The condensation of various aldehydes with Ellman's chiral sulfinamide provides chiral N-sulfinylimines, which were reacted with (trimethylsilylethynyllithium to afford diastereomerically pure N-sulfinyl propargylamines. Diverse functional groups present in the propargylic position resemble the side chain present at the Cα of amino acids. Whereas propargylamines with (cycloalkyl substituents can be prepared in a direct manner, residues with polar functional groups require suitable protective groups. The presence of particular functional groups in the side chain in some cases leads to remarkable side reactions of the alkyne moiety. Thus, electron-withdrawing substituents in the Cα-position facilitate a base induced rearrangement to α,β-unsaturated imines, while azide-substituted propargylamines form triazoles under surprisingly mild conditions. A panel of propargylamines bearing fluoro or chloro substituents, polar functional groups, or basic and acidic functional groups is accessible for the use as precursors of peptidomimetics.
A Convenient Synthesis of Amino Acid Methyl Esters
Directory of Open Access Journals (Sweden)
Yaowu Sha
Full Text Available A series of amino acid methyl ester hydrochlorides were prepared in good toexcellent yields by the room temperature reaction of amino acids with methanol in thepresence of trimethylchlorosilane. This method is not only compatible with natural aminoacids, but also with other aromatic and aliphatic amino acids.
Ionotropic excitatory amino acid receptor ligands. Synthesis and pharmacology of a new amino acid AMPA antagonist
DEFF Research Database (Denmark)
Madsen, U; Sløk, F A; Stensbøl, T B
We have previously described the potent and selective (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor agonist, (RS)-2-amino-3-(3-carboxy-5-methyl-4-isoxazolyl)propionic acid (ACPA), and the AMPA receptor antagonist (RS)-2-amino-3-[3-(carboxymethoxy)-5-methyl-4......-isoxazolyl]propionic acid (AMOA). Using these AMPA receptor ligands as leads, a series of compounds have been developed as tools for further elucidation of the structural requirements for activation and blockade of AMPA receptors. The synthesized compounds have been tested for activity at ionotropic...... excitatory amino acid (EAA) receptors using receptor binding and electrophysiological techniques, and for activity at metabotropic EAA receptors using second messenger assays. Compounds 1 and 4 were essentially inactive. (RS)-2-Amino-3-[3-(2-carboxyethyl)-5-methyl-4-isoxazolyl]propionic acid (ACMP, 2...
A direct method for the synthesis of orthogonally protected furyl- and thienyl- amino acids.
Hudson, Alex S; Caron, Laurent; Colgin, Neil; Cobb, Steven L
The synthesis of unnatural amino acids plays a key part in expanding the potential application of peptide-based drugs and in the total synthesis of peptide natural products. Herein, we report a direct method for the synthesis of orthogonally protected 5-membered heteroaromatic amino acids.
Prebiotic synthesis of carboxylic acids, amino acids and nucleic acid bases from formamide under photochemical conditions⋆
Botta, Lorenzo; Mattia Bizzarri, Bruno; Piccinino, Davide; Fornaro, Teresa; Robert Brucato, John; Saladino, Raffaele
The photochemical transformation of formamide in the presence of a mixture of TiO2 and ZnO metal oxides as catalysts afforded a large panel of molecules of biological relevance, including carboxylic acids, amino acids and nucleic acid bases. The reaction was less effective when performed in the presence of only one mineral, highlighting the role of synergic effects between the photoactive catalysts. Taken together, these results suggest that the synthesis of chemical precursors for both the genetic and the metabolic apparatuses might have occurred in a simple environment, consisting of formamide, photoactive metal oxides and UV-radiation.
Amino acids attached to 2'-amino-LNA: Synthesis of DNA mixmer oligonucleotides with increased duplex stability
DEFF Research Database (Denmark)
Johannsen, Marie Willaing; Wengel, Jesper; Wamberg, Michael Chr.
-LNA nucleosides derivatized with amino acids have been synthesized and incorporated into DNA oligonucleotides. Following oligonucleotide synthesis, peptides have been added using solid phase peptide coupling chem. Modification of oligonucleotides with pos. charged residues greatly improves thermal stability....
Synthesis and accumulation of free amino acids during somatic and ...
African Journals Online (AJOL)
In ZE, glutamine and asparagine appeared to be fundamental to the process of induction of zygotic embryos. On the other hand, the induction of somatic embryos that appeared require glutamine, gamma-aminobutyric acid (GABA) and glutamic acid. The results suggest the involvement of amino acids in the ontogenesis of ...
Asymmetric synthesis of α-deuterated α-amino acids.
Takeda, Ryosuke; Abe, Hidenori; Shibata, Norio; Moriwaki, Hiroki; Izawa, Kunisuke; Soloshonok, Vadim A
α-Deuterated-α-amino acids represent a very special class of stable isotopically labeled compounds, used in advanced biomedical research. Herein, we disclose a generalized approach for the preparation of α- 2 H-α-amino acids in enantiomerically pure form and with up to 99% deuteration. The reaction chemistry involved in this process is based on the dynamic kinetic resolution of racemates or (S)-(R) interconversion via the formation of intermediate Ni(ii) complexes derived from unprotected amino acids and recyclable tridentate ligands. Operationally convenient conditions, excellent chemical yields, diastereoselectivity and the degree of the deuteration bode well for the wide application of this methodology for the preparation of tailor-made α- 2 H-α-amino acids.
Enzymatic stereoselective synthesis of B-amino acids
CSIR Research Space (South Africa)
Chhiba, V
Full Text Available , antimicrobials, and as nonstandard amino acids in therapeutic peptides or peptidomimetics. Access to these compounds can be achieved through diverse synthetic routes with enantioselective steps catalyzed in different ways, including by means of nitrile hydrolysis...
Synthesis and Antimicrobial Activity of Amino Acids Conjugated Diphenylmethylpiperazine Derivatives
Directory of Open Access Journals (Sweden)
K. N. Shivakumara
Full Text Available A series of amino acid conjugated diphenylmethylpiperazine derivatives were synthesized by coupling diphenylmethylpiperazine with different Boc-amino acids using EDCI/HOBt as coupling agent and NMM as base. The synthesized compounds were characterized by 1H-NMR and elemental analysis. The Boc-deblocked derivatives were tested for their antimicrobial activity. We are here reporting that Phe and Trp conjugated diphenylmethylpiperazine showed equally good antibacterial activities as that of conventional antimicrobial drugs.
Stereo- and regio-selective one-pot synthesis of triazole-based unnatural amino acids and β- amino triazoles
Synthesis of triazole based unnatural amino acids and β-amino triazole has been described via stereo and regioselective one-pot multi-component reaction of sulfamidates, sodium azide, and alkynes under MW conditions. The developed method is applicable to a broad substrate scope a...
Synthesis of carboranyl amino acids, hydantoins, and barbiturates
International Nuclear Information System (INIS)
Wyzlic, I.M.; Tjarks, W.; Soloway, A.H.
The syntheses of three novel boronated hydantoins, 5-(o-carboran-1-ylmethyl)hydantoin, 14, the tetraphenylphosphonium salt of 7-(hydantoin-5-ylmethyl)dodecahydro-7,8-dicarba-nido-undecaborate, 15, 5-(o-carboran-1-ylmethyl)-2-thiohydantoin, 16, and two new barbiturates, 5,5-bis(but-2-ynyl)barbiturate, 18, and 5,5-bis[(2-methyl-0-carboran-1-yl)methyl]barbiturate, 20, are described. Hydantoins 14-16 were synthesized from o-carboranylalanine (Car, 13). The detailed synthesis of Car and two other carborane-containing amino acids, O-(o-carboran-1-ylmethyl)tyrosine (CBT, 5a) and p-(o-carboran-1-yl)phenylalanine (CBPA, 5b), presented earlier as a communication, 16 are also described. Hydantoin 14 and barbiturates 18 and 20 were tested for their potential anticonvulsant activity. Initial qualitative screening showed moderate activities for hydantoin 14 and barbiturate 18. Barbiturate 20 had no activity. Compound 14 appeared to be nontoxic at doses of 300 mg/kg (mice, ip) and 50 mg/kg (rats, oral). However, 18 was very toxic under similar conditions
Synthesis and NMR Elucidation of Novel Octa-Amino Acid Resorcin ...
African Journals Online (AJOL)
The synthesis of nine novel protected amino acid cavitands is reported. All have four pendant n-undecyl chains and 'headgroups' connected by a two-carbon spacer at eight positions on the aromatic rings. The amino acids employed are glycine, alanine, phenylalanine, leucine, proline, tryptophan, serine, glutamine and ...
Stereoselective synthesis of a-hydroxy-b-amino acids: the chiral pool approach
Directory of Open Access Journals (Sweden)
Full Text Available A method for the stereoselective homologation of a-amino acids into syn-a-hydroxy-b-amino acids is described, based on the conversion of stereoisomeric cyanohydrins into trans-oxazolines. The synthetic potential of the method is illustrated in the enantioselective formal synthesis of Bestatin.
A novel synthesis of chromone based unnatural α-amino acid ...
Indian Academy of Sciences (India)
Home; Journals; Journal of Chemical Sciences; Volume 129; Issue 8. A novel synthesis of chromone based unnatural α-amino acid derivatives. VENU KANDULA RAMAKRISHNA GUDIPATI ANINDITA CHATTERJEE MURALIDARAN KALIYAPERUMALA SATYANARAYANA YENNAM MANORANJAN BEHERA. REGULAR ...
Synthesis of glycosyl-amino acids of biological interest; Sintese de glicoaminoacidos de interesse biologico
Energy Technology Data Exchange (ETDEWEB)
Campo, Vanessa Leiria; Carvalho, Ivone [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas]. E-mail: email@example.com
This work describes the synthesis of the glycosylated amino acids {alpha}GlcNAc-Thr, {beta}GlcNAc-Thr and {alpha}LacNAc-Thr by the glycosylation reaction of the amino acid threonine with the corresponding glycosyl donors {alpha}GlcNAcCl and {alpha}LacN3Cl. The glycosylated amino acids containing the sugar units {alpha}-D-GlcNAc and {alpha}-D-LacNAc O-linked to threonine amino acids are related to O-glycans found in mucins of the parasite Trypanosoma cruzi, while the corresponding {beta}-D-GlcNAc isomer is involved in cellular signaling events. (author)
Radiotracer studies on the synthesis of prorennin and rennin using 14C-amino acids
International Nuclear Information System (INIS)
Angelo, I.A.; Ganguli, N.C.
In vivo incorporation of 14 C-amino acids into the prorennin and rennin fractions of the abomasal tissue of the intact animal (i.e. calf) has been investigated by : (1) intravenous injection of the label and subsequent isolation of rennin and prorennin fractions from the excised abomasum and (2) feeding. of milk whey fortified with the label to a fistulated kid and subsequent processing of the abomasal juice for rennet extraction. Prorennin incorporates more radioactivity than rennin. This indicates that abomasal tissue uses blood amino acids for prorennin synthesis, but amino acids fed through dietary channels may not be used for rennin synthesis. (M.G.B.)
Synthesis of (S)-2-Boc-Amino-8-(R)-(tert-butyldimethylsilanyloxy) decanoic acid, a Precursor to the Unusual Amino Acid Residue of the Anticancer Agent Microsporin B
Gu, Wenxin; Silverman, Richard B.
(S)-2-Boc-Amino-8-(R)-(tert-butyldimethylsilanyloxy) decanoic acid, the Boc-protected precursor of an unusual amino acid residue for the synthesis of microsporin B, was synthesized. The key steps include a Suzuki coupling followed by asymmetric homogeneous hydrogenation.
Amino acid starvation has opposite effects on mitochondrial and cytosolic protein synthesis.
Directory of Open Access Journals (Sweden)
Mark A Johnson
Full Text Available Amino acids are essential for cell growth and proliferation for they can serve as precursors of protein synthesis, be remodelled for nucleotide and fat biosynthesis, or be burnt as fuel. Mitochondria are energy producing organelles that additionally play a central role in amino acid homeostasis. One might expect mitochondrial metabolism to be geared towards the production and preservation of amino acids when cells are deprived of an exogenous supply. On the contrary, we find that human cells respond to amino acid starvation by upregulating the amino acid-consuming processes of respiration, protein synthesis, and amino acid catabolism in the mitochondria. The increased utilization of these nutrients in the organelle is not driven primarily by energy demand, as it occurs when glucose is plentiful. Instead it is proposed that the changes in the mitochondrial metabolism complement the repression of cytosolic protein synthesis to restrict cell growth and proliferation when amino acids are limiting. Therefore, stimulating mitochondrial function might offer a means of inhibiting nutrient-demanding anabolism that drives cellular proliferation.
The Synthesis of cis- and trans-Fused Bicyclic Sugar Amino Acids
Risseeuw, Martijn D.P.; Grotenbreg, Gijsbert M.; Witte, Martin D.; Tuin, Adriaan W.; Leeuwenburgh, Michiel A.; Marel, Gijsbert A. van der; Overkleeft, Herman S.; Overhand, Mark
Four isomeric bicyclic sugar amino acids (SAAs) were prepared from an α-acetylenic-C-glucoside by employing a Petasis olefination and a ring-closing metathesis (RCM) as key steps. The applicability of the resulting SAAs in solid-phase peptide synthesis was demonstrated by the synthesis of a
Amino Acid Based Synthesis of Chiral Long Chain Diamines and Tetramines
Directory of Open Access Journals (Sweden)
George Kokotos
Full Text Available A method for the synthesis of long chain diamines and tetramines starting from natural α-amino acids is reported. Diamines and tetramines were prepared through the Wittig olefination reaction of N-protected amino aldehydes obtained from phenylalanine and lysine. A 1,2,17,18-tetramine was synthesized using (2S-1-azido-2-[bis(tert-butoxycarbonyl-amino]-5-oxopentane as key-intermediate compound.
Synthesis and applications of silicon-containing alpha-amino acids.
Mortensen, Matthew; Husmann, Ralph; Veri, Elisabetta; Bolm, Carsten
Amino acids serve not only as monomers for proteins and enzymes but also as important players in signal transduction pathways. They belong to the abundant feedstock of the pharmaceutical, food science and agrochemical industries, and some are used as catalysts or ligand components. In recent years, non-proteogenic amino acids have taken on important roles. This tutorial review summarises the progress in the development of strategies to construct silicon-containing alpha-amino acid frameworks and the studies concerned with their structure and activity. It shall be of interest for the synthesis and biosciences communities.
Ammonia lyases and aminomutases as biocatalysts for the synthesis of α-amino and β-amino acids.
Turner, Nicholas J
Ammonia lyases catalyse the reversible addition of ammonia to cinnamic acid (1: R=H) and p-hydroxycinnamic (1: R=OH) to generate L-phenylalanine (2: R=H) and L-tyrosine (2: R=OH) respectively (Figure 1a). Both phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL) are widely distributed in plants, fungi and prokaryotes. Recently there has been interest in the use of these enzymes for the synthesis of a broader range of L-arylalanines. Aminomutases catalyse a related reaction, namely the interconversion of α-amino acids to β-amino acids (Figure 1b). In the case of L-phenylalanine, this reaction is catalysed by phenylalanine aminomutase (PAM) and proceeds stereospecifically via the intermediate cinnamic acid to generate β-Phe 3. Ammonia lyases and aminomutases are related in sequence and structure and share the same active site cofactor 4-methylideneimidazole-5-one (MIO). There is currently interest in the possibility of using these biocatalysts to prepare a wide range of enantiomerically pure l-configured α-amino and β-amino acids. Recent reviews have focused on the mechanism of these MIO containing enzymes. The aim of this review is to review recent progress in the application of ammonia lyase and aminomutase enzymes to prepare enantiomerically pure α-amino and β-amino acids. Copyright © 2010 Elsevier Ltd. All rights reserved.
Aqueous Microwave-Assisted Solid-Phase Synthesis Using Boc-Amino Acid Nanoparticles
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Yoshinobu Fukumori
Full Text Available We have previously developed water-based microwave (MW-assisted peptide synthesis using Fmoc-amino acid nanopaticles. It is an organic solvent-free, environmentally friendly method for peptide synthesis. Here we describe water-based MW-assisted solid-phase synthesis using Boc-amino acid nanoparticles. The microwave irradiation allowed rapid solid-phase reaction of nanoparticle reactants on the resin in water. We also demonstrated the syntheses of Leu-enkephalin, Tyr-Gly-Gly-Phe-Leu-OH, and difficult sequence model peptide, Val-Ala-Val-Ala-Gly-OH, using our water-based MW-assisted protocol with Boc-amino acid nanoparticles.
Effect of nerve growth factor on the synthesis of amino acids in PC12 cells
International Nuclear Information System (INIS)
Zielke, H.R.; Tildon, J.T.; Kauffman, F.C.; Baab, P.J.
Radioactive short-chain fatty acids preferentially label glutamine relative to glutamate in brain due to compartmentation of glutamine and glutamate. To determine whether this phenomenon occurs in a single cell culture model, we examined the effect of fatty acid chain length on the synthesis as well as pool size of selected amino acids in rat pheochromocytoma PC12 cells, a cell culture model of the large glutamate compartment in neurons. Intracellular 14C-amino acids were quantitated by HPLC, and the incorporation of [U-14C]-glucose, [1-14C]-butyrate, [1-14C]-octanoate, and [1-14C]-palmitate into five amino acids was measured in native and NGF-treated PC12 cells. NGF pretreatment decreased the intracellular concentration of amino acids as did addition of fatty acids but these effects were not additive. Specific activities of amino acids in native cells labelled by 14C-octanoate were 1,300 DPM/nmol, 490 DPM/nmol, 200 DPM/nmol, and 110 DPM/nmol for glutamate, aspartate, glutamine, and serine, respectively. No radioactivity was detected in alanine. Similar specific activities were noted when 14C-butyrate was the precursor; however, there was at least 5-fold less if 14C-palmitate was the precursor. Pretreatment of cells with NGF decreased the specific activity of amino acids by 25-65%. Specific activities of amino acids synthesized from 14C-glucose decreased in the following order: glutamate, 1,640 DPM/nmol; aspartate, 1,210 DPM/nmol; alanine, 580 DPM/nmol; glutamine, 275 DPM/nmol; and serine, 80 DPM/nmol for native cells. NGF pretreatment decreased the specific activities of glutamate and glutamine, but not of the other 3 amino acids. The preferred precursor for glutamate synthesis in native PC12 cells was glucose followed by octanoate, butyrate and palmitate (16:6:3:1)
Role of ferrocyanides in the prebiotic synthesis of α-amino acids.
Ruiz-Bermejo, Marta; Osuna-Esteban, Susana; Zorzano, María-Paz
We investigated the synthesis of α-amino acids under possible prebiotic terrestrial conditions in the presence of dissolved iron (II) in a simulated prebiotic ocean. An aerosol-liquid cycle with a prebiotic atmosphere is shown to produce amino acids via Strecker synthesis with relatively high yields. However, in the presence of iron, the HCN was captured in the form of a ferrocyanide, partially inhibiting the formation of amino acids. We showed how HCN captured as Prussian Blue (or another complex compound) may, in turn, have served as the HCN source when exposed to UV radiation, allowing for the sustained production of amino acids in conjunction with the production of oxyhydroxides that precipitate as by-products. We conclude that ferrocyanides and related compounds may have played a significant role as intermediate products in the prebiotic formation of amino acids and oxyhydroxides, such as those that are found in iron-containing soils and that the aerosol cycle of the primitive ocean may have enhanced the yield of the amino acid production.
Effect of amino acids on the repression of alkaline protease synthesis in haloalkaliphilic Nocardiopsis dassonvillei
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Amit K. Sharma
Full Text Available A newly isolated salt-tolerant alkaliphilic actinomycete, Nocardiopsis dassonvillei strain OK-18 grows on mineral salts medium with glucose as carbon source. It also grows and produces protease with amino acids as sole carbon source. The synthesis of extracellular alkaline protease parallel to growth was repressible by substrate concentrations. The absolute production of the protease was delinked with growth under nutritional stress, as protease production was high, despite poor growth. When amino acids served as the sole source of carbon and nitrogen, the enzyme production was significantly controlled by the number of amino acids. Maximal protease production was achieved with proline, asparagine, tyrosine, alanine, methionine and valine as sole source of carbon and nitrogen in minimal medium. With the increasing number of different amino acids in the presence and absence of glucose, the protease production was synergistically lower as compared to complex medium.
Enhanced Synthesis of Alkyl Amino Acids in Miller's 1958 H2S Experiment
Parker, Eric T.; Cleaves, H. James; Callahan, Michael P.; Dworkin, James P.; Glavin, Daniel P.; Lazcano, Antonio; Bada, Jeffrey L.
Stanley Miller's 1958 H2S-containing experiment, which included a simulated prebiotic atmosphere of methane (CH4), ammonia (NH3), carbon dioxide (CO2), and hydrogen sulfide (H2S) produced several alkyl amino acids, including the alpha-, beta-, and gamma-isomers of aminobutyric acid (ABA) in greater relative yields than had previously been reported from his spark discharge experiments. In the presence of H2S, aspariic and glutamic acids could yield alkyl amino acids via the formation of thioimide intermediates. Radical chemistry initiated by passing H2S through a spark discharge could have also enhanced alkyl amino acid synthesis by generating alkyl radicals that can help form the aldehyde and ketone precursors to these amino acids. We propose mechanisms that may have influenced the synthesis of certain amino acids in localized environments rich in H2S and lightning discharges, similar to conditions near volcanic systems on the early Earth, thus contributing to the prebiotic chemical inventory of the primordial Earth.
New enzymatic method of chiral amino acid synthesis by dynamic kinetic resolution of amino acid amides: use of stereoselective amino acid amidases in the presence of alpha-amino-epsilon-caprolactam racemase.
Yamaguchi, Shigenori; Komeda, Hidenobu; Asano, Yasuhisa
D- and L-amino acids were produced from L- and D-amino acid amides by D-aminopeptidase from Ochrobactrum anthropi C1-38 and L-amino acid amidase from Pseudomonas azotoformans IAM 1603, respectively, in the presence of alpha-amino-epsilon-caprolactam racemase from Achromobacter obae as the catalyst by dynamic kinetic resolution of amino acid amides.
Glutathione synthesis rates after amino acid administration directly after birth in preterm infants
te Braake, Frans W. J.; Schierbeek, Henk; de Groof, Karien; Vermes, Andras; Longini, Mariangela; Buonocore, Giuseppe; van Goudoever, Johannes B.
The availability of glutathione, the main intracellular antioxidant, is compromised in preterm neonates. A possible explanation is the low availability of substrate for synthesis, because many neonatologists are reluctant to administer amino acids in the direct postnatal period for fear of
Synthesis of Novel N-9-Substituted Purine Derivatives from Polymer Supported alpha-Amino Acids
Czech Academy of Sciences Publication Activity Database
Vanda, D.; Jorda, Radek; Lemrová, B.; Volná, T.; Kryštof, Vladimír; McMaster, C.; Soural, M.
Roč. 17, č. 7 (2015), s. 426-432 ISSN 2156-8952 R&D Projects: GA MŠk(CZ) LO1204; GA MŠk(CZ) LO1304 Institutional support: RVO:61389030 Keywords : alpha-amino acids * solid-phase synthesis * purine derivatives Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.317, year: 2015
Recent advances in the catalytic asymmetric synthesis of β-amino acids
Weiner, Barbara; Szymanski, Wiktor; Janssen, Dick B.; Minnaard, Adriaan J.; Feringa, Ben L.
In this critical review, the progress in catalytic asymmetric synthesis of β-amino acids is discussed, covering the literature since 2002. The review treats transition metal catalysis, organocatalysis and biocatalysis and covers the most important synthetic methods, such as hydrogenation, the
One-Pot Enantiomeric Synthesis of Thiazole-Containing Amino Acids: Total Synthesis of Venturamides A and B.
Liu, Yi; He, Peng; Zhang, Yang; Zhang, Xiangyu; Liu, Jun; Du, Yuguo
An effective one-pot procedure for enantiomerical synthesis of thiazole-containing amino acid (TCAA) has been established via a cascade disulfide cleavage/thiocarbonylation/intramolecular Staudinger reduction/aza-Wittig/oxidation reaction. Starting from the commercially available amino acid building blocks, a number of TCAAs were prepared in good yields and with excellent optical purities. This method bears features of mild reaction conditions, wide substrate adaptability, and good functional group tolerance. The power of this method was also demonstrated through the concise total synthesis of cyclic hexapeptide Venturamides A and B.
Phospholyl(borane) Amino Acids and Peptides: Stereoselective Synthesis and Fluorescent Properties with Large Stokes Shift.
Arribat, Mathieu; Rémond, Emmanuelle; Clément, Sébastien; Lee, Arie Van Der; Cavelier, Florine
The synthesis of phospholyl(borane) amino acids was stereoselectively achieved by reaction of phospholide anion with iodo α-amino ester derived from l-aspartic acid or l-serine, followed by in situ complexation with borane. Phospholyl(borane) amino acids are easy to store and can be subjected to direct transformation into the corresponding free phospholyl, gold complex, oxide or sulfur derivatives as well as phospholinium salts, thus offering a variety of side chains. After selective deprotection of carboxylic function or amine, C- or N- peptide coupling with an alanine moiety proved the possible incorporation into peptides. Such phospholyl amino acid and peptide derivatives exhibit fluorescent properties with a large Stokes shift (160 nm) and fluorescence up to 535 nm, depending on the phosphole aromaticity and the chemical environment. These phospholyl(borane) amino acids constitute a new class of unnatural amino acids useful for structure-activities relationship studies and appear to be promising fluorophores for the development of labeled peptides.
Amino acid-assisted synthesis of strontium hydroxyapatite bone ...
Indian Academy of Sciences (India)
adhesives and for treatment of osteoporosis (Ni et al 2006). The synthesis of strontium hydroxyapatite can be accom- plished by using various methods of synthesis like sol–gel. (Balamurugan et al 2009), solid titrations (Pan et al 2009), wet chemical (Bigi et al 2007) and sol–gel- supercritical fluid drying (SCFD) methods ...
Amino acid-assisted synthesis of strontium hydroxyapatite bone ...
Indian Academy of Sciences (India)
Strontium hydroxyapatite, a bioac- tive bone cement, is used in spinal and bone fracture surgery and it is also used in bone replacement, bone fillings, bone adhesives and for treatment of osteoporosis (Ni et al 2006). The synthesis of strontium hydroxyapatite can be accom- plished by using various methods of synthesis like ...
Synthesis and Biological Activity of Novel Amino Acid-(N'-Benzoyl Hydrazide and Amino Acid-(N'-Nicotinoyl Hydrazide Derivatives
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Sherine N. Khattab
Full Text Available The coupling reaction of benzoic acid and nicotinic acid hydrazides with N- protected L-amino acids including valine, leucine, phenylalanine, glutamic acid and tyrosine is reported. The target compounds, N-Boc-amino acid-(N`-benzoyl- and N- Boc-amino acid-(N`-nicotinoyl hydrazides 5a-5e and 6a-6e were prepared in very high yields and purity using N-[(dimethylamino-1H-1,2,3-triazolo[4,5-b]pyridin-1-yl- methylene]-N-methyl-methanaminium hexafluorophosphate N-oxide (HATU as coupling reagent. The antimicrobial activity of the Cu and Cd complexes of the designed compounds was tested. The products were deprotected affording the corresponding amino acid-(N`-benzoyl hydrazide hydrochloride salts (7a-7e and amino acid-(N`- nicotinoyl hydrazide hydrochloride salts (8a-8e. These compounds and their Cu and Cd complexes were also tested for their antimicrobial activity. Several compounds showed comparable activity to that of ampicillin against S. aureus and E. coli.
Concise and Straightforward Asymmetric Synthesis of a Cyclic Natural Hydroxy-Amino Acid
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Mario J. Simirgiotis
Full Text Available An enantioselective total synthesis of the natural amino acid (2S,4R,5R-4,5-di-hydroxy-pipecolic acid starting from D-glucoheptono-1, 4-lactone is presented. The best sequence employed as a key step the intramolecular nucleophilic displacement by an amino function of a 6-O-p-toluene-sulphonyl derivative of a methyl D-arabino-hexonate and involved only 12 steps with an overall yield of 19%. The structures of the compounds synthesized were elucidated on the basis of comprehensive spectroscopic (NMR and MS and computational analysis.
Stimulation of glycogen synthesis in hepatocytes by added amino acids is related to the total intracellular content of amino acids
Plomp, P. J.; Boon, L.; Caro, L. H.; van Woekom, G. M.; Meijer, A. J.
Katz et al. [Katz, J., Golden, S. & Wals, P.A. (1976) Proc. Natl Acad. Sci. USA 73, 3433-3437] were the first to report that in hepatocytes isolated from fasted rats and incubated with either dihydroxyacetone, glucose or other sugars, glycogen synthesis was greatly accelerated by addition of amino
Electroenzymatic strategies for deracemization, stereoinversion and asymmetric synthesis of amino acids
International Nuclear Information System (INIS)
Maerkle, Wolfgang; Luetz, Stephan
A combination of a selective enzymatic oxidation with an unselective electrochemical reduction step was applied for deracemization, stereoinversion and asymmetric synthesis of L-leucine (starting from racemic leucine, D-leucine or 4-methyl-2-oxovaleric acid) in a batch reactor. D-Amino acid oxidase (D-AAO) from Trigonopsis variabilis was used as enzyme. Reaction conditions for the electrochemical and enzymatic reactions were investigated separately and finally combined to an electroenzymatic synthesis, yielding 3.5 mmol L -1 d -1 of L-leucine (ee 91%)
Triazole-linked glycosyl amino acids and peptides : synthesis
Kuijpers, B.H.M.
Naturally occurring glycosylated peptides play an important role in various biological processes and are therefore interesting lead molecules for the preparation of new therapeutic drugs.Synthesis of these natural glycopeptides is frequently hampered by the sensitivity of the natural glycosidic
New Enzymatic Method of Chiral Amino Acid Synthesis by Dynamic Kinetic Resolution of Amino Acid Amides: Use of Stereoselective Amino Acid Amidases in the Presence of α-Amino-ɛ-Caprolactam Racemase▿
Yamaguchi, Shigenori; Komeda, Hidenobu; Asano, Yasuhisa
d- and l-amino acids were produced from l- and d-amino acid amides by d-aminopeptidase from Ochrobactrum anthropi C1-38 and l-amino acid amidase from Pseudomonas azotoformans IAM 1603, respectively, in the presence of α-amino-ɛ-caprolactam racemase from Achromobacter obae as the catalyst by dynamic kinetic resolution of amino acid amides. PMID:17586677
Recent Advances in Substrate-Controlled Asymmetric Induction Derived from Chiral Pool α-Amino Acids for Natural Product Synthesis.
Paek, Seung-Mann; Jeong, Myeonggyo; Jo, Jeyun; Heo, Yu Mi; Han, Young Taek; Yun, Hwayoung
Chiral pool α-amino acids have been used as powerful tools for the total synthesis of structurally diverse natural products. Some common naturally occurring α-amino acids are readily available in both enantiomerically pure forms. The applications of the chiral pool in asymmetric synthesis can be categorized prudently as chiral sources, devices, and inducers. This review specifically examines recent advances in substrate-controlled asymmetric reactions induced by the chirality of α-amino acid templates in natural product synthesis research and related areas.
Stereoselective Synthesis of α-Amino-C-phosphinic Acids and Derivatives
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José Luis Viveros-Ceballos
Full Text Available α-Amino-C-phosphinic acids and derivatives are an important group of compounds of synthetic and medicinal interest and particular attention has been dedicated to their stereoselective synthesis in recent years. Among these, phosphinic pseudopeptides have acquired pharmacological importance in influencing physiologic and pathologic processes, primarily acting as inhibitors for proteolytic enzymes where molecular stereochemistry has proven to be critical. This review summarizes the latest developments in the asymmetric synthesis of acyclic and phosphacyclic α-amino-C-phosphinic acids and derivatives, following in the first case an order according to the strategy used, whereas for cyclic compounds the nitrogen embedding in the heterocyclic core is considered. In addition selected examples of pharmacological implications of title compounds are also disclosed.
The Synthesis of a Dipeptide from its Component Amino Acids: Protecting Groups in the Elementary Organic Laboratory.
Young, Paul E.; Campbell, Andrew
A simple, three-step procedure for synthesizing a dipeptide from its component amino acids is described. The dipeptide synthesized uses inexpensive amino acids having hydrocarbon side-chains and can be observed in E/Z forms by nuclear magnetic resonance spectroscopy. Each step in the synthesis produces white crystalline products using standard…
Stereocontrolled synthesis of syn-β-Hydroxy-α-amino acids by direct aldolization of pseudoephenamine glycinamide.
Seiple, Ian B; Mercer, Jaron A M; Sussman, Robin J; Zhang, Ziyang; Myers, Andrew G
β-Hydroxy-α-amino acids figure prominently as chiral building blocks in chemical synthesis and serve as precursors to numerous important medicines. Reported herein is a method for the synthesis of β-hydroxy-α-amino acid derivatives by aldolization of pseudoephenamine glycinamide, which can be prepared from pseudoephenamine in a one-flask protocol. Enolization of (R,R)- or (S,S)-pseudoephenamine glycinamide with lithium hexamethyldisilazide in the presence of LiCl followed by addition of an aldehyde or ketone substrate affords aldol addition products that are stereochemically homologous with L- or D-threonine, respectively. These products, which are typically solids, can be obtained in stereoisomerically pure form in yields of 55-98 %, and are readily transformed into β-hydroxy-α-amino acids by mild hydrolysis or into 2-amino-1,3-diols by reduction with sodium borohydride. This new chemistry greatly facilitates the construction of novel antibiotics of several different classes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Synthesis of copper graphene materials functionalized by amino acids and their catalytic applications.
Huang, Qiang; Zhou, Limei; Jiang, Xiaohui; Zhou, Yafen; Fan, Hongwei; Lang, Wencheng
Graphene oxide and its derivative have attracted extensive interests in many fields, including catalytic chemistry, organic synthesis, and electrochemistry, recently. We explored whether the use of graphene after chemical modification with amino acids to immobilize copper nanoparticles could achieve a more excellent catalytic activity for N-arylation reactions. A facile and novel method to prepare copper supported on amino-acid-grafted graphene hybrid materials (A-G-Cu) was first reported. The as-prepared hybrid materials were characterized by a variety of techniques, including Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, atomic force microscopy, transmission electron microscopy, and inductively coupled plasma-atomic emission spectrometry. The results showed that the morphology, distribution, and loading of copper nanoparticles could be well-adjusted by controlling the type of amino acids grafted on graphene. Moreover, most A-G-Cu hybrid materials could catalyze N-arylation of imidazole with iodobenzene with yields more than 90%, while the copper supported on graphene (G-Cu) displayed a yield of just 65.8%. The high activity of A-G-Cu can be ascribed to the good synergistic effects of copper nanoparticles (Cu NPs) and amino-acid-grafted graphene.
The first proton sponge-based amino acids: synthesis, acid-base properties and some reactivity.
Ozeryanskii, Valery A; Gorbacheva, Anastasia Yu; Pozharskii, Alexander F; Vlasenko, Marina P; Tereznikov, Alexander Yu; Chernov'yants, Margarita S
The first hybrid base constructed from 1,8-bis(dimethylamino)naphthalene (proton sponge or DMAN) and glycine, N-methyl-N-(8-dimethylamino-1-naphthyl)aminoacetic acid, was synthesised in high yield and its hydrobromide was structurally characterised and used to determine the acid-base properties via potentiometric titration. It was found that the basic strength of the DMAN-glycine base (pKa = 11.57, H2O) is on the level of amidine amino acids like arginine and creatine and its structure, zwitterionic vs. neutral, based on the spectroscopic (IR, NMR, mass) and theoretical (DFT) approaches has a strong preference to the zwitterionic form. Unlike glycine, the DMAN-glycine zwitterion is N-chiral and is hydrolytically cleaved with the loss of glycolic acid on heating in DMSO. This reaction together with the mild decarboxylative conversion of proton sponge-based amino acids into 2,3-dihydroperimidinium salts under air-oxygen was monitored with the help of the DMAN-alanine amino acid. The newly devised amino acids are unique as they combine fluorescence, strongly basic and redox-active properties.
Boron Stress Activates the General Amino Acid Control Mechanism and Inhibits Protein Synthesis
Uluisik, Irem; Kaya, Alaattin; Fomenko, Dmitri E.; Karakaya, Huseyin C.; Carlson, Bradley A.; Gladyshev, Vadim N.; Koc, Ahmet
Boron is an essential micronutrient for plants, and it is beneficial for animals. However, at high concentrations boron is toxic to cells although the mechanism of this toxicity is not known. Atr1 has recently been identified as a boron efflux pump whose expression is upregulated in response to boron treatment. Here, we found that the expression of ATR1 is associated with expression of genes involved in amino acid biosynthesis. These mechanisms are strictly controlled by the transcription factor Gcn4 in response to boron treatment. Further analyses have shown that boron impaired protein synthesis by promoting phosphorylation of eIF2α in a Gcn2 kinase dependent manner. The uncharged tRNA binding domain (HisRS) of Gcn2 is necessary for the phosphorylation of eIF2α in the presence of boron. We postulate that boron exerts its toxic effect through activation of the general amino acid control system and inhibition of protein synthesis. Since the general amino acid control pathway is conserved among eukaryotes, this mechanism of boron toxicity may be of general importance. PMID:22114689
Convenient Synthesis and Antimicrobial Activity of Some Novel Amino Acid Coupled Triazoles
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S. M. El Rayes
Full Text Available This study describes a promising one-pot synthesis of [2-(5-benzyl-4-phenyl-4H-[1,2,4]triazol-3-thio-acetyl]-amino acid methyl esters 6a-h and dipeptides 10a-e, which were successfully synthesized starting from amino acid esters 5a-h, 9a-e and azides 4, 8a,b, respectively. On the other hand, azide 4 underwent Curtius rearrangement to the corresponding isocyanate, which subsequently reacted with selected aliphatic amine and/or aniline derivatives to give the corresponding urea derivatives 11 and 12a,b. Reactions of the isocyanate with secondary amines gave amide derivatives 13a,b. The structural elucidation of products is reported and some of the products were also screened for their antimicrobial activity.
Synthesis of Chiral 1,4-Disubstituted-1,2,3-Triazole Derivatives from Amino Acids
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Morten Grøtli
Full Text Available A versatile method for the synthesis of chiral 1,4-disubstituted-1,2,3-triazole derivatives starting from easily accessible naturally occurring D-or L-amino acids as chiral synthons is described. The amino acids were converted into azido alcohols, followed by copper catalyzed [3+2] cycloaddition reactions between the azido alcohols and methyl propiolate and subsequent ester aminolysis with primary and secondary amines furnished the target compounds, which were obtained in excellent yields with no racemization. Docking of selected target compounds shows that the chiral 1,4-disubstituted-1,2,3-triazoles derivatives has the potential of mimicking the binding mode of known purine analogues.
Synthesis of tripeptides containing heterocyclic α -amino acids by using heterospirocyclic 3-amino-2H-azirines
Strässler, Christoph; Linden, Anthony; Heimgartner, Heinz
By using the 'azirine/oxazolone method', di- and tripeptides containing six-membered heterocyclic 4-amino-4-carboxylic acids with a piperidine, tetrahydropyran or tetrahydrothiopyran ring have been synthesized. It has been shown that the corresponding heterospirocyclic 3-(N-methyl-N-phenylamino)-2H-azirines are suitable synthons for these heterocyclic α-amino acids. As expected, the presence of these α,α-disubstituted α-amino acids stabilizes β-turn conformations in the prepared tripeptides o...
Gamma-amino butyric acid (GABA) synthesis of Lactobacillus in fermentation of defatted rice bran extract
Dat, Lai Quoc; Ngan, Tran Thi Kim; Nu, Nguyen Thi Xuan
This research focused on the synthesis of GABA by Lactobacillus bacteria in fermentation of defatted rice bran extract without adding glutamate. Two strains of Lactobacillus were investigated into capacity of GABA synthesis. Result indicates that, Lactobacillus brevis VTCC - B - 454 exhibited the higher capacity of GABA synthesis in fermentation of defatted rice bran extract than that of Lactobacillus plantarum VTCC - B - 890. Total dissolved solid (TDS), free amino acids (AA) and reducing sugar (RS) contents in fermentation of defatted rice bran extract with two strains also significantly decreased. At pH 5 and 9 %w/w of TDS content in defatted rice bran extract, Lactobacillus brevis VTCC - B - 454 accumulated 2,952 ppm of GABA in 24 hours of fermentation. The result implies that fermentation with Lactobacillus brevis VTCC - B - 454 can be applied for GABA production from defatted rice bran extract.
Amino acids blood test ... types of methods used to determine the individual amino acid levels in the blood. ... test is done to measure the level of amino acids in the blood. An increased level of a ...
Investigation of phospholipid synthesis and the disposition of amino acid and carbohydrate
International Nuclear Information System (INIS)
Boehme, D.S.
The synthesis of pulmonary phospholipids by offspring of diabetic female rats was assessed by means of high performance liquid chromatography combined with automated phosphate analysis. No changes in the pool sizes of the major phospholipids or their precursors were observed. However, offspring of both insulin-treated and untreated diabetic mothers displayed increased pulmonary lyso-phosphatidylcholine. The concentration of glycerylphosphorylcholine, the metabolic product of lyso-phosphatidylcholine, was also increased in these offspring, providing further evidence of a reduced reacylation pathway in the offspring of diabetic mothers. The concentration of phosphatidylglycerol was reduced in the lungs from offspring of diabetic mothers. Preliminary investigation suggested that the mechanism of insulin action on lungs from offspring of diabetic rats may be the diversion of substrate from lipid synthetic pathways into protein synthesis. The utilization of [14C]-labeled amino acids and carbohydrates by normal fetal rat lung, however, revealed no direct insulin effect on protein synthesis. The ability of the fetal lung to convert amino acids into Krebs Cycle intermediates was demonstrated
Nitrogen in dietary glutamate is utilized exclusively for the synthesis of amino acids in the rat intestine.
Nakamura, Hidehiro; Kawamata, Yasuko; Kuwahara, Tomomi; Torii, Kunio; Sakai, Ryosei
Although previous studies have shown that virtually the entire carbon skeleton of dietary glutamate (glutamate-C) is metabolized in the gut for energy production and amino acid synthesis, little is known regarding the fate of dietary glutamate nitrogen (glutamate-N). In this study, we hypothesized that dietary glutamate-N is an effective nitrogen source for amino acid synthesis and investigated the fate of dietary glutamate-N using [(15)N]glutamate. Fischer male rats were given hourly meals containing [U-(13)C]- or [(15)N]glutamate. The concentration and isotopic enrichment of several amino acids were measured after 0-9 h of feeding, and the net release of each amino acid into the portal vein was calculated. Most of the dietary glutamate-C was metabolized into CO(2), lactate, or alanine (56, 13, and 12% of the dietary input, respectively) in the portal drained viscera (PDV). Most of the glutamate-N was utilized for the synthesis of other amino acids such as alanine and citrulline (75 and 3% of dietary input, respectively) in the PDV, and only minor amounts were released into the portal vein in the form of ammonia and glutamate (2 and 3% of the dietary input, respectively). Substantial incorporation of (15)N into systemic amino acids such as alanine, glutamine, and proline, amino acids of the urea cycle, and branched-chain amino acids was also evident. These results provide quantitative evidence that dietary glutamate-N distributes extensively to amino acids synthesized in the PDV and, consequently, to circulating amino acids.
Asymmetric synthesis of quaternary aryl amino acid derivatives via a three-component aryne coupling reaction
Directory of Open Access Journals (Sweden)
Elizabeth P. Jones
Full Text Available A method was developed for the synthesis of α-alkyl, α-aryl-bislactim ethers in good to excellent yields and high diastereoselectivities, consisting of a facile one-pot procedure in which the aryl group is introduced by means of a nucleophilic addition to benzyne and the alkyl group by alkylation of a resultant benzylic anion. Hydrolysis of the sterically less hindered adducts gave the corresponding quaternary amino acids with no racemization, whereas hydrolytic ring opening gave the corresponding valine dipeptides from bulkier bislactims.
Asymmetric Synthesis of Carbon-11 Labelled alpha-Amino Acids for PET
Popkov, Alexander; Elsinga, Philip H.
For PET applications in oncological and neurological diagnostics, amino acids have been studied both clinically and pre-clinically during the last 35 years. Nowadays two applications of labelled amino acids for visualisation of tumours attract the main attention: [C-11] or [F-18]amino acids as
Increasing the fidelity of noncanonical amino acid incorporation in cell-free protein synthesis.
Gan, Qinglei; Fan, Chenguang
Cell-free protein synthesis provides a robust platform for co-translational incorporation of noncanonical amino acid (ncAA) into proteins to facilitate biological studies and biotechnological applications. Recently, eliminating the activity of release factor 1 has been shown to increase ncAA incorporation in response to amber codons. However, this approach could promote mis-incorporation of canonical amino acids by near cognate suppression. We performed a facile protocol to remove near cognate tRNA isoacceptors of the amber codon from total tRNAs, and used the phosphoserine (Sep) incorporation system as validation. By manipulating codon usage of target genes and tRNA species introduced into the cell-free protein synthesis system, we increased the fidelity of Sep incorporation at a specific position. By removing three near cognate tRNA isoacceptors of the amber stop codon [tRNA Lys , tRNA Tyr , and tRNA Gln (CUG)] from the total tRNA, the near cognate suppression decreased by 5-fold without impairing normal protein synthesis in the cell-free protein synthesis system. Mass spectrometry analyses indicated that the fidelity of ncAA incorporation was improved. Removal of near cognate tRNA isoacceptors of the amber codon could increase ncAA incorporation fidelity towards the amber stop codon in release factor deficiency systems. We provide a general strategy to improve fidelity of ncAA incorporation towards stop, quadruplet and sense codons in cell-free protein synthesis systems. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue. Copyright © 2016 Elsevier B.V. All rights reserved.
The effects of borate minerals on the synthesis of nucleic acid bases, amino acids and biogenic carboxylic acids from formamide.
Saladino, Raffaele; Barontini, Maurizio; Cossetti, Cristina; Di Mauro, Ernesto; Crestini, Claudia
The thermal condensation of formamide in the presence of mineral borates is reported. The products afforded are precursors of nucleic acids, amino acids derivatives and carboxylic acids. The efficiency and the selectivity of the reaction was studied in relation to the elemental composition of the 18 minerals analyzed. The possibility of synthesizing at the same time building blocks of both genetic and metabolic apparatuses, along with the production of amino acids, highlights the interest of the formamide/borate system in prebiotic chemistry.
Synthesis of amino acid rare earth complexes and its application in agriculture
International Nuclear Information System (INIS)
Luo, G.-T.; Lian, P.; Hu, Y.H.; Guo, G.-R.
Full text: The application of rare-earth compounds in agriculture has been widely reported. So far, most rare-earth compounds used in agriculture were inorganic salt and they were difficult to be absorbed by croup. The synthesis method and structure of amino acid rare-earth complexes have been reported. In this paper, we reported the preparation of mixed amino acids rare-earth complexes and their application in agriculture. The mixed amino acids were obtained by hydrolysis of waste natural protein. Rare earth was lanthanum oxide(99%). Mixed amino acids lanthanum complexes(MALa) was prepared according to the previous method. Investigation to the effect of croup by MALa, we have make tests of citrus, rice and mung bean. The results show as follows: 1) When the experiment group citrus was sprinkled twice 400ppm MALa at bouquet stage and young fruit stage, the sugar, morose, sucrose, soluble solid matter and vitamin C of fruit were increased 21%, 20%, 22%, 22% and 6% as compared to the control group, respectively. The area of leaf and foliage branch in Spring were also increased 4.6% and 2.2%. 2) When the rice was sprinkled 300ppm MALa at early tillering stage, the productively of rice was addition to 10-15%, and the relative effect of prevention was 45.61% for sheath and culm blight of rice. 3) In the test of mungbean growth, the low consistency of MALa ( 250ppm) retain from sprouting seed. As the same time, it was similar action to seeding growth. Preliminary results indicated MLAa could used as the plant growth regulation agent on the croup. Investigation to the effect of MALa on other croup and the mechanism of biological effect on the croup are still going on
Synthesis and coupling reactions of alpha,alpha-dialkylated amino acids with nucleobase side chains.
Azumaya, I; Aebi, R; Kubik, S; Rebek, J
Several di- and tripeptides containing protected purine (adenine) and pyrimidine (thymine) residues on their side chains were synthesized. The parent amino acids alpha, alpha-dialkylated in a symmetrical manner. An effective coupling procedure was developed for these sterically hindered amino acids: the fluoren-9-ylmethyloxycarbonyl-protected amino acid was dehydrated to its oxazolinone form, which was coupled in good yields with amino esters in hot tetrachloroethane.
Synthesis and pharmacology of 3-isoxazolol amino acids as selective antagonists at group I metabotropic glutamic acid receptors
DEFF Research Database (Denmark)
Madsen, U; Bräuner-Osborne, H; Frydenvang, Karla Andrea
GluRs), the few analogues of (RS)-2-amino-3-(3-hydroxy-5-isoxazolyl)propionic acid [HIBO, (RS)-4] so far known typically interact with iGluRs as well as metabotropic Glu receptors (mGluRs). We here report the synthesis and pharmacology of a series of 4-substituted analogues of HIBO. The hexyl analogue 9 was shown......Using ibotenic acid (2) as a lead, two series of 3-isoxazolol amino acid ligands for (S)-glutamic acid (Glu, 1) receptors have been developed. Whereas analogues of (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid [AMPA, (RS)-3] interact selectively with ionotropic Glu receptors (i...... to originate in (S)-11 (EC(50) = 395 microM, K(b) = 86 and 90 microM, respectively). Compound 9, administered icv, but not sc, was shown to protect mice against convulsions induced by N-methyl-D-aspartic acid (NMDA). Compounds 9 and 11 were resolved using chiral HPLC, and the configurational assignments...
Synthesis and pharmacology of 3-isoxazolol amino acids as selective antagonists at group I metabotropic glutamic acid receptors
DEFF Research Database (Denmark)
Madsen, U; Bräuner-Osborne, H; Frydenvang, Karla Andrea
Using ibotenic acid (2) as a lead, two series of 3-isoxazolol amino acid ligands for (S)-glutamic acid (Glu, 1) receptors have been developed. Whereas analogues of (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid [AMPA, (RS)-3] interact selectively with ionotropic Glu receptors (i......GluRs), the few analogues of (RS)-2-amino-3-(3-hydroxy-5-isoxazolyl)propionic acid [HIBO, (RS)-4] so far known typically interact with iGluRs as well as metabotropic Glu receptors (mGluRs). We here report the synthesis and pharmacology of a series of 4-substituted analogues of HIBO. The hexyl analogue 9 was shown...... to originate in (S)-11 (EC(50) = 395 microM, K(b) = 86 and 90 microM, respectively). Compound 9, administered icv, but not sc, was shown to protect mice against convulsions induced by N-methyl-D-aspartic acid (NMDA). Compounds 9 and 11 were resolved using chiral HPLC, and the configurational assignments...
Sulfur containing activated hydantions. Synthesis and screening some novel benzylidenehydantoins amino acids derivatives
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Full Text Available 5-Benzylidenehydantoin reacts with chlorosulfonic acid to give the corresponding p-sulfonyl chloride 1. Condensation with nucleophiles gives amino acid derivatives 27. Coupling reactions of some amino acid derivatives (26 with amino acid methyl ester hydrochloride in THF-Et3N medium using the dicyclohexylcarbodiimide method (DCC furnish the desired dipeptide methyl esters 812. The spectral data of the synthesized compounds are briefly discussed.
Phenylalanine ammonia lyase catalyzed synthesis of amino acids by an MIO-cofactor independent pathway.
Lovelock, Sarah L; Lloyd, Richard C; Turner, Nicholas J
Phenylalanine ammonia lyases (PALs) belong to a family of 4-methylideneimidazole-5-one (MIO) cofactor dependent enzymes which are responsible for the conversion of L-phenylalanine into trans-cinnamic acid in eukaryotic and prokaryotic organisms. Under conditions of high ammonia concentration, this deamination reaction is reversible and hence there is considerable interest in the development of PALs as biocatalysts for the enantioselective synthesis of non-natural amino acids. Herein the discovery of a previously unobserved competing MIO-independent reaction pathway, which proceeds in a non-stereoselective manner and results in the generation of both L- and D-phenylalanine derivatives, is described. The mechanism of the MIO-independent pathway is explored through isotopic-labeling studies and mutagenesis of key active-site residues. The results obtained are consistent with amino acid deamination occurring by a stepwise E1 cB elimination mechanism. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
<論文・報告>Microbial Synthesis of Oxo Cyclic Amino Acids
Kise, Miki; Morita, Shuhei; Takenaka, Ryota; Mitsukawa, Yuki; Takeuchi, Michiki; Ogawa, Jun
In order to obtain microorganisms that can synthesize of oxo cyclic amino acids from hydroxy cyclic amino acids, we performed screening of microorganisms that are able to do so from 10 microbial samples collected from the Kyoto University Botanical Garden. Isolated microorganism colonies were shake-incubated in a liquid nutrient medium containing hydroxy cyclic amino acids as the only source of carbon, and the resulting suspension was subjected to TLC analysis with ninhydrin detection. Accord...
In vivo synthesis of cholecystokinin in the rat cerebral cortex: identification of COOH-terminal peptides with labeled amino acids
International Nuclear Information System (INIS)
Goltermann, N.R.
The synthesis of the COOH-terminal octa- and tetrapeptides of cholecystokinin (CCK) has been studied in rat cerebral cortex after intraventricular administration of radioactive amino acids characteristic of the porcine COOH-terminal octapeptide of CCK, CCK-8. After immunosorption with a COOH-terminal directed antibody, cortical CCK was fractionated on Sephadex G-50 columns. The experiments demonstrated newly synthesized CCK forms which coeluted with porcine CCK-8 and CCK-4. Except for threonine the amino acids employed, methionine, tryptophan, aspartic acid, glycine and phenylalanine were incorporated. The sequence-specific radioimmunoassay, the incorporation of the employed labeled amino acids, and the elution pattern by gel filtration, suggest an almost identical structure of porcine and rat cortical CCK-8, and a concomitant synthesis of CCK-8 and CCK-4 in rat cerebral cortex
Synthesis, physicochemical and biological properties of poly-α-amino acids - the simplest of protein models
International Nuclear Information System (INIS)
Katchalski-Katzir, Ephraim
During the 1950s, linear and multichain poly-α-amino acids were synthesized by polymerization of the corresponding N-carboxy-amino acid anhydrides in solution in the presence of suitable catalysts. The resulting homo- and heteropolymers have since been widely employed as simple protein models. Under appropriate conditions, poly-α-amino acids, in the solid state and in solution, were found to acquire conformations of an α-helix and β-parallel and antiparallel pleased sheets, or to exist as random coils. Their use in experimental and theoretical investigations of helix-coil transitions helped to shed new light on the mechanisms involved in protein denaturation. Poly-α-amino acids played an important role in the deciphering of the genetic code. In addition, analysis of the antigenicity of poly-α-amino acids led to the clucidation of the factors determining the antigenicity of proteins and peptides. Interest in the biological and physicochemical characteristics of poly-α-amino acids was recently renewed because of the reported novel finding that some copolymers of amino acids are effective as drugs in multiple sclerosis, and that glutamine repeats and reiteration of other amino acids occur in inherited neurodegenerative diseases. The presence of repeating sequences of amino acids in proteins, and of nucleotides in DNA, raises many interesting questions about their respective roles in determining protein structure and function, and gene performance and regulation. (author). 35 refs, 3 figs, 2 tabs
The synthesis of mycosporine-like amino acids (MAAs) by cultured, symbiotic dinoflagellates.
T Banaszak1 A; LaJeunesse; Trench
We tested the hypothesis that there is a relation between phylotypes (phylogenetic types, as determined by restriction fragment length polymorphism (RFLP) and partial sequence analysis of the small subunit ribosomal RNA gene (SSUrDNA)) and the synthesis of mycosporine-like amino acids (MAAs) by symbiotic dinoflagellates under the influence of ultraviolet radiation (UV-B/A) and photosynthetically active radiation (PAR). We exposed 27 isolates of symbiotic dinoflagellates simultaneously to UV-B/A and PAR, and subsequently determined the MAAs present in cell extracts and in the media. The algae used included 24 isolates of Symbiodinium spp. originating from jellyfishes, sea anemones, zoanthids, scleractinians, octocorals, and bivalves, and three others in the genera Gymnodinium, Gloeodinium and Amphidinium from a jellyfish, an hydrocoral and a flatworm, respectively. In this study, all of the phylotype A Symbiodinium spp. synthesized up to three identified MAAs. None of the 11 cultured phylotypes B and C Symbiodinium spp. synthesized MAAs. The three non-Symbiodinium symbionts also synthesized up to three MAAs. The results support a conclusion that phylotype A Symbiodinium spp. have a high predilection for the synthesis of MAAs, while phylotypes B and C do not. Synthesis of MAAs by symbiotic dinoflagellates in culture does not appear to relate directly to depths or to the UV exposure regimes from which the consortia were collected.
Synthesis of Chiral TFA-Protected α-Amino Aryl-Ketone Derivatives with Friedel–Crafts Acylation of α-Amino Acid N-Hydroxysuccinimide Ester
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Zetryana Puteri Tachrim
Full Text Available Chiral N-protected α-amino aryl-ketones are one of the useful precursors used in the synthesis of various biologically active compounds and can be constructed via Friedel–Crafts acylation of N-protected α-amino acids. One of the drawbacks of this reaction is the utilization of toxic, corrosive and moisture-sensitive acylating reagents. In peptide construction via amide bond formation, N-hydroxysuccinimide ester (OSu, which has high storage stability, can react rapidly with amino components and produces fewer side reactions, including racemization. This study reports the first synthesis and utilization of N-trifluoroacetyl (TFA-protected α-amino acid-OSu as a potential acyl donor for Friedel–Crafts acylation into various arenes. The TFA-protected isoleucine derivative and its diastereomer TFA-protected allo-isoleucine derivative were investigated to check the retention of α-proton chirality in the Friedel–Crafts reaction. Further utilization of OSu in other branched-chain and unbranched-chain amino acids results in an adequate yield of TFA-protected α-amino aryl-ketone without loss of optical purity.
Synthesis of Chiral TFA-Protected α-Amino Aryl-Ketone Derivatives with Friedel-Crafts Acylation of α-Amino Acid N-Hydroxysuccinimide Ester.
Tachrim, Zetryana Puteri; Oida, Kazuhiro; Ikemoto, Haruka; Ohashi, Fumina; Kurokawa, Natsumi; Hayashi, Kento; Shikanai, Mami; Sakihama, Yasuko; Hashidoko, Yasuyuki; Hashimoto, Makoto
Chiral N -protected α-amino aryl-ketones are one of the useful precursors used in the synthesis of various biologically active compounds and can be constructed via Friedel-Crafts acylation of N -protected α-amino acids. One of the drawbacks of this reaction is the utilization of toxic, corrosive and moisture-sensitive acylating reagents. In peptide construction via amide bond formation, N -hydroxysuccinimide ester (OSu), which has high storage stability, can react rapidly with amino components and produces fewer side reactions, including racemization. This study reports the first synthesis and utilization of N -trifluoroacetyl (TFA)-protected α-amino acid-OSu as a potential acyl donor for Friedel-Crafts acylation into various arenes. The TFA-protected isoleucine derivative and its diastereomer TFA-protected allo -isoleucine derivative were investigated to check the retention of α-proton chirality in the Friedel-Crafts reaction. Further utilization of OSu in other branched-chain and unbranched-chain amino acids results in an adequate yield of TFA-protected α-amino aryl-ketone without loss of optical purity.
Zeolite-Encapsulated Copper(II) Amino Acid Complexes: Synthesis, Spectroscopy, and Catalysis
Weckhuysen, B.M.; Verberckmoes, A.A.; Fu, L.; Schoonheydt, R.A.
The spectroscopic properties and catalytic behavior of Cu(AA)n m+ complexes (AA ) amino acid (glycine, lysine, histidine, alanine, serine, proline, tyrosine, phenylalanine, glutamine, glutamic acid, cysteine, tryptophan, leucine, and arginine)) in faujasite-type zeolites have been investigated.
Asymmetric synthesis of α-amino acids by reduction of N-tert-butanesulfinyl ketimine esters.
Reddy, Leleti Rajender; Gupta, Aditya P; Liu, Yugang
A highly regio- and diastereoselective reduction of various N-tert-butanesulfinyl ketimine esters with L-Selectride resulting in the formation of α-amino acids is reported. This method is quite general and also practical for the preparation of both enantiomers of aryl or aliphatic α-amino acids in high yields. © 2011 American Chemical Society
Synthesis of nucleotide–amino acid conjugates designed for photo-CIDNP experiments by a phosphotriester approach
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Tatyana V. Abramova
Full Text Available Conjugates of 2'-deoxyguanosine, L-tryptophan and benzophenone designed to study pathways of fast radical reactions by the photo Chemically Induced Dynamic Nuclear Polarization (photo-CIDNP method were obtained by the phosphotriester block liquid phase synthesis. The phosphotriester approach to the oligonucleotide synthesis was shown to be a versatile and economic strategy for preparing the required amount of high quality samples of nucleotide–amino acid conjugates.
Gluconeogenesis, non-essential amino acid synthesis and substrate partitioning in chicken embryos during later development.
Hu, Q; Agarwal, U; Bequette, B J
We aimed to quantify the rate of gluconeogenesis (GNG), non-essential amino-acid (NEAA) synthesis, and substrate partitioning to the Krebs cycle in embryonic (e) day e14 and e19 chicken embryos. An in ovo continuous tracer infusion approach was employed to test the hypotheses that GNG and NEAA synthesis in developing chicken embryo increases from e14 to e19. [ 13 C 6 ]Glucose or [ 13 C 3 ]glycerol was continuously infused (8 h) into the chorio-allantoic compartment of eggs on e14 and e19. Glucose entry rate, Cori cycling, and GNG were higher (P < 0.05) in e19 compared to e14 embryos, presumably to support higher glycogen deposition in liver and muscle. Whereas de novo synthesis of alanine, aspartate, and glutamate via glycolysis and the Krebs cycle was higher (P < 0.01) in e14 embryos, synthesis of these NEAA from glycerol was higher (P < 0.05) in e19 compared to e14 embryos. These patterns of glucose and glycerol utilization suggest a metabolic shift to conserve glucose for glycogen synthesis and an increased utilization of yolk glycerol (from triacylglyceride) after e14. Although the contribution of glycerol to GNG in e19 embryos was higher (P < 0.05) than that in e14 embryos, the contribution of glycerol to GNG (1.3 to 6.0%) was minor. Based on [ 13 C 6 ]glucose tracer kinetics, the activities of both pyruvate carboxylase (PC) and pyruvate dehydrogenase (PDH) in the liver were higher (P < 0.05) in e19 embryos; whereas the higher (P < 0.01) relative activity of liver PC compared to PDH in e14 embryos suggests a greater anaplerotic flux into the Krebs cycle. In summary, the in ovo continuous tracer infusion approach allowed for a measurement of chicken embryo whole body and liver metabolism over a shorter window of development. This study provided quantitative estimates of the developmental shifts in substrate utilization, GNG, and NEAA synthesis by chicken embryos, as well as qualitative estimates of the activities of enzymes central to the Krebs cycle
Primordial Synthesis of Amines and Amino Acids in a 1958 Miller H2S-Rich Spark Discharge Experiment
Parker, Eric T.; Cleaves, Henderson J.; Dworkin, Jason P.; Glavin, Daniel P.; Callahan, Michael; Aubrey, Andrew; Lazcano, Antonio; Bada, Jeffrey L.
Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H2S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H2S, CH4, NH3, and CO2. A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples. The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordia! environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment. The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H2S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H2S may have played an important role in prebiotic reactions in early solar system environments.
van Goudoever, Johannes B.; Vlaardingerbroek, Hester; van den Akker, Chris H.; de Groof, Femke; van der Schoor, Sophie R. D.
Amino acids and protein are key factors for growth. The neonatal period requires the highest intake in life to meet the demands. Those demands include amino acids for growth, but proteins and amino acids also function as signalling molecules and function as neurotransmitters. Often the nutritional
Adding a functional handle to nature's building blocks: the asymmetric synthesis of β-hydroxy-α-amino acids.
Zhang, Yinfeng; Farrants, Helen; Li, Xuechen
β-Hydroxy-α-amino acids are not only used by synthetic chemists but are also found in natural products, many of which show anti-microbial or anti-cancer properties. Over the past 30 years, chemists have searched for many asymmetric routes to these useful building blocks. Initial attempts to synthesize these compounds utilized chiral auxiliaries and the reactions of glycine equivalents with aldehydes to form two stereocenters in one step. Other methods with the formation of specific intermediates or that were aimed at a specific amino acid have also been investigated. Asymmetric hydrogenation by dynamic kinetic resolution has emerged as a high-yielding method for the synthesis of an array of modified amino acids with good stereoselectivity. More recently, amino-acid functionalization and multicomponent reactions have increased the atom economy and simplified many long and difficult routes. In this Focus Review, many of the elegant syntheses of these compounds are explored. The applications of β-hydroxy-α-amino acids in natural-product synthesis are also mentioned. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Enzymatic Synthesis of Amino Acids Endcapped Polycaprolactone: A Green Route Towards Functional Polyesters
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Stéphane W. Duchiron
Full Text Available ε-caprolactone (CL has been enzymatically polymerized using α-amino acids based on sulfur (methionine and cysteine as (co-initiators and immobilized lipase B of Candida antarctica (CALB as biocatalyst. In-depth characterizations allowed determining the corresponding involved mechanisms and the polymers thermal properties. Two synthetic strategies were tested, a first one with direct polymerization of CL with the native amino acids and a second one involving the use of an amino acid with protected functional groups. The first route showed that mainly polycaprolactone (PCL homopolymer could be obtained and highlighted the lack of reactivity of the unmodified amino acids due to poor solubility and affinity with the lipase active site. The second strategy based on protected cysteine showed higher monomer conversion, with the amino acids acting as (co-initiators, but their insertion along the PCL chains remained limited to chain endcapping. These results thus showed the possibility to synthesize enzymatically polycaprolactone-based chains bearing amino acids units. Such cysteine endcapped PCL materials could then find application in the biomedical field. Indeed, subsequent functionalization of these polyesters with drugs or bioactive molecules can be obtained, by derivatization of the amino acids, after removal of the protecting group.
Synthesis and antimicrobial activities of new higher amino acid Schiff base derivatives of 6-aminopenicillanic acid and 7-aminocephalosporanic acid
Özdemir (nee Güngör), Özlem; Gürkan, Perihan; Özçelik, Berrin; Oyardı, Özlem
Novel β-lactam derivatives (1c-3c) (1d-3d) were produced by using 6-aminopenicillanic acid (6-APA), 7-aminocephalosporanic acid (7-ACA) and the higher amino acid Schiff bases. The synthesized compounds were characterized by elemental analysis, IR, 1H/13C NMR and UV-vis spectra. Antibacterial activities of all the higher amino acid Schiff bases (1a-3a) (1b-3b) and β-lactam derivatives were screened against three gram negative bacteria (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Acinetobacter baumannii RSKK 02026), three gram positive bacteria (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 07005, Bacillus subtilis ATCC 6633) and their drug-resistant isolates by using broth microdilution method. Two fungi (Candida albicans and Candida krusei) were used for antifungal activity.
Synthesis and immunobiological activity of base substituted 2-amino-3-(purin-9-yl)propanoic acid derivatives.
Doláková, Petra; Holý, Antonín; Zídek, Zdenek; Masojídková, Milena; Kmonícková, Eva
2-Amino-3-(purin-9-yl)propanoic acids substituted at position 6 of the purine base moiety by dimethylamino, cyclopropylamino, pyrrolidin-1-yl, hydroxy, and sulfanyl group as well as their 2-aminopurine analogues were prepared from corresponding 9-(2,2-diethoxyethyl)purines and 2-aminopurines, respectively, by the Strecker synthesis. 2-Aminopropanoic acid derivatives were tested for their immunostimulatory and immunomodulatory potency. Some of these compounds significantly enhanced secretion of chemokines RANTES and MIP-1alpha, the most potent was 2-amino-6-sulfanylpurine derivative. Most of these compounds also augmented NO biosynthesis triggered primarily by IFN-gamma.
Asymmetric synthesis of chiral heterocyclic amino acids via the alkylation of the Ni(II) complex of glycine and alkyl halides.
Chen, Hui; Wang, Jiang; Zhou, Shengbin; Liu, Hong
An investigation into the reactivity profile of alkyl halides has led to the development of a new method for the asymmetric synthesis of chiral heterocyclic amino acids. This protocol involves the asymmetric alkylation of the Ni(II) complex of glycine to form an intermediate, which then decomposes to form a series of valuable chiral amino acids in high yields and with excellent diastereoselectivity. The chiral amino acids underwent a smooth intramolecular cyclization process to afford the valuable chiral heterocyclic amino acids in high yields and enantioselectivities. This result paves the way for the development of a new synthetic method for chiral heterocyclic amino acids.
Leucine-enriched essential amino acids attenuate muscle soreness and improve muscle protein synthesis after eccentric contractions in rats.
Kato, Hiroyuki; Suzuki, Hiromi; Mimura, Masako; Inoue, Yoshiko; Sugita, Mayu; Suzuki, Katsuya; Kobayashi, Hisamine
Eccentric exercise results in prolonged muscle weakness and muscle soreness, which are typical symptoms of muscle damage. Recovery from muscle damage is related to mammalian target of rapamycin (mTOR) activity. Leucine-enriched essential amino acids (LEAAs) stimulate muscle protein synthesis via activation of the mTOR pathway. Therefore, we investigated the effect of LEAAs on muscle protein synthesis and muscle soreness after eccentric contractions (EC). Male Sprague-Dawley rats (9-11 weeks old) were administered an LEAA solution (AminoL40; containing 40 % leucine and 60 % other essential amino acids) at 1 g/kg body weight or distilled water (control) 30 min before and 10 min after EC. Tibialis anterior (TA) muscle was exposed to 500 EC by electrical stimulation under anesthesia. The fractional synthesis rate (FSR; %/h) in the TA muscle was measured by incorporating L-[ring-(2)H5] phenylalanine into skeletal muscle protein. Muscle soreness was evaluated by the paw withdrawal threshold using the Randal-Selitto test with some modifications from 1 to 3 days after EC. The FSR in the EC-control group (0.147 ± 0.016 %/h) was significantly lower than in the sedentary group (0.188 ± 0.016 %/h, p soreness. Furthermore, AminoL40 administration alleviated the decreased paw withdrawal threshold. These findings suggest that LEAA supplementation improves the rate of muscle protein synthesis and ameliorates muscle soreness after eccentric exercise.
Synthesis, Gastroprotective Effect and Cytotoxicity of New Amino Acid Diterpene Monoamides and Diamides
Schmeda-Hirschmann, Guillermo; Pertino, Mariano Walter; Rodriguez, Jaime A.; Monsalve, Francisco; Droguett, Daniel; Theoduloz, Cristina
Following our studies on the gastroprotective effect and cytotoxicity of terpene derivatives, new amides were prepared from the diterpene 8(17)-labden-15,19-dioic acid (junicedric acid) and its 8(9)-en isomer with C-protected amino acids (amino acid esters). The new compounds were evaluated for their gastroprotective effect in the ethanol/HCl-induced gastric lesions model in mice, as well as for cytotoxicity using the following human cell lines: normal lung fibroblasts (MRC-5), gastric adenoc...
Impact of Amino-Acid Coating on the Synthesis and Characteristics of Iron-Oxide Nanoparticles (IONs)
Energy Technology Data Exchange (ETDEWEB)
Ebrahiminezhad, Alireza; Barar, Jaleh; Davaran, Soodabeh [Tabriz Univ. of Medical Sciences, Tabriz (Iran, Islamic Republic of); Ghasemi, Younes; Sara, Rasoulamini [Shiraz Univ. of Medical Sciences, Shiraz (Iran, Islamic Republic of)
Iron-oxide nanoparticles (IONs) with biocompatible coatings are the only nanostructural materials which have been approved by the FDA for clinical use. Common biocompatible coatings such as hydrocarbons, polymers, and silica have profound influences on critical characteristics of IONs. Recently, amino acids were introduced as a novel biocompatible coating. In the present study, the effects of amino acids on IONs synthesis and characteristics have been evaluated. Magnetite nanoparticles with {sub L}-arginine and {sub L}-lysine coatings were synthesised by a coprecipitation reaction in aqueous solvent and their characteristics were compared with naked magnetite nanoparticles. The results showed that amino acids can be a perfect coating for IONs and would increase particle stability without any significant effects on the critical properties of nanoparticles such as particle size and magnetization saturation value.
Novel class of amino acid antagonists at non-N-methyl-D-aspartic acid excitatory amino acid receptors. Synthesis, in vitro and in vivo pharmacology, and neuroprotection
International Nuclear Information System (INIS)
Krogsgaard-Larsen, P.; Ferkany, J.W.; Nielsen, E.O.; Madsen, U.; Ebert, B.; Johansen, J.S.; Diemer, N.H.; Bruhn, T.; Beattie, D.T.; Curtis, D.R.
The isoxazole amino acid 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl) propionic acid (AMPA) (1), which is a highly selective agonist at the AMPA subtype of excitatory amino acid (EAA) receptors, has been used as a lead for the development of two novel EAA receptor antagonists. One of the compounds, 2-amino-3-[3-(carboxymethoxy)-5-methylisoxazol-4-yl]propionic acid (AMOA, 7), was synthesized via O-alkylation by ethyl chloroacetate of the amino acid protected AMPA derivative 4. The other compound, 2-amino-3-[2-(3-hydroxy-5-methylisoxazol-4-yl)-methyl-5-methyl-3-+ ++oxoisoxazolin -4-yl]propionic acid (AMNH, 14) was synthesized with use of 4-(chloromethyl)-3-methoxy-5-methylisoxazole (8) as the starting material. The intermediate 4-(chloromethyl)-2-(3-methoxy-5-methylisoxazol-4-yl)methyl-5-me thylisoxazolin- 3-one (11) was converted into the acetamidomalonate (12), which was stepwise deprotected to give 14. Compounds 7 and 14 were stable in aqueous solution at pH values close to physiological pH. Neither 7 nor 14 showed detectable affinities for the receptor, ion channel, or modulatory sites of the N-methyl-D-aspartic acid (NMDA) receptor complex. Quantitative receptor autoradiographic and conventional binding techniques were used to study the affinities of 7 and 14 for non-NMDA receptor sites. Both compounds were inhibitors of the binding of [3H]AMPA (IC50 = 90 and 29 microM, respectively). Compounds 14 and 7 were both very weak inhibitors of the high-affinity binding of radioactive kainic acid [(3H]KAIN). Compound 14, but not 7, was, however, shown to be an inhibitor of low-affinity [3H]KAIN binding as determined in the presence of 100 mM calcium chloride. In the rat cortical slice preparation, 7 was shown to antagonize excitation induced by 1 with some selectivity, whereas 14 proved to be a rather selective antagonist of KAIN-induced excitation
Synthesis and in vivo distribution of 1-amino-3-boronocylopentanecarboxylic acids
International Nuclear Information System (INIS)
Kabalka, G.; Naravane, A.; Yao, M.-L.; Coderre, J.; Chung, Y.; Riley, K.
The success of boron neutron capture therapy (BNCT) is dependent on the selective deposition of boron-10 in tumor cells. For a number of years, we have focused our attention on the potential use of boronated cyclic amino acids as boron carriers for BNCT. The studies are an outgrowth of our earlier nuclear medicine studies using positron emission tomography that demonstrated that amino acids are preferentially taken up by tumor cells. Boronated 1-aminocyclobutanecarboxylic acid and 1-aminocyclopentanecarboxylic acid were found to be at least as tumor selective as the currently utilized BNCT agent, para-boronophenylalanine, in our tumor-bearing animal models. We wish to report the results of a study in which the diastereoisomers of 1-amino-3-boronocyclopentanecarboxylic acid were separated and their biodistribution evaluated in mice bearing EMT-6 tumors. (author)
Winitz, M.; Graff, J. (Inventor)
The process and apparatus for qualitative and quantitative analysis of the amino acid content of a biological sample are presented. The sample is deposited on a cation exchange resin and then is washed with suitable solvents. The amino acids and various cations and organic material with a basic function remain on the resin. The resin is eluted with an acid eluant, and the eluate containing the amino acids is transferred to a reaction vessel where the eluant is removed. Final analysis of the purified acylated amino acid esters is accomplished by gas-liquid chromatographic techniques.
Regulatory role for amino acids in mammary gland growth and milk synthesis.
Kim, Sung Woo; Wu, Guoyao
The health and growth of mammalian neonates critically depend on the yield and composition of their mothers' milk. However, impaired lactogenesis occurs in both women in response to stress and hormonal imbalance and in primiparous sows which exhibit low voluntary feed intake and underdevelopment of mammary tissues. Because of ethical concerns over lactation research with women and children, swine is often used as an animal model to study mammary gland development and the underlying regulatory mechanisms. Available evidence from work with lactating sows shows that amino acids are not only building blocks for protein but are also key regulators of metabolic pathways critical to milk production. Particularly, arginine is the common substrate for the generation of nitric oxide (NO; a major vasodilator and angiogenic factor) and polyamines (key regulators of protein synthesis). Thus, modulation of the arginine-NO pathway may provide a new strategy to enhance the growth (including vascular growth) of mammary tissue and its uptake of nutrients, therefore improving lactation performance in mammals. In support of this proposition, supplementing 0.83% L: -arginine (as 1% L: -arginine-HCl) or 50 mg/day diethylenetriamine-NO adduct (NO donor) to diets of lactating primiparous sows increased milk production and the growth of suckling piglets. Future studies with animal models (e.g., pigs, sheep, cows, and rats) are necessary to elucidate the underlying mechanisms at molecular, cellular, tissue, and whole-body levels.
Versatile synthesis of amino acid functionalized nucleosides via a domino carboxamidation reaction
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Vicky Gheerardijn
Full Text Available Functionalized oligonucleotides have recently gained increased attention for incorporation in modified nucleic acid structures both for the design of aptamers with enhanced binding properties as well as the construction of catalytic DNA and RNA. As a shortcut alternative to the incorporation of multiple modified residues, each bearing one extra functional group, we present here a straightforward method for direct linking of functionalized amino acids to the nucleoside base, thus equipping the nucleoside with two extra functionalities at once. As a proof of principle, we have introduced three amino acids with functional groups frequently used as key-intermediates in DNA- and RNAzymes via an efficient and straightforward domino carboxamidation reaction.
Synthesis and structure-activity studies on acidic amino acids and related diacids as NMDA receptor ligands
DEFF Research Database (Denmark)
Johansen, T N; Frydenvang, Karla Andrea; Ebert, B
The 3-isoxazolol amino acids (S)-2-amino-3-(3-hydroxy-5-methyl-4- isoxazolyl)propionic acid [(S)-AMPA, 2] and (R,S)-2-amino-2-(3-hydroxy-5-methyl-4-isoxazolyl)acetic acid (AMAA, 5a) (Figure 1) are potent and specific agonists at the AMPA and N-methyl-D-aspartic acid (NMDA) subtypes, respectively......, of (S)-glutamic acid (1) receptors. A number of amino acids and diacids structurally related to AMAA were synthesized and tested electrophysiologically and in receptor-binding assays. The hydroxymethyl analogue 7c of AMAA was an NMDA agonist approximately equipotent with AMAA in the [3H...... by molecular mechanics calculations. Compound 7a possesses extra steric bulk and shows significant restriction of conformational flexibility compared to AMAA and 7c, which may be determining factors for the observed differences in biological activity. Although the nitrogen atom of quinolinic acid (6) has very...
Branched-Chain Amino Acid Ingestion Stimulates Muscle Myofibrillar Protein Synthesis following Resistance Exercise in Humans
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Sarah R. Jackman
Full Text Available The ingestion of intact protein or essential amino acids (EAA stimulates mechanistic target of rapamycin complex-1 (mTORC1 signaling and muscle protein synthesis (MPS following resistance exercise. The purpose of this study was to investigate the response of myofibrillar-MPS to ingestion of branched-chain amino acids (BCAAs only (i.e., without concurrent ingestion of other EAA, intact protein, or other macronutrients following resistance exercise in humans. Ten young (20.1 ± 1.3 years, resistance-trained men completed two trials, ingesting either 5.6 g BCAA or a placebo (PLA drink immediately after resistance exercise. Myofibrillar-MPS was measured during exercise recovery with a primed, constant infusion of L-[ring13C6] phenylalanine and collection of muscle biopsies pre and 4 h-post drink ingestion. Blood samples were collected at time-points before and after drink ingestion. Western blotting was used to measure the phosphorylation status of mTORC1 signaling proteins in biopsies collected pre, 1-, and 4 h-post drink. The percentage increase from baseline in plasma leucine (300 ± 96%, isoleucine (300 ± 88%, and valine (144 ± 59% concentrations peaked 0.5 h-post drink in BCAA. A greater phosphorylation status of S6K1Thr389 (P = 0.017 and PRAS40 (P = 0.037 was observed in BCAA than PLA at 1 h-post drink ingestion. Myofibrillar-MPS was 22% higher (P = 0.012 in BCAA (0.110 ± 0.009%/h than PLA (0.090 ± 0.006%/h. Phenylalanine Ra was ~6% lower in BCAA (18.00 ± 4.31 μmol·kgBM−1 than PLA (21.75 ± 4.89 μmol·kgBM−1; P = 0.028 after drink ingestion. We conclude that ingesting BCAAs alone increases the post-exercise stimulation of myofibrillar-MPS and phosphorylation status mTORC1 signaling.
carcass amino acid composition and utilization of dietary amino
African Journals Online (AJOL)
Maynard (1954), Fisher & Scott (1954), Forbes &. Rao (1959), Hartsook & Mitchell (1956). King (1963) showed that individual amino acids in the carcass could differ widely from the requirement by the anirnal for those particular amino acids used for purposes other than protein synthesis and subsequent retention. How-.
Carbon-based Solid Acid Catalyzed One-pot Mannich Reaction: A Facile Synthesis of β-Amino Carbonyl Compounds
Energy Technology Data Exchange (ETDEWEB)
Davoodnia, Abolghasem; Tavakoli-Nishaburi, Afsaneh; Tavakoli-Hoseini, Niloofar [Islamic Azad University, Mashhad (Iran, Islamic Republic of)
A simple and efficient method for the synthesis of β-amino carbonyl compounds by one-pot three-component Mannich reaction of acetophenone, aromatic aldehydes and aromatic amines using a carbon-based solid acid (CBSA), as an effective and reusable catalyst, is described. The present methodology offers several advantages such as simple procedure with an easy work-up, shorter reaction times, and high yields.
Selective antagonists at group I metabotropic glutamate receptors: synthesis and molecular pharmacology of 4-aryl-3-isoxazolol amino acids
DEFF Research Database (Denmark)
Kromann, Hasse; Sløk, Frank A; Stensbøl, Tine B
Homologation of (S)-glutamic acid (Glu, 1) and Glu analogues has previously provided ligands with activity at metabotropic Glu receptors (mGluRs). The homologue of ibotenic acid (7), 2-amino-3-(3-hydroxy-5-isoxazolyl)propionic acid (HIBO, 8), and the 4-phenyl derivative of 8, compound 9a, are bot...... antagonists at group I mGluRs. Here we report the synthesis and molecular pharmacology of HIBO analogues 9b-h containing different 4-aryl substituents. All of these compounds possess antagonist activity at group I mGluRs but are inactive at group II and III mGluRs....
The effects of enhanced methionine synthesis on amino acid and anthocyanin content of potato tubers
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Bánfalvi Zsófia
Full Text Available Abstract Background Potato is a staple food in the diet of the world's population and also being used as animal feed. Compared to other crops, however, potato tubers are relatively poor in the essential amino acid, methionine. Our aim was to increase the methionine content of tubers by co-expressing a gene involved in methionine synthesis with a gene encoding a methionine-rich storage protein in potato plants. Results In higher plants, cystathionine γ-synthase (CgS is the first enzyme specific to methionine biosynthesis. We attempted to increase the methionine content of tubers by expressing the deleted form of the Arabidopsis CgS (CgSΔ90, which is not regulated by methionine, in potato plants. To increase the incorporation of free methionine into a storage protein the CgSΔ90 was co-transformed with the methionine-rich 15-kD β-zein. Results demonstrated a 2- to 6-fold increase in the free methionine content and in the methionine content of the zein-containing protein fraction of the transgenic tubers. In addition, in line with higher methionine content, the amounts of soluble isoleucine and serine were also increased. However, all of the lines with high level of CgSΔ90 expression were phenotypically abnormal showing severe growth retardation, changes in leaf architecture and 40- to 60% reduction in tuber yield. Furthermore, the colour of the transgenic tubers was altered due to the reduced amounts of anthocyanin pigments. The mRNA levels of phenylalanine ammonia-lyase (PAL, the enzyme catalysing the first step of anthocyanin synthesis, were decreased. Conclusion Ectopic expression of CgSΔ90 increases the methionine content of tubers, however, results in phenotypic aberrations in potato. Co-expression of the 15-kD β-zein with CgSΔ90 results in elevation of protein-bound methionine content of tubers, but can not overcome the phenotypical changes caused by CgSΔ90 and can not significantly improve the nutritional value of tubers. The level
Sustainable and Continuous Synthesis of Enantiopure l-Amino Acids by Using a Versatile Immobilised Multienzyme System.
Velasco-Lozano, Susana; da Silva, Eunice S; Llop, Jordi; López-Gallego, Fernando
The enzymatic synthesis of α-amino acids is a sustainable and efficient alternative to chemical processes, through which achieving enantiopure products is difficult. To more address this synthesis efficiently, a hierarchical architecture that irreversibly co-immobilises an amino acid dehydrogenase with polyethyleneimine on porous agarose beads has been designed and fabricated. The cationic polymer acts as an irreversible anchoring layer for the formate dehydrogenase. In this architecture, the two enzymes and polymer colocalise across the whole microstructure of the porous carrier. This multifunctional heterogeneous biocatalyst was kinetically characterised and applied to the enantioselective synthesis of a variety of canonical and noncanonical α-amino acids in both discontinuous (batch) and continuous modes. The co-immobilised bienzymatic system conserves more than 50 % of its initial effectiveness after five batch cycles and 8 days of continuous operation. Additionally, the environmental impact of this process has been semiquantitatively calculated and compared with the state of the art. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Synthesis of new gold(I) thiolates containing amino acid moieties with potential biological interest.
Gutiérrez, Alejandro; Bernal, Javier; Villacampa, M Dolores; Cativiela, Carlos; Laguna, Antonio; Gimeno, M Concepción
The reaction of the gold(I) complex [Au(SpyCOOH)(PPh3)], which contains nicotinic acid thiolate, with several amino acid esters such as glycine methyl ester or the enantiomerically pure L isomers of alanine methyl ester, phenylalanine methyl ester, valine methyl ester, methionine methyl ester, and proline methyl ester produces the gold(I) derivatives with the new thiolate containing amino acid ester ligands [Au{SpyCONHCH(R)COOMe}(PPh3)]. The reaction of these amino acid ester derivatives with LiOH in methanol and acidification with KHSO4 until pH 3-4 afford the corresponding acids, which are water-soluble species. These amino acid compounds can be further coupled with other amines, such as, for example, isopropylamine, to give the corresponding amide derivatives. The species with glycine methyl ester and valine methyl ester have been characterized by X-ray crystallography, showing, in the second case, only one of the enantiomers, which proves that retention of the configuration after reaction occurs.
Available versus digestible dietary amino acids.
Rutherfurd, Shane M; Moughan, Paul J
Available amino acids are those absorbed from the gastrointestinal tract in a form suitable for body protein synthesis. True ileal digestible amino acids are determined based on the difference between dietary amino acid intake and unabsorbed dietary amino acids at the terminal ileum. The accuracy of ileal digestible amino acid estimates for predicting available amino acid content depends on several factors, including the accuracy of the amino acid analysis procedure. In heat processed foods, lysine can react with compounds to form nutritionally unavailable derivatives that are unstable during the hydrochloric acid hydrolysis step of amino acid analysis and can revert back to lysine causing an overestimate of available lysine. Recently, the true ileal digestible reactive (available) lysine assay based on guanidination has provided a means of accurately determining available lysine in processed foods. Methionine can be oxidised during processing to form methionine sulphoxide and methionine sulphone and cysteine oxidised to cysteic acid. Methionine sulphoxide, but not methionine sulphone or cysteic acid, is partially nutritionally available in some species of animal. Currently, methionine and cysteine are determined as methionine sulphone and cysteic acid respectively after quantitative oxidation prior to acid hydrolysis. Consequently, methionine and cysteine are overestimated if methionine sulphone or cysteic acid are present in the original material. Overall, given the problems associated with the analysis of some amino acids in processed foodstuffs, the available amino acid content may not always be accurately predicted by true ileal amino acid digestibility estimates. For such amino acids specific analytical strategies may be required.
Development of a method for environmentally friendly chemical peptide synthesis in water using water-dispersible amino acid nanoparticles
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Fukumori Yoshinobu
Full Text Available Abstract Due to the vast importance of peptides in biological processes, there is an escalating need for synthetic peptides to be used in a wide variety of applications. However, the consumption of organic solvent is extremely large in chemical peptide syntheses because of the multiple condensation steps in organic solvents. That is, the current synthesis method is not environmentally friendly. From the viewpoint of green sustainable chemistry, we focused on developing an organic solvent-free synthetic method using water, an environmentally friendly solvent. Here we described in-water synthesis technology using water-dispersible protected amino acids.
Amino Acids from Icy Amines: A Radiation-Chemical Approach to Extraterrestrial Synthesis
Dworkin, J. P.; Moore, M. H.
Detections of amino acids in meteorites go back several decades, with at least 100 such compounds being reported for the Murchison meteorite alone. The presence of these extraterrestrial molecules raises questions as to their formation, abundance, thermal stability, racemization, and possible subsequent reactions. Although all of these topics have been studied in laboratories, such work often involves many variables and unknowns. This has led us to seek out model systems with which to uncover reaction products, test chemical predictions, and sited light on underlying reaction mechanisms. This presentation will describe one such study, focusing on amino-acid formation in ices.
Amino-Acid-Based Polymerizable Surfactants for the Synthesis of Chiral Nanoparticles.
Preiss, Laura C; Wagner, Manfred; Mastai, Yitzhak; Landfester, Katharina; Muñoz-Espí, Rafael
Amino-acid-based chiral surfactants with polymerizable moieties are synthesized, and a versatile approach to prepare particles thereof with a chiral surface functionality is presented. As an example of an application, the synthesized particles are tested for their ability as nucleating agents in the enantioselective crystallization of amino acid conglomerate systems, taking rac-asparagine as a model system. Particles resulting from chiral surfactants with different tail groups are compared and the results demonstrate that only the chiral nanoparticles made of the polymerizable surfactant are able to act efficiently as nucleation agent in enantioselective crystallization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Synthesis, photophysical properties of triazolyl-donor/acceptor chromophores decorated unnatural amino acids: Incorporation of a pair into Leu-enkephalin peptide and application of triazolylperylene amino acid in sensing BSA.
Bag, Subhendu Sekhar; Jana, Subhashis; Pradhan, Manoj Kumar
The research in the field of design and synthesis of unnatural amino acids is growing at a fast space for the increasing demand of proteins of potential therapeutics and many other diversified novel functional applications. Thus, we report herein the design and synthesis of microenvironment sensitive fluorescent triazolyl unnatural amino acids (UNAA) decorated with donor and/or acceptor aromatic chromophores via click chemistry. The synthesized fluorescent amino acids show interesting solvatochromic characteristic and/or intramolecular charge transfer (ICT) feature as is revealed from the UV-visible, fluorescence photophysical properties and DFT/TDDFT calculation. HOMO-LUMO distribution shows that the emissive states of some of the amino acids are characterized with more significant electron redistribution between the triazolyl moiety and the aromatic chromophores linked to it leading to modulated emission property. A pair of donor-acceptor amino acid shows interesting photophysical interaction property indicating a FRET quenching event. Furthermore, one of the amino acid, triazolyl-perylene amino acid, has been exploited for studying interaction with BSA and found that it is able to sense BSA with an enhancement of fluorescence intensity. Finally, we incorporated a pair of donor/acceptor amino acids into a Leu-enkephalin analogue pentapeptide which was found to adopt predominantly type II β-turn conformation. We envisage that our investigation is of importance for the development of new fluorescent donor-acceptor unnatural amino acids a pair of which can be exploited for generating fluorescent peptidomimetic probe of interesting photophysical property for applications in studying peptide-protein interaction. Copyright © 2016 Elsevier Ltd. All rights reserved.
Amino Acid Metabolism Disorders
... acids are "building blocks" that join together to form proteins. If you have one of these disorders, your body may have trouble breaking down certain amino acids. Or there may be a problem getting the ...
Versatile Synthesis of Amino Acid Functional Polymers without Protection Group Chemistry.
Brisson, Emma R L; Xiao, Zeyun; Franks, George V; Connal, Luke A
The copolymerization of N-isopropylacrylamide (NiPAm) with aldehyde functional monomers facilitates postpolymerization functionalization with amino acids via reductive amination, negating the need for protecting groups. In reductive amination, the imine formed from the condensation reaction between an amine and an aldehyde is reduced to an amine. In this work, we categorize amino acids into four classes based on the functionality of their side chains (acidic, polar neutral, neutral, and basic) and use their amine groups in condensation reactions with aldehyde functional polymers. The dynamic nature of the imine as well as the versatility of reductive amination to functionalize a polymer with a range of amino acids is highlighted. In this manner, amino acid functional polymers are synthesized without the use of protecting groups with high yields, demonstrating the high functional group tolerance of carbonyl condensation chemistry and the subsequent reduction of the imine. Prior to the reduction of the imine bond, transimination reactions are used to demonstrate dynamic polymers that shuffle from a glycine- to a histidine-functional polymer.
Synthesis of new isoxazoline-based acidic amino acids and investigation of their affinity and selectivity profile at ionotropic glutamate receptors
DEFF Research Database (Denmark)
Pinto, Andrea; Conti, Paola; Grazioso, Giovanni
The synthesis of four new isoxazoline-based amino acids being analogues of previously described glutamate receptor ligands is reported and their affinity for ionotropic glutamate receptors is analyzed in comparison with that of selected model compounds. Molecular modelling investigations have been...
Sims, Paul A.
Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;…
Synthesis, gastroprotective effect and cytotoxicity of new amino acid diterpene monoamides and diamides.
Schmeda-Hirschmann, Guillermo; Pertino, Mariano Walter; Rodriguez, Jaime A; Monsalve, Francisco; Droguett, Daniel; Theoduloz, Cristina
Following our studies on the gastroprotective effect and cytotoxicity of terpene derivatives, new amides were prepared from the diterpene 8(17)-labden-15,19-dioic acid (junicedric acid) and its 8(9)-en isomer with C-protected amino acids (amino acid esters). The new compounds were evaluated for their gastroprotective effect in the ethanol/HCl-induced gastric lesions model in mice, as well as for cytotoxicity using the following human cell lines: normal lung fibroblasts (MRC-5), gastric adenocarcinoma cells (AGS) and liver hepatocellular carcinoma (Hep G2). A dose-response experiment showed that at 25 mg/kg the C-15 leucyl and C-15,19-dileucylester amides of junicedric acid reduced gastric lesions by about 65.6 and 49.6%, respectively, with an effect comparable to lansoprazole at 20 mg/kg (79.3% lesion reduction). The comparison of the gastroprotective effect of 18 new amino acid ester amides was carried out at a single oral dose of 25 mg/kg. Several compounds presented a strong gastroprotective effect, reducing gastric lesions in the 70.9-87.8% range. The diprolyl derivative of junicedric acid, the most active product of this study (87.8% lesion reduction at 25 mg/kg) presented a cytotoxicity value comparable with that of the reference compound lansoprazole. The structure-activity relationships are discussed.
Synthesis, Gastroprotective Effect and Cytotoxicity of New Amino Acid Diterpene Monoamides and Diamides
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Daniel Droguett
Full Text Available Following our studies on the gastroprotective effect and cytotoxicity of terpene derivatives, new amides were prepared from the diterpene 8(17-labden-15,19-dioic acid (junicedric acid and its 8(9-en isomer with C-protected amino acids (amino acid esters. The new compounds were evaluated for their gastroprotective effect in the ethanol/HCl-induced gastric lesions model in mice, as well as for cytotoxicity using the following human cell lines: normal lung fibroblasts (MRC-5, gastric adenocarcinoma cells (AGS and liver hepatocellular carcinoma (Hep G2. A dose-response experiment showed that at 25 mg/kg the C-15 leucyl and C-15,19-dileucylester amides of junicedric acid reduced gastric lesions by about 65.6 and 49.6%, respectively, with an effect comparable to lansoprazole at 20 mg/kg (79.3% lesion reduction. The comparison of the gastroprotective effect of 18 new amino acid ester amides was carried out at a single oral dose of 25 mg/kg. Several compounds presented a strong gastroprotective effect, reducing gastric lesions in the 70.9-87.8% range. The diprolyl derivative of junicedric acid, the most active product of this study (87.8% lesion reduction at 25 mg/kg presented a cytotoxicity value comparable with that of the reference compound lansoprazole. The structure-activity relationships are discussed.
Metabolism of Nonessential N15-Labeled Amino Acids and the Measurement of Human Whole-Body Protein Synthesis Rates
Stein, T. P.; Settle, R. G.; Albina, J. A.; Dempsey, D. T.; Melnick, G.
Eight N-15 labeled nonessential amino acids plus (15)NH4Cl were administered over a 10 h period to four healthy adult males using a primed-constant dosage regimen. The amount of N-15 excreted in the urine and the urinary ammonia, hippuric acid, and plasma alanine N-15 enrichments were measured. There was a high degree of consistency across subjects in the ordering of the nine compounds based on the fraction of N-15 excreted (Kendall coefficient of concordance W = 0.83, P is less than 0.01). Protein synthesis rates were calculated from the urinary ammonia plateau enrichment and the cumulative excretion of N-15. Glycine was one of the few amino acids that gave similar values by both methods.
Regional differences in glutathione accumulation pathways in the rat cornea: Mapping of amino acid transporters involved in glutathione synthesis.
Yoganandarajah, Vithushiya; Li, Bo; Umapathy, Ankita; Donaldson, Paul J; Lim, Julie C
In this study we have sought to complete the identification and localisation of uptake pathways involved in accumulating precursor amino acids involved in GSH synthesis in the rat cornea. To do this, we performed reverse transcription PCR (RT-PCR) to identify the Excitatory Amino Acid Transporters (EAAT 1-5) responsible for glutamate uptake, and glycine transporters (GLYT 1-2) at the transcript level. Western blotting was used to verify protein expression, while immunolabelling of sagittal sections was used to localise transporters to the different layers of the cornea. Immunolabelling of en face sections was used to examine the subcellular distribution of proteins in the corneal endothelium. Our findings revealed EAAT 1-5 and GLYT 1-2 to be expressed at the transcript and protein level in the rat cornea. Immunohistochemistry revealed all amino acid transporters to be localised to the epithelium. In the majority of cases, labelling was restricted to the epithelium, and labelling absent from the stroma or endothelium. However, EAAT 4 and GLYT 2 labelling was detected in the stroma with EAAT 4 labelling also present in the endothelium. Overall, the identification of amino acid transporters strongly supports the existence of an intracellular GSH synthesis pathway in the rat corneal epithelium. This suggests that regional differences in GSH accumulation pathways exist, with direct uptake of GSH and intracellular synthesis of GSH restricted to the endothelial and epithelial cell layers, respectively. This information is important in the design of targeted strategies to enhance GSH levels in specific layers of the cornea to prevent against oxidative damage, corneal swelling and loss of corneal transparency. Copyright © 2017 Elsevier Ltd. All rights reserved.
Recent approaches towards the asymmetric synthesis of α,α-disubstituted α-amino acids
DEFF Research Database (Denmark)
Vogt, Henning; Brase, S.
The class of alpha,alpha-disubstituted alpha-amino acids has gained considerable attention in the past decades and continues doing so. The ongoing interest in biological and chemical properties of the substance class has inspired the development of many new methodologies for their asymmetric...
Design, synthesis and stimuli responsive gelation of novel stigmasterol-amino acid conjugates
Czech Academy of Sciences Publication Activity Database
Svobodová, Hana; Nonappa, J.; Wimmer, Zdeněk; Kolehmainen, E.
Roč. 361, č. 2 (2011), s. 587-593 ISSN 0021-9797 R&D Projects: GA MŠk 2B06024; GA MŠk(CZ) OC10001 Institutional research plan: CEZ:AV0Z50380511 Keywords : Stigmasterol * Amino acid * LMOG Subject RIV: CC - Organic Chemistry Impact factor: 3.070, year: 2011
Synthesis of amino acids with methyleneoxy bond: application in peptide analogs
Czech Academy of Sciences Publication Activity Database
Hlaváček, Jan; Mařík, Jan
Roč. 25, - (2003), s. 123 ISSN 0939-4451. [International Congress on Amino Acids and Proteins /8./. Rome, 05.09.2003-09.09.2003] Institutional research plan: CEZ:AV0Z4055905 Keywords : pseudodipeptides * peptidomimetics Subject RIV: CC - Organic Chemistry Impact factor: 1.582, year: 2003
Telluro amino acids-synthesis, characterization and properties of a new and potentially useful class of compounds
International Nuclear Information System (INIS)
Knapp, F.F. Jr.; Ambrose, K.R.; Callahan, A.P.
The Te-123m nuclide emits 159 keV photons suggesting that agents labeled with this nuclide would be attractive candidates for tissue imaging. Amino acids labeled with Te-123m are of particular interest since some of these compounds would be isosteric with the sulfur analogs and might behave similarly in vivo. Such agents could possibly be useful for pancreatic imaging and for other biomedical applications. The goal of this investigation was to develop a general chemical method for the preparation of telluro amino acids. Attempts by other workers to prepare such compounds by microbiological methods have been unsuccessful. Since telluro amino acids were unknown prior to our studies we attempted the synthesis of a representative member of this class of compounds by several routes. Two general approaches were considered which involved either the introduction of an (organo telluro) reagent into a substrate that contained the protected -CH(NH 2 )COOH moiety or introduction of the reagent into a substrate that could subsequently be converted to the α-amino acid after the coupling step
Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases. Part 2: aldol, Mannich addition reactions, deracemization and (S) to (R) interconversion of α-amino acids.
Sorochinsky, Alexander E; Aceña, José Luis; Moriwaki, Hiroki; Sato, Tatsunori; Soloshonok, Vadim
This review provides a comprehensive treatment of literature data dealing with asymmetric synthesis of α-amino-β-hydroxy and α,β-diamino acids via homologation of chiral Ni(II) complexes of glycine Schiff bases using aldol and Mannich-type reactions. These reactions proceed with synthetically useful chemical yields and thermodynamically controlled stereoselectivity and allow direct introduction of two stereogenic centers in a single operation with predictable stereochemical outcome. Furthermore, new application of Ni(II) complexes of α-amino acids Schiff bases for deracemization of racemic α-amino acids and (S) to (R) interconversion providing additional synthetic opportunities for preparation of enantiomerically pure α-amino acids, is also reviewed. Origin of observed diastereo-/enantioselectivity in the aldol, Mannich-type and deracemization reactions, generality and limitations of these methodologies are critically discussed.
One-Pot Synthesis of Novel Chiral β-Amino Acid Derivatives by Enantioselective Mannich Reactions Catalyzed by Squaramide Cinchona Alkaloids
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Kankan Zhang
Full Text Available An efficient one-pot synthesis of novel β-amino acid derivatives containing a thiadiazole moiety was developed using a chiral squaramide cinchona alkaloid as organocatalyst. The reactions afforded chiral β-amino acid derivatives in moderate yields and with moderate to excellent enantioselectivities. The present study demonstrated for the first time the use of a Mannich reaction catalyzed by a chiral bifunctional organocatalyst for the one-pot synthesis of novel β-amino acid derivatives bearing a 1,3,4-thiadiazole moiety on nitrogen.
Synthesis and antitumour activity of arctigenin amino acid ester derivatives against H22 hepatocellular carcinoma.
Cai, Enbo; Guo, Shijie; Yang, Limin; Han, Mei; Xia, Jing; Zhao, Yan; Gao, Xiaorui; Wang, Yu
Arctigenin (ARG) is famous in its abundant pharmacological activity. However, many researches in it entered the bottleneck period because of its poor water solubility. The derivatives of ARG have been synthesised with five amino acids which have t-Butyloxy carbonyl (BOC) as a protective group. We examined the effects of removing BOC. The results showed that the amino acid derivatives without protective group have better water solubility and nitrite-clearing ability than ARG. Based on these results, ARG6' and ARG9' were selected at a dosage of 40 mg/kg to evaluate their antitumour activity. The percentage inhibition rate of ARG6' and ARG9' were 55.87 and 51.40, respectively, which was twice as much as ARG. Furthermore, they could increase liver and kidney indexes and produce less damage in these organs. In brief, this study provides a basis for new drug development.
Synthesis, antimicrobial activity of Schiff base compounds of cinnamaldehyde and amino acids.
Wang, Hui; Yuan, Haijian; Li, Shujun; Li, Zhuo; Jiang, Mingyue
The purpose of this study was to synthesize hydrophilic cinnamaldehyde Schiff base compounds and investigate those bioactivity. A total of 24 Schiff base compounds were synthesized using a simple approach with 3 cinnamaldehyde derivates and 8 amino acids as raw materials. The structures of synthesized compounds were confirmed using FTIR, (1)HNMR, HRMS purity and melting point. The antimicrobial activities of new compounds were evaluated with fluconazole and ciprofloxacin as the control against Aspergillus niger, Penicillium citrinum, Escherichia coli and Staphylococcus aureus. Findings show that major compounds exhibited significant bioactivity. Results from the structure-activity relationship suggest that both -p-Cl on benzene ring of cinnamaldehyde and the number of -COOK of amino acid salts significantly contributed to antimicrobial activity. Copyright © 2015 Elsevier Ltd. All rights reserved.
Cook, Jamie E.
Amino acids are among the most heavily studied organic compound class in carbonaceous chondrites. The abundance, distributions, enantiomeric compositions, and stable isotopic ratios of amino acids have been determined in carbonaceous chondrites fi'om a range of classes and petrographic types, with interesting correlations observed between these properties and the class and typc of the chondritcs. In particular, isomeric distributions appear to correlate with parent bodies (chondrite class). In addition, certain chiral amino acids are found in enantiomeric excess in some chondrites. The delivery of these enantiomeric excesses to the early Earth may have contributed to the origin of the homochirality that is central to life on Earth today. This talk will explore the amino acids in carbonaceous chondritcs and their relevance to the origin of life.
Amino acid racemisation dating
International Nuclear Information System (INIS)
Murray-Wallace, C.V.
The potential of the time-dependent amino acid racemisation reaction as a method of age assessment was first reported by Hare and Abelson (1968). They noted that in specimens of the bivalve mollusc Mercenaria sp., greater concentrations of amino acids in the D-configuration with increasing fossil age. Hare and Abelson (1968) also reported negligible racemisation in a modern specimen of Mecanaria sp. On this basis they suggested that the extent of amino acid racemisation (epimerisation in the case of isoleucine) may be used to assess the age of materials within and beyond the range of radiocarbon dating. For the past thirty years amino acid racemisation has been extensively applied in Quaternary research as a method of relative and numeric dating, and a particularly large literature has emerged on the subject
Synthesis of unnatural amino acids via microwave-assisted regio-selective one-pot multi-component reactions of sulfamidates
Synthesis of triazole-based unnatural amino acids, triazole bisaminoacids and β-amino triazole has been described via stereo and regioselective one-pot multi-component reaction of sulfamidates, sodium azide, and alkynes under MW irradiation conditions. The developed method is app...
Amino acid synthesis in photosynthesizing spinach cells: effects of ammonia on pool sizes and rates of labeling from 14CO2
International Nuclear Information System (INIS)
Larsen, P.O.; Cornwell, K.L.; Gee, S.L.; Bassham, J.A.
Isolated cells from leaves of Spinacia oleracea have been maintained in a state capable of high rates of photosynthetic CO 2 fixation for more than 60 hours. The incorporation of 14 CO 2 under saturating CO 2 conditions into carbohydrates, carboxylic acids, and amino acids, and the effect of ammonia on this incorporation have been studied. Total incorporation, specific radioactivity, and pool size have been determined as a function of time for most of the protein amino acids and for γ-aminobutyric acid. The measurements of specific radio-activities and of the approaches to 14 C saturation of some amino acids indicate the presence and relative sizes of metabolically active and passive pools of these amino acids. Added ammonia decreased carbon fixation into carbohydrates and increased fixation into carboxylic acids and amino acids. The results indicate that added ammonia stimulates the reactions mediated by pyruvate kinase and phosphenoenolpyruvate carboxylase, as seen with other plant systems. The data on the effects of added ammonia on total labeling, pool sizes, and specific radioactivities of several amino acids provides a number of indications about the intracellular sites of principal synthesis from carbon skeletons of these amino acids and the selective nature of effects of increased intracellular ammonia concentration on-such synthesis
Synthesis and pH-dependent assembly of isotropic and anisotropic gold nanoparticles functionalized with hydroxyl-bearing amino acids
Swami, Anuradha; Mittal, Sherry; Chopra, Adity; Sharma, Rohit K.; Wangoo, Nishima
In recent years, the synthesis of gold nanostructures of controllable shapes and dimensions has become a subject of intensive and interesting studies. Especially, anisotropic gold nanostructures such as nanoplates, nanoribbons, nanoprisms and nanorods have attracted much attention due to their striking optical properties and promising applications in electronics, photonics, sensing and biomedicine. Keeping this in mind, in the present report, an unprecedented, facile and one pot synthesis of isotropic (spherical) and anisotropic (triangular, pentagonal, hexagonal, rod shaped) gold nanomaterials via pH controlled shape modulation using hydroxyl moeity containing α-amino acids (Serine, Threonine, Tyrosine) as both reducing and capping agents is reported. The synthesized nanostructures have been further characterized by UV-Vis spectroscopy and transmission electron microscopy. It was deduced from these studies that pH played a key role in the anisotropic growth of gold nanostructures. These gold nanoparticles can be further used for applications in biosensing, plasmonics, and electrocatalysis and others involving surface enhanced raman scattering. This study is therefore, important from the point of view of using amino acids for the synthesis of gold nanoparticles of different shapes and sizes leading towards the development of inventive biosensors and biocompatible nanoconstructs.
Asymmetric synthesis of syn-propargylamines and unsaturated β-amino acids under Brønsted base catalysis
Wang, Yingcheng; Mo, Mingjie; Zhu, Kongxi; Zheng, Chao; Zhang, Hongbin; Wang, Wei; Shao, Zhihui
Propargylamines are important intermediates for the synthesis of polyfunctional amino derivatives and natural products and biologically active compounds. The classic method of synthesizing chiral propargylamines involves the asymmetric alkynylation of imines. Here, we report a significant advance in the catalytic asymmetric Mannich-type synthesis of propargylamines through catalytic asymmetric addition of carbon nucleophiles to C-alkynyl imines, culminating in a highly syn-selective catalytic asymmetric Mannich reaction of C-alkynyl imines that provide syn-configured propargylamines with two adjacent stereogenic centres and a transition metal-free organocatalytic asymmetric approach to β-alkynyl-β-amino acids with high efficiency and practicality, via a chiral Brønsted base-catalysed asymmetric Mannich-type reaction of in situ generated challenging N-Boc C-alkynyl imines from previously unreported C-alkynyl N-Boc-N,O-acetals, with α-substituted β-keto esters and less-acidic malonate (thio)esters as nucleophiles, respectively. A catalytic activation strategy is also disclosed, which may have broad implications for use in catalysis and synthesis. PMID:26423837
DEFF Research Database (Denmark)
Bräuner-Osborne, Hans; Bunch, Lennart; Chopin, Nathalie
A set of ten azetidinic amino acids, that can be envisioned as C-4 alkyl substituted analogues of trans-2-carboxyazetidine-3-acetic acid (t-CAA) and/or conformationally constrained analogues of (R)- or (S)-glutamic acid (Glu) have been synthesized in a diastereo- and enantiomerically pure form from...... of two diastereoisomers that were easily separated and converted in two steps into azetidinic amino acids. Azetidines 35-44 were characterized in binding studies on native ionotropic Glu receptors and in functional assays at cloned metabotropic receptors mGluR1, 2 and 4, representing group I, II and III...
Oostatic peptides containing d-amino acids: synthesis, oostatic activity, degradation, accumulation in ovaries and NMR study
Czech Academy of Sciences Publication Activity Database
Hlaváček, Jan; Tykva, Richard; Holík, Josef; Bennettová, Blanka; Buděšínský, Miloš; Vlasáková, Věra; Černý, Bohuslav; Slaninová, Jiřina
Roč. 42, č. 5 (2012), s. 1715-1725 ISSN 0939-4451 R&D Projects: GA ČR GA203/06/1272 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50380511; CEZ:AV0Z50070508 Keywords : D-amino acids * oostatic peptide synthesis * H-3 labeling * oostatic activity in Neobellieria bullata * H-3 incorporation * Peptide degradation * NMR study Subject RIV: CC - Organic Chemistry Impact factor: 3.914, year: 2012
Synthesis of Highly Substituted 3-Pyrrolin-2-ones from N,N-Disubstituted α-Amino Acids.
Samper Barceló, Víctor; Bienz, Stefan
Highly functionalized 5-membered N-heterocyclic compounds, 4-aryl-3-chloro-5-methoxy-1-methyl-3-pyrrolin-2-ones, have been synthesized in moderate to high yields by the reaction of N,N-dimethylated aromatic α-amino acids with oxalyl chloride, followed by solvolysis with MeOH. The products possess a number of functional groups such as an amide, a mixed amido/alkoxy acetal, a vinyl halide, and an alkene and thus are promising candidates to be used as starting materials for the synthesis of diverse five-membered N-heterocyclic compounds.
Synthesis of a Hoechst 32258 analogue amino acid building block for direct incorporation of a fluorescent, high-affinity DNA binding motif into peptides
DEFF Research Database (Denmark)
Behrens, C; Harrit, N; Nielsen, P E
The synthesis of a new versatile "Hoechst 33258-like" Boc-protected amino acid building block for peptide synthesis is described. It is demonstrated that this new ligand is an effective mimic of Hoechst 33258 in terms of DNA affinity and sequence specificity. Furthermore, this minor groove binder...
In situ synthesis carbonated hydroxyapatite layers on enamel slices with acidic amino acids by a novel two-step method.
Wu, Xiaoguang; Zhao, Xu; Li, Yi; Yang, Tao; Yan, Xiujuan; Wang, Ke
In situ fabrication of carbonated hydroxyapatite (CHA) remineralization layer on an enamel slice was completed in a novel, biomimetic two-step method. First, a CaCO3 layer was synthesized on the surface of demineralized enamel using an acidic amino acid (aspartic acid or glutamate acid) as a soft template. Second, at the same concentration of the acidic amino acid, rod-like carbonated hydroxyapatite was produced with the CaCO3 layer as a sacrificial template and a reactant. The morphology, crystallinity and other physicochemical properties of the crystals were characterized using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDAX), respectively. Acidic amino acid could promote the uniform deposition of hydroxyapatite with rod-like crystals via absorption of phosphate and carbonate ions from the reaction solution. Moreover, compared with hydroxyapatite crystals coated on the enamel when synthesized by a one-step method, the CaCO3 coating that was synthesized in the first step acted as an active bridge layer and sacrificial template. It played a vital role in orienting the artificial coating layer through the template effect. The results show that the rod-like carbonated hydroxyapatite crystals grow into bundles, which are similar in size and appearance to prisms in human enamel, when using the two-step method with either aspartic acid or acidic glutamate (20.00 mmol/L). Copyright © 2015 Elsevier B.V. All rights reserved.
Synthesis and properties of amino acid functionalized water-soluble perylene diimides
Energy Technology Data Exchange (ETDEWEB)
Ma, Yongshan; Li, Xuemei; Wei, Xiaofeng; Jiang, Tianyi; Wu, Junsen; Ren, Huixue [Shandong Jianzhu University, Jinan (China)
We prepared amino acid functionalized water-soluble perylene diimides: N,N'-bi(L-glutamic acid)-perylene-3,4;9,10-dicarboxylic diimide (1), N,N'-bi(L-phenylalanine acid)-perylene-3,4;9,10-dicarboxylic diimide (2), N,N'-bi(Lglutamic amine)-perylene-3,4;9,10-dicarboxylic diimide (3) and N,N'-bi(L-phenylalanine amine)-perylene-3,4;9,10-dicarboxylic diimide (4). The structures of 3 and 4 were confirmed by {sup 1}H NMR, FT-IR and MS. The maximal absorption bands of compound 1 and 2 in concentrated sulfuric acid were red-shifted for about 48 and 74 nm, respectively, compared with that of Perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA). Nearly no fluorescence was observed for compounds 1 and 2 in water, while compounds 3 and 4 were significantly water-soluble and had very high fluorescent quantum. The mechanism of the optical properties change was discussed, and the π-π stacking caused by H{sup +} led to the changes of fluorescence spectrum and absorption spectrum. The calculated molecular orbital energies and the frontier molecular orbital maps of compounds 1-2 based on density function theory (DFT) calculations were reported. Owing to the high water-soluble, the perylene derivatives 3 and 4 were successfully applied as high-performance fluorochromes for living hela cells imaging.
Synthesis of the C8'-epimeric thymine pyranosyl amino acid core of amipurimycin
Directory of Open Access Journals (Sweden)
Pramod R. Markad
Full Text Available The C8'-epimeric pyranosyl amino acid core 2 of amipurimycin was synthesized from D-glucose derived alcohol 3 in 13 steps and 14% overall yield. Thus, the Sharpless asymmetric epoxidation of allyl alcohol 7 followed by trimethyl borate mediated regio-selective oxirane ring opening with azide, afforded azido diol 10. The acid-catalyzed 1,2-acetonide ring opening in 10 concomitantly led to the formation of the pyranose ring skeleton to give 2,7-dioxabicyclo[3.2.1]octane 12. Functional group manipulation in 12 gave 21 that on stereoselective β-glycosylation afforded the pyranosyl thymine nucleoside 2 – a core of amipurimycin.
Upregulation of capacity for glutathione synthesis in response to amino acid deprivation: regulation of glutamate-cysteine ligase subunits
Sikalidis, Angelos K.; Mazor, Kevin M.; Lee, Jeong-In; Roman, Heather B.; Hirschberger, Lawrence L.; Stipanuk, Martha H.
Using HepG2/C3A cells and MEFs, we investigated whether induction of GSH synthesis in response to sulfur amino acid deficiency is mediated by the decrease in cysteine levels or whether it requires a decrease in GSH levels per se. Both the glutamate-cysteine ligase catalytic (GCLC) and modifier (GCLM) subunit mRNA levels were upregulated in response to a lack of cysteine or other essential amino acids, independent of GSH levels. This upregulation did not occur in MEFs lacking GCN2 (general control non-derepressible 2, also known as eIF2α kinase 4) or in cells expressing mutant eIF2α lacking the eIF2α kinase Ser51 phosphorylation site, indicating that expression of both GCLC and GCLM was mediated by the GCN2/ATF4 stress response pathway. Only the increase in GCLM mRNA level, however, was accompanied by a parallel increase in protein expression, suggesting that the enhanced capacity for GSH synthesis depended largely on increased association of GCLC with its regulatory subunit. Upregulation of both GCLC and GLCM mRNA levels in response to cysteine deprivation was dependent on new protein synthesis, which is consistent with expression of GCLC and GCLM being mediated by proteins whose synthesis depends on activation of the GCN2/ATF4 pathway. Our data suggest that the regulation of GCLC expression may be mediated by changes in the abundance of transcriptional regulators, whereas the regulation of GCLM expression may be mediated by changes in the abundance of mRNA stabilizing or destabilizing proteins. Upregulation of GCLM levels in response to low cysteine levels may serve to protect the cell in the face of a future stress requiring GSH as an antioxidant or conjugating/detoxifying agent. PMID:24557597
Syn-Selective Synthesis of β-Branched α-Amino Acids by Alkylation of Glycine-Derived Imines with Secondary Sulfonates.
Lou, Sha; McKenna, Grace M; Tymonko, Steven A; Ramirez, Antonio; Benkovics, Tamas; Conlon, David A; González-Bobes, Francisco
A syn-selective synthesis of β-branched α-amino acids has been developed based on the alkylation of glycine imine esters with secondary sulfonates. The potassium counterion for the enolate, the solvent, and the leaving group on the electrophile were key levers to maximize the diasteroselectivity of the alkylation. The optimized conditions enabled a straightforward preparation of a number of β-branched α-amino acids that can be challenging to obtain.
Diastereoselective Three-Component Reactions of Chiral Nickel(II Glycinate for Convenient Synthesis of Novel α-Amino-β-Substituted-γ,γ-Disubstituted Butyric Acids
Directory of Open Access Journals (Sweden)
Rui Zhou
Full Text Available The convenient, high yielding and diastereoselective synthesis of α-amino-β-substituted-γ,γ-disubstituted butyric acid derivatives was carried out by a three-component tandem reaction of a chiral equivalent of nucleophilic glycine. The reaction was performed smoothly under mild conditions and enabled the construction of two or three adjacent chiral centers in one step, thus affording a novel and convenient route to α-amino-β-substituted-γ,γ-disubstituted butyric acid derivatives.
Shock wave synthesis of amino acids from solutions of ammonium formate and ammonium bicarbonate
Suzuki, Chizuka; Furukawa, Yoshihiro; Kobayashi, Takamichi; Sekine, Toshimori; Nakazawa, Hiromoto; Kakegawa, Takeshi
The emergence of life's building blocks, such as amino acids and nucleobases, on the prebiotic Earth was a critical step for the beginning of life. Reduced species with low mass, such as ammonia, amines, or carboxylic acids, are potential precursors for these building blocks of life. These precursors may have been provided to the prebiotic ocean by carbonaceous chondrites and chemical reactions related to meteorite impacts on the early Earth. The impact of extraterrestrial objects on Earth occurred more frequently during this period than at present. Such impacts generated shock waves in the ocean, which have the potential to progress chemical reactions to form the building blocks of life from reduced species. To simulate shock-induced reactions in the prebiotic ocean, we conducted shock-recovery experiments on ammonium bicarbonate solution and ammonium formate solution at impact velocities ranging from 0.51 to 0.92 km/s. In the products from the ammonium formate solution, several amino acids (glycine, alanine, ß-alanine, and sarcosine) and aliphatic amines (methylamine, ethylamine, propylamine, and butylamine) were detected, although yields were less than 0.1 mol % of the formic acid reactant. From the ammonium bicarbonate solution, smaller amounts of glycine, methylamine, ethylamine, and propylamine were formed. The impact velocities used in this study represent minimum cases because natural meteorite impacts typically have higher velocities and longer durations. Our results therefore suggest that shock waves could have been involved in forming life's building blocks in the ocean of prebiotic Earth, and potentially in aquifers of other planets, satellites, and asteroids.
Graphene quantum dots decorated with magnetic nanoparticles: Synthesis, electrodeposition, characterization and application as an electrochemical sensor towards determination of some amino acids at physiological pH
International Nuclear Information System (INIS)
Hasanzadeh, Mohammad; Karimzadeh, Ayub; Shadjou, Nasrin; Mokhtarzadeh, Ahad; Bageri, Leyla; Sadeghi, Sattar; Mahboob, Soltanali
This study reports on the synthesis and characterization of a novel nano-composite, Fe 3 O 4 magnetic nanoparticles/graphene quantum dots (Fe 3 O 4 MNP-GQDs), for sensing of some amino acids. For the first time, as-synthesized GQDs and Fe 3 O 4 MNPs-GQDs was electrodeposited on the glassy carbon electrode (GCE) by cyclic voltammetry (CV) regime in the potential range from − 1.0 to 1.0 V. Fe 3 O 4 MNP-GQDs is engineered to specifically and effectively capture and enhancement the electrochemical signals of some amino acids at physiological pH due to the synergy among GQDs and magnetic nanoparticles. We have illustrated that the obtained Fe 3 O 4 MNPs-GQDs exhibited a much higher electroactivity individual GQDs and Fe 3 O 4 MNPs for the electrooxidation and detection of amino acid which was about 10 fold higher than for GQDs. Magnetic and specific properties of the Fe 3 O 4 MNP-GQDs can be exploited to capture and pre-concentration the amino acids onto its surface, which are important for detection of multi-amino acids. - Highlights: • Electrooxidation of amino acids was performed using Fe 3 O 4 MNP-GQDs. • Modified electrode shows new advantages as an amino acids sensor. • Excellent electrocatalytic activity was obtained for amino acids oxidation.
Synthesis of orthogonally protected (2S)-2-amino-adipic acid (α-AAA) and (2S,4R)-2-amino-4-hydroxyadipic acid (Ahad).
Yadav, Saroj; Taylor, Carol M
(2S,4R)-2-amino-4-hydroxyadipic acid (Ahad) building block 45 was synthesized in 11 steps and 6.5% overall yield from commercially available materials. Key steps in stereocontrol were an asymmetric conjugate addition employing a proline-based catalyst and a syn-selective intramolecular-conjugate addition of an oxygen nucleophile to an α,β-unsaturated ester. To enable incorporation of α-amino-adipic acid (α-AAA) and Ahad into peptides, a truly orthogonal protecting group scheme was developed, encompassing an allyloxycarbonyl (Alloc) carbamate for Nα, a tert-butyl ester for the δ-COOH, an acetol ester for the α-COOH, and a tert-butyldimethylsilyl ether for the γ-hydroxy group of Ahad.
Effect of vertical mixing on short-term mycosporine-like amino acid synthesis in the Antarctic diatom, Thalasiossira sp.
Directory of Open Access Journals (Sweden)
Marcelo Pablo Hernando
Full Text Available One of the adaptations whereby phytoplankton can alleviate damage induced by ultraviolet radiation (280-400 nm is the synthesis of mycosporine-like amino acids (MAAs. The synthesis of MAAs was studied after exposure of the Antarctic diatom Thalassiosira sp. isolated from Potter Cove (South Shetland Is., Antarctica to 2 treatments with a solar simulator: surface (Sfix and vertical mixing (Mix irradiance conditions. Light exposure was simulated in daily cycles with maximum irradiance at noon. Only 2 MAAs, Porphyra-334 (82-85% and Shinorine (15-18%, were identified. The concentration of the two compounds increased during experimental light exposure (50-55% and declined in the dark (10-15%. During the light period the synthesis rate of MAAs per unit of chlorophyll a was higher in the Sfix treatment (µ=0.17 h-1 than in the Mix treatment (µ=0.05 h-1. In spite of the higher MAA levels, low cell numbers were observed in the Sfix treatment, suggesting that the algae synthesized photoprotective compounds at the expense of growth. Our results document overlapping effects of both daily light cycles and vertical mixing affecting the synthesis of MAAs. This, and the high thermal dissipation of the ultraviolet B radiation energy (280-320 nm absorbed by these substances, suggest a rapid photoadaptive response of Thalasiossira sp. upon exposure to elevated irradiance in a stratified water column, as well as the complementary role of vertical mixing in photo-protection.
Indian Academy of Sciences (India)
(L-Trp), were obtained from Sigma Chemical Company (USA). All the metal ions Cu(II),. Ni(II) and .... respective free amino acids show characteristic band positions, shifts and intensities, which can be correlated to ..... Financial support from the University Grants Commission, New Delhi to Prof P Rabindra. Reddy is gratefully ...
Isocyanides Derived from α,α-Disubstituted Amino Acids: Synthesis and Antifouling Activity Assessment.
Inoue, Yuki; Takashima, Shuhei; Nogata, Yasuyuki; Yoshimura, Erina; Chiba, Kazuhiro; Kitano, Yoshikazu
Herein, we contribute to the development of environmentally friendly antifoulants by synthesizing eighteen isocyanides derived from α,α-disubstituted amino acids and evaluating their antifouling activity/toxicity against the cypris larvae of the Balanus amphitrite barnacle. Almost all isocyanides showed good antifouling activity without significant toxicity and exhibited EC 50 values of 0.07 - 7.30 μg/mL after 120-h exposure. The lowest EC 50 values were observed for valine-, methionine-, and phenylalanine-derived isocyanides, which achieved > 95% cypris larvae settlement inhibition at concentrations of less than 30 μg/mL without exhibiting significant toxicity. Thus, the prepared isocyanides should be useful for further research focused on the development of environmentally friendly antifouling agents. © 2018 Wiley-VHCA AG, Zurich, Switzerland.
Synthesis and Site-Specific Incorporation of Red-Shifted Azobenzene Amino Acids into Proteins.
John, Alford A; Ramil, Carlo P; Tian, Yulin; Cheng, Gang; Lin, Qing
A series of red-shifted azobenzene amino acids were synthesized in moderate-to-excellent yields via a two-step procedure in which tyrosine derivatives were first oxidized to the corresponding quinonoidal spirolactones followed by ceric ammonium nitrate-catalyzed azo formation with the substituted phenylhydrazines. The resulting azobenzene-alanine derivatives exhibited efficient trans/cis photoswitching upon irradiation with a blue (448 nm) or green (530 nm) LED light. Moreover, nine superfolder green fluorescent protein (sfGFP) mutants carrying the azobenzene-alanine analogues were expressed in E. coli in good yields via amber codon suppression with an orthogonal tRNA/PylRS pair, and one of the mutants showed durable photoswitching with the LED light.
Synthesis of homochiral acyclic mono- and bis(ŕ-amino acid)s with oligo(oxyethylene) chains
Czech Academy of Sciences Publication Activity Database
Bělohradský, Martin; Ridvan, Luděk; Závada, Jiří
Roč. 68, č. 7 (2003), s. 1319-1325 ISSN 0010-0765 R&D Projects: GA AV ČR KSK4050111; GA ČR GA203/03/0087; GA ČR GA203/00/0137 Institutional research plan: CEZ:AV0Z4055905 Keywords : amino-acids * crown ethers Subject RIV: CC - Organic Chemistry Impact factor: 1.041, year: 2003
Group 11 complexes with amino acid derivatives: Synthesis and antitumoral studies.
Ortego, Lourdes; Meireles, Margarida; Kasper, Cornelia; Laguna, Antonio; Villacampa, M Dolores; Gimeno, M Concepción
Gold(I), gold(III), silver(I) and copper(I) complexes with modified amino acid esters and phosphine ligands have been prepared in order to test their cytotoxic activity. Two different phosphine fragments, PPh3 and PPh2py (py=pyridine), have been used. The amino acid esters have been modified by introducing an aromatic amine as pyridine that coordinates metal fragments through the nitrogen atom, giving complexes of the type [M(L)(PR3)](+) or [AuCl3(L)] (L=l-valine-N-(4-pyridylcarbonyl) methyl ester (L1), l-alanine-N-(4-pyridylcarbonyl) methyl ester (L2), l-phenylalanine-N-(4-pyridylcarbonyl) methyl-ester) (L3); M=Au(I), Ag(I), Cu(I), PR3=PPh3, PPh2py). The in vitro cytotoxic activity of metal complexes was tested against four tumor human cell lines and one tumor mouse cell line. A metabolic activity test (3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide, MTT) was used and IC50 values were compared with those obtained for cisplatin. Several complexes displayed significant cytotoxic activities. In order to determine whether antiproliferation and cell death are associated with apoptosis, NIH-3T3 cells were exposed to five selected complexes (Annexin V+ FITC, PI) and analyzed by flow cytometry. These experiments showed that the mechanism by which the complexes inhibit cell proliferation inducing cell death in NIH-3T3 cells is mainly apoptotic. Copyright © 2015 Elsevier Inc. All rights reserved.
Synthesis of novel N1-substituted bicyclic pyrazole amino acids and evaluation of their interaction with glutamate receptors
DEFF Research Database (Denmark)
Conti, Paola; Grazioso, Giovanni; di Ventimiglia, Samuele Joppolo
N1-substituted bicyclic pyrazole amino acids (S)-9a-9c and (R)-9a-9c, which are conformationally constrained analogues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested for activity at ionotropic and metabotropic glutamate recepto...
Amino acids supply in culture media is not a limiting factor in the matrix synthesis of engineered cartilage tissue
Ng, K. W.; DeFrancis, J. G.; Kugler, L. E.; Kelly, T.-A. N.; Ho, M. M.; O'Conor, C. J.; Ateshian, G. A.; Hung, C. T.
Summary Increased amino acid supplementation (0.5×, 1.0×, and 5.0× recommended concentrations or additional proline) was hypothesized to increase the collagen content in engineered cartilage. No significant differences were found between groups in matrix content or dynamic modulus. Control constructs possessed the highest compressive Young's modulus on day 42. On day 42, compared to controls, decreased type II collagen was found with 0.5×, 1.0×, and 5.0× supplementation and significantly increased DNA content found in 1.0× and 5.0×. No effects were observed on these measures with added proline. These results lead us to reject our hypothesis and indicate that the low collagen synthesis in engineered cartilage is not due to a limited supply of amino acids in media but may require a further stimulatory signal. The results of this study also highlight the impact that culture environment can play on the development of engineered cartilage. PMID:17713744
Inhibition of radical reactions for an improved potassium tert-butoxide-promoted (11) C-methylation strategy for the synthesis of α-(11) C-methyl amino acids.
Suzuki, Chie; Kato, Koichi; Tsuji, Atsushi B; Zhang, Ming-Rong; Arano, Yasushi; Saga, Tsuneo
α-(11) C-Methyl amino acids are useful tools for biological imaging studies. However, a robust procedure for the labeling of amino acids has not yet been established. In this study, the (11) C-methylation of Schiff-base-activated α-amino acid derivatives has been optimized for the radiosynthesis of various α-(11) C-methyl amino acids. The benzophenone imine analog of methyl 2-amino butyrate was (11) C-methylated with [(11) C]methyl iodide following its initial deprotonation with potassium tert-butoxide (KOtBu). The use of an alternative base such as tetrabutylammonium fluoride, triethylamine, and 1,8-diazabicyclo[5.4.0]undec-7-ene did not result in the (11) C-methylated product. Furthermore, the KOtBu-promoted (11) C-methylation of the Schiff-base-activated amino acid analog was enhanced by the addition of 1,2,4,5-tetramethoxybenzene or 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and inhibited by the addition of 1,10-phenanthroline. These results suggest that inhibition of radical generation induced by KOtBu improves the α-(11) C-methylation of the Schiff-base-activated amino acids. The addition of a mixture of KOtBu and TEMPO to a solution of Schiff-base-activated amino acid ester and [(11) C]methyl iodide provided optimal results, and the tert-butyl ester and benzophenone imine groups could be readily hydrolyzed to give the desired α-(11) C-methyl amino acids with a high radiochemical conversion. This strategy could be readily applied to the synthesis of other α-(11) C-methyl amino acids. Copyright © 2015 John Wiley & Sons, Ltd.
Amino-acid- and peptide-directed synthesis of chiral plasmonic gold nanoparticles.
Lee, Hye-Eun; Ahn, Hyo-Yong; Mun, Jungho; Lee, Yoon Young; Kim, Minkyung; Cho, Nam Heon; Chang, Kiseok; Kim, Wook Sung; Rho, Junsuk; Nam, Ki Tae
Understanding chirality, or handedness, in molecules is important because of the enantioselectivity that is observed in many biochemical reactions 1 , and because of the recent development of chiral metamaterials with exceptional light-manipulating capabilities, such as polarization control 2-4 , a negative refractive index 5 and chiral sensing 6 . Chiral nanostructures have been produced using nanofabrication techniques such as lithography 7 and molecular self-assembly 8-11 , but large-scale and simple fabrication methods for three-dimensional chiral structures remain a challenge. In this regard, chirality transfer represents a simpler and more efficient method for controlling chiral morphology 12-18 . Although a few studies 18,19 have described the transfer of molecular chirality into micrometre-sized helical ceramic crystals, this technique has yet to be implemented for metal nanoparticles with sizes of hundreds of nanometres. Here we develop a strategy for synthesizing chiral gold nanoparticles that involves using amino acids and peptides to control the optical activity, handedness and chiral plasmonic resonance of the nanoparticles. The key requirement for achieving such chiral structures is the formation of high-Miller-index surfaces ({hkl}, h ≠ k ≠ l ≠ 0) that are intrinsically chiral, owing to the presence of 'kink' sites 20-22 in the nanoparticles during growth. The presence of chiral components at the inorganic surface of the nanoparticles and in the amino acids and peptides results in enantioselective interactions at the interface between these elements; these interactions lead to asymmetric evolution of the nanoparticles and the formation of helicoid morphologies that consist of highly twisted chiral elements. The gold nanoparticles that we grow display strong chiral plasmonic optical activity (a dis-symmetry factor of 0.2), even when dispersed randomly in solution; this observation is supported by theoretical calculations and direct
Gemini surfactants from natural amino acids.
Pérez, Lourdes; Pinazo, Aurora; Pons, Ramon; Infante, Mrosa
In this review, we report the most important contributions in the structure, synthesis, physicochemical (surface adsorption, aggregation and phase behaviour) and biological properties (toxicity, antimicrobial activity and biodegradation) of Gemini natural amino acid-based surfactants, and some potential applications, with an emphasis on the use of these surfactants as non-viral delivery system agents. Gemini surfactants derived from basic (Arg, Lys), neutral (Ser, Ala, Sar), acid (Asp) and sulphur containing amino acids (Cys) as polar head groups, and Geminis with amino acids/peptides in the spacer chain are reviewed. © 2013.
Synthesis, Spectral, and In Vitro Antibacterial Studies of Organosilicon(IV) Complexes with Schiff Bases Derived from Amino Acids.
Singh, Har Lal; Singh, Jangbhadur; Mukherjee, A
The present work stems from our interest in the synthesis, characterization, and antibacterial evaluation of organosilicon(IV) complexes of a class of amino-acid-based Schiff base which have been prepared by the interaction of ethoxytrimethylsilane with the Schiff bases (N OH) in 1 : 1 molar ratio. These complexes have been characterized by elemental analysis, molar conductance, and spectroscopic studies including electronic IR and NMR ((1)H, (13)C, and (29)Si) spectroscopy. The analytical and spectral data suggest trigonal bipyramidal geometry around the silicon atom in the resulting complexes. The ligands and their organosilicon complexes have also been evaluated for in vitro antimicrobial activity against bacteria (Bacillus cereus, Nocardia spp., E. aerogenes, Escherichia coli, Klebsiella spp., and Staphylococcus spp.). The complexes were found to be more potent as compared to the ligands.
Synthesis and characterization of tin(II) complexes of fluorinated Schiff bases derived from amino acids.
Singh, Har Lal
New tin(II) complexes of general formula Sn(L)(2) (L=monoanion of 3-methyl-4-fluoro-acetophenone phenylalanine L(1)H, 3-methyl-4-fluoro-acetophenone alanine L(2)H, 3-methyl-4-fluoro acetophenone tryptophan L(3)H, 3-methyl-4-fluoro-acetophenone valine L(4)H, 3-methyl-4-fluoro-acetophenone isoleucine L(5)H and 3-methyl-4-fluoro-acetophenone glycine L(6)H) have been prepared. It is characterized by elemental analyses, molar conductance measurements and molecular weight determinations. Bonding of these complexes is discussed in terms of their UV-visible, infrared, and nuclear magnetic resonance ((1)H, (13)C, (19)F and (119)Sn NMR) spectral studies. The ligands act as bidentate towards metal ions, via the azomethine nitrogen and deprotonated oxygen of the respective amino acid. Elemental analyses and NMR spectral data of the ligands with their tin(II) complexes agree with their proposed square pyramidal structures. A few representative ligands and their tin complexes have been screened for their antibacterial activities and found to be quite active in this respect. Copyright 2010 Elsevier B.V. All rights reserved.
Macrocyclic polyether complexes of amino acids and amino acid salts
International Nuclear Information System (INIS)
Bidzilya, V.A.; Oleksenko, LP.
This paper deals with the isolation of the complexes formed between various types of amino acid derivatives and macrocyclic polyethers, and the characterisation of their physical and chemical properties. The study shows that macrocyclic polyethers form 1:1 complexes with amino acids and amino acid derivatives, and that these complexes can be isolated in pure form. Amino acids can be bound to these complexes in their anionic forms, in switterionic forms, as well as in their protonated forms. These types of complexes may be useful for the transport of amino acids or their derivatives across both synthetic and natural membranes
In situ synthesis carbonated hydroxyapatite layers on enamel slices with acidic amino acids by a novel two-step method
International Nuclear Information System (INIS)
Wu, Xiaoguang; Zhao, Xu; Li, Yi; Yang, Tao; Yan, Xiujuan; Wang, Ke
In situ fabrication of carbonated hydroxyapatite (CHA) remineralization layer on an enamel slice was completed in a novel, biomimetic two-step method. First, a CaCO 3 layer was synthesized on the surface of demineralized enamel using an acidic amino acid (aspartic acid or glutamate acid) as a soft template. Second, at the same concentration of the acidic amino acid, rod-like carbonated hydroxyapatite was produced with the CaCO 3 layer as a sacrificial template and a reactant. The morphology, crystallinity and other physicochemical properties of the crystals were characterized using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDAX), respectively. Acidic amino acid could promote the uniform deposition of hydroxyapatite with rod-like crystals via absorption of phosphate and carbonate ions from the reaction solution. Moreover, compared with hydroxyapatite crystals coated on the enamel when synthesized by a one-step method, the CaCO 3 coating that was synthesized in the first step acted as an active bridge layer and sacrificial template. It played a vital role in orienting the artificial coating layer through the template effect. The results show that the rod-like carbonated hydroxyapatite crystals grow into bundles, which are similar in size and appearance to prisms in human enamel, when using the two-step method with either aspartic acid or acidic glutamate (20.00 mmol/L). - Graphical abstract: FESEM images of enamel slices etched for 60 s and repaired by the two-step method with Glu concentration of 20.00 mmol/L. (A) The boundary (dotted line) of the repaired areas (b) and unrepaired areas (a). (Some selected areas of etched enamel slices were coated with a nail polish before the reaction, which was removed by acetone after the reaction); (B) high magnification image of Ga, (C) high magnification image of Gb. In situ fabrication of carbonated
In situ synthesis carbonated hydroxyapatite layers on enamel slices with acidic amino acids by a novel two-step method
Energy Technology Data Exchange (ETDEWEB)
Wu, Xiaoguang [Department of Pediatric Dentistry, The Hospital of Stomatology, Jilin University, Changchun 130021 (China); Zhao, Xu [College of Chemistry, Jilin University, Changchun 130021 (China); Li, Yi, E-mail: firstname.lastname@example.com [Department of Pediatric Dentistry, The Hospital of Stomatology, Jilin University, Changchun 130021 (China); Yang, Tao [Department of Stomatology, Children' s Hospital of Changchun, 130051 (China); Yan, Xiujuan; Wang, Ke [Department of Pediatric Dentistry, The Hospital of Stomatology, Jilin University, Changchun 130021 (China)
In situ fabrication of carbonated hydroxyapatite (CHA) remineralization layer on an enamel slice was completed in a novel, biomimetic two-step method. First, a CaCO{sub 3} layer was synthesized on the surface of demineralized enamel using an acidic amino acid (aspartic acid or glutamate acid) as a soft template. Second, at the same concentration of the acidic amino acid, rod-like carbonated hydroxyapatite was produced with the CaCO{sub 3} layer as a sacrificial template and a reactant. The morphology, crystallinity and other physicochemical properties of the crystals were characterized using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDAX), respectively. Acidic amino acid could promote the uniform deposition of hydroxyapatite with rod-like crystals via absorption of phosphate and carbonate ions from the reaction solution. Moreover, compared with hydroxyapatite crystals coated on the enamel when synthesized by a one-step method, the CaCO{sub 3} coating that was synthesized in the first step acted as an active bridge layer and sacrificial template. It played a vital role in orienting the artificial coating layer through the template effect. The results show that the rod-like carbonated hydroxyapatite crystals grow into bundles, which are similar in size and appearance to prisms in human enamel, when using the two-step method with either aspartic acid or acidic glutamate (20.00 mmol/L). - Graphical abstract: FESEM images of enamel slices etched for 60 s and repaired by the two-step method with Glu concentration of 20.00 mmol/L. (A) The boundary (dotted line) of the repaired areas (b) and unrepaired areas (a). (Some selected areas of etched enamel slices were coated with a nail polish before the reaction, which was removed by acetone after the reaction); (B) high magnification image of Ga, (C) high magnification image of Gb. In situ fabrication of
The single-biopsy approach in determining protein synthesis in human slow-turning-over tissue: use of flood-primed, continuous infusion of amino acid tracer
DEFF Research Database (Denmark)
Holm, Lars; Reitelseder, Søren; Dideriksen, Kasper
Muscle protein synthesis (MPS) rate is determined conventionally by obtaining two or more tissue biopsies during a primed, continuous infusion of a stable isotopically labeled amino acid. The purpose of the present study was to test whether tracer priming given as a flooding dose, thereby securin...
Silica sulfuric acid and as an efficient catalyst for the Friedlander quinoline synthesis from simple ketones and ortho - amino aryl ketones under microwave irradiation
International Nuclear Information System (INIS)
Zolfigol, M. A.; Salehi, P.; Shiri, M.; Faal Rastegar, T.; Ghaderi, A.
The synthesis of quinoline derivatives via Friedlander method from ortho-amino aryl ketones in the presence of a catalytic amount of silica sulfuric acid under solvent-free condition and microwave irradiation was described. A good range of simple ketones such as cyclohexanone and deoxybenzoin were used
Enterobacter sp. I-3, a bio-herbicide inhibits gibberellins biosynthetic pathway and regulates abscisic acid and amino acids synthesis to control plant growth.
Radhakrishnan, Ramalingam; Park, Jae-Man; Lee, In-Jung
Very few bacterial species were identified as bio-herbicides for weed control. The present research was focused to elucidate the plant growth retardant properties of Enterobacter sp. I-3 during their interaction by determining the changes in endogenous photosynthetic pigments, plant hormones and amino acids. The two bacterial isolates I-4-5 and I-3 were used to select the superior bacterium for controlling weed seeds (Echinochloa crus-galli L. and Portulaca oleracea L.) germination. The post-inoculation of I-3 (Enterobacter sp. I-3) significantly inhibited the weeds seed germination than their controls. The mechanism of bacterium induced plant growth reduction was identified in lettuce treated with I-3 bacterium and compared their effects with known chemical herbicide, trinexapac-ethyl (TE). The treatment of I-3 and TE showed a significant inhibitory effect on shoot length, leaf number, leaf length, leaf width, shoot weight, root weight and chlorophyll content in lettuce seedlings. The endogenous gibberellins (GAs) and abscisic acid (ABA) analysis showed that Enterobacter sp. I-3 treated plants had lower levels of GAs (GA 12 , GA 19 , GA 20 and GA 8 ) and GAs/ABA ratio and then, the higher level of ABA when compared to their controls. Indeed, the individual amino acids ie., aspartic acid, glutamic acid, glycine, threonine, alanine, serine, leucine, isoleucine and tyrosine were declined in TE and I-3 exposed plants. Our results suggest that the utilization of Enterobacter sp. I-3 inhibits the GAs pathway and amino acids synthesis in weeds to control their growth can be an alternative to chemical herbicides. Copyright © 2016 Elsevier GmbH. All rights reserved.
Synthesis and characterization of a lipidic alpha amino acid: solubility and interaction with serum albumin and lipid bilayers.
Filipe, Hugo A L; Coreta-Gomes, Filipe M; Velazquez-Campoy, Adrian; Almeida, Ana R; Peixoto, Andreia F; Pereira, Mariette M; Vaz, Winchil L C; Moreno, Maria J
The lipidic α-amino acid with 11 carbons in the alkyl lateral chain (α-aminotridecanoic acid) was synthesized via multicomponent hydroformylation/Strecker reaction, which is a greener synthetic approach to promote this transformation relative to previously described methods. Its solubility and aggregation behavior in aqueous solutions was characterized, as well as the interaction with lipid bilayers. Lipidic amino acids are very promising molecules in the development of prodrugs with increased bioavailability due to the presence of the two polar functional groups and nonpolar alkyl chain. They are also biocompatible surfactants that may be used in the food and pharmaceutical industry. In this work we have conjugated the lipidic amino acid with a fluorescent polar group (7-nitrobenz-2-oxa-1,3-diazol-4-yl), to mimic drug conjugates, and its association with serum proteins and lipid bilayers was characterized. The results obtained indicate that conjugates of polar molecules with lipidic α-amino acid, via covalent attachment to the amine group, have a relatively high solubility in aqueous solutions due to their negative global charge. They bind to serum albumin with intermediate affinity and show a very high partition coefficient into lipid bilayers in the liquid-disordered state. The attachment of the polar group to the lipidic amino acid increased strongly the aqueous solubility of the amphiphile, although the partition coefficient into lipid membranes was not significantly reduced. Conjugation of polar drugs with lipidic amino acids is therefore an efficient approach to increase their affinity for biomembranes.
Selective antagonists at group I metabotropic glutamate receptors: synthesis and molecular pharmacology of 4-aryl-3-isoxazolol amino acids
DEFF Research Database (Denmark)
Kromann, Hasse; Sløk, Frank A; Stensbøl, Tine B
Homologation of (S)-glutamic acid (Glu, 1) and Glu analogues has previously provided ligands with activity at metabotropic Glu receptors (mGluRs). The homologue of ibotenic acid (7), 2-amino-3-(3-hydroxy-5-isoxazolyl)propionic acid (HIBO, 8), and the 4-phenyl derivative of 8, compound 9a, are bot...
24-Epibrassinolide Restores the Synthesis of Proteins and Amino Acids in Brassica juncea L. Leaves Under Imidacloprid Stress
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Sharma Anket
Full Text Available Pesticides are applied to protect crops from a variety of insect pests but their application cause toxicity to plants that results, among others, in reduction of protein as well as amino acid contents. The present study is aimed at observing the effect of seed pre-soaking with 24-epibrassinolide (EBL on the protein and amino acid content in the leaves of Brassica juncea L. grown in soil that is amended with pesticide im-idacloprid (IMI. Soil amendment with IMI resulted in a decrease in the contents in leaves of total proteins and 21 amino acids studied. Seed soaking with 100 nM of EBL resulted in the recovery of total protein as well as amino acid contents in leaves, when compared with plants grown in only IMI amended soils.
Synthesis of C3-symmetric and C4-symmetric amino acid derivatives via Suzuki-Miyaura cross-coupling reaction.
Kotha, S; Shah, V R
Various non-natural C(3)- and C(4)-symmetric alpha-amino acid derivatives have been synthesized via Suzuki-Miyaura cross-coupling reaction between aromatic iodides or bromide and a suitably protected DL-4-boronophenylalanine derivative.
Effects of dietary amino acids, carbohydrates, and choline on neurotransmitter synthesis
Wurtman, Richard J.
The ability of a meal to increase or decrease brain neurotransmitter synthesis has been studied. It is concluded that brain serotonin synthesis is directly controlled by the proportions of carbohydrate to protein in meals and snacks that increase or decrease brain tryptophan levels, thereby changing the substrate saturation of tryptophan hydroxylase and the rate of serotonin synthesis. The ability of serotoninergic neurons to have their output coupled to dietary macronutrients enables them to function as sensors of peripheral metabolism, and to subserve an important role in the control of appetite. The robust and selective responses of catecholaminergic and cholinergic neurons to supplemental tyrosine and choline suggest that these compounds may become useful as a new type of drug for treating deseases or conditions in which adequate quantities of the transmitter would otherwise be unavailable.
Synthesis and NMR characterization of dendrimers based on 2, 2-bis-(hydroxymethyl-propanoic acid (bis-HMPA containing peripheral amino acid residues for gene transfection
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Silvana Alfei
Full Text Available Dendrimers, the emerging man made, highly branched, star-shaped macromolecules with nanometer-scale dimensions are well known for their well defined and high controlled architecture, their versatility and high functionality and are of eminent interest in nanomedical applications such as drug delivery, gene transfection, and imaging. In this paper, versatile protocols for the synthesis of polyester-based, hydrolysable, polycationic dendrimers have been setup. A fourth generation dendrimer equipped with 48 peripheral hydroxyl groups was prepared from 2,2-bis(hydroxymethylpropanoic acid and was used for grafting BOC-amino acids or as "hypercores" on which dendrons functionalized with BOC-amino acids were attached. A library of 15 polycationic homo- and hetero-dendrimers in the form of hydrochloride was obtained. Their structures and composition were confirmed by NMR analysis and by experimental molecular weight computed by volumetric titration. Their buffer capacity and results obtained from cytotoxicity assays and tests of binding with both pDNA and siRNA were very satisfactory.
Excitatory amino acid receptor antagonists
DEFF Research Database (Denmark)
Johansen, T N; Frydenvang, Karla Andrea; Ebert, B
We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation...
Molecular cloning and expression of Corynebacterium glutamicum genes for amino acid synthesis in Escherichia coli cells
International Nuclear Information System (INIS)
Beskrovnaya, O.Yu.; Fonshtein, M.Yu.; Kolibaba, L.G.; Yankovskii, N.K.; Debabov, V.G.
Molecular cloning of Corynebacterium glutamicum genes for threonine and lysine synthesis has been done in Escherichia coli cells. The clonal library of EcoRI fragments of chromosomal DNA of C. glutamicum was constructed on the plasmid vector λpSL5. The genes for threonine and lysine synthesis were identified by complementation of E. coli mutations in thrB and lysA genes, respectively. Recombinant plasmids, isolated from independent ThrB + clone have a common 4.1-kb long EcoRI DNA fragment. Hybrid plasmids isolated from LysA + transductants of E. coli have common 2.2 and 3.3 kb long EcoRI fragments of C. glutamicum DNA. The hybrid plasmids consistently transduced the markers thrB + and lysA + . The Southern hybridization analysis showed that the cloned DNA fragments hybridized with the fragments of identical length in C. glutamicum chromosomes
Catabolism of Branched Chain Amino Acids Contributes Significantly to Synthesis of Odd-Chain and Even-Chain Fatty Acids in 3T3-L1 Adipocytes.
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Scott B Crown
Full Text Available The branched chain amino acids (BCAA valine, leucine and isoleucine have been implicated in a number of diseases including obesity, insulin resistance, and type 2 diabetes mellitus, although the mechanisms are still poorly understood. Adipose tissue plays an important role in BCAA homeostasis by actively metabolizing circulating BCAA. In this work, we have investigated the link between BCAA catabolism and fatty acid synthesis in 3T3-L1 adipocytes using parallel 13C-labeling experiments, mass spectrometry and model-based isotopomer data analysis. Specifically, we performed parallel labeling experiments with four fully 13C-labeled tracers, [U-13C]valine, [U-13C]leucine, [U-13C]isoleucine and [U-13C]glutamine. We measured mass isotopomer distributions of fatty acids and intracellular metabolites by GC-MS and analyzed the data using the isotopomer spectral analysis (ISA framework. We demonstrate that 3T3-L1 adipocytes accumulate significant amounts of even chain length (C14:0, C16:0 and C18:0 and odd chain length (C15:0 and C17:0 fatty acids under standard cell culture conditions. Using a novel GC-MS method, we demonstrate that propionyl-CoA acts as the primer on fatty acid synthase for the production of odd chain fatty acids. BCAA contributed significantly to the production of all fatty acids. Leucine and isoleucine contributed at least 25% to lipogenic acetyl-CoA pool, and valine and isoleucine contributed 100% to lipogenic propionyl-CoA pool. Our results further suggest that low activity of methylmalonyl-CoA mutase and mass action kinetics of propionyl-CoA on fatty acid synthase result in high rates of odd chain fatty acid synthesis in 3T3-L1 cells. Overall, this work provides important new insights into the connection between BCAA catabolism and fatty acid synthesis in adipocytes and underscores the high capacity of adipocytes for metabolizing BCAA.
Evolutionary systems biology of amino acid biosynthetic cost in yeast.
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Michael D Barton
Full Text Available Every protein has a biosynthetic cost to the cell based on the synthesis of its constituent amino acids. In order to optimise growth and reproduction, natural selection is expected, where possible, to favour the use of proteins whose constituents are cheaper to produce, as reduced biosynthetic cost may confer a fitness advantage to the organism. Quantifying the cost of amino acid biosynthesis presents challenges, since energetic requirements may change across different cellular and environmental conditions. We developed a systems biology approach to estimate the cost of amino acid synthesis based on genome-scale metabolic models and investigated the effects of the cost of amino acid synthesis on Saccharomyces cerevisiae gene expression and protein evolution. First, we used our two new and six previously reported measures of amino acid cost in conjunction with codon usage bias, tRNA gene number and atomic composition to identify which of these factors best predict transcript and protein levels. Second, we compared amino acid cost with rates of amino acid substitution across four species in the genus Saccharomyces. Regardless of which cost measure is used, amino acid biosynthetic cost is weakly associated with transcript and protein levels. In contrast, we find that biosynthetic cost and amino acid substitution rates show a negative correlation, but for only a subset of cost measures. In the economy of the yeast cell, we find that the cost of amino acid synthesis plays a limited role in shaping transcript and protein expression levels compared to that of translational optimisation. Biosynthetic cost does, however, appear to affect rates of amino acid evolution in Saccharomyces, suggesting that expensive amino acids may only be used when they have specific structural or functional roles in protein sequences. However, as there appears to be no single currency to compute the cost of amino acid synthesis across all cellular and environmental
Synthesis and antiulcer activity evaluation of conjugates of amino acids with N-aroyl- N, N'-dicyclohexyl urea
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Subudhi Bharat
Full Text Available Abstract Amino acids are safe molecules with variable efficacy against ulceration. Considering the good antioxidant potential of N-aroyl- N, N'-dicyclohexyl urea and antiulcer activities of amino acids, a series of amino acid conjugates of N-aroyl- N, N'-dicyclohexyl urea was synthesized and the effect against ulceration in albino rats induced by pyloric ligation was screened. All these compounds were found to be safe and active. Reduction of ulcer index was significant for all compounds. Conjugates of methionine and histidine exhibited enhanced antiulcer activity comparable to omeprazole in terms of inhibition of release of gastric juice, hydrochloric acid and neutralization activity. The promising efficacy and safety of these compounds is interesting for further investigation.
Biosynthesis of natural products containing β-amino acids.
Kudo, Fumitaka; Miyanaga, Akimasa; Eguchi, Tadashi
Covering: up to January, 2014. We focus here on β-amino acids as components of complex natural products because the presence of β-amino acids produces structural diversity in natural products and provides characteristic architectures beyond those of ordinary α-L-amino acids, thus generating significant and unique biological functions in nature. In this review, we first survey the known bioactive β-amino acid-containing natural products including nonribosomal peptides, macrolactam polyketides, and nucleoside-β-amino acid hybrids. Next, the biosynthetic enzymes that form β-amino acids from α-amino acids and the de novo synthesis of β-amino acids are summarized. Then, the mechanisms of β-amino acid incorporation into natural products are reviewed. Because it is anticipated that the rational swapping of the β-amino acid moieties with various side chains and stereochemistries by biosynthetic engineering should lead to the creation of novel architectures and bioactive compounds, the accumulation of knowledge regarding β-amino acid-containing natural product biosynthetic machinery could have a significant impact in this field. In addition, genome mining of characteristic β-amino acid biosynthetic genes and unique β-amino acid incorporation machinery could lead to the discovery of new β-amino acid-containing natural products.
Tetrazolyl isoxazole amino acids as ionotropic glutamate receptor antagonists: synthesis, modelling and molecular pharmacology
DEFF Research Database (Denmark)
Frølund, Bente; Greenwood, Jeremy R; Holm, Mai Marie
and 1b were pharmacologically characterized in receptor binding assays, and electrophysiologically on homomeric AMPA receptors (GluR1-4), homomeric (GluR5 and GluR6) and heteromeric (GluR6/KA2) kainic acid receptors, using two-electrode voltage-clamped Xenopus laevis oocytes expressing these receptors...
Synthesis of Molecularly Imprinted Polymers for Amino Acid Derivates by Using Different Functional Monomers
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Sonia Scorrano
Full Text Available Fmoc-3-nitrotyrosine (Fmoc-3-NT molecularly imprinted polymers (MIPs were synthesized to understand the influence of several functional monomers on the efficiency of the molecular imprinting process. Acidic, neutral and basic functional monomers, such as acrylic acid (AA, methacrylic acid (MAA, methacrylamide (MAM, 2-vinylpyridine (2-VP, 4-vinylpyridine (4-VP, have been used to synthesize five different polymers. In this study, the MIPs were tested in batch experiments by UV-visible spectroscopy in order to evaluate their binding properties. The MIP prepared with 2-VP exhibited the highest binding affinity for Fmoc-3NT, for which Scatchard analysis the highest association constant (2.49 × 104 M−1 was obtained. Furthermore, titration experiments of Fmoc-3NT into acetonitrile solutions of 2-VP revealed a stronger bond to the template, such that a total interaction is observed. Non-imprinted polymers as control were prepared and showed no binding affinities for Fmoc-3NT. The results are indicative of the importance of ionic bonds formed between the –OH residues of the template molecule and the pyridinyl groups of the polymer matrix. In conclusion, 2-VP assists to create a cavity which allows better access to the analytes.
Alkyl pyrazine synthesis via an open heated bath with variable sugars, ammonia, and various amino acids.
Ara, Katayoun Mahdavi; Taylor, Larry T; Ashraf-Khorassani, Mehdi; Coleman, William M
Semi-quantitative characteristics of headspace volatile pyrazines which constituted around 1% by weight of the final product have been previously described. The influence of reactant concentration, reaction temperature, and reaction time on both the yield of total alkyl pyrazines and the distribution pattern of specific identified pyrazines has not been reported. The optimum synthetic conditions were 5 mol L -1 NH 4 OH, 2 mol L -1 rhamnose, 0.5 mol L -1 leucine at 110°C for 2 h. The greatest total amount of pyrazines obtained was 17 280 µg of extracted product which translated into 31% 2,6-dimethyl pyrazine, 17% 2-methyl pyrazine, 15% 2-ethyl-6-methyl pyrazine, and 16% 2-isoamyl-6-methyl pyrazine. The yield of synthesized pyrazines increased at higher temperatures. Quantitative total and specific pyrazine results as opposed to analysis of only headspace volatiles are more representative of pyrazine synthesis. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.
Synthesis, biocompatibility and luminescence properties of quantum dots conjugated with amino acid-functionalized β-cyclodextrin
International Nuclear Information System (INIS)
Zhao Meixia; Su Hua; Mao Zongwan; Ji Liangnian
A series of CdSe and CdSe/CdS quantum dots (QDs) labeled with amino acid-modified β-cyclodextrin (β-CD) was prepared by a simple ultrasonic method. These amino acid-modified β-CD-coated QDs are very soluble and stable in biological buffer. They also have high colloidal stability and strong optical emission properties that are similar to those of untreated tri-n-octylphosphine oxide (TOPO)-coated QDs. The quantum yields (QYs) of these amino acid-modified β-CD-coated CdSe and CdSe/CdS QDs in biological buffer were found to be very high. In particular, the QYs of the positively charged L-His-β-CD-coated CdSe/CdS QDs were as high as 33.5±1.8%. In addition, the fluorescence lifetime of these QDs was also very long in PBS solutions as determined by frequency domain spectroscopy. For example, the lifetime of L-His-β-CD-coated CdSe/CdS QDs was 8.6 ns. The in vitro cytotoxicity of these QDs in ECV-304, SH-SY5Y and HeLa cells was found to be lower. L-His-β-CD-coated CdSe/CdS QDs were the least cytotoxic (IC 50 95.6±3.2 mg mL -1 in ECV-304 cells after 48 h). The flow cytometry results show that the positively charged amino acid led to a considerable increase in biocompatibility of QDs. This may be attributed to the presence of an amino acid-modified β-CD outer layer, which enhanced the biocompatibility. - Highlights: → Amino acid-modified β-CD-coated QDs were prepared by a simple ultrasonic method. → Amino acid-modified β-CD-coated QDs have appropriate size, high colloidal stability and strong optical emission properties. → In vitro cytotoxicity is lower in ECV-304, SH-SY5Y and HeLa cells. → The positive charge of amino acid resulted in a considerable increase in biocompatibility of QDs.
Synthesis of C5-tetrazole derivatives of 2-amino-adipic acid displaying NMDA glutamate receptor antagonism.
Lenda, Fatimazohra; Crouzin, Nadine; Cavalier, Mélanie; Guiramand, Janique; Lanté, Fabien; Barbanel, Gérard; Cohen-Solal, Catherine; Martinez, Jean; Guenoun, Farhate; Lamaty, Frédéric; Vignes, Michel
Five derivatives of 2-amino-adipic acid bearing a tetrazole-substituted in C5 position were synthesized. These compounds displayed selective antagonism towards N-methyl-D: -aspartate (NMDA) receptors compared with AMPA receptors, and they were devoid of any neurotoxicity. Among these five analogues, one exhibited a higher affinity for synaptic NMDA responses than the other four. Therefore, C5 tetrazole-substituted of 2-amino-adipic acid represent an interesting series of new NMDA receptor antagonists. This approach may be considered as a new strategy to develop ligands specifically targeted to synaptic or extra-synaptic NMDA receptors.
DNA Three Way Junction Core Decorated with Amino Acids-Like Residues-Synthesis and Characterization
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Claudia Addamiano
Full Text Available Construction and physico-chemical behavior of DNA three way junction (3WJ functionalized by protein-like residues (imidazole, alcohol and carboxylic acid at unpaired positions at the core is described. One 5′-C(S-propargyl-thymidine nucleotide was specifically incorporated on each strand to react through a post synthetic CuACC reaction with either protected imidazolyl-, hydroxyl- or carboxyl-azide. Structural impacts of 5′-C(S-functionalization were investigated to evaluate how 3WJ flexibility/stability is affected.
A highly enantioselective amino acid-catalyzed route to functionalized alpha-amino acids.
Córdova, Armando; Notz, Wolfgang; Zhong, Guofu; Betancort, Juan M; Barbas, Carlos F
The development of syntheses providing enantiomerically pure alpha-amino acids has intrigued generations of chemists and been the subject of intense research. This report describes a general approach to functionalized alpha-amino acids based on catalytic asymmetric synthesis. Proline catalyzed Mannich-type reactions of N-PMP-protected alpha-imino ethyl glyoxylate with a variety of unmodified ketones to provide functionalized alpha-amino acids in high yields with excellent regio-, diastereo-, and enantioselectivities. Study of seven examples yielded six with product ee values of > or = 99%. In reactions involving ketone donors where diastereoisomeric products could be formed, two adjacent stereogenic centers were created simultaneously upon carbon-carbon bond formation with complete syn-stereocontrol. Significantly, this methodology utilizes readily available and rather inexpensive starting materials, does not require any preactivation of substrates or metal ion assistance, and can be carried out on a gram scale under operationally simple reaction conditions. The keto-functionality present in the products provides a particularly attractive site for versatile modifications. This study compliments and extends our bioorganic approach to asymmetric synthesis to a versatile synthon class. Given that we have shown that a variety of optically active amino acids can be synthesized with proline catalysis, where an L-amino acid begets other L-amino acids, our results may stimulate thoughts concerning prebiotic syntheses of optically active amino acids based on this route.
Studies on radiolysis of amino acids, (4)
International Nuclear Information System (INIS)
Oku, Tadatake
In order to elucidate the effect of adding methionine on the loss of amino acid by γ-irradiation in amino acid mixture, because methionine is one of the most radio-sensitive in amino acids, the remaining amino acids in γ-irradiated aqueous solution of amino acid mixture were studied by determining the total amount of each remaining amino acid. The mixture of 18 amino acids which contains methionine and that of 17 amino acids without methionine were used. Amino acids and the irradiation products were determined with an automatic amino acid analyzer. The total amount of remaining amino acids in the irradiated solution of 18 amino acid mixture was more than that of 17 amino acid mixture. The order of the total amount of each remaining amino acid by low-dose irradiation was Gly>Ala>Asp>Glu>Val>Ser, Pro>Ile, Leu>Thr>Lys>Tyr>Arg>His>Phe>Try>Cys>Met. In case of the comparison of amino acids of same kinds, the total remaining amount of each amino acid in amino acid mixture was more than that of individually irradiated amino acid. The total remaining amounts of glycine, alanine and aspartic acid in irradiated 17 amino acid mixture resulted in slight increase. Ninhydrin positive products formed from 18 amino acid mixture irradiated with 2.640 x 10 3 rad were ammonia, methionine sulfoxide and DOPA of 1.34, 0.001 and 0.25 μmoles/ml of the irradiated solution, respectively. (Kobake, H.)
Amino acid derived 1,4-dialkyl substituted imidazolones
DEFF Research Database (Denmark)
Diness, Frederik; Meldal, Morten Peter
A general method for synthesis of 1,4-substituted imidazolones from amino acids on solid support or in solution has been developed. Amino acid derived 3-Boc-(1,3)-oxazinane (Box) protected amino aldehyde building blocks were coupled through urea bonds to the amino terminal of dipeptides or amino...... acids. Upon acidic release, the aldehyde instantaneously formed the cyclic N-carbamyliminium ion, which rearranged to the corresponding imidazolone. Under strongly acidic conditions the imidazolones acted as nuclophiles in the Pictet-Spengler reaction....
Sterically hindered C(alpha, alpha)-disubstituted alpha-amino acids: synthesis from alpha-nitroacetate and incorporation into peptides.
Fu, Y; Hammarström, L G; Miller, T J; Fronczek, F R; McLaughlin, M L; Hammer, R P
The preparation of sterically hindered and polyfunctional C(alpha,alpha)-disubstituted alpha-amino acids (alpha alpha AAs) via alkylation of ethyl nitroacetate and transformation into derivatives ready for incorporation into peptides are described. Treatment of ethyl nitroacetate with N,N-diisopropylethylamine (DIEA) in the presence of a catalytic amount of tetraalkylammonium salt, followed by the addition of an activated alkyl halide or Michael acceptor, gives the doubly C-alkylated product in good to excellent yields. Selective nitro reduction with Zn in acetic acid or hydrogen over Raney Ni gives the corresponding amino ester that, upon saponification, can be protected with the fluorenylmethyloxycarbonyl (Fmoc) group. The first synthesis of an orthogonally protected, tetrafunctional C(alpha,alpha)-disubstituted analogue of aspartic acid, 2,2-bis(tert-butylcarboxymethyl)glycine (Bcmg), is described. Also, the sterically demanding C(alpha,alpha)-dibenzylglycine (Dbg) has been incorporated into a peptide using solid-phase synthesis. It was found that once sterically congested Dbg is at the peptide N-terminus, further chain extension becomes very difficult using uronium or phosphonium salts (PyAOP, PyAOP/HOAt, HATU). However, preformed amino acid symmetrical anhydride couples to N-terminal Dbg in almost quantitative yield in nonpolar solvent (dichloroethane-DMF, 9:1).
Metabolism of nonessential N-15-labeled amino acids and the measurement of human whole-body protein synthesis rates
Stein, T. P.; Settle, R. G.; Albina, J. A.; Melnick, G.; Dempsey, D. T.
Eight N-15-labeled nonessential amino acids plus (N-15)H4Cl were administered over a 10-h period to four healthy adult males using a primed-constant dosage regimen. The amount of N-15 excreted in the urine and the urinary ammonia, hippuric acid, and plasma alanine N-15 enrichments were measured. There was a high degree of consistency across subjects in the ordering of the nine compounds based on the fraction of N-15 excreted.
Synthesis and biological activity of oxytocin analogues containing unnatural amino acids in position 9: structure activity study
Czech Academy of Sciences Publication Activity Database
Magafa, V.; Borovičková, Lenka; Slaninová, Jiřina; Cordopatis, P.
Roč. 38, č. 5 (2010), s. 1549-1559 ISSN 0939-4451 Institutional research plan: CEZ:AV0Z40550506 Keywords : oxytocin antagonists * position 9 * unnatural amino acids * biological activity Subject RIV: CC - Organic Chemistry Impact factor: 4.106, year: 2010
Synthesis of peptide-immunogens corresponding to amino acid sequences from human histocompatibility class II membrane glycoproteins.
Chillemi, F; Cappelletti, S; Francescato, P; Chersi, A
Six peptides with amino acid sequences of human histocompatibility Class II membrane glycoproteins were synthesized by conventional solution methods. Five peptides were prepared by stepwise procedures from the carboxyterminus. The sixth was synthesized by fragment condensation (5 + 10 coupling). Antibodies to synthetic peptides were then used to locate exposed and buried regions in the membrane glycoproteins.
Dietary supplementation with aromatic amino acids increases protein synthesis in children wHh severe acute malnutrition
Although 2 earlier studies reported that aromatic amino acid (AAA) supplementation of children with severe acute malnutrition (SAM) improved whole-body protein anabolism during the early postadmission (maintenance) phase of rehabilitation, it is not known whether this positive effect was maintained ...
Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis.
Pasiakos, Stefan M; McClung, Holly L; McClung, James P; Margolis, Lee M; Andersen, Nancy E; Cloutier, Gregory J; Pikosky, Matthew A; Rood, Jennifer C; Fielding, Roger A; Young, Andrew J
The effects of essential amino acid (EAA) supplementation during moderate steady state (ie, endurance) exercise on postexercise skeletal muscle metabolism are not well described, and the potential role of supplemental leucine on muscle protein synthesis (MPS) and associated molecular responses remains to be elucidated. This randomized crossover study examined whether EAA supplementation with 2 different concentrations of leucine affected post-steady state exercise MPS, whole-body protein turnover, and mammalian target of rapamycin 1 (mTORC1) intracellular signaling. Eight adults completed 2 separate bouts of cycle ergometry [60 min, 60% VO(2)peak (peak oxygen uptake)]. Isonitrogenous (10 g EAA) drinks with different leucine contents [leucine-enriched (l)-EAA, 3.5 g leucine; EAA, 1.87 g leucine] were consumed during exercise. MPS and whole-body protein turnover were determined by using primed continuous infusions of [(2)H(5)]phenylalanine and [1-(13)C]leucine. Multiplex and immunoblot analyses were used to quantify mTORC1 signaling. MPS was 33% greater (P < 0.05) after consumption of L-EAA (0.08 ± 0.01%/h) than after consumption of EAA (0.06 ± 0.01%/h). Whole-body protein breakdown and synthesis were lower (P < 0.05) and oxidation was greater (P < 0.05) after consumption of L-EAA than after consumption of EAA. Regardless of dietary treatment, multiplex analysis indicated that Akt and mammalian target of rapamycin phosphorylation were increased (P < 0.05) 30 min after exercise. Immunoblot analysis indicated that phosphorylation of ribosomal protein S6 and extracellular-signal regulated protein kinase increased (P < 0.05) and phosphorylation of eukaryotic elongation factor 2 decreased (P < 0.05) after exercise but was not affected by dietary treatment. These findings suggest that increasing the concentration of leucine in an EAA supplement consumed during steady state exercise elicits a greater MPS response during recovery. This trial is registered at clinicaltrials
Amino Acid Catabolism in Plants.
Hildebrandt, Tatjana M; Nunes Nesi, Adriano; Araújo, Wagner L; Braun, Hans-Peter
Amino acids have various prominent functions in plants. Besides their usage during protein biosynthesis, they also represent building blocks for several other biosynthesis pathways and play pivotal roles during signaling processes as well as in plant stress response. In general, pool sizes of the 20 amino acids differ strongly and change dynamically depending on the developmental and physiological state of the plant cell. Besides amino acid biosynthesis, which has already been investigated in great detail, the catabolism of amino acids is of central importance for adjusting their pool sizes but so far has drawn much less attention. The degradation of amino acids can also contribute substantially to the energy state of plant cells under certain physiological conditions, e.g. carbon starvation. In this review, we discuss the biological role of amino acid catabolism and summarize current knowledge on amino acid degradation pathways and their regulation in the context of plant cell physiology. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.
Cook, Jamie Elisla
NASA's Stardust spacecraft returned samples from comet 81P/Wild 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary- vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a coetary amino acid.
Synthesis, physical and chemical properties of 2-((4-(R-amino-5-(thiophen-2-ylmethyl-4H-1,2,4-triazol-3-ylthioacetic acids salts
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А.А. Safonov
Full Text Available Thanks to the rapid development of science, humanity has achieved remarkable success in various fields. This also applies to the synthesis of biological compounds. Over the centuries, scientists have invented many methods and drugs that are being actively used to date. Derivatives of 1,2,4-triazole can be the foundation for the manufacture of new native drugs that will compete with foreign ones. The aim of work was synthesis and confirmation the structure of 2-((4-(R-amino-5-(thiophen-2-ylmethyl-4H-1,2,4-triazol-3-ylthioacetate acids salts. Materials and methods. As starting substances we used 2-((4-(R-amino-5-(thiophen-2-ylmethyl-4H-1,2,4-triazol-3-ylthioacetic acids, which were synthesized by previously described methods. The structure of synthesized compounds was confirmed by the complex use of modern physical-chemical methods of analysis: elemental analysis, 1H-NMR spectroscopy, HPLC-MS. Results. Salts of 2-((4-(R-amino-5-(thiophen-2-ylmethyl-4H-1,2,4-triazol-3-ylthioacetic acids were synthesized by the interaction of the appropriate acids with organic (morpholin, methanamin, 2-hydroxyethanamin, inorganic basics (aqueous ammonia solution, sodium hydroxide and salts (zinc sulfate, ferrum (III chloride, magnesium sulfate, copper (II sulfate in alcoholic or aqueous media. Conclusions. A series of novel 2-((4-(R-amino-5-(thiophen-2-ylmethyl-4H-1,2,4-triazol-3-ylthioacetic acids salts were synthesized. The structure of synthesized compounds is established using modern physical-chemical methods of analysis.
Main: Amino acid Analysis [KOME
Lifescience Database Archive (English)
Full Text Available Amino acid Analysis GO classification InterPro Result of GO classification by Inter...Pro motif search result kome_go_classification_interpro.zip kome_go_classification_interpro ...
Main: Amino acid Analysis [KOME
Lifescience Database Archive (English)
Full Text Available Amino acid Analysis GO classification GenBank Result of GO classification by GenBan...k homology search result kome_go_classification_genbank.zip kome_go_classification_genbank ...
Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases. Part 3: Michael addition reactions and miscellaneous transformations.
Aceña, José Luis; Sorochinsky, Alexander E; Soloshonok, Vadim
The major goal of this review is a critical discussion of the literature data on asymmetric synthesis of α-amino acids via Michael addition reactions involving Ni(II)-complexes of amino acids. The material covered is divided into two conceptually different groups dealing with applications of: (a) Ni(II)-complexes of glycine as C-nucleophiles and (b) Ni(II)-complexes of dehydroalanine as Michael acceptors. The first group is significantly larger and consequently subdivided into four chapters based on the source of stereocontrolling element. Thus, a chiral auxiliary can be used as a part of nucleophilic glycine Ni(II) complex, Michael acceptor or both, leading to the conditions of matching vs. mismatching stereochemical preferences. The particular focus of the review is made on the practical aspects of the methodology under discussion and mechanistic considerations.
Some transition metal ions complexes of tricine (Tn and amino acids: pH-titration, synthesis and antimicrobial activity
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M.E. Zayed
Full Text Available Equilibrium studies have been carried out on complex formation of M(II (M = Co(II, Cu(II and Zn(II with tricine (Tn and L = amino acids in aqueous solution, at 25 °C and ionic strength of I = 0.1 M (NaNO3. The ternary complexes of amino acids are formed by simultaneous reactions. The concentration distribution of the complexes is evaluated. The solid complexes of [M(II–Tn–Histidine (Hist] have been synthesized and characterized by elemental analysis, infrared, magnetic and conductance measurements. The synthesized complexes have been screened for their antibacterial activities and the complexes show a significant antibacterial activity against four bacterial species: Staphylococcus aureus (Gram +ve, Streptococcus pyogenesr (Gram +ve, Serratia marcescens (Gram −ve and Escherichia coli (Gram −ve. The activity increases by increasing the concentration of the complexes.
Synthesis, insecticidal activity and inhibition on topoisomerase I of 20(S)-t-Boc-amino acid derivatives of camptothecin.
Wang, Liping; Li, Zhe; Zhang, Lan; Zhang, Yanning; Mao, Liangang; Jiang, Hongyun
Camptothecin (CPT), a quinolone alkaloid extracted from Camptotheca acuminata Decne, exhibits potential insecticidal activities against various insect species. Our previous studies have showed that CPT induced apoptosis in Spodoptera exigua Hübner cell line and inhibited the relaxation activity of topoisomerase I (Topo I). In this study, total seven 20(S)-t-butoxy carbonyl-amino acid derivatives of CPT were synthesized and evaluated for insecticidal activities, cytotoxicity and Topo I inhibitory activities. Results showed that introduction of t-Boc amino acids to 20-position on CPT improves contact assay and cytotoxicity of most derivatives toward S. exigua but reduces inhibitory effect on relaxation activity of S. exigua Topo I. Furthermore, compounds 1d and 1g demonstrated higher level of contact activities and cytotoxicity than CPT and hydroxyl-camptothecin (HCPT), which are potential to be developed as potential insecticides targeted at more than Topo I. Copyright © 2017 Elsevier Inc. All rights reserved.
Biodegradable polymers derived from amino acids.
Khan, Wahid; Muthupandian, Saravanan; Farah, Shady; Kumar, Neeraj; Domb, Abraham J
In the past three decades, the use of polymeric materials has increased dramatically for biomedical applications. Many α-amino acids derived biodegradable polymers have also been intensely developed with the main goal to obtain bio-mimicking functional biomaterials. Polymers derived from α-amino acids may offer many advantages, as these polymers: (a) can be modified further to introduce new functions such as imaging, molecular targeting and drugs can be conjugated chemically to these polymers, (b) can improve on better biological properties like cell migration, adhesion and biodegradability, (c) can improve on mechanical and thermal properties and (d) their degradation products are expected to be non-toxic and readily metabolized/excreted from the body. This manuscript focuses on biodegradable polymers derived from natural amino acids, their synthesis, biocompatibility and biomedical applications. It is observed that polymers derived from α-amino acids constitute a promising family of biodegradable materials. These provide innovative multifunctional polymers possessing amino acid side groups with biological activity and with innumerous potential applications. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
The Mannich Reaction of Malonates with Simple Imines Catalyzed by Bifunctional Cinchona Alkaloids: Enantioselective Synthesis of β-Amino Acids
Song, Jun; Wang, Yi; Deng, Li
We describe the first efficient, direct asymmetric Mannich reactions with malonates and N-Boc aryl and alkyl imines by cooperative hydrogen bonding catalysis with a cinchona alkaloid bearing a thiourea functionality. We have also extended the scope of this reaction to β-ketoesters. The synthetic value of this new reaction is demonstrated in the establishment of a convergent enantioselective route toward the biologically important β-amino acids under mild and air- and moisture-tolerant conditions. PMID:16669669
SYNTHESIS, CHARACTERIZATION AND ANTITUMOR ACTIVITY OF A Ca (II COORDINATION POLYMER BASED ON 3-AMINO-2-PYRAZINECARBOXYLIC ACID
Directory of Open Access Journals (Sweden)
Full Text Available A new Ca(II coordination polymer has been obtained by reaction of Ca(ClO42·H2O with 3-amino-2-pyrazinecarboxylic acid in CH3CH2OH/H2O. It was characterized by IR, 1HNMR, thermal analysis and X-ray single crystal diffraction analysis. X-ray analysis reveals that each Ca(II center is seven-coordination with a N2O5 distorted pentagonal bipyramidal coordination environment. The Ca(II ions are linked through the O atoms of 3-amino-2-pyrazinecarboxylic acid ligands to form 1D chain structure. And then a 3D network structure is constructed by hydrogen bonds and π-π stacking. The antitumor activity of 3-amino-2-pyrazinecarboxylic acid ligand and its Ca(II coordination polymer against human intestinal adenocarcinoma HCT-8 cells, lung adenocarcinoma HCT-116 cells and human lung adenocarcinoma A549 cells line have been investigated.
A novel Dps-type protein from insect gut bacteria catalyses hydrolysis and synthesis of N-acyl amino acids.
Ping, Liyan; Büchler, Rita; Mithöfer, Axel; Svatos, Ales; Spiteller, Dieter; Dettner, Konrad; Gmeiner, Sophie; Piel, Jörn; Schlott, Bernhard; Boland, Wilhelm
A novel type of a microbial N-acyl amino acid hydrolase (AAH) from insect gut bacteria was purified, cloned and functionally characterized. The enzyme was obtained from Microbacterium arborescens SE14 isolated from the foregut of larvae of the generalist herbivore Spodoptera exigua. The substrates of AAH are N-acyl-glutamines previously reported to elicit plant defence reactions after introduction into the leaf during feeding. The isolated AAH catalyses the hydrolysis of the amide bond (K(m) = 36 micromol l(-1)) and, less efficient, the formation (K(m) = 3 mmol l(-1)) of the elicitor active N-acyl amino acids. The AAH from M. arborescens SE14 shows no homology to known fatty acyl amidases (EC 126.96.36.199) but belongs to the family of Dps proteins (DNA-binding protein from starved cell). In line with other DPS proteins AAH is a homododecamer (monomer 17 181 Da) and contains iron atoms (c. 1-16 iron atoms per subunit). Unlike genuine DPS proteins the enzyme does not significantly bind DNA. Amino acid hydrolase is the first member of the DPS family that catalyses the cleavage or formation of amide bonds. The participation of a microbial enzyme in the homeostasis of N-acyl-glutamines in the insect gut adds further complexity to the interaction between plants and their herbivores.
Synthesis and Biological Activity of 3-[Phenyl(1,3-thiazol-2-yl-amino]propanoic Acids and Their Derivatives
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Vytautas Mickevičius
Full Text Available New N,N-disubstituted β-amino acids and their derivatives with thiazole, aromatic, and heterocyclic substituents were synthesized from N-phenyl-N-thiocarbamoyl-β-alanine by the Hantzsch method; derivatives with hydrazone fragments were also obtained. Some of the synthesized compounds exhibited discrete antimicrobial activity, and 3-[(4-oxo-4,5-dihydro-1,3-thiazol-2-yl(phenylamino]propanoic acid was found to promote rapeseed growth and to increase seed yield and oil content.
Synthesis and characterization of new amino acyl-4-thiazolidones
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Ana Cristina Lima Leite
Full Text Available A series of heterocyclic compounds with a 4-thiazolidone nucleus and amino acyl moiety were synthesized by protection reaction of thiosemicarbazide using the symmetrical anhydride (Boc2O and cyclization with chloroacetic acid under mild conditions. Trifluoroacetic acid was used to obtain 4-thiazolidone and the alpha-amino acid condensation reactions were carried out using strategies for peptide synthesis. The characterization of this new class of compounds was performed using IR and ¹H-NMR spectroscopy.
Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases; Part 1: alkyl halide alkylations.
Sorochinsky, Alexander E; Aceña, José Luis; Moriwaki, Hiroki; Sato, Tatsunori; Soloshonok, Vadim A
Alkylations of chiral or achiral Ni(II) complexes of glycine Schiff bases constitute a landmark in the development of practical methodology for asymmetric synthesis of α-amino acids. Straightforward, easy preparation as well as high reactivity of these Ni(II) complexes render them ready available and inexpensive glycine equivalents for preparing a wide variety of α-amino acids, in particular on a relatively large scale. In the case of Ni(II) complexes containing benzylproline moiety as a chiral auxiliary, their alkylation proceeds with high thermodynamically controlled diastereoselectivity. Similar type of Ni(II) complexes derived from alanine can also be used for alkylation providing convenient access to quaternary, α,α-disubstituted α-amino acids. Achiral type of Ni(II) complexes can be prepared from picolinic acid or via recently developed modular approach using simple secondary or primary amines. These Ni(II) complexes can be easily mono/bis-alkylated under homogeneous or phase-transfer catalysis conditions. Origin of diastereo-/enantioselectivity in the alkylations reactions, aspects of practicality, generality and limitations of this methodology is critically discussed.
Physiological and biochemical studies of bacterial amino acid amide metabolism
Hermes, Hubertus Franciscus Maria
Amino acids represent a class of versatile chiral building blocks for a whole range of fine chemicals, used in the pharmaceutical and agro-chemical industry. Considerable experience currently is available with a wide variety of chemo-enzymatic processes for the synthesis of amino acids, which is
Synthesis and structure-activity studies on acidic amino acids and related diacids as NMDA receptor ligands
DEFF Research Database (Denmark)
Johansen, T N; Frydenvang, Karla Andrea; Ebert, B
]CPP-binding assay (IC50 = 7 +/- 3 microM) and electropharmacologically in the rat cortical wedge model (EC50 = 8 +/- 2 microM). In contrast to this, the tertbutyl analogue 7a of AMAA turned out to be an antagonist at NMDA and AMPA receptors. The conformational characteristics of AMAA and 7a, c were studied...... by molecular mechanics calculations. Compound 7a possesses extra steric bulk and shows significant restriction of conformational flexibility compared to AMAA and 7c, which may be determining factors for the observed differences in biological activity. Although the nitrogen atom of quinolinic acid (6) has very...
Direct N-alkylation of unprotected amino acids with alcohols
Yan, Tao; Feringa, Ben L; Barta, Katalin
N-alkyl amino acids find widespread application as highly valuable, renewable building blocks. However, traditional synthesis methodologies to obtain these suffer from serious limitations, providing a major challenge to develop sustainable alternatives. We report the first powerful catalytic
Synthesis of Substituted Thioureas and Their Sulfur Heterocyclic Systems of p-Amino Salicylic Acid as Antimycobacterial Agents
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Mohammed Saleh I. T. Makki
Full Text Available A series of new N,N′-substituted thioureas (2, 6, and 8 and their sulfur heterocycles as thiobarbituric acids (3, 4, and 7, 2-thioxothiazoliodin-4-one (10, thiazolidin-4-one (11, 1,2,4-triazol-5-thione (14, and 1,3,4-thiadiazole (15 of p-Amino salicylic acid (PAS have been synthesized from treatment with dithiocarbazinate (1, 5 and 12 followed by heterocyclization with dimethyl malonate, chloroacetic acid, and/or trifluoroacetic anhydride. The structures of the newly synthesized compounds were substantiated with IR, H1, and C13 NMR spectral data and elementary microanalyses. The in vitro antitubercular activity of synthesized compounds against M. tuberculosis strain H37Rv showed moderate-to-good activity.
Studies on radiolysis of amino acids, 1
International Nuclear Information System (INIS)
Oku, Tadatake
In order to elucidate the radiolysis of amino acid, peptide, protein and enzyme, the radiolytic mechanisms of neutral amino acids (glycine, L-alanine, L-valine, L-leucine, L-isoleucine, L-serine, and L-threonine) and acidic amino acids (L-aspartic acid, L-glutamic acid and DL-amino-n-adipic acid) were studied in the presence of air or in the atmosphere nitrogen. An aqueous solution of 1 mM. of each amino acid was sealed in a glass ampoule under air or nitrogen. Irradiation of amino acid solutions was carried out with γ-rays of 60 Co at doses of 4.4-2,640x10 3 rads. The amino acids and the radiolytic products formed were determined by ion-exchange chromatography. From the results of determining amino acids and the radiolytic products formed and their G-values, the radiolytic mechanisms of the amino acids were discussed. (auth.)
Glutamic Acid - Amino Acid, Neurotransmitter, and Drug - Is Responsible for Protein Synthesis Rhythm in Hepatocyte Populations in vitro and in vivo.
Brodsky, V Y; Malchenko, L A; Konchenko, D S; Zvezdina, N D; Dubovaya, T K
Primary cultures of rat hepatocytes were studied in serum-free media. Ultradian protein synthesis rhythm was used as a marker of cell synchronization in the population. Addition of glutamic acid (0.2 mg/ml) to the medium of nonsynchronous sparse cultures resulted in detection of a common protein synthesis rhythm, hence in synchronization of the cells. The antagonist of glutamic acid metabotropic receptors MCPG (0.01 mg/ml) added together with glutamic acid abolished the synchronization effect; in sparse cultures, no rhythm was detected. Feeding rats with glutamic acid (30 mg with food) resulted in protein synthesis rhythm in sparse cultures obtained from the rats. After feeding without glutamic acid, linear kinetics of protein synthesis was revealed. Thus, glutamic acid, a component of blood as a non-neural transmitter, can synchronize the activity of hepatocytes and can form common rhythm of protein synthesis in vitro and in vivo. This effect is realized via receptors. Mechanisms of cell-cell communication are discussed on analyzing effects of non-neural functions of neurotransmitters. Glutamic acid is used clinically in humans. Hence, a previously unknown function of this drug is revealed.
Synthesis and antimycobacterial activity of N-(2-aminopurin-6-yl) and N-(purin-6-yl) amino acids and dipeptides.
Krasnov, Victor P; Vigorov, Alexey Yu; Musiyak, Vera V; Nizova, Irina A; Gruzdev, Dmitry A; Matveeva, Tatyana V; Levit, Galina L; Kravchenko, Marionella A; Skornyakov, Sergey N; Bekker, Olga B; Danilenko, Valery N; Charushin, Valery N
Synthetic routes to novel N-(purin-6-yl)- and N-(2-aminopurin-6-yl) conjugates with amino acids and glycine-containing dipeptides were developed. In vitro testing of 42 new and known compounds made it possible to reveal a series of N-(purin-6-yl)- and N-(2-aminopurin-6-yl) conjugates exhibiting significant antimycobacterial activity against Mycobacterium tuberculosis H37Rv, Mycobacterium avium, Mycobacterium terrae, and multidrug-resistant M. tuberculosis strain isolated from tuberculosis patients in the Ural region (Russia). N-(2-Aminopurin-6-yl)- and N-(purin-6-yl)-glycyl-(S)-glutamic acids were the most active compounds. Copyright © 2016 Elsevier Ltd. All rights reserved.
Azide- and alkyne-derivatised α-amino acids
DEFF Research Database (Denmark)
Johansson, Karl Henrik; Pedersen, D.S.
With the emergence of the copper-catalysed Huisgen cycloaddition the use of azide- and alkyne-derivatised α-amino acids has found widespread use within most chemistry disciplines. Despite a growing interest in these building blocks researchers are struggling to identify the best way...... for their synthesis. In this review we have compiled available methods for synthesising optically active azide- and alkyne-derivatised α-amino acids that can be prepared from readily available α-amino acids. We highlight a number of commonly overlooked problems associated with existing methods and direct attention...... to unexplored possibilities. Azide- and alkyne-derivatised α-amino acids are finding widespread use within most chemistry disciplines. However, it is far from clear what the best way for the synthesis of these useful building blocks is. Herein we show the available methods for synthesis of optically active...
Catalytic pyrolysis of amino acids: Comparison of aliphatic amino acid and cyclic amino acid
International Nuclear Information System (INIS)
Liu, Guangyi; Wright, Mark M.; Zhao, Qingliang; Brown, Robert C.; Wang, Kaige; Xue, Yuan
Highlights: • Catalytic pyrolysis of leucine and proline were carried out in a micro-furnace pyrolyzer. • Distributions of carbon, oxygen and nitrogen were comparatively investigated. • Leucine yielded 29.6% aromatic hydrocarbons, 34.9% olefins, and 8.1% alkanes. • Proline yielded 25.3% aromatic hydrocarbons, 14.0% olefins, and 5.5% alkanes. • Insights into the deoxygenation pathways of leucine and proline were elucidated. - Abstract: Catalytic pyrolysis (CP) of protein-rich biomass such as microalgae is a promising approach to biofuel production. CP of amino acids can help understand the cracking of protein-rich biomass in the presence of zeolite catalysts. In this study, as representatives of aliphatic amino acid and cyclic amino acid, respectively, leucine and proline were pyrolyzed with ZSM-5 catalyst in a Tandem micro-furnace reactor coupled with a MS/FID/TCD. At 650 °C, leucine produced more hydrocarbons (aromatic hydrocarbons of 29.6%, olefins of 34.9% and alkanes of 8.1%) than proline (aromatic hydrocarbons of 25.3%, olefins of 14.0% and alkanes of 5.5%) because its relatively simpler amino structure readily detached as ammonia during CP. However, with an N-cyclic structure, proline produced large quantities of nitrogen-containing heterocyclic compounds that favored coke formation in CP. Accordingly, 28.2% of the nitrogen in proline was retained in the solid residue while most of the nitrogen in leucine was converted into ammonia leaving only 4.3% in the solid residue. In addition, though decarboxylation to carbon dioxide was favored in non-catalytic pyrolysis of leucine and proline, decarbonylation to carbon monoxide became the primary deoxygenation pathway in CP. These results indicate that the chemical structures of amino acids have significant effects on product distributions during CP and N-cyclic amino acid is less favored in CP for production of hydrocarbons and ammonia.
Synthetic versatility of 2-substituted-6-methyl 2,3-dihydropyridinones in the synthesis of polyfunctional piperidine-based compounds and related β amino acid derivatives.
Yang, Yang; Hardman, Clayton
Chiral 2-substituted-6-methyl 2,3-dihydropyidinones 9, which can be facilely obtained from an asymmetric vinylogous Mannich reaction (VMR) with 1,3-bis-trimethysily enol ether, were used as versatile intermediates in constructing chiral polyfunctional piperidine-based compounds. The 6-methyl group of such compounds can be conveniently functionalized via alkylation and acylation reactions to provide efficient entries to the synthesis of a variety of chiral multi-substituted piperidine-based compounds. Further elaboration of the corresponding intermediates also provided access to polyfunctional indolizidine-based compounds. These methods were showcased in an asymmetric synthesis of 2,6-di-substituted piperidine compound 13, reported as the key intermediate in the synthesis of (+)-calvine and a natural alkaloid (-)-indolizidine 209D. Furthermore, selective C5 iodination of compound 9 enabled the installation of additional functional groups at this position. Finally, we demonstrated that the oxidative cleavage of 2-substituted-6-methyl-2,3-dihydropyidinones is a practical and efficient method for the enantioselective synthesis of β-amino acids, which can undergo further intra-molecular cyclization to give the corresponding chiral four-membered β-lactam derivatives.
Solution-phase synthesis of a hindered N-methylated tetrapeptide using Bts-protected amino acid chlorides: efficient coupling and methylation steps allow purification by extraction.
Vedejs, E; Kongkittingam, C
N-Benzothiazole-2-sulfonyl (Bts)-protected amino acid chlorides were used to prepare the hindered cyclosporin 8-11 tetrapeptide subunit 1. The synthesis was performed via 3a and the deprotected amines 5a, 13, and 19, including three repeated cycles involving N-methylation using iodomethane/potassium carbonate, deprotection of the Bts group, and N-acylation with a N-Bts-amino acid chloride such as 9b or 9c. Among three Bts cleavage methods compared (H3PO2/THF; NaBH4/EtOH; PhSH/K2CO3), the third gave somewhat higher overall yields. N-Acylation of 5a with the Bts-protected N-methylamino acid chloride 10b followed by deprotection was also highly efficient and could be used as an alternative route to 11. Each of the deprotected amines was isolated without chromatography using simple extraction methods to remove neutral byproducts. The tetrapeptide 1 was obtained in analytically pure form as the monohydrate.
On the synthesis of radiofluorinated amino acids by isotope exchange based on the example of 6-[18F]Fluor-L-DOPA
International Nuclear Information System (INIS)
Wagner, F.M.
In nuclear medical diagnosis, 6-[ 18 F]fluoro-L-3,4-dihydroxyphenylalanine (6-[ 18 F]fluoro-LDOPA), an analogue of L-DOPA, is one of the few established radiopharmaceuticals used for the in vivo investigation of the presynaptic dopaminergic metabolism and of some kind of tumours via Positron Emission Tomography (PET). The presently used method of preparation of the radiotracer by electrophilic labelling is limited to low amounts of activity at high costs. Known nucleophilic syntheses, however, result either in insufficient enantiomeric purity or the known multi-step syntheses are hard to automate, due to their complexity. During this work a novel, easy to automate alternative for the preparation of 6-[ 18 F]fluoro-L-DOPA, was developed and evaluated, using a direct nucleophilic 18 F-fluorination of a protected amino acid derivative. The resulting product has a very high enantiomeric purity. At first, the general suitability of the (S)-BOC-BMI-derivatives for the synthesis of 18 F-labelled amino acids, used in this work, was investigated using a less complex precursor, which resulted in the amino acid 6-[ 18 F]fluoro-L-m-tyrosin via acidic hydrolysis. The preparation of a useful precursor for the nucleophilic 18 F-isotope substitution, namely the (2S,5S)-tert.-butyl- 5-(2-fluoro-5-formylbenzyl)-2-tert. -butyl-3-methyl-4-oxoimidazolidine-1-carbox= yl ate, was investigated in three general different ways. At first it was tried to obtain this product via formylation after coupling with the BOC-BMI, secondly via α,β-dehydro amino acid derivatives and finally via a systematic multi-step synthesis. Only the last mentioned way resulted in a precursor with sufficient purity that could be labelled. The radiochemical yield of the isotopic exchange was about 60 %. In the next step, the presented concept was modified to synthesize a precursor for the preparation of 6-[ 18 F]fluoro-L-DOPA. Only a combination of the protecting groups benzyl and THP resulted in the useful
Preference for and learning of amino acids in larval Drosophila
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Nana Kudow
Full Text Available Relative to other nutrients, less is known about how animals sense amino acids and how behaviour is organized accordingly. This is a significant gap in our knowledge because amino acids are required for protein synthesis − and hence for life as we know it. Choosing Drosophila larvae as a case study, we provide the first systematic analysis of both the preference behaviour for, and the learning of, all 20 canonical amino acids in Drosophila. We report that preference for individual amino acids differs according to the kind of amino acid, both in first-instar and in third-instar larvae. Our data suggest that this preference profile changes across larval instars, and that starvation during the third instar also alters this profile. Only aspartic acid turns out to be robustly attractive across all our experiments. The essentiality of amino acids does not appear to be a determinant of preference. Interestingly, although amino acids thus differ in their innate attractiveness, we find that all amino acids are equally rewarding. Similar discrepancies between innate attractiveness and reinforcing effect have previously been reported for other tastants, including sugars, bitter substances and salt. The present analyses will facilitate the ongoing search for the receptors, sensory neurons, and internal, homeostatic amino acid sensors in Drosophila.
Propylene glycol-linked amino acid/dipeptide diester prodrugs of oleanolic acid for PepT1-mediated transport: synthesis, intestinal permeability, and pharmacokinetics.
Cao, Feng; Gao, Yahan; Wang, Meng; Fang, Lei; Ping, Qineng
In our previous studies, ethylene glycol-linked amino acid diester prodrugs of oleanolic acid (OA), a Biopharmaceutics Classification System (BCS) class IV drug, designed to target peptide transporter 1 (PepT1) have been synthesized and evaluated. Unlike ethylene glycol, propylene glycol is of very low toxicity in vivo. In this study, propylene glycol was used as a linker to further compare the effect of the type of linker on the stability, permeability, affinity, and bioavailability of the prodrugs of OA. Seven diester prodrugs with amino acid/dipeptide promoieties containing L-Val ester (7a), L-Phe ester (7b), L-Ile ester (7c), D-Val-L-Val ester (9a), L-Val-L-Val ester (9b), L-Ala-L-Val ester (9c), and L-Ala-L-Ile ester (9d) were designed and successfully synthesized. In situ rat single-pass intestinal perfusion (SPIP) model was performed to screen the effective permeability (P(eff)) of the prodrugs. P(eff) of 7a, 7b, 7c, 9a, 9b, 9c, and 9d (6.7-fold, 2.4-fold, 1.24-fold, 1.22-fold, 4.15-fold, 2.2-fold, and 1.4-fold, respectively) in 2-(N-morpholino)ethanesulfonic acid buffer (MES) with pH 6.0 showed significant increase compared to that of OA (p propylene glycol-linked amino acid/dipeptide diester prodrugs showed better stability, permeability, affinity, and bioavailability. In conclusion, propylene glycol-linked amino acid/dipeptide diester prodrugs of OA may be suitable for PepT1-targeted prodrugs of OA to improve the oral bioavailability of OA.
Toward Sustainable Amino Acid Production.
Usuda, Yoshihiro; Hara, Yoshihiko; Kojima, Hiroyuki
Because the global amino acid production industry has been growing steadily and is expected to grow even more in the future, efficient production by fermentation is of great importance from economic and sustainability viewpoints. Many systems biology technologies, such as genome breeding, omics analysis, metabolic flux analysis, and metabolic simulation, have been employed for the improvement of amino acid-producing strains of bacteria. Synthetic biological approaches have recently been applied to strain development. It is also important to use sustainable carbon sources, such as glycerol or pyrolytic sugars from cellulosic biomass, instead of conventional carbon sources, such as glucose or sucrose, which can be used as food. Furthermore, reduction of sub-raw substrates has been shown to lead to reduction of environmental burdens and cost. Recently, a new fermentation system for glutamate production under acidic pH was developed to decrease the amount of one sub-raw material, ammonium, for maintenance of culture pH. At the same time, the utilization of fermentation coproducts, such as cells, ammonium sulfate, and fermentation broth, is a useful approach to decrease waste. In this chapter, further perspectives for future amino acid fermentation from one-carbon compounds are described.
Diastereoselective Ugi reaction for the synthesis of unnatural amino esters
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Rafael Oliveira Rocha
Full Text Available Multicomponent Reactions (MCR are useful reactions to obtain complex products by the simple mixture of 3 or more reactants. The classic Ugi reaction (4-UCR involves a mixture of an amine, aldehyde, isocyanide and a carboxylic acid, giving peptoides as products. Some modifications of this reaction have been reported, among which the use of amino acids and Lewis acids, such as titanium (IV chloride, to induce stereoselectivity in good ratio. In this work we demonstrate the efficiency of different Lewis acids in the modified Ugi reaction and good levels of diastereoselectivity and yields in the synthesis of unnatural secondary amino esters.
Response of hepatic amino acid consumption to chronic metabolic acidosis
Boon, L.; Blommaart, P. J.; Meijer, A. J.; Lamers, W. H.; Schoolwerth, A. C.
In a previous paper, we showed that an inhibition of amino acid transport across the liver plasma membrane is responsible for the decrease in urea synthesis in acute metabolic acidosis. We have now studied the mechanism responsible for the decline in urea synthesis in chronic acidosis. Chronic
Amino acid, Antioxidant and Ion Profiles of Carpolobia lutea Leaf ...
African Journals Online (AJOL)
synthesis depends on the local availability of amino acid pool found in the organism [2]. Healing of dermal lesions require synthesis of newly formed collagen at different times. Antioxidants, such as polyphenols ..... in vitamin B12, a co-enzyme in some biochemical processes [24]; these metals and some of their complexes ...
Prazosin-Conjugated Matrices Based on Biodegradable Polymers and α-Amino Acids--Synthesis, Characterization, and in Vitro Release Study.
Oledzka, Ewa; Sawicka, Anna; Sobczak, Marcin; Nalecz-Jawecki, Grzegorz; Skrzypczak, Agata; Kolodziejski, Waclaw
Novel and promising macromolecular conjugates of the α1-adrenergic blocker prazosin were directly synthesized by covalent incorporation of the drug to matrices composed of biodegradable polymers and α-amino acids for the development of a polymeric implantable drug delivery carrier. The cyto- and genotoxicity of the synthesized matrices were evaluated using a bacterial luminescence test, protozoan assay, and Salmonella typhimurium TA1535. A new urethane bond was formed between the hydroxyl end-groups of the synthesized polymer matrices and an amine group of prazosin, using 1,1'-carbonyldiimidazole (CDI) as a coupling agent. The structure of the polymeric conjugates was characterized by various spectroscopy techniques. A study of hydrogen nuclear magnetic resonance ((1)H-NMR) and differential scanning calorimetry (DSC) thermodiagrams indicated that the presence of prazosin pendant groups in the macromolecule structures increased the polymer's rigidity alongside increasing glass transition temperature. It has been found that the kinetic release of prazosin from the obtained macromolecular conjugates, tested in vitro under different conditions, is strongly dependent on the physicochemical properties of polymeric matrices. Furthermore, the presence of a urethane bond in the macromolecular conjugates allowed for obtaining a relatively controlled release profile of the drug. The obtained results confirm that the pharmacokinetics of prazosin might be improved through the synthesis of polymeric conjugates containing biomedical polymers and α-amino acids in the macromolecule.
Chemical Synthesis of Glycoproteins with the Specific Installation of Gradient-Enriched15N-Labeled Amino Acids for Getting Insights into Glycoprotein Behavior.
Minh Hien, Nguyen; Izumi, Masayuki; Sato, Hajime; Okamoto, Ryo; Kajihara, Yasuhiro
Elucidating the effects of oligosaccharides on glycoprotein properties, such as local conformational changes, stability, and dynamics, has still been challenging. In this paper, a novel partial 15 N-labeling method for the amide backbone of a synthetic glycoprotein is proposed. Using solid-phase peptide synthesis (SPPS) and native chemical ligation (NCL), thirteen 15 N-labeled amino acids were inserted at specific positions of the protein backbone, while intentionally varying the enrichment of 15 N atoms. This idea discriminated even the same type of amino acid based on the intensities of 1 H- 15 N HSQC signals, combined with classic homonuclear TOCSY and NOESY methods, thus allowing for understanding the dynamics of the local conformation of a synthetic homogeneous glycoprotein. Results suggested that the attachment of an oligosaccharide of either a bi-antennary complex-type or a high-mannose-type did not disturb protein conformation. However, T 1 values suggested that the oligosaccharide influenced dynamics at the local conformation. Temperature-varied circular dichroism (CD) spectra and T 1 values clearly indicated that oligosaccharides appeared to inhibit protein fluctuation or, in other words, stabilize protein structure. This insight into oligosaccharide behavior suggests some further effects on binding affinity between a glycoprotein and its receptor. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Repression of branched-chain amino acid synthesis in Staphylococcus aureus is mediated by isoleucine via CodY, and by a leucine-rich attenuator peptide.
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Julienne C Kaiser
Full Text Available Staphylococcus aureus requires branched-chain amino acids (BCAAs; isoleucine, leucine, valine for protein synthesis, branched-chain fatty acid synthesis, and environmental adaptation by responding to their availability via the global transcriptional regulator CodY. The importance of BCAAs for S. aureus physiology necessitates that it either synthesize them or scavenge them from the environment. Indeed S. aureus uses specialized transporters to scavenge BCAAs, however, its ability to synthesize them has remained conflicted by reports that it is auxotrophic for leucine and valine despite carrying an intact BCAA biosynthetic operon. In revisiting these findings, we have observed that S. aureus can engage in leucine and valine synthesis, but the level of BCAA synthesis is dependent on the BCAA it is deprived of, leading us to hypothesize that each BCAA differentially regulates the biosynthetic operon. Here we show that two mechanisms of transcriptional repression regulate the level of endogenous BCAA biosynthesis in response to specific BCAA availability. We identify a trans-acting mechanism involving isoleucine-dependent repression by the global transcriptional regulator CodY and a cis-acting leucine-responsive attenuator, uncovering how S. aureus regulates endogenous biosynthesis in response to exogenous BCAA availability. Moreover, given that isoleucine can dominate CodY-dependent regulation of BCAA biosynthesis, and that CodY is a global regulator of metabolism and virulence in S. aureus, we extend the importance of isoleucine availability for CodY-dependent regulation of other metabolic and virulence genes. These data resolve the previous conflicting observations regarding BCAA biosynthesis, and reveal the environmental signals that not only induce BCAA biosynthesis, but that could also have broader consequences on S. aureus environmental adaptation and virulence via CodY.
Synthesis and research of the physical-chemical properties of 5-((2-bromphenyl-4-amino-4H-1,2,4-triazole-3-ylthioacetic acid salts
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Ye. S. Pruglo
Full Text Available At this stage of the development of modern science the scientists get a lot of questions in the field of medicine and pharmacy, and one of the most important among them is the study and search of new ways of synthesis of high-performance and low-toxic substances. Special attention is paid to 1,2,4-triazole and xanthine. On their basis some medical drugs were made, which are widely used in medicine. The aim of this work was the synthesis and study of properties of salts of 5-(2-bromophenyl-4-amino-4H-1,2,4-triazole-3-ylthioacetic acid. Methods and results. As starting material theophylline was selected. Through a number of stages 5-(2-bromphenyl-4-amino-4H-1,2,4-triazole-3-thion was obtained. By the reaction of neutralization the salts with organic and inorganic bases were obtained. The physical-chemical properties of the compounds were determined. The structure of the substances was confirmed by elemental analysis on an Elementar Vario L cube (CHNS instrument; IR spectra (4000–400 cm-1 were taken on the ALPHA-T modules of the Bruker ALPHA FT-IR spectrometer. The 1H NMR spectra of the compounds were recorded using a Varian Mercury VX 200 spectrometer (solvent – DMSO-d6, internal standard: tetramethylsilane. The formation of salts was confirmed by the signals of the corresponding protonated amines. Chromato-mass spectral studies were carried out on the LC MS: Agilent 1260 Infinity HPLC System , ionization method – chemical ionization at atmospheric pressure (APCI. Conclusions. The interaction of the resulting thiol with monochloracetic acid in aqueous solution with double quantity of alkali and subsequent neutralization leads to corresponding carboxylic acid obtaining. It was confirmed that the greatest outputs of salts as the reaction products were observed when using water as the solvent with the subsequent replacement of acetone. the optimum conditions of obtaining salts of 5-(2-bromophenyl-4-amino-4H-1,2,4-triazole-3-ylthioacetic acid
Effects of S-adenosylmethionine decarboxylase, polyamines, amino acids, and weak bases (amines and ammonia) on development and ribosomal RNA synthesis in Xenopus embryos.
Shiokawa, Koichiro; Aso, Mai; Kondo, Takeshi; Takai, Jun-Ichi; Yoshida, Junki; Mishina, Takamichi; Fuchimukai, Kota; Ogasawara, Tsukasa; Kariya, Taro; Tashiro, Kosuke; Igarashi, Kazuei
We have been studying control mechanisms of gene expression in early embryogenesis in a South African clawed toad Xenopus laevis, especially during the period of midblastula transition (MBT), or the transition from the phase of active cell division (cleavage stage) to the phase of extensive morphogenesis (post-blastular stages). We first found that ribosomal RNA synthesis is initiated shortly after MBT in Xenopus embryos and those weak bases, such as amines and ammonium ion, selectively inhibit the initiation and subsequent activation of rRNA synthesis. We then found that rapidly labeled heterogeneous mRNA-like RNA is synthesized in embryos at pre-MBT stage. We then performed cloning and expression studies of several genes, such as those for activin receptors, follistatin and aldolases, and then reached the studies of S-adenosylmethionine decarboxylase (SAMDC), a key enzyme in polyamine metabolism. Here, we cloned a Xenopus SAMDC cDNA and performed experiments to overexpress the in vitro-synthesized SAMDC mRNA in Xenopus early embryos, and found that the maternally preset program of apoptosis occurs in cleavage stage embryos, which is executed when embryos reach the stage of MBT. In the present article, we first summarize results on SAMDC and the maternal program of apoptosis, and then describe our studies on small-molecular-weight substances like polyamines, amino acids, and amines in Xenopus embryos. Finally, we summarize our studies on weak bases, especially on ammonium ion, as the specific inhibitor of ribosomal RNA synthesis in Xenopus embryonic cells.
Amino acids as antioxidants for frying oil
Amino acids, proteins and hydrolysates of proteins have been known to protect edible oils from oxidation. While amino acids and related materials have high potential as antioxidants for frying oil, effectiveness of each amino acid and mechanisms of their activities are not well understood yet. Propo...
Symmetry Scheme for Amino Acid Codons
Balakrishnan, J.
Group theoretical concepts are invoked in a specific model to explain how only twenty amino acids occur in nature out of a possible sixty four. The methods we use enable us to justify the occurrence of the recently discovered twenty first amino acid selenocysteine, and also enables us to predict the possible existence of two more, as yet undiscovered amino acids.
Nonprotein amino acids from Cycas revoluta.
Pan, M; Mabry, T J; Beale, J M; Mamiya, B M
Two nonprotein amino acids, cycasindene and cycasthioamide, along with eight known nonprotein amino acids, were isolated from the seeds of Cycas revoluta Thunb. The structures of cycasindene and cycasthioamide were elucidated as 3-[3'-amino-indenyl-2]-alanine (1) and N-[glycinyl-alaninyl-11-thio]-5-one-pipecolic acid (2) by chemical and spectral methods.
Unnatural reactive amino acid genetic code additions
Energy Technology Data Exchange (ETDEWEB)
Deiters, Alexander; Cropp, T. Ashton; Chin, Jason W.; Anderson, Christopher J.; Schultz, Peter G.
This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.
Reactions of tritium atoms with amino acids, deuterated amino acids and mixtures of amino acids. Additivity property and isotope effect
International Nuclear Information System (INIS)
Badun, G.A.; Filatov, Eh.S.
Interaction of tritium atoms with glycine (1) and leucine (2) amino acids, deuterated amino acids, their mixtures and glycylleucine (3) peptide in the 77-300 K temperature range is studied in isothermal and gradient regimes. Tagged amino acids were separated from targets after conducting the reaction. At T 150 K are associated with intermolecular transmission of free valence in the mixture of amino acids. Regularities of the reaction found for the mixture of amino acids are conserved for (3) as well, i.e. the peptide bond does not essentially affect the reaction of isotopic exchange conditioned by atomic tritium
Efficient Enzymatic Routes for the Synthesis of New Eight-membered Cyclic β-Amino Acid and β-Lactam Enantiomers
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Enikő Forró
Full Text Available Efficient enzymatic resolutions are reported for the preparation of new eight-membered ring-fused enantiomeric β-amino acids [(1R,2S-9 and (1S,2R-9] and β-lactams [(1S,8R-3, (1R,8S-3 (1S,8R-4 and (1R,8S-7], through asymmetric acylation of (±-4 (E > 100 or enantioselective hydrolysis (E > 200 of the corresponding inactivated (±-3 or activated (±-4 β-lactams, catalyzed by PSIM or CAL-B in an organic solvent. CAL-B-catalyzed ring cleavage of (±-6 (E > 200 resulted in the unreacted (1S,8R-6, potential intermediate for the synthesis of enantiomeric anatoxin-a. The best strategies, in view of E, reaction rate and product yields, which underline the importance of substrate engineering, are highlighted.
Regulation of intestinal protein metabolism by amino acids.
Bertrand, Julien; Goichon, Alexis; Déchelotte, Pierre; Coëffier, Moïse
Gut homeostasis plays a major role in health and may be regulated by quantitative and qualitative food intake. In the intestinal mucosa, an intense renewal of proteins occurs, at approximately 50% per day in humans. In some pathophysiological conditions, protein turnover is altered and may contribute to intestinal or systemic diseases. Amino acids are key effectors of gut protein turnover, both as constituents of proteins and as regulatory molecules limiting intestinal injury and maintaining intestinal functions. Many studies have focused on two amino acids: glutamine, known as the preferential substrate of rapidly dividing cells, and arginine, another conditionally essential amino acid. The effects of glutamine and arginine on protein synthesis appear to be model and condition dependent, as are the involved signaling pathways. The regulation of gut protein degradation by amino acids has been minimally documented until now. This review will examine recent data, helping to better understand how amino acids regulate intestinal protein metabolism, and will explore perspectives for future studies.
Modifying tetramethyl–nitrophenyl–imidazoline with amino acids: design, synthesis, and 3D-QSAR for improving inflammatory pain therapy
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Jiang X
Full Text Available Xueyun Jiang,1 Yuji Wang,1 Haimei Zhu,1 Yaonan Wang,1 Ming Zhao,1,2 Shurui Zhao,1 Jianhui Wu,1 Shan Li,1 Shiqi Peng11Beijing Area Major Laboratory of Peptide and Small Molecular Drugs, Engineering Research Center of Endogenous Prophylactic of Ministry of Education of China, Beijing Laboratory of Biomedical Materials, College of Pharmaceutical Sciences, Capital Medical University, Beijing, People's Republic of China; 2Faculty of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, TaiwanAbstract: With the help of pharmacophore analysis and docking investigation, 15 novel 1-(4,4,5,5-tetramethyl-2-(3-nitrophenyl-4,5-dihydroimidazol-1-yl-oxyacetyl-L-amino acids (6a–o were designed, synthesized, and assayed. On tail-flick and xylene-induced ear edema models, 10 µmol/kg 6a–o exhibited excellent oral anti-inflammation and analgesic activity. The dose-dependent assay of their representative 6f indicates that the effective dose should be 3.3 µmol/kg. The correlation of the three-dimensional quantitative structure–activity relationship with the docking analysis provides a basis for the rational design of drugs to treat inflammatory pain.Keywords: tetramethylimidazoline, analgesic, anti-inflammatory, 3D-QSAR
MS-READ: Quantitative measurement of amino acid incorporation.
Mohler, Kyle; Aerni, Hans-Rudolf; Gassaway, Brandon; Ling, Jiqiang; Ibba, Michael; Rinehart, Jesse
Ribosomal protein synthesis results in the genetically programmed incorporation of amino acids into a growing polypeptide chain. Faithful amino acid incorporation that accurately reflects the genetic code is critical to the structure and function of proteins as well as overall proteome integrity. Errors in protein synthesis are generally detrimental to cellular processes yet emerging evidence suggest that proteome diversity generated through mistranslation may be beneficial under certain conditions. Cumulative translational error rates have been determined at the organismal level, however codon specific error rates and the spectrum of misincorporation errors from system to system remain largely unexplored. In particular, until recently technical challenges have limited the ability to detect and quantify comparatively rare amino acid misincorporation events, which occur orders of magnitude less frequently than canonical amino acid incorporation events. We now describe a technique for the quantitative analysis of amino acid incorporation that provides the sensitivity necessary to detect mistranslation events during translation of a single codon at frequencies as low as 1 in 10,000 for all 20 proteinogenic amino acids, as well as non-proteinogenic and modified amino acids. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue. Copyright © 2017 Elsevier B.V. All rights reserved.
Hybride magnetic nanostructure based on amino acids functionalized polypyrrole
Energy Technology Data Exchange (ETDEWEB)
Nan, Alexandrina, E-mail: firstname.lastname@example.com; Bunge, Alexander; Turcu, Rodica [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, 400293 Cluj-Napoca (Romania)
Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.
Synthesis and Biophysical Studies of Coronene Functionalized 2′-Amino-LNA: A Novel Class of Fluorescent Nucleic Acids
DEFF Research Database (Denmark)
Gupta, Pankaj; Langkjær, Niels; Wengel, Jesper
Incorporation of 2'-N-(coronen-1-yl)methyl-2'-amino-LNA monomer X or 2'-N-4-(coronen-1-yl)-4-oxobutanoyl-2'-amino-LNA monomer Y into short DNA strands induces high binding affinity toward DNA or RNA and a marked red-shift in steady-state fluorescence emission upon hybridization to cDNA or RNA....
Amino acid properties conserved in molecular evolution.
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Witold R Rudnicki
Full Text Available That amino acid properties are responsible for the way protein molecules evolve is natural and is also reasonably well supported both by the structure of the genetic code and, to a large extent, by the experimental measures of the amino acid similarity. Nevertheless, there remains a significant gap between observed similarity matrices and their reconstructions from amino acid properties. Therefore, we introduce a simple theoretical model of amino acid similarity matrices, which allows splitting the matrix into two parts - one that depends only on mutabilities of amino acids and another that depends on pairwise similarities between them. Then the new synthetic amino acid properties are derived from the pairwise similarities and used to reconstruct similarity matrices covering a wide range of information entropies. Our model allows us to explain up to 94% of the variability in the BLOSUM family of the amino acids similarity matrices in terms of amino acid properties. The new properties derived from amino acid similarity matrices correlate highly with properties known to be important for molecular evolution such as hydrophobicity, size, shape and charge of amino acids. This result closes the gap in our understanding of the influence of amino acids on evolution at the molecular level. The methods were applied to the single family of similarity matrices used often in general sequence homology searches, but it is general and can be used also for more specific matrices. The new synthetic properties can be used in analyzes of protein sequences in various biological applications.
Nature's starships. I. Observed abundances and relative frequencies of amino acids in meteorites
International Nuclear Information System (INIS)
Cobb, Alyssa K.; Pudritz, Ralph E.
The class of meteorites called carbonaceous chondrites are examples of material from the solar system which have been relatively unchanged from the time of their initial formation. These meteorites have been classified according to the temperatures and physical conditions of their parent planetesimals. We collate available data on amino acid abundance in these meteorites and plot the concentrations of different amino acids for each meteorite within various meteorite subclasses. We plot average concentrations for various amino acids across meteorites separated by subclass and petrologic type. We see a predominance in the abundance and variety of amino acids in CM2 and CR2 meteorites. The range in temperature corresponding to these subclasses indicates high degrees of aqueous alteration, suggesting aqueous synthesis of amino acids. Within the CM2 and CR2 subclasses, we identify trends in relative frequencies of amino acids to investigate how common amino acids are as a function of their chemical complexity. These two trends (total abundance and relative frequencies) can be used to constrain formation parameters of amino acids within planetesimals. Our organization of the data supports an onion shell model for the temperature structure of planetesimals. The least altered meteorites (type 3) and their amino acids originated near cooler surface regions. The most active amino acid synthesis likely took place at intermediate depths (type 2). The most altered materials (type 1) originated furthest toward parent body cores. This region is likely too hot to either favor amino acid synthesis or for amino acids to be retained after synthesis.
Stable isotope fingerprinting: a novel method for identifying plant, fungal, or bacterial origins of amino acids
Thomas Larsen; D. Lee Taylor; Mary Beth Leigh; Diane M. O' Brien
Amino acids play an important role in ecology as essential nutrients for animals and as currencies in symbiotic associations. Here we present a new approach to tracing the origins of amino acids by identifying unique patterns of carbon isotope signatures generated by amino acid synthesis in plants, fungi, and bacteria ("13C fingerprints...
Mycosporine like amino acids in brown algae
Serban Radu; Stoian Gheorghe
Biosynthesis of mycosporine and accumulation in cells serves as protection, by shielding the cells sensitive molecules Mycosporine-like aminoacids (MAAs) are derivated compounds of mycosporine that contains an amino-cyclohexenimine ring liked to an amino acid, amino alcohol or amino group. They preesent absorbtion maximum between 320 and 360 nm.
Mycosporine like amino acids in brown algae
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Serban Radu
Full Text Available Biosynthesis of mycosporine and accumulation in cells serves as protection, by shielding the cells sensitive molecules Mycosporine-like aminoacids (MAAs are derivated compounds of mycosporine that contains an amino-cyclohexenimine ring liked to an amino acid, amino alcohol or amino group. They preesent absorbtion maximum between 320 and 360 nm.
Branched Chain Amino Acids: Beyond Nutrition Metabolism.
Nie, Cunxi; He, Ting; Zhang, Wenju; Zhang, Guolong; Ma, Xi
Branched chain amino acids (BCAAs), including leucine (Leu), isoleucine (Ile), and valine (Val), play critical roles in the regulation of energy homeostasis, nutrition metabolism, gut health, immunity and disease in humans and animals. As the most abundant of essential amino acids (EAAs), BCAAs are not only the substrates for synthesis of nitrogenous compounds, they also serve as signaling molecules regulating metabolism of glucose, lipid, and protein synthesis, intestinal health, and immunity via special signaling network, especially phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signal pathway. Current evidence supports BCAAs and their derivatives as the potential biomarkers of diseases such as insulin resistance (IR), type 2 diabetes mellitus (T2DM), cancer, and cardiovascular diseases (CVDs). These diseases are closely associated with catabolism and balance of BCAAs. Hence, optimizing dietary BCAA levels should have a positive effect on the parameters associated with health and diseases. This review focuses on recent findings of BCAAs in metabolic pathways and regulation, and underlying the relationship of BCAAs to related disease processes.
Method Development for Efficient Incorporation of Unnatural Amino Acids
Harris, Paul D.
The synthesis of proteins bearing unnatural amino acids has the potential to enhance and elucidate many processes in biochemistry and molecular biology. There are two primary methods for site specific unnatural amino acid incorporation, both of which use the cell's native protein translating machinery: in vitro chemical acylation of suppressor tRNAs and the use of orthogonal amino acyl tRNA synthetases. Total chemical synthesis is theoretically possible, but current methods severely limit the maximum size of the product protein. In vivo orthogonal synthetase methods suffer from the high cost of the unnatural amino acid. In this thesis I sought to address this limitation by increasing cell density, first in shake flasks and then in a bioreactor in order to increase the yield of protein per amount of unnatural amino acid used. In a parallel project, I used the in vitro chemical acylation system to incorporate several unnatural amino acids, key among them the fluorophore BODIPYFL, with the aim of producing site specifically fluorescently labeled protein for single molecule FRET studies. I demonstrated successful incorporation of these amino acids into the trial protein GFP, although incorporation was not demonstrated in the final target, FEN1. This also served to confirm the effectiveness of a new procedure developed for chemical acylation.
Amino acid fermentation at the origin of the genetic code.
de Vladar, Harold P
There is evidence that the genetic code was established prior to the existence of proteins, when metabolism was powered by ribozymes. Also, early proto-organisms had to rely on simple anaerobic bioenergetic processes. In this work I propose that amino acid fermentation powered metabolism in the RNA world, and that this was facilitated by proto-adapters, the precursors of the tRNAs. Amino acids were used as carbon sources rather than as catalytic or structural elements. In modern bacteria, amino acid fermentation is known as the Stickland reaction. This pathway involves two amino acids: the first undergoes oxidative deamination, and the second acts as an electron acceptor through reductive deamination. This redox reaction results in two keto acids that are employed to synthesise ATP via substrate-level phosphorylation. The Stickland reaction is the basic bioenergetic pathway of some bacteria of the genus Clostridium. Two other facts support Stickland fermentation in the RNA world. First, several Stickland amino acid pairs are synthesised in abiotic amino acid synthesis. This suggests that amino acids that could be used as an energy substrate were freely available. Second, anticodons that have complementary sequences often correspond to amino acids that form Stickland pairs. The main hypothesis of this paper is that pairs of complementary proto-adapters were assigned to Stickland amino acids pairs. There are signatures of this hypothesis in the genetic code. Furthermore, it is argued that the proto-adapters formed double strands that brought amino acid pairs into proximity to facilitate their mutual redox reaction, structurally constraining the anticodon pairs that are assigned to these amino acid pairs. Significance tests which randomise the code are performed to study the extent of the variability of the energetic (ATP) yield. Random assignments can lead to a substantial yield of ATP and maintain enough variability, thus selection can act and refine the assignments
Amino acid fermentation at the origin of the genetic code
There is evidence that the genetic code was established prior to the existence of proteins, when metabolism was powered by ribozymes. Also, early proto-organisms had to rely on simple anaerobic bioenergetic processes. In this work I propose that amino acid fermentation powered metabolism in the RNA world, and that this was facilitated by proto-adapters, the precursors of the tRNAs. Amino acids were used as carbon sources rather than as catalytic or structural elements. In modern bacteria, amino acid fermentation is known as the Stickland reaction. This pathway involves two amino acids: the first undergoes oxidative deamination, and the second acts as an electron acceptor through reductive deamination. This redox reaction results in two keto acids that are employed to synthesise ATP via substrate-level phosphorylation. The Stickland reaction is the basic bioenergetic pathway of some bacteria of the genus Clostridium. Two other facts support Stickland fermentation in the RNA world. First, several Stickland amino acid pairs are synthesised in abiotic amino acid synthesis. This suggests that amino acids that could be used as an energy substrate were freely available. Second, anticodons that have complementary sequences often correspond to amino acids that form Stickland pairs. The main hypothesis of this paper is that pairs of complementary proto-adapters were assigned to Stickland amino acids pairs. There are signatures of this hypothesis in the genetic code. Furthermore, it is argued that the proto-adapters formed double strands that brought amino acid pairs into proximity to facilitate their mutual redox reaction, structurally constraining the anticodon pairs that are assigned to these amino acid pairs. Significance tests which randomise the code are performed to study the extent of the variability of the energetic (ATP) yield. Random assignments can lead to a substantial yield of ATP and maintain enough variability, thus selection can act and refine the assignments
Amino acid fermentation at the origin of the genetic code
Directory of Open Access Journals (Sweden)
de Vladar Harold P
Full Text Available Abstract There is evidence that the genetic code was established prior to the existence of proteins, when metabolism was powered by ribozymes. Also, early proto-organisms had to rely on simple anaerobic bioenergetic processes. In this work I propose that amino acid fermentation powered metabolism in the RNA world, and that this was facilitated by proto-adapters, the precursors of the tRNAs. Amino acids were used as carbon sources rather than as catalytic or structural elements. In modern bacteria, amino acid fermentation is known as the Stickland reaction. This pathway involves two amino acids: the first undergoes oxidative deamination, and the second acts as an electron acceptor through reductive deamination. This redox reaction results in two keto acids that are employed to synthesise ATP via substrate-level phosphorylation. The Stickland reaction is the basic bioenergetic pathway of some bacteria of the genus Clostridium. Two other facts support Stickland fermentation in the RNA world. First, several Stickland amino acid pairs are synthesised in abiotic amino acid synthesis. This suggests that amino acids that could be used as an energy substrate were freely available. Second, anticodons that have complementary sequences often correspond to amino acids that form Stickland pairs. The main hypothesis of this paper is that pairs of complementary proto-adapters were assigned to Stickland amino acids pairs. There are signatures of this hypothesis in the genetic code. Furthermore, it is argued that the proto-adapters formed double strands that brought amino acid pairs into proximity to facilitate their mutual redox reaction, structurally constraining the anticodon pairs that are assigned to these amino acid pairs. Significance tests which randomise the code are performed to study the extent of the variability of the energetic (ATP yield. Random assignments can lead to a substantial yield of ATP and maintain enough variability, thus selection can
Sugar amino acids and related molecules
Indian Academy of Sciences (India)
Sugar amino acids constitute an important class of such polyfunctional scaffolds where the carboxyl, amino and hydroxyl termini provide an excellent opportunity to organic chemists to create structural diversities akin to Nature's molecular arsenal. In recent years, sugar amino acids have been used extensively in the area of ...
Yamamoto, Keisuke; Tsuchisaka, Atsunari; Yukawa, Hideaki
Branched-chain amino acids (BCAAs), viz., L-isoleucine, L-leucine, and L-valine, are essential amino acids that cannot be synthesized in higher organisms and are important nutrition for humans as well as livestock. They are also valued as synthetic intermediates for pharmaceuticals. Therefore, the demand for BCAAs in the feed and pharmaceutical industries is increasing continuously. Traditional industrial fermentative production of BCAAs was performed using microorganisms isolated by random mutagenesis. A collection of these classical strains was also scientifically useful to clarify the details of the BCAA biosynthetic pathways, which are tightly regulated by feedback inhibition and transcriptional attenuation. Based on this understanding of the metabolism of BCAAs, it is now possible for us to pursue strains with higher BCAA productivity using rational design and advanced molecular biology techniques. Additionally, systems biology approaches using augmented omics information help us to optimize carbon flux toward BCAA production. Here, we describe the biosynthetic pathways of BCAAs and their regulation and then overview the microorganisms developed for BCAA production. Other chemicals, including isobutanol, i.e., a second-generation biofuel, can be synthesized by branching the BCAA biosynthetic pathways, which are also outlined.
Amino-acid contamination of aqueous hydrochloric acid.
Wolman, Y.; Miller, S. L.
Considerable amino-acid contamination in commercially available analytical grade hydrochloric acid (37% HCl) was found. One bottle contained 8,300 nmol of amino-acids per liter. A bottle from another supplier contained 6,700 nmol per liter. The contaminants were mostly protein amino-acids and several unknowns. Data on the volatility of the amino-acids during HCl distillation were also obtained.
Interactive network analysis of the plasma amino acids profile in a mouse model of hyperglycemia
Tanaka, Takayuki; Mochida, Taiga; Maki, Yukihiro; Shiraki, Yasuko; Mori, Hiroko; Matsumoto, Shirou; Shimbo, Kazutaka; Ando, Toshihiko; Nakamura, Kimitoshi; Endo, Fumio; Okamoto, Masahiro
Amino acids are a group of metabolites that are important substrates for protein synthesis, are important as signaling molecules and play central roles as highly connected metabolic hubs, and therefore, there are many reports that describe disease-specific abnormalities in plasma amino acids profile. However, the causes of progression from a healthy control to a manifestation of the plasma amino acid changes remain obscure. Here, we extended the plasma amino acids profile to relationships tha...
Studies on radiolysis of amino acids, 2
International Nuclear Information System (INIS)
Oku, Tadatake
Continuing from the previous paper, the radiolytic mechanisms of basic amino acids, imino acids and aromatic amino acids were studied. Aqueous solutions of L-histidine.HCI.H 2 O, L-lysine.HCI, L-arginine.HCI, DL-ornithine.HCI, L-citrulline, L-proline, L-hydroxyproline, L-tyrosine, L-tryptophan, L-phenylalanine and L-dihydroxyphenyl-alanine (1 mM) were irradiated with γ-rays of 60 Co at doses of 4.4-2,640x10 3 rads in the presence of air or in the atmosphere of nitrogen. The amino acids and the radiolytic products of the amino acid in aqueous solutions were determined by ion-exchange chromatography. The ultraviolet spectra of the aromatic amino acid solutions were measured. From the results obtained and G-values calculated, the radiolytic mechanisms of amino acids were assumed. (auth.)
Beneficial Effects of the Amino Acid Glycine.
Pérez-Torres, Israel; Zuniga-Munoz, Alejandra María; Guarner-Lans, Veronica
Glycine is the smallest non-essential, neutral and metabolically inert amino acid, with a carbon atom bound to two hydrogen atoms, and to an amino and a carboxyl group. This amino acid is an essential substrate for the synthesis of several biologically important biomolecules and compounds. It participates in the synthesis of proteins, of the tripeptide glutathione and in detoxification reactions. It has a broad spectrum of anti-inflammatory, cytoprotective and immunomodulatory properties. To exert its actions, glycine binds to different receptors. The GlyR anion channel is the most studied receptor for glycine. However, there are GlyR-independent mechanisms for glycine cytoprotection and other possible binding molecules of glycine are the NMDA receptor and receptors GlyT1 and GlyT2. Although, in humans, the normal serum level of glycine is approximately 300 μM, increasing glycine intake can lead to blood levels of more than 900 μM that increase its benefic actions without having harmful side effects. The herbal pesticide glyphosate might disrupt glycine homeostasis. Many in vitro studies involving different cell types have demonstrated beneficial effects of the addition of glycine. Glycine also improved conditions of isolated perfused or stored organs. In vivo studies in experimental animals have also tested glycine as a protector molecule and some studies on the beneficial effects of glycine after its clinical application have been done. Although at high-doses, glycine may cause toxic effects, further studies are needed to investigate the safe range of usage of this aminoacid and to test the diverse routes of administration.
Bacterial expression and/or solid phase peptide synthesis of 20-40 amino acid long polypeptides and miniproteins, the case study of Class B GPCR ligands.
Stráner, Pál; Taricska, Nóra; Szabó, Mária; Tóth, Gábor K; Perczel, András
By using two different synthetic techniques several polypeptides interacting with Class B type G-protein coupled receptors were prepared. These polypeptides of different lengths (20 ≤ amino acids ≤ 40), structural and aggregation properties, were prepared both by solid phase peptide synthesis (SPPS) and E.coli bacterial expression. Their purity, synthetic yields, by-products and (15)N/(13)Clabelling characteristics were compared as function of i) the applied method, ii) amino acid length and iii) folding propensities. Their tentative yields, costs and "environmental footprints" were analyzed and found as follows. For unlabelled and short polypeptides (n= 20 aa.) the method of choice is the less environmentally friendly however, quick and effective SPPS. If the polypeptide is (un)folded and/or has no aggregation propensity, then SPPS gives relatively good yield (e.g. 14 ± 4%) and a pure product (>97%). For aggregating polypeptides production yields drop for both methods 4 ± 2% (SPPS) and 2 ± 1% (E. coli), respectively. For longer (n≥ 30 aa.) macromolecules (e.g. miniproteins) bacterial expression efficacy gets higher. Moreover biotechnology is "greener", the resulting in raw material is purer (2.8 ± 1.5 mg). All these advantages for at a lower cost: ~4 €/aa. If isotopic labelling is needed for heteronuclear NMR measurements, bacterial expression is the sole option, due to the high cost of (15)N/(13)C labelled Fmoc(Boc)-L-aa-OH starting materials needed for SPPS. In E.coli uniformly double-labelled, pure polypeptides can be obtained for less than 5-700 €/mg, regardless of the length of the polypeptide chain. Thus, chemists are encouraged to use E.coli expression systems when adequate to make not only proteins but polypeptides and miniproteins as well.
Electrokinetic characterization of magnetite nanoparticles functionalized with amino acids.
Viota, J L; Arroyo, F J; Delgado, A V; Horno, J
The synthesis of nanoparticles consisting of a magnetite core coated with one or more layers of amino acid (L-arginine, L-lysine, glycine, and L-glutamine) is described in this paper. For all the amino acids it is found that adsorption increases with concentration in solution in the range 0.5-10 mg/mL. The adsorption, however, differs substantially from one amino acid to another, depending on the length of the hydrocarbon chain and the polarity and charge of the side group. Thus, for given concentration and pH, adsorption is found to increase in the order L-arginine magnetite and the charge of the amino acid molecules for different pHs, indicating a significant role of electrostatics in adsorption. This is further checked by means of determinations of the electrophoretic mobility of amino acid-coated magnetite as a function of pH: the results indicate a shift of the isoelectric point of the raw magnetite toward more basic pHs, an indication of adsorption of positive species, as confirmed by the tendency of the mobility of amino acid-coated magnetite toward more positive values below neutral pH. The electrophoretic mobility of coated particles was also measured as a function of the concentration of amino acid, and it was found that for low concentrations the four amino acids provoke charge inversion and overcharging of the magnetite surface at pH 6. Finally, the dependence of the electrophoretic mobility on the ionic strength indicated that from an electrophoretic point of view, the functionalized magnetite-amino acid particles do not behave as soft particles, and that the amino acid coating should be very compact. Copyright 2009 Elsevier Inc. All rights reserved.
Dependence of the metabolic fecal amino acids on the amino acid content of the feed. 2
International Nuclear Information System (INIS)
Krawielitzki, K.; Schadereit, R.; Voelker, T.; Reichel, K.
In an experiment with 20 15 N-labelled growing rats the excretion of amino acids as well as of metabolic fecal amino acids were investigated after feeding of soybean oil meal as sole protein source. A low, yet statistically significant increase of the excretion of amino acids and metabolic fecal amino acids was ascertained in accordance with a growing quota of soybean oil meal in the ration. The true digestibility of amino acids ascertained according to conventional methods is above 90% and, under consideration of the increase of metabolic fecal amino acids, on the average increases by 3.5 digestibility units (1.4 to 6.2). (author)
Α-amino-β-fluorocyclopropanecarboxylic acids as a new tool for drug development: synthesis of glutamic acid analogs and agonist activity towards metabotropic glutamate receptor 4.
Lemonnier, Gérald; Lion, Cédric; Quirion, Jean-Charles; Pin, Jean-Philippe; Goudet, Cyril; Jubault, Philippe
Herein we describe the diastereoselective synthesis of glutamic acid analogs and the evaluation of their agonist activity towards metabotropic glutamate receptor subtype 4 (mGluR4). These analogs are based on a monofluorinated cyclopropane core substituted with an α-aminoacid function. The potential of this new building block as a tool for the development of a novel class of drugs is demonstrated with racemic analog 11a that displayed the best agonist activity with an EC50 of 340 nM. Copyright © 2012 Elsevier Ltd. All rights reserved.
Synthesis and Characterization of Micelle-Forming PEG-Poly(Amino Acid) Copolymers with Iron-Hydroxamate Cross-Linkable Blocks for Encapsulation and Release of Hydrophobic Drugs.
Sill, Kevin N; Sullivan, Bradford; Carie, Adam; Semple, J Edward
Described is the development of a polymeric micelle drug delivery platform that addresses the physical property limitations of many nanovectors. The system employs triblock copolymers comprised of a hydrophilic poly(ethylene glycol) (PEG) block, and two poly(amino acid) (PAA) blocks: a stabilizing cross-linking central block, and a hydrophobic drug encapsulation block. Detailed description of synthetic strategies and considerations found to be critical are discussed. Of note, it was determined that the purity of the α-amino acid-N-carboxyanhydrides (NCA) monomers and PEG macroinitiator are ultimately responsible for impurities that arise during the polymerization. Also, contrary to current beliefs in the field, the presence of water does not adversely affect the polymerization of NCAs. Furthermore, we describe the impact of poly(amino acid) conformational changes, through the incorporation of d-amino acids to form mixed stereochemistry PAA blocks, with regard to the physical and pharmacokinetic properties of the resulting micelles.
Regulation of intestinal mucosal growth by amino acids.
Ray, Ramesh M; Johnson, Leonard R
Amino acids, especially glutamine (GLN) have been known for many years to stimulate the growth of small intestinal mucosa. Polyamines are also required for optimal mucosal growth, and the inhibition of ornithine decarboxylase (ODC), the first rate-limiting enzyme in polyamine synthesis, blocks growth. Certain amino acids, primarily asparagine (ASN) and GLN stimulate ODC activity in a solution of physiological salts. More importantly, their presence is also required before growth factors and hormones such as epidermal growth factor and insulin are able to increase ODC activity. ODC activity is inhibited by antizyme-1 (AZ) whose synthesis is stimulated by polyamines, thus, providing a negative feedback regulation of the enzyme. In the absence of amino acids mammalian target of rapamycin complex 1 (mTORC1) is inhibited, whereas, mTORC2 is stimulated leading to the inhibition of global protein synthesis but increasing the synthesis of AZ via a cap-independent mechanism. These data, therefore, explain why ASN or GLN is essential for the activation of ODC. Interestingly, in a number of papers, AZ has been shown to inhibit cell proliferation, stimulate apoptosis, or increase autophagy. Each of these activities results in decreased cellular growth. AZ binds to and accelerates the degradation of ODC and other proteins shown to regulate proliferation and cell death, such as Aurora-A, Cyclin D1, and Smad1. The correlation between the stimulation of ODC activity and the absence of AZ as influenced by amino acids is high. Not only do amino acids such as ASN and GLN stimulate ODC while inhibiting AZ synthesis, but also amino acids such as lysine, valine, and ornithine, which inhibit ODC activity, increase the synthesis of AZ. The question remaining to be answered is whether AZ inhibits growth directly or whether it acts by decreasing the availability of polyamines to the dividing cells. In either case, evidence strongly suggests that the regulation of AZ synthesis is the
Single step synthesis of gold-amino acid composite, with the evidence of the catalytic hydrogen atom transfer (HAT) reaction, for the electrochemical recognition of Serotonin
Choudhary, Meenakshi; Siwal, Samarjeet; Nandi, Debkumar; Mallick, Kaushik
A composite architecture of amino acid and gold nanoparticles has been synthesized using a generic route of 'in-situ polymerization and composite formation (IPCF)' [1,2]. The formation mechanism of the composite has been supported by a model hydrogen atom (H•≡H++e-) transfer (HAT) type of reaction which belongs to the proton coupled electron transfer (PCET) mechanism. The 'gold-amino acid composite' was used as a catalyst for the electrochemical recognition of Serotonin.
Synthesis of gamma,delta-unsaturated and delta,epsilon-unsaturated alpha-amino acids from fragmentation of gamma- and delta-lactones.
Tarver, James E; Joullié, Madeleine M
A noncoded amino acid of cyclomarin A (1) was synthesized in a racemic fashion. The method employs a six-membered ring template to control the relative stereochemistry and introduction of the functional groups. Ultimately, Pd-catalyzed fragmentation of the lactone provided gamma,delta-unsaturated and delta,epsilon-unsaturated alpha-amino acids. A Pd-catalyzed ring opening of a gamma-lactone is also reported.
African Journals Online (AJOL)
Levels of amino acids were determined in the grains of guinea corn, Sorghum bicolor (L.) Moench. ... essential amino acids of 30.70 g/100 g c.p., 28.33 g/100 g c.p. and 21.48 g/100 g c.p. Percentage cystine/total sulfur amino acid ..... F.A.O. Sorghum and millets in human nutrition, FAO Food and Nutrition Series, No. 27,.
Amino acid composition of some Mexican foods.
Morales de León, Josefina; Camacho, M Elena; Bourges, Héctor
Knowledge of the amino acid composition of foods is essential to calculate their chemical score, which is used to predict protein quality of foods and diets. Though amino acid composition of many foods is reasonably well established, better knowledge is needed on native foods consumed in different regions and countries. This paper presents the amino acid composition of different presentations of raw and processed foods produced and consumed in Mexico. The amino acid composition was determined using Beckman amino acid analyzers (models 116 and 6300). Tryptophan was determined using the Spies and Chambers method. Of the different foods analyzed, some comments are made on native or basic foods in Mexico: Spirulin, where lysine is the limiting amino acid, with a chemical score of 67%, is a good source of tryptophan (1.16g/16 gN); amaranth contains high levels of sulphur amino acids (4.09 to 5.34 g/16gN), with a protein content of 15 g/100g; and pulque, a Pre-Hispanic beverage that contains high levels of tryptophan (2.58 g/16 gN) and sulphur amino acids (2.72 g/16 gN). Finally, insects are good sources of sulphur amino acids and lysine.
Synthesis of O-Amino Sugars and Nucleosides.
Chen, Na; Xie, Juan
Nucleic acids and carbohydrates are essential biomolecules involved in numerous biological and pathological processes. Development of multifunctional building blocks based on nucleosides and sugars is in high demand for the generation of novel oligonucleotide mimics and glycoconjugates for biomedical applications. Recently, aminooxyl-functionalized compounds have attracted increasing research interest because of their easy derivatization through oxime ligation or N -oxyamide formation reactions. Various biological applications have been reported for O -amino carbohydrate- and nucleoside-derived compounds. Here, we report our efforts in the design and synthesis of glyco-, glycosyl, nucleoside- and nucleo-aminooxy acid derivatives from readily available sugars and amino acids, and their use for the generation of N -oxyamide-linked oligosaccharides, glycopeptides, glycolipids, oligonucleosides and nucleopeptides as novel glycoconjugates or oligonucleotide mimics. Delicate and key points in the synthesis will be emphasized.
Pyrolysis of amino acids - Mechanistic considerations
Ratcliff, M. A., Jr.; Medley, E. E.; Simmonds, P. G.
Pyrolysis of several structurally different amino acids in a column at 500 C showed differences in the mechanisms and final products. The aliphatic protein amino acids decompose mainly by simple decarboxylation and condensation reactions, while the beta amino acids undergo deamination to unsaturated acids. Alpha amino acids with alpha alkyl substituents undergo an unusual intramolecular SN1 reaction with the formation of an intermediate alpha lactone which decomposes to yield a ketone. The alpha alkyl substituents appear to stabilize the developing negative charge formed by partial heterolytic cleavage of the alpha carbon - NH3 bond. The gamma and delta amino acids give 2-pyrrolidinone and 2-piperidone respectively, while the epsilon acids yield mixed products.
Immobilized Cu (II)—Amino Acid Complexes as Prospective Highly Efficient Catalytic Materials: Synthesis, Structural Characterization and Catalytic Activities
Pálinkó, István; Ordasi, Adrien; Kiss, János T.; Labádi, Imre
In this work the covalent anchoring of N-or C-protected Cu(II)—L-tyrosine complexes onto a swellable resin or surface-modified silica gel is described. Experimental conditions (solvents, the availability of ligands) of the synthesis were varied; the structures (by IR spectroscopy) and the superoxide dismutase activities of the anchored complexes were studied.
Amphipathic helices from aromatic amino acid oligomers.
Gillies, Elizabeth R; Dolain, Christel; Léger, Jean-Michel; Huc, Ivan
Synthetic helical foldamers are of significant interest for mimicking the conformations of naturally occurring molecules while at the same time introducing new structures and properties. In particular, oligoamides of aromatic amino acids are attractive targets, as their folding is highly predictable and stable. Here the design and synthesis of new amphipathic helical oligoamides based on quinoline-derived amino acids having either hydrophobic or cationic side chains are described. Their structures were characterized in the solid state by single-crystal X-ray diffraction and in solution by NMR. Results of these studies suggest that an oligomer as short as a pentamer folds into a stable helical conformation in protic solvents, including MeOH and H(2)O. The introduction of polar proteinogenic side chains to these foldamers, as described here for the first time, promises to provide possibilities for the biological applications of these molecules. In particular, amphipathic helices are versatile targets to explore due to their importance in a variety of biological processes, and the unique structure and properties of the quinoline-derived oligoamides may allow new structure-activity relationships to be developed.
Studies on the distribution of radioactivity in the organism during constant intravenous infusion of tracer amino acids and on the calculation of the rate of tissue protein synthesis in rats
International Nuclear Information System (INIS)
Simon, O.; Bergner, H.; Wolf, E.
Male wistar rats (100 p body weight) were infused into the tail vein with 14 C-leucine and 14 C-lysine simultaneously for 0.5; 1.0; 2.0; 3.0; 4.5; 6.0 and 7.0 hours. At the end of the infusion the specific radioactivity was determined of the free leucine and lysine in the blood plasma, liver, M. gastrocnemius, small intestine, and colon as well as of the protein-bound leucine and lysine. In all the tissues tested the specific radioactivity of the free amino acids attained a plateau during the 6-hour and 7-hour infusions. The rate constants for the increase were calculated for each organ tested. The two amino acids used are suitable for calculating the fractional rate of protein synthesis in tissues. The values of the fractional rate of protein synthesis calculated on the basis of the 6-hour and 7-hour infusions were: 54+-7.7%/day for the liver, 9.4+-1.2%/day for the muscles, 89+-12.2%/day for the small intestine, and 42+-5.9%/day for the colon. The simultaneous application of two tracer amino acids is recommendable for estimating the precursor pool of the protein synthesis and the more accurate calculation of the rate of protein synthesis. (author)
Adsorption of amino acids on hydrophilic surfaces
International Nuclear Information System (INIS)
Paszti, Z; Keszthelyi, T; Hakkel, O; Guczi, L
Sum frequency generation vibrational spectroscopy (SFG) is a powerful tool for in situ investigation of adsorption processes at biologically important solid-liquid interfaces. In this work adsorption of selected amino acids on fused silica, calcium fluoride and titanium dioxide substrates was studied by this technique. SFG spectra taken at the amino acid solution-fused SiO 2 interface revealed the lack of formation of any ordered adsorbate layer, regardless of whether acidic or other, e.g. aromatic, amino acids were used. Ex situ spectra (measured after drying the substrate) showed the formation and gradual growth of amino acid crystallites. In the case of CaF 2 , growth of randomly oriented aspartic acid crystallites was observed even at the solution-substrate interface. Finally, on the TiO 2 substrate, acidic amino acids formed a stable, uniform, more or less ordered coating, which remained unchanged even after drying the sample. On the other hand, non-acidic amino acids like phenylalanine showed very little affinity towards TiO 2 , emphasizing the role of the acidic side chain in the bonding to the substrate. The fact that formation of an amino acid overlayer was observed only on titanium dioxide is probably related to its biocompatibility property
Arrangement of Proteinogenic α-Amino Acids on a Cyclic Peptide Comprising Alternate Biphenyl-Cored ζ-Amino Acids.
Tashiro, Shohei; Chiba, Masayuki; Shionoya, Mitsuhiko
Aiming at precisely arranging several proteinogenic α-amino acids on a folded scaffold, we have developed a cyclic hexapeptide comprising an alternate sequence of biphenyl-cored ζ-amino acids and proteinogenic α-amino acids such as l-leucine. The amino acids were connected by typical peptide synthesis, and the resultant linear hexapeptide was intramolecularly cyclized to form a target cyclic peptide. Theoretical analyses and NMR spectroscopy suggested that the cyclic peptide was folded into an unsymmetrical conformation, and the structure was likely to be flexible in CHCl 3 . The optical properties including UV/Vis absorption, fluorescence, and circular dichroism (CD) were also evaluated. Furthermore, the cyclic peptide became soluble in water by introducing three carboxylate groups at the periphery of the cyclic skeleton. This α/ζ-alternating cyclic peptide is therefore expected to serve as a unique scaffold for arranging several functionalities. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
The Monosodium Glutamate Story: The Commercial Production of MSG and Other Amino Acids
Ault, Addison
Examples of the industrial synthesis of pure amino acids are presented. The emphasis is on the synthesis of ( S )-glutamic acid and, to a lesser extent, ( S )-lysine and ( R,S )-methionine. These amino acids account for about 90% of the total world production of amino acids, ( S )-glutamic acid being used as a flavor-enhancing additive (MSG) for the human diet, and ( S )-lysine and ( R,S )-methionine as supplements for the feeding of domestic animals. Examples include chemical, enzymatic, and fermentation synthesis, and two clever continuous processes for the resolution of enantiomers. See Featured Molecules .
One-step electrochemical synthesis of 6-amino-4-hydroxy-2-napthalene-sulfonic acid functionalized graphene for green energy storage electrode materials
Kuila, Tapas; Khanra, Partha; Kim, Nam Hoon; Kuk Choi, Sung; Yun, Hyung Joong; Lee, Joong Hee
A green approach for the one-step electrochemical synthesis of water dispersible graphene is reported. An alkaline solution of 6-amino-4-hydroxy-2-naphthalene-sulfonic acid (ANS) serves the role of electrolyte as well as surface modifier. High-purity graphite rods are used as electrodes which can be exfoliated under a constant electrical potential (˜20 V) to form ANS functionalized graphene (ANEG). The aqueous dispersion of ANEG obeyed Beer's law at moderate concentrations, as evidenced from ultraviolet-visible spectroscopy analysis. X-ray diffraction analysis suggests complete exfoliation of graphite into graphene. Fourier transform infrared and x-ray photoelectron spectroscopy not only confirm the functionalization of graphene with ANS, but also suggest the formation of oxygen containing functional groups on the surface of ANEG. Raman spectra analysis indicates the presence of defects in ANEG as compared to pure graphite. Cyclic voltammetry and charge-discharge measurements of ANEG using three electrode systems show a specific capacitance of 115 F g-1 at a current density of 4 A g-1. The ANEG electrode exhibits 93% retention in specific capacitance after 1000 charge-discharge cycles, confirming its utility as a green energy storage electrode material.
Enantiomeric radiochemical synthesis of R and S (1-(6-amino-9H-purin-9-yl)-3-fluoropropan-2-yloxy)methylphosphonic acid (FPMPA).
Kiesewetter, Dale O; Knudson, Kathleen; Collins, Matt; Srinivasula, Sharat; Lim, Esther; Di Mascio, Michele
Therapy for human immunodeficiency virus (HIV)-infected patients requires chronic multidrug administration. The eventual failure of therapy in some patients has brought into question the tissue concentration of the drugs. With an appropriately radiolabeled compound, we could utilize positron emission tomography to provide quantitative time-activity curves for various tissues. We have developed a fluorine-18 labeled analog of Tenofovir, the active metabolite of Tenofovir DF, a commonly prescribed component of multidrug therapy. Because (1-(6-amino-9H-purin-9-yl)-3-fluoropropan-2-yloxy)methylphosphonic acid (FPMPA) has a chiral center, we prepared both enantiomers and confirmed that the S-isomer exhibited significantly higher antiviral activity than the R-isomer. In viral replication inhibition assays in human MT4 cells infected with SHIV(DH12R), S-FPMPA had an IC(50) of 1.85 muM (95% CI; 0.8-5.53), while the R-isomer was inactive. An appropriate chiral precursor was prepared to allow the incorporation of fluorine-18. The [(18)F]FPMPA in racemic, R, or S form was prepared in a 50 min synthesis in 38+/-5% yield (n = 23, corrected for decay). The product was of high radiochemical and enantiomeric purity. The specific activity of the final product was 4.0+/-1.8 Ci/mumol at EOB (end of bombardment). This product may provide information about drug tissue distribution in animal models under chronic drug treatment.
Synthesis of Copper-Chelates Derived from Amino Acids and Evaluation of Their Efficacy as Copper Source and Growth Stimulator for Lactuca sativa in Nutrient Solution Culture.
Kaewchangwat, Narongpol; Dueansawang, Sattawat; Tumcharern, Gamolwan; Suttisintong, Khomson
Five tetradentate ligands were synthesized from l-amino acids and utilized for the synthesis of Cu(II)-chelates 1-5. The efficacy of Cu(II)-chelates as copper (Cu) source and growth stimulator in hydroponic cultivation was evaluated with Lactuca sativa. Their stability test was performed at pH 4-10. The results suggested that Cu(II)-chelate 3 is the most pH tolerant complex. Levels of Cu, Zn, and Fe accumulated in plants supplied with Cu(II)-chelates were compared with those supplied with CuSO 4 at the same Cu concentration of 8.0 μM. The results showed that Cu(II)-chelate 3 significantly enhanced Cu, Zn, and Fe content in shoot by 35, 15, and 48%, respectively. Application of Cu(II)-chelate 3 also improved plant dry matter yield by 54%. According to the results, Cu(II)-chelate 3 demonstrated the highest stimulating effect on plant growth and plant mineral accumulation so that it can be used as an alternative to CuSO 4 for supplying Cu in nutrient solutions and enhancing the plant growth.
Non-canonical amino acids bearing thiophene and bithiophene: synthesis by an Ugi multicomponent reaction and studies on ion recognition ability.
Esteves, Cátia I C; Raposo, M Manuela M; Costa, Susana P G
Novel thienyl and bithienyl amino acids with different substituents were obtained by a multicomponent Ugi reaction between a heterocyclic aldehyde, an amine, an acid and an isocyanide. Due to the presence of the sulphur heterocycle at the side chain, these unnatural amino acids are highly emissive and bear extra electron donating atoms so they were tested for their ability to act as fluorescent probes and chemosensors in the recognition of biomedically relevant ions in acetonitrile and acetonitrile/water solutions. The results obtained from spectrophotometric/spectrofluorimetric titrations in the presence of organic and inorganic anions, and alkaline; alkaline-earth and transition metal cations indicated that the bithienyl amino acid bearing a methoxy group is a selective colorimetric chemosensor for Cu 2+ , while the other (bi)thienyl amino acids act as fluorimetric chemosensors with high sensitivity towards Fe 3+ and Cu 2+ in a metal-ligand complex with 1:2 stoichiometry. The photophysical and ion sensing properties of these amino acids confirm their potential as fluorescent probes suitable for incorporation into peptidic frameworks with chemosensory ability.
Amino acids as regulators and components of nonproteinogenic pathways
Meijer, Alfred J.
Amino acids are not only important precursors for the synthesis of proteins and other N-containing compounds, but also participate in the regulation of major metabolic pathways. Glutamate and aspartate, for example, are components of the malate/aspartate shuttle and their concentrations control the
Genetics Home Reference: aromatic l-amino acid decarboxylase deficiency
... and treatment of a new inborn error of neurotransmitter amine synthesis. Neurology. 1992 Oct;42(10):1980-8. Citation on PubMed Hyland K. Inherited disorders affecting dopamine and serotonin: critical neurotransmitters derived from aromatic amino acids. J Nutr. 2007 ...
Peptide regulators of insect reproduction containing D-amino acids
Czech Academy of Sciences Publication Activity Database
Hlaváček, Jan; Bennettová, Blanka; Slaninová, Jiřina; Černý, B.; Vlasáková, Věra; Holík, Josef; Tykva, Richard
Roč. 16, S1 (2010), s. 193-194 ISSN 1075-2617. [European Peptide Symposium /31./. 05.09.2010-09.09.2010, Copenhagen] R&D Projects: GA ČR GA203/06/1272 Institutional research plan: CEZ:AV0Z40550506 Keywords : D-amino acids * peptide synthesis * degradation * radioactivity accumulation Subject RIV: CC - Organic Chemistry
Incorporation of radioactive amino acids into protein in isolated rat hepatocytes
International Nuclear Information System (INIS)
Seglin, P.O.
The incorporation of radioactivity from a 14 C-labelled amino acid mixture (algal protein hydrolysate) into protein in isolated rat hepatocytes has been studied. The incorporation rate declined with increasing cell concentration, an effect which could be explained by isotope consumption, partly (and largely) by isotope dilution due to the formation of non-labelled amino acids by the cells. At a high extracellular amino acid concentration, the rate of incorporation into protein became independent of cell concentration because the isotope dilution effect was now quantitatively insignificant. The time course of protein labelling at various cell concentrations correlated better with the intracellular than with the extracellular amino acid specific activity, suggesting that amino acids for protein synthesis were taken from an intracellular pool. With increasing extracellular amino acid concentrations, both the intracellular amino acid concentration, the intracellular radioactivity and the rate of incorporation into protein increased. Protein labelling exhibited a distinct time lag at high amino acid concentrations, presumable reflecting the time-dependent expansion of the intracellular amino acid pool. The gradual increase in the rate of protein labelling could be due either to an increased intracellular specific activity, or to a real stimulation of protein synthesis by amino acids, depending on whether the total intracellular amino acid pool or just the expandable compartment is the precursor pool for protein synthesis
The impacts of temperature, alcoholic degree and amino acids content on biogenic amines and their precursor amino acids content in red wine.
Lorenzo, C; Bordiga, M; Pérez-Álvarez, E P; Travaglia, F; Arlorio, M; Salinas, M R; Coïsson, J D; Garde-Cerdán, T
The aim was to study how factors such as temperature, alcoholic degree, and amino acids supplementation are able to influence the content of tyramine, histamine, 2-phenylethylamine, tryptamine and their precursor amino acids in winemaking process. Biogenic amines and amino acids were quantified at the beginning, middle and end of alcoholic fermentation, and at the end of malolactic fermentation. In general, samples produced with amino acid supplementation did not show the highest concentrations of biogenic amines, except for histamine, which content increased with the addition of the four amino acids. The synthesis of tyramine was mainly affected by the temperature and alcoholic degree, the formation of phenylethylamine was largely influenced by alcoholic degree, and tryptamine synthesis principally depended on temperature. Interestingly, there was interaction between these three factors for the biogenic amines studied. In conclusion, winemaking conditions should be established depending on the biogenic amine which synthesis is required to be controlled. Copyright © 2017 Elsevier Ltd. All rights reserved.
Discovery of novel histidine-derived lipo-amino acids: applied in the synthesis of ultra-short antimicrobial peptidomimetics having potent antimicrobial activity, salt resistance and protease stability.
Ahn, Mija; Murugan, Ravichandran N; Jacob, Binu; Hyun, Jae-Kyung; Cheong, Chaejoon; Hwang, Eunha; Park, Hyo-Nam; Seo, Ji-Hyung; Srinivasrao, G; Lee, Kyung S; Shin, Song Yub; Bang, Jeong Kyu
Here we report for the first time the synthesis of Histidine (His) derived lipo-amino acids having pendant lipid tails at N(τ)- and N(π)-positions on imidazole group of His and applied it into synthesis of lipo-peptides. The attachment of His-derived lipo-amino acid into the very short inactive cationic peptides endows potent antimicrobial activity against Gram-positive and Gram-negative bacteria without hemolytic activity. Furthermore, our designed His-derived lipo-peptidomimetics (HDLPs) consisting of two or three residues displayed strong anti-MRSA activity and protease stability as well as retained potent antimicrobial activity under high salt concentration. Our results demonstrate that the novel lipo-amino acid is highly flexible to synthesize and carry out the extensive structure-activity relationship (SAR) on lipo-antimicrobial peptidomimetics and represents a unique amenable platform for modifying parameters important for antimicrobial activity. Through this study, we proved that the discovery of His-derived lipo-amino acid and the corresponding HDLPs are an excellent candidate as a lead compound for the development of novel antimicrobial agents. Copyright © 2013 Elsevier Masson SAS. All rights reserved.
Dependence of the metabolic fecal amino acids on the amino acid content of the feed. 1
International Nuclear Information System (INIS)
Krawielitzki, K.; Schadereit, R.; Voelker, T.; Reichel, K.
The amount of metabolic fecal amino acids (MFAA) in dependence on the amino acid intake was determined for graded maize rations in 15 N-labelled rats and the part of labelled endogenous amino acids in feces was calculated by the isotope dilution method. The excretion of amino acids and MFAA in feces are described as functions of the amino acid intake for 17 amino acids and calculated regressively. For all 17 amino acids investigated, there was a more or less steep increase of MFAA according to an increasing amino acid intake. In contrast to N-free feeding, the MFAA increase to the 2- to 4.5-fold value in feeding with pure maize (16.5% crude protein). The thesis of the constancy of the excretion of MFAA can consequently be no longer maintained. The true digestibility according to the conventional method is, on an average of all amino acids, 7.3 units below ascertained according to the 15 N method. The limiting amino acids lysine and threonine revealed the greatest difference. Tryptophane as first limiting amino acid could not be determined. The true digestibility of nearly all amino acids ascertained for maize by the isotope method is above 90%. (author)
Enzymatically and reductively degradable α-amino acid-based poly(ester amide)s: Synthesis, cell compatibility, and intracellular anticancer drug delivery
Sun, H.; Cheng, Ru; Deng, Chao; Meng, Fenghua; Dias, Aylvin A.; Hendriks, Marc; Feijen, Jan; Zhong, Zhiyuan
A novel and versatile family of enzymatically and reductively degradable α-amino acid-based poly(ester amide)s (SS-PEAs) were developed from solution polycondensation of disulfide-containing di-p-toluenesulfonic acid salts of bis-l-phenylalanine diesters (SS-Phe-2TsOH) with di-p-nitrophenyl adipate
Synthesis of pyrazole containing α-amino acids via a highly regioselective condensation/aza-Michael reaction of β-aryl α,β-unsaturated ketones
Gilfillan, Lynne; Artschwager, Raik; Harkiss, Alexander H.; Liskamp, Rob M J; Sutherland, Andrew
A synthetic approach for the preparation of a new class of highly conjugated unnatural α-amino acids bearing a 5-arylpyrazole side-chain has been developed. Horner-Wadsworth-Emmons reaction of an aspartic acid derived β-keto phosphonate ester with a range of aromatic aldehydes gave β-aryl
Amino acid regulation of autophagosome formation
Meijer, Alfred J.
Amino acids are not only substrates for various metabolic pathways, but can also serve as signaling molecules controlling signal transduction pathways. One of these signaling pathways is mTOR-dependent and is activated by amino acids (leucine in particular) in synergy with insulin. Activation of
Amino acids transport in lactic streptococci
Driessen, Arnold Jacob Mathieu
Lactic streptococci are extremely fastidious bacteria. For growth an exogenous source of amino acids and other nutrients is essential. The amino acid requirement in milk is fulfilled by the milk-protein casein, which is degraded by sequential hydrolysis, involving proteases and peptidases. ... Zie:
Crystalline amino acids and nitrogen emission
Verstegen, M.W.A.; Jongbloed, A.W.
Reductions in dietary protein level and supplementation with certain crystalline amino acids is a well-established method of formulating diets to achieve a more ideal amino acid pattern and to reduce nitrogen excretion. Up to 35% reduction in nitrogen excretion may be achieved by supplementing pig
The amino acid sequence of hypertensin. II.
The amino acid sequence of horse hypertensin II has been determined by the use of chymotrypsin, the fluorodinitrobenzene method, and stepwise phenylisothiocyanate degradation. The results indicate that the amino acids of hypertensin II are arranged in the following order: asp-arg-val-tyr-iso-hist-pro-phe.
Differential distribution of amino acids in plants.
Kumar, Vinod; Sharma, Anket; Kaur, Ravdeep; Thukral, Ashwani Kumar; Bhardwaj, Renu; Ahmad, Parvaiz
Plants are a rich source of amino acids and their individual abundance in plants is of great significance especially in terms of food. Therefore, it is of utmost necessity to create a database of the relative amino acid contents in plants as reported in literature. Since in most of the cases complete analysis of profiles of amino acids in plants was not reported, the units used and the methods applied and the plant parts used were different, amino acid contents were converted into relative units with respect to lysine for statistical analysis. The most abundant amino acids in plants are glutamic acid and aspartic acid. Pearson's correlation analysis among different amino acids showed that there were no negative correlations between the amino acids. Cluster analysis (CA) applied to relative amino acid contents of different families. Alismataceae, Cyperaceae, Capparaceae and Cactaceae families had close proximity with each other on the basis of their relative amino acid contents. First three components of principal component analysis (PCA) explained 79.5% of the total variance. Factor analysis (FA) explained four main underlying factors for amino acid analysis. Factor-1 accounted for 29.4% of the total variance and had maximum loadings on glycine, isoleucine, leucine, threonine and valine. Factor-2 explained 25.8% of the total variance and had maximum loadings on alanine, aspartic acid, serine and tyrosine. 14.2% of the total variance was explained by factor-3 and had maximum loadings on arginine and histidine. Factor-4 accounted 8.3% of the total variance and had maximum loading on the proline amino acid. The relative content of different amino acids presented in this paper is alanine (1.4), arginine (1.8), asparagine (0.7), aspartic acid (2.4), cysteine (0.5), glutamic acid (2.8), glutamine (0.6), glycine (1.0), histidine (0.5), isoleucine (0.9), leucine (1.7), lysine (1.0), methionine (0.4), phenylalanine (0.9), proline (1.1), serine (1.0), threonine (1
Kinetics of oxidation of acidic amino acids by sodium N ...
Indian Academy of Sciences (India)
... the mechanism of amino acids metabolism. Amino acids find a number of applications in biochemical research, metabolism, microbiology, nutrition, pharmaceuticals and fortification of foods and feeds. Generally only the amino and carboxyl functional groups in RCH(NH2)COOH undergo chemical transformations while.
Genetics of Amino Acid Taste and Appetite.
Bachmanov, Alexander A; Bosak, Natalia P; Glendinning, John I; Inoue, Masashi; Li, Xia; Manita, Satoshi; McCaughey, Stuart A; Murata, Yuko; Reed, Danielle R; Tordoff, Michael G; Beauchamp, Gary K
The consumption of amino acids by animals is controlled by both oral and postoral mechanisms. We used a genetic approach to investigate these mechanisms. Our studies have shown that inbred mouse strains differ in voluntary amino acid consumption, and these differences depend on sensory and nutritive properties of amino acids. Like humans, mice perceive some amino acids as having a sweet (sucrose-like) taste and others as having an umami (glutamate-like) taste. Mouse strain differences in the consumption of some sweet-tasting amino acids (d-phenylalanine, d-tryptophan, and l-proline) are associated with polymorphisms of a taste receptor, type 1, member 3 gene (Tas1r3), and involve differential peripheral taste responsiveness. Strain differences in the consumption of some other sweet-tasting amino acids (glycine, l-alanine, l-glutamine, and l-threonine) do not depend on Tas1r3 polymorphisms and so must be due to allelic variation in other, as yet unknown, genes involved in sweet taste. Strain differences in the consumption of l-glutamate may depend on postingestive rather than taste mechanisms. Thus, genes and physiologic mechanisms responsible for strain differences in the consumption of each amino acid depend on the nature of its taste and postingestive properties. Overall, mouse strain differences in amino acid taste and appetite have a complex genetic architecture. In addition to the Tas1r3 gene, these differences depend on other genes likely involved in determining the taste and postingestive effects of amino acids. The identification of these genes may lead to the discovery of novel mechanisms that regulate amino acid taste and appetite. © 2016 American Society for Nutrition.
Effects of Supplementation of Branched-Chain Amino Acids to Reduced-Protein Diet on Skeletal Muscle Protein Synthesis and Degradation in the Fed and Fasted States in a Piglet Model
Zheng, Liufeng; Wei, Hongkui; He, Pingli; Zhao, Shengjun; Xiang, Quanhang; Pang, Jiaman; Peng, Jian
Supplementation of branched-chain amino acids (BCAA) has been demonstrated to promote skeletal muscle mass gain, but the mechanisms underlying this observation are still unknown. Since the regulation of muscle mass depends on a dynamic equilibrium (fasted losses–fed gains) in protein turnover, the aim of this study was to investigate the effects of BCAA supplementation on muscle protein synthesis and degradation in fed/fasted states and the related mechanisms. Fourteen 26- (Experiment 1) and ...
In situ synthesis, electrochemical and quantum chemical analysis of an amino acid-derived ionic liquid inhibitor for corrosion protection of mild steel in 1M HCl solution
International Nuclear Information System (INIS)
Kowsari, E.; Arman, S.Y.; Shahini, M.H.; Zandi, H.; Ehsani, A.; Naderi, R.; PourghasemiHanza, A.; Mehdipour, M.
Highlights: • Electrochemical analysis of effectiveness of an amino acid-derived ionic liquid inhibitor. • Quantum chemical analysis of effectiveness of an amino acid-derived ionic liquid inhibitor. • Finding correlation between electrochemical analysis and quantum chemical analysis. - Abstract: In this study, an amino acid-derived ionic liquid inhibitor, namely tetra-n-butyl ammonium methioninate, was synthesized and the role this inhibitor for corrosion protection of mild steel exposed to 1.0 M HCl was investigated using electrochemical, quantum and surface analysis. By taking advantage of potentiodynamic polarization, the inhibitory action of tetra-n-butyl ammonium methioninate was found to be mainly mixed-type with dominant anodic inhibition. The effectiveness of the inhibitor was also indicated using electrochemical impedance spectroscopy (EIS). Moreover, to provide further insight into the mechanism of inhibition, electrochemical noise (EN) and quantum chemical calculations of the inhibitor were performed.
Amino acid analogs for tumor imaging
Goodman, Mark M.; Shoup, Timothy
The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.
A novel l-amino acid ionic liquid for quick and highly efficient synthesis of oxime derivatives – An environmental benign approach
Directory of Open Access Journals (Sweden)
Parasuraman Karthikeyan
Full Text Available A mild, efficient, and eco-friendly procedure for the conversion of aliphatic, alicyclic and aromatic carbonyl compounds into the corresponding oximes, was catalyzed by a novel imidazolium based ionic liquid coupled with amino acid (asparagine (l-AAIL, l-Amino acid functionalized ionic liquid catalytic system. The quantitative conversion of aryl and alkyl carbonyl compounds into the corresponding oximes was achieved by simply grinding at ambient temperature using 0.05 mmol of catalyst in 50 s. In addition, this L-AAIL catalyst exhibited good reusability for five consecutive trials without significant loss of its catalytic activity.
Whole-body nitrogen and tyrosine metabolism in surgical patients receiving branched-chain amino acid solutions
International Nuclear Information System (INIS)
Desai, S.P.; Bistrian, B.R.; Moldawer, L.L.; Blackburn, G.L.
Fifteen patients undergoing gastric bypass surgery for morbid obesity received preoperatively a standard crystalline amino acid solution containing 15.6% branched-chain amino acids. During the first five postoperative days, the patients were randomized to receive one of three amino acid solutions of different branched-chain amino acid content. Whole-body amino acid appearance and oxidation were estimated using a continuous intravenous infusion of L-(U- 14 C)-tyrosine preoperatively and on the third postoperative day. This study suggests that an adequate nitrogen intake of a balanced amino acid mixture, as well as a solution enriched with branched-chain amino acids, maintains protein homeostasis and supports protein synthesis similarly in well-nourished patients following major abdominal surgery. A diet containing only branched-chain amino acids in isomolar ratios was as effective at maintaining protein retention and whole-body protein synthesis and albumin renewal postoperatively when compared with a standard amino acid formula
Distribution of Amino Acids in Lunar Regolith
Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Dworkin, J. P.; Noble, S. K.; Gibson, E. K., Jr.
One of the most eagerly studied questions upon initial return of lunar samples was whether significant amounts of organic compounds, including amino acids, were present. Analyses during the 1970s produced only tentative and inconclusive identifications of indigenous amino acids. Those analyses were hampered by analytical difficulties including relative insensitivity to certain compounds, the inability to separate chiral enantiomers, and the lack of compound-specific isotopic measurements, which made it impossible to determine whether the detected amino acids were indigenous to the lunar samples or the results of contamination. Numerous advances have been made in instrumentation and methodology for amino acid characterization in extraterrestrial samples in the intervening years, yet the origin of amino acids in lunar regolith samples has been revisited only once for a single lunar sample, (3) and remains unclear. Here, we present initial data from the analyses of amino acid abundances in 12 lunar regolith samples. We discuss these abundances in the context of four potential amino acid sources: (1) terrestrial biological contamination; (2) contamination from lunar module (LM) exhaust; (3) derivation from solar windimplanted precursors; and (4) exogenous delivery from meteorites.
Enantiomer-specific selection of amino acids.
Ren, Xueying; Tellez, Luis A; de Araujo, Ivan E
Dietary intake of L-amino acids impacts on several physiological functions, including the control of gastrointestinal motility, pancreatic secretion, and appetite. However, the biological mechanisms regulating behavioral predilections for certain amino acid types remain poorly understood. We tested the hypothesis that, in mice, the potency with which a given glucogenic amino acid increases glucose utilization reflects its rewarding properties. We have found that: (1) during long-, but not short-, term preference tests, L-alanine and L-serine were preferred over their D-enantiomer counterparts, while no such effect was observed for L-threonine vs. D-threonine; (2) these behavioral patterns were closely associated with the ability of L-amino acids to promote increases in respiratory exchange ratios such that those, and only those, L-amino acids able to promote increases in respiratory exchange ratios were preferred over their D-isomers; (3) these behavioral preferences were independent of gustatory influences, since taste-deficient Trpm5 knockout mice displayed ingestive responses very similar to those of their wild-type counterparts. We conclude that the ability to promote increases in respiratory exchange ratios enhances the reward value of nutritionally relevant amino acids and suggest a mechanistic link between substrate utilization and amino acid preferences.
Amino acid nitrosation products as alkylating agents.
García-Santos, M del P; Calle, E; Casado, J
Nitrosation reactions of alpha-, beta-, and gamma-amino acids whose reaction products can act as alkylating agents of DNA were investigated. To approach in vivo conditions for the two-step mechanism (nitrosation and alkylation), nitrosation reactions were carried out in aqueous acid conditions (mimicking the conditions of the stomach lumen) while the alkylating potential of the nitrosation products was investigated at neutral pH, as in the stomach lining cells into which such products can diffuse. These conclusions were drawn: (i) The alkylating species resulting from the nitrosation of amino acids with an -NH(2) group are the corresponding lactones; (ii) the sequence of alkylating power is: alpha-lactones > beta-lactones > gamma-lactones, coming respectively from the nitrosation of alpha-, beta-, and gamma-amino acids; and (iii) the results obtained may be useful in predicting the mutagenic effectiveness of the nitrosation products of amino acids.
Cytokines: muscle protein and amino acid metabolism
DEFF Research Database (Denmark)
van Hall, Gerrit
raises TNF-α and IL-6 to moderate levels, has only identified IL-6 as a potent cytokine, decreasing systemic amino acid levels and muscle protein metabolism. The marked decrease in circulatory and muscle amino acid concentrations was observed with a concomitant reduction in both the rates of muscle...... of IL-6 on the regulation of muscle protein metabolism but indirectly via IL-6 reducing amino acid availability. SUMMARY: Recent studies suggest that the best described cytokines TNF-α and IL-6 are unlikely to be the major direct mediators of muscle protein loss in inflammatory diseases. However...
Absorption of proteins and amino acids
International Nuclear Information System (INIS)
Jeejeebhoy, K.N.
Although the absorption of proteins and amino acids is an important issue in nutrition, its measurement is not common because of the methodological difficulties. Complications are attributable in particular to the magnitude of endogenous protein secretion and to the diversity of absorption mechanisms for amino acids either as individual units or as peptides. Methods for studying absorption include balance techniques, tolerance tests, tracer techniques using proteins or amino acids labelled with 131 I, 3 H, or 15 N, intestinal perfusion studies, and others; they must be selected according to the nature of the information sought. Improvements over the current methods would be useful. (author)
Solid state radiolysis of non-proteinaceous amino acids in vacuum. Astrochemical implications
International Nuclear Information System (INIS)
Franco Cataldo; Giancarlo Angelini; Yaser Hafez; Susana Iglesias-Groth
The analysis of the amino acids present in Murchison meteorite and in other carbonaceous chondrites has revealed the presence of 66 different amino acids. Only eight of these 66 amino acids are proteinaceous amino acids used by the present terrestrial biochemistry in protein synthesis, the other 58 amino acids are somewhat 'rare' or unusual or even 'unknown' for the current terrestrial biochemistry. For this reason in the present work a series of 'uncommon' non-proteinaceous amino acids, namely, l-2-aminobutyric acid, R(-)-2-aminobutyric acid, 2-aminoisobutyric acid (or α-aminoisobutyric acid), l-norleucine, l-norvaline, l-β-leucine, l-β-homoalanine, l-β-homoglutamic acid, S(-)-α-methylvaline and dl-3-aminoisobutyric acid were radiolyzed in vacuum at 3.2 MGy a dose equivalent to that emitted in 1.05 x 10 9 years from the radionuclide decay in the bulk of asteroids or comets. The residual amount of each amino acid under study remained after radiolysis was determined by differential scanning calorimetry in comparison to pristine samples. For optically active amino acids, the residual amount of each amino acid remained after radiolysis was also determined by optical rotatory dispersion spectroscopy and by polarimetry. With these analytical techniques it was possible to measure also the degree of radioracemization undergone by each amino acid after radiolysis. It was found that the non-proteinaceous amino acids in general do not show a higher radiation and radioracemization resistance in comparison to the common 20 proteinaceous amino acids studied previously. The unique exception is represented by ?-aminoisobutyric acid which shows an extraordinary resistance to radiolysis since 96.6 % is recovered unchanged after 3.2 MGy. Curiously α-aminoisobutyric acid is the most abundant amino acid found in carbonaceous chondrites. In Murchison meteorite α-aminoisobutyric acid represents more than 20 % of the total 66 amino acids found in this meteorite. (author)
The protein digestibility-corrected amino acid score.
Schaafsma, G
The protein digestibility-corrected amino acid score (PDCAAS) has been adopted by FAO/WHO as the preferred method for the measurement of the protein value in human nutrition. The method is based on comparison of the concentration of the first limiting essential amino acid in the test protein with the concentration of that amino acid in a reference (scoring) pattern. This scoring pattern is derived from the essential amino acid requirements of the preschool-age child. The chemical score obtained in this way is corrected for true fecal digestibility of the test protein. PDCAAS values higher than 100% are not accepted as such but are truncated to 100%. Although the principle of the PDCAAS method has been widely accepted, critical questions have been raised in the scientific community about a number of issues. These questions relate to 1) the validity of the preschool-age child amino acid requirement values, 2) the validity of correction for fecal instead of ileal digestibility and 3) the truncation of PDCAAS values to 100%. At the time of the adoption of the PDCAAS method, only a few studies had been performed on the amino acid requirements of the preschool-age child, and there is still a need for validation of the scoring pattern. Also, the scoring pattern does not include conditionally indispensable amino acids. These amino acids also contribute to the nutrition value of a protein. There is strong evidence that ileal, and not fecal, digestibility is the right parameter for correction of the amino acid score. The use of fecal digestibility overestimates the nutritional value of a protein, because amino acid nitrogen entering the colon is lost for protein synthesis in the body and is, at least in part, excreted in urine as ammonia. The truncation of PDCAAS values to 100% can be defended only for the limited number of situations in which the protein is to be used as the sole source of protein in the diet. For evaluation of the nutritional significance of proteins as
{omicron}-iodoxybenzoic acid in water: optimized green alternative for multicomponent one-pot synthesis of 2-amino-3,5-dicarbonitrile-6-thiopyridines
Energy Technology Data Exchange (ETDEWEB)
Takale, Santosh; Patil, Jaidas; Pisal, Rajaram, E-mail: firstname.lastname@example.com [Changu Kana Thakur Research Centre, Mumbai (India); Padalkar, Vikas [Institute of Chemical Technology, Matunga, Mumbai (India); Chaskar, Atul [Department of Chemistry, National Taiwan University, Taipei (China)
A multicomponent one-pot reaction of aromatic aldehyde, malononitrile and thiophenol in the presence of iodoxybenzoic acid (IBX) in aqueous media furnished 2-amino-3,5-dicarbonitrile- 6-thiopyridine in good to excellent yield. Eventually, a catalyst could be easily recovered and reused without loss of its catalytic property. (author)
Synthesis of enantiomerically pure (purin-6-yl)phenylalanines and their nucleosides, a novel type of purine-amino acid conjugates
Czech Academy of Sciences Publication Activity Database
Čapek, Petr; Pohl, Radek; Hocek, Michal
Roč. 70, č. 20 (2005), s. 8001-8008 ISSN 0022-3263 R&D Projects: GA ČR(CZ) GA203/03/0035; GA MŠk(CZ) 1M0508 Institutional research plan: CEZ:AV0Z40550506 Keywords : purin es * nucleosides * amino acids Subject RIV: CC - Organic Chemistry Impact factor: 3.675, year: 2005
Oligopyridine-ruthenium(II)-amino acid conjugates: synthesis, characterization, DNA binding properties and interactions with the oligonucleotide duplex d(5'-CGCGCG-3')2
Czech Academy of Sciences Publication Activity Database
Triantafillidi, K.; Karidi, K.; Malina, Jaroslav; Garoufis, A.
-, č. 32 (2009), s. 6403-6415 ISSN 1477-9226 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : oligopyridine- ruthenium (II)-amino acid conjugates * diastereomeric DNA binding * DNA photocleavage Subject RIV: BO - Biophysics Impact factor: 4.081, year: 2009
Chemo-enzymatic synthesis of (2S,4R)-2-amino-4-(3-(2,2-diphenylethylamino)-3-oxopropyl)pentanedioic acid
DEFF Research Database (Denmark)
Sagot, Emanuelle; Jensen, Anders A.; Pickering, Darryl S
In the mammalian central nervous system (CNS), the action of sodium dependent excitatory amino acid transporters (EAATs) is responsible for termination of glutamatergic neurotransmission by reuptake of ( S) -glutamate (Glu) from the synaptic cleft. Five EAAT subtypes have been identified, of which...
Asymmetric organocatalytic decarboxylative Mannich reaction using β-keto acids: A new protocol for the synthesis of chiral β-amino ketones
Jiang, Chunhui; Zhong, Fangrui
Summary The first decarboxylative Mannich reaction employing β-keto acids, catalyzed by cinchonine-derived bifunctional thiourea catalyst has been described. The desired β-amino ketones were obtained in excellent yields and with moderate to good enantioselectivities. PMID:23019459
Asymmetric organocatalytic decarboxylative Mannich reaction using β-keto acids: A new protocol for the synthesis of chiral β-amino ketones
Directory of Open Access Journals (Sweden)
Chunhui Jiang
Full Text Available The first decarboxylative Mannich reaction employing β-keto acids, catalyzed by cinchonine-derived bifunctional thiourea catalyst has been described. The desired β-amino ketones were obtained in excellent yields and with moderate to good enantioselectivities.
Synthesis of .alpha.-Amino Acids via Asymmetric Phase Transfer-Catalyzed Alkylation of Achiral Niclkel(II) Complexes of Glycine-Derived Schiff bases
Czech Academy of Sciences Publication Activity Database
Belokon, Y. N.; Bespalova, N. B.; Churkina, T. D.; Císařová, I.; Ezernitskaya, M. G.; Harutyunyan, S. R.; Hrdina, R.; Kagan, H. B.; Kočovský, P.; Kochetkov, K. A.; Larionov, O. G.; Lysenko, K. A.; North, M.; Polášek, Miroslav; Peregudov, A. S.; Prisyazhnyuk, V. V.; Vyskočil, Š.
Roč. 125, - (2003), s. 12860-12870 ISSN 0002-7863 R&D Projects: GA ČR GP203/01/D051 Institutional research plan: CEZ:AV0Z4040901 Keywords : .alpha.amino acids * achiral nickel(II) * glycine-derived schiff bases Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 6.516, year: 2003
Effect of amino acids and amino acid derivatives on crystallization of hemoglobin and ribonuclease A
Energy Technology Data Exchange (ETDEWEB)
Ito, Len, E-mail: email@example.com; Kobayashi, Toyoaki [School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337 (Japan); Shiraki, Kentaro [Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Yamaguchi, Hiroshi [School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337 (Japan)
The effect of the addition of amino acids and amino acid derivatives on the crystallization of hemoglobin and ribonuclease A has been evaluated. The results showed that certain types of additives expand the concentration conditions in which crystals are formed. Determination of the appropriate conditions for protein crystallization remains a highly empirical process. Preventing protein aggregation is necessary for the formation of single crystals under aggregation-prone solution conditions. Because many amino acids and amino acid derivatives offer a unique combination of solubility and stabilizing properties, they open new avenues into the field of protein aggregation research. The use of amino acids and amino acid derivatives can potentially influence processes such as heat treatment and refolding reactions. The effect of the addition of several amino acids, such as lysine, and several amino acid derivatives, such as glycine ethyl ester and glycine amide, on the crystallization of equine hemoglobin and bovine pancreatic ribonuclease A has been examined. The addition of these amino acids and amino acid derivatives expanded the range of precipitant concentration in which crystals formed without aggregation. The addition of such additives appears to promote the crystallization of proteins.
Effect of amino acids and amino acid derivatives on crystallization of hemoglobin and ribonuclease A
International Nuclear Information System (INIS)
Ito, Len; Kobayashi, Toyoaki; Shiraki, Kentaro; Yamaguchi, Hiroshi
The effect of the addition of amino acids and amino acid derivatives on the crystallization of hemoglobin and ribonuclease A has been evaluated. The results showed that certain types of additives expand the concentration conditions in which crystals are formed. Determination of the appropriate conditions for protein crystallization remains a highly empirical process. Preventing protein aggregation is necessary for the formation of single crystals under aggregation-prone solution conditions. Because many amino acids and amino acid derivatives offer a unique combination of solubility and stabilizing properties, they open new avenues into the field of protein aggregation research. The use of amino acids and amino acid derivatives can potentially influence processes such as heat treatment and refolding reactions. The effect of the addition of several amino acids, such as lysine, and several amino acid derivatives, such as glycine ethyl ester and glycine amide, on the crystallization of equine hemoglobin and bovine pancreatic ribonuclease A has been examined. The addition of these amino acids and amino acid derivatives expanded the range of precipitant concentration in which crystals formed without aggregation. The addition of such additives appears to promote the crystallization of proteins
Amino acid composition of cottage cheese and whey with bifidobacteria
Directory of Open Access Journals (Sweden)
N. S. Rodionova
Full Text Available Breaking condition intestinal flora, the simplest way to create sensitive parts of the body microbiocenosis caused by various factors. Reasons for people microecology imbalances – antibiotics, preservatives, stress. The result is an imbalance – the number of gastrointestinal disorders, immune deficiency disorders metabolic processes in the body. Therapeutic effect of probiotic microorganisms is the result of exogenous and endometabolitov synthesis the character of the protein. Acid activity information probiotic microorganisms and the distribution of amino acids between the products and intermediates in biopotential evaluation process foods produced with probiotic microflora by fermentation. Test results from the amino acid composition of whey and quark are obtained by fermenting raw milk probiotics bifidobacterias. It was found that during the fermentation of the quark consortium, Bifidobacterium bifidum, Bifidobacterium longum, Bifidobacterium adolescentis, Bifidobacterium bifidum Y enriched curd 4 of leucine and glutamine. Rate of transfer amino acids in serum to 2–6% of essential amino acids is irrelevant 3–7%. The highest value observed transient threonine, isoleucyl, lysine, valine, alanine, glycine, proline, serine. The mean value of the prototype amino acid protein curd and whey protein biological value was 71.89 and 74.58. Preservation of active forms of probiotic microorganisms after heating the bunch to 53–55 °C, lg concentration of not less than 7 (in 1 g in cottage cheese and serum. The received data are actual for formation of an information data bank, necessary for the development of prescription-component solutions of eubiotic products.
Discovery and History of Amino Acid Fermentation.
Hashimoto, Shin-Ichi
There has been a strong demand in Japan and East Asia for L-glutamic acid as a seasoning since monosodium glutamate was found to present umami taste in 1907. The discovery of glutamate fermentation by Corynebacterium glutamicum in 1956 enabled abundant and low-cost production of the amino acid, creating a large market. The discovery also prompted researchers to develop fermentative production processes for other L-amino acids, such as lysine. Currently, the amino acid fermentation industry is so huge that more than 5 million metric tons of amino acids are manufactured annually all over the world, and this number continues to grow. Research on amino acid fermentation fostered the notion and skills of metabolic engineering which has been applied for the production of other compounds from renewable resources. The discovery of glutamate fermentation has had revolutionary impacts on both the industry and science. In this chapter, the history and development of glutamate fermentation, including the very early stage of fermentation of other amino acids, are reviewed.
High-level production of C-11-carboxyl-labeled amino acids
International Nuclear Information System (INIS)
Washburn, L.C.; Sun, T.T.; Byrd, B.L.; Hayes, R.L.; Butler, T.A.; Callahan, A.P.
Carbon-11-labeled amino acids have significant potential as agents for positron tomographic functional imaging. We have developed a rapid, high-temperature, high-pressure modification of the Buecherer--Strecker amino acid synthesis and found it to be quite general for the production of C-11-carboxyl-labeled neutral amino acids. Production of C-11-carboxyl-labeled DL-tryptophan requires certain modifications in the procedure. Twelve different amino acids have been produced to date by this technique. Synthesis and chromatographic purification require approximately 40 min, and C-11-carboxyl-labeled amino acids have been produced in yields of up to 425 mCi. Two C-11-carboxyl-labeled amino acids are being investigated clinically for tumor scanning and two others for pancreatic imaging. Over 120 batches of the various agents have been produced for clinical use over a three-year period
tRNAs: cellular barcodes for amino acids
DEFF Research Database (Denmark)
Banerjee, Rajat; Chen, Shawn; Dare, Kiley
The role of tRNA in translating the genetic code has received considerable attention over the last 50 years, and we now know in great detail how particular amino acids are specifically selected and brought to the ribosome in response to the corresponding mRNA codon. Over the same period, it has...... also become increasingly clear that the ribosome is not the only destination to which tRNAs deliver amino acids, with processes ranging from lipid modification to antibiotic biosynthesis all using aminoacyl-tRNAs as substrates. Here we review examples of alternative functions for tRNA beyond...... translation, which together suggest that the role of tRNA is to deliver amino acids for a variety of processes that includes, but is not limited to, protein synthesis....
Nonessential amino acid metabolism in breast cancer.
Geck, Renee C; Toker, Alex
Interest in studying cancer metabolism has risen in recent years, as it has become evident that the relationship between cancer and metabolic pathways could reveal novel biomarkers and therapeutic targets. Metabolic starvation therapy is particularly promising due to its low toxicity. Nonessential amino acids are promising metabolites for such therapy because they become essential in many tumor cells, including breast cancer cells. This review will focus on four nonessential amino acid metabolism pathways: glutamine-glutamate, serine-glycine, cysteine, and arginine-proline metabolism. Recent studies of these amino acids have revealed metabolic enzymes that have the potential to be effective as cancer therapy targets or biomarkers for response to metabolic starvation therapy. The review will also discuss features of nonessential amino acid metabolism that merit further investigation to determine their relevancy to breast cancer treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.
Genetically encoded fluorescent coumarin amino acids
Wang, Jiangyun; Xie, Jianming; Schultz, Peter G.
The invention relates to orthogonal pairs of tRNAs and aminoacyl-tRNA synthetases that can incorporate the coumarin unnatural amino acid L-(7-hydroxycoumarin-4-yl) ethylglycine into proteins produced in eubacterial host cells such as E. coli. The invention provides, for example but not limited to, novel orthogonal synthetases, methods for identifying and making the novel synthetases, methods for producing proteins containing the unnatural amino acid L-(7-hydroxycoumarin-4-yl)ethylglycine and related translation systems.
Dynamics of human whole body amino acid metabolism
International Nuclear Information System (INIS)
Young, V.R.
The mechanism of regulation of the nitrogen metabolism in humans under various nutritional and physiological states was examined using stable isotopes. In the simultaneous continuous infusion of 1- [ 13 ] - leucine and α- [ 15 N]- lysine, their fluxed decreased when individuals received lower protein intake. The rates of oxidation and incorporation into body proteins of leucine changed in parallel with the protein intake. Such effects of diet on whole body leucine kinetics were modified by the energy state and dietary energy level. The nitrogen balance was also improved by an excess level of dietary energy. When the intake of dietary protein was lowered below the maintenance level, the whole body flux and de novo synthesis of glycine were lowered, but alanine synthesis was clearly increased. The intravenous infusion of glucose at 4 mg/kg.min, which causes increase in excess blood sugar and plasma insulin, increased the alanine flux, but had no effect on the glycine flux. The rate of albumin synthesis, determined by giving 15 N-glycine orally every 3 hr, decreased with the lowered intake of dietary protein in young men, but not in elderly men. This explains why the serum albumin synthesis increases with the increase in the intake of dietary protein in young men, but not in elderly men. The rate of whole body protein synthesis in young men receiving the L-amino acid diets providing with the required intake of specific amino acid was much lower than that in the men receiving the diets providing with generous intake of specific amino acid. Thus the control mechanism to maintain the homeostasis of body nitrogen and amino acids is related in some unknown way to the nutritional requirement of the hosts. (Kaihara, S.)
Metal based pharmacologically active agents: Synthesis, structural characterization, molecular modeling, CT-DNA binding studies and in vitro antimicrobial screening of iron(II) bromosalicylidene amino acid chelates
Abdel-Rahman, Laila H.; El-Khatib, Rafat M.; Nassr, Lobna A. E.; Abu-Dief, Ahmed M.; Ismael, Mohamed; Seleem, Amin Abdou
In recent years, great interest has been focused on Fe(II) Schiff base amino acid complexes as cytotoxic and antitumor drugs. Thus a series of new iron(II) complexes based on Schiff bases amino acids ligands have been designed and synthesized from condensation of 5-bromosalicylaldehyde (bs) and α-amino acids (L-alanine (ala), L-phenylalanine (phala), L-aspartic acid (aspa), L-histidine (his) and L-arginine (arg)). The structure of the investigated iron(II) complexes was elucidated using elemental analyses, infrared, ultraviolet-visible, thermogravimetric analysis, as well as conductivity and magnetic susceptibility measurements. Moreover, the stoichiometry and the stability constants of the prepared complexes have been determined spectrophotometrically. The results suggest that 5-bromosalicylaldehyde amino acid Schiff bases (bs:aa) behave as dibasic tridentate ONO ligands and coordinate to Fe(II) in octahedral geometry according to the general formula [Fe(bs:aa)2]ṡnH2O. The conductivity values between 37 and 64 ohm-1 mol-1 cm2 in ethanol imply the presence of nonelectrolyte species. The structure of the complexes was validated using quantum mechanics calculations based on accurate DFT methods. Geometry optimization of the Fe-Schiff base amino acid complexes showed that all complexes had octahedral coordination. In addition, the interaction of these complexes with (CT-DNA) was investigated at pH = 7.2, by using UV-vis absorption, viscosity and agarose gel electrophoresis measurements. Results indicated that the investigated complexes strongly bind to calf thymus DNA via intercalative mode and showed a different DNA binding according to the sequence: bsari > bshi > bsali > bsasi > bsphali. Moreover, the prepared compounds are screened for their in vitro antibacterial and antifungal activity against three types of bacteria, Escherichia coli, Pseudomonas aeruginosa and Bacillus cereus and three types of anti fungal cultures, Penicillium purpurogenium, Aspergillus
Studies on radiolysis of amino acids, (3)
International Nuclear Information System (INIS)
Oku, Tadatake
For the purpose of investigating the radiolysis of amino acids and the safeness to radiation, the radiolytic mechanism and radio-sensitivity of sulfur-containing amino acids in aqueous solution in the presence of air or in the atmosphere of nitrogen were studied. Aqueous solutions of L-methionine, cysteine (both 1mM) and L-cystine (0.3mM) were irradiated with γ-ray of 60 Co at the dose of 4.2 - 2,640 x 10 3 rad. The amino acids and the radiolytic products were determined with an amino acid analyzer. The volatile sulfur compounds formed from γ-irradiated methionine were estimated by a flame photometric detector-gas chromatograph. From the results obtained, G values of the radiolysis of sulfur-containing amino acids and the products were calculated, and the radiolytic mechanisms of methionine, cysteine and cystine were proposed. The radio-sensitivity of sulfur-containing amino acids was shown as follows: cysteine (C3-SH) > methionine (C5, -SCH 3 ) > cystine (C 6 , -S-S-). Off-flavor development from γ-irradiated methionine when oxidizing agent was added was less than that when reducing agent was added. (Kobatake, H.)
The synthesis of glutamic acid in the absence of enzymes: Implications for biogenesis
Morowitz, Harold; Peterson, Eta; Chang, Sherwood
This paper reports on the non-enzymatic aqueous phase synthesis of amino acids from keto acids, ammonia and reducing agents. The facile synthesis of key metabolic intermediates, particularly in the glycolytic pathway, the citric acid cycle, and the first step of amino acid synthesis, lead to new ways of looking at the problem of biogenesis.
A molecular rotor based ratiometric sensor for basic amino acids
Pettiwala, Aafrin M.; Singh, Prabhat K.
The inevitable importance of basic amino acids, arginine and lysine, in human health and metabolism demands construction of efficient sensor systems for them. However, there are only limited reports on the 'ratiometric' detection of basic amino acids which is further restricted by the use of chemically complex sensor molecules, which impedes their prospect for practical applications. Herein, we report a ratiometric sensor system build on simple mechanism of disassociation of novel emissive Thioflavin-T H-aggregates from heparin surface, when subjected to interaction with basic amino acids. The strong and selective electrostatic and hydrogen bonding interaction of basic amino acids with heparin leads to large alteration in photophysical attributes of heparin bound Thioflavin-T, which forms a highly sensitive sensor platform for detection of basic amino acids in aqueous solution. These selective interactions between basic amino acids and heparin allow our sensor system to discriminate arginine and lysine from other amino acids. This unique mechanism of dissociation of Thioflavin-T aggregates from heparin surface provides ratiometric response on both fluorimetric and colorimetric outputs for detection of arginine and lysine, and thus it holds a significant advantage over other developed sensor systems which are restricted to single wavelength detection. Apart from the sensitivity and selectivity, our system also provides the advantage of simplicity, dual mode of sensing, and more importantly, it employs an inexpensive commercially available probe molecule, which is a significant advantage over other developed sensor systems that uses tedious synthesis protocol for the employed probe in the detection scheme, an impediment for practical applications. Additionally, our sensor system also shows response in complex biological media of serum samples.
A molecular rotor based ratiometric sensor for basic amino acids.
Pettiwala, Aafrin M; Singh, Prabhat K
The inevitable importance of basic amino acids, arginine and lysine, in human health and metabolism demands construction of efficient sensor systems for them. However, there are only limited reports on the 'ratiometric' detection of basic amino acids which is further restricted by the use of chemically complex sensor molecules, which impedes their prospect for practical applications. Herein, we report a ratiometric sensor system build on simple mechanism of disassociation of novel emissive Thioflavin-T H-aggregates from heparin surface, when subjected to interaction with basic amino acids. The strong and selective electrostatic and hydrogen bonding interaction of basic amino acids with heparin leads to large alteration in photophysical attributes of heparin bound Thioflavin-T, which forms a highly sensitive sensor platform for detection of basic amino acids in aqueous solution. These selective interactions between basic amino acids and heparin allow our sensor system to discriminate arginine and lysine from other amino acids. This unique mechanism of dissociation of Thioflavin-T aggregates from heparin surface provides ratiometric response on both fluorimetric and colorimetric outputs for detection of arginine and lysine, and thus it holds a significant advantage over other developed sensor systems which are restricted to single wavelength detection. Apart from the sensitivity and selectivity, our system also provides the advantage of simplicity, dual mode of sensing, and more importantly, it employs an inexpensive commercially available probe molecule, which is a significant advantage over other developed sensor systems that uses tedious synthesis protocol for the employed probe in the detection scheme, an impediment for practical applications. Additionally, our sensor system also shows response in complex biological media of serum samples. Copyright © 2017 Elsevier B.V. All rights reserved.
Synthesis, structure elucidation, biological screening, molecular modeling and DNA binding of some Cu(II) chelates incorporating imines derived from amino acids
Abdel-Rahman, Laila H.; Abu-Dief, Ahmed M.; Ismael, Mohammed; Mohamed, Mounir A. A.; Hashem, Nahla Ali
Three tridentate Schiff bases amino acids were prepared by direct condensation of 3-methoxysalicylaldehyde (MS) or 4-diethylaminosalicylaldehyde (DS) with α-amino acid ligands [L-phenylalanine (P), L-histidine (H) and DL-tryptophan (T)]. The prepared Schiff bases amino acids were investigated by melting points, elemental analysis, 1HNMR and 13CNMR, IR, UV-Vis spectra, conductivity and magnetic measurements analyses. Subsequently, copper was introduced and Cu(II) complexes formed. These complexes were analyzed by thermal and elemental analyses and further investigated by FT-IR and UV/Vis spectroscopies. The experimental results indicating that all Cu(II) complexes contain hydrated water molecules (except DSPCu complex) and don't contain coordinated water molecules. The kinetic and thermal parameters were extracted from the thermal data using Coast and Redfern method. The molar conductance values of the Schiff base amino acid ligands and their Cu(II) complexes were relatively low, showing that these compounds have non-electrolytic nature. Magnetic susceptibility measurements showed the diamagnetic nature of the Schiff base amino acid ligands and paramagnetic nature of their complexes. Additionally, a spectrophotometric method was determined to extract their stability constants. It was found that the complexes possess 1:2 (M:L) stoichiometry. The results suggested that 3-methoxysalicylaldehyde and 4-diethylaminosalicylaldehyde amino acid Schiff bases behave as monobasic tridentate ONO ligands and coordinate Cu(II) ions in octahedral geometry according to the general formula [Cu(HL)2]·nH2O. To further understanding the structural and electronic properties of these complexes, Density Functional Theory (DFT) calculations were employed and provided a satisfactory description. The optimized structures of MST Schiff base ligand and its complex were calculated using DFT. The antimicrobial activity of the Schiff base ligands and their complexes were screened against some
Solid-phase synthesis of 3-amino-2-pyrazolines
DEFF Research Database (Denmark)
Nielsen, John
The development of a solid-phase synthesis of 3-amino-2-pyrazolines is described. Conjugate addition of hydrazines to alpha,beta-unsaturated nitriles followed by cyclization yields 3-amino-2-pyrazolines. Acylation or sulfonation of the free amino-group yields a 24 member library of 3-amino-2...
Solid-phase synthesis of 3-amino-2-pyrazolines
DEFF Research Database (Denmark)
Lyngsø, Lars O.; Nielsen, John
The development of a solid-phase synthesis of 3-amino-2-pyrazolines is described. Conjugate addition of hydrazines to α,β-unsaturated nitriles followed by cyclization yields 3-amino-2-pyrazolines. Acylation or sulfonation of the free amino-group yields a 24 member library of 3-amino-2- pyrazolines....
Composition of amino acids, fatty acids and dietary fibre monomers ...
African Journals Online (AJOL)
There is increasing demand for sources of energy and non-meat protein with balanced amino acid profiles worldwide. Nuts are rich in protein and essential amino acids, and have a high energy value due to their high fat content. Kernels from two wild fruits in Mozambique, Adansonia digitata and Sclerocarya birrea, were ...
Amino acid availability regulates the effect of hyperinsulinemia on skin protein metabolism in pigs
The effects of amino acid supply and insulin infusion on skin protein kinetics (fractional synthesis rate (FSR), fractional breakdown rate (FBR), and net balance (NB)) in pigs were investigated. Four-month-old pigs were divided into four groups as follows: control, insulin (INS), amino acid (AA), an...
Synthesis and biodegradation studies of optically active poly (amide–imide) s based on N, N′-(pyromellitoyl)-bis-l-amino acid
DEFF Research Database (Denmark)
Wu, Qiuxiang; Yang, Zhizhou; Yao, Jinshui
Five new optically active poly(amide–imide)s (PAIs) (PAI3a–PAI3e) were synthesized through the direct polycondensation reaction between chiral N,N′-(pyromellitoyl)-bis-l-amino acids and 4,4′-diaminodiphenyl ether. The resulted polymers were fully characterized by means of Fourier transform infrar...... in water and had absorption in ultraviolet and visible light region. Possible biodegradation mechanism of amino acid-based PAIs was explored....... (FTIR) and proton nuclear magnetic resonance spectroscopy, elemental analysis, inherent viscosity measurement, solubility tests, specific rotation, and thermogravimetric analysis (TGA). The biodegradation studies of the PAIs were performed in soil and in phosphate buffer solution. The surface morphology...... and hydrophobicity of the biodegraded PAI films were investigated. FTIR spectra showed structural changes on PAI powders being treated in phosphate buffer solution. The TGA data showed that the thermal stability of PAI powders decreased with the degradation time. The collected degradation products were soluble...
Enantioselective synthesis of tricyclic amino acid derivatives based on a rigid 4-azatricyclo[5.2.1.02,6]decane skeleton
Directory of Open Access Journals (Sweden)
Matthias Breuning
Full Text Available An enantioselective route to four tricyclic amino acids and N-tosylamides, composed of a central norbornane framework with a 2-endo,3-endo-annelated pyrrolidine ring and a 5-endo-C1 or -C2 side chain, has been developed. A key intermediate was the chiral, N-Boc-protected ketone (1R,2S,6S,7R-4-azatricyclo[5.2.1.02,6]decan-8-one, available from inexpensive endo-carbic anhydride in five steps and 47% yield. The rigid scaffold makes these amino acid derivatives promising candidates for β-turn-inducing building blocks in peptidomimetics and for chiral auxiliaries in asymmetric organocatalysis.
Amino Acid Carbamates As Prodrugs Of Resveratrol.
Mattarei, Andrea; Azzolini, Michele; La Spina, Martina; Zoratti, Mario; Paradisi, Cristina; Biasutto, Lucia
Resveratrol (3, 5, 4'-trihydroxy-trans-stilbene), a plant polyphenol, has important drug-like properties, but its pharmacological exploitation in vivo is hindered by its rapid transformation via phase II conjugative metabolism. One approach to bypass this problem relies on prodrugs. We report here the synthesis, characterization, stability and in vivo pharmacokinetic behaviour of prodrugs of resveratrol in which the OH groups are engaged in an N-monosubstituted carbamate ester (-OC(O)NHR) linkage with a natural amino acid (Leu, Ile, Phe, Thr) to prevent conjugation and modulate the physicochemical properties of the molecule. We also report a convenient, high-yield protocol to obtain derivatives of this type. The new carbamate ester derivatives are stable at pH 1, while they undergo slow hydrolysis at physiological pH and hydrolyse with kinetics suitable for use in prodrugs in whole blood. After administration to rats by oral gavage the isoleucine-containing prodrug was significantly absorbed, and was present in the bloodstream as non-metabolized unaltered or partially deprotected species, demonstrating effective shielding from first-pass metabolism. We conclude that prodrugs based on the N-monosubstituted carbamate ester bond have the appropriate stability profile for the systemic delivery of phenolic compounds.
Cyclic Sulfamidate Enabled Syntheses of Amino Acids, Peptides, Carbohydrates, and Natural Products
This article reviews the emergence of cyclic sulfamidates as versatile intermediatesfor the synthesis of unnatural amino acids, chalcogen peptides, modified sugars, drugs and drug candidates, and important natural products.
Amino acids and autophagy: cross-talk and co-operation to control cellular homeostasis.
Carroll, Bernadette; Korolchuk, Viktor I; Sarkar, Sovan
Maintenance of amino acid homeostasis is important for healthy cellular function, metabolism and growth. Intracellular amino acid concentrations are dynamic; the high demand for protein synthesis must be met with constant dietary intake, followed by cellular influx, utilization and recycling of nutrients. Autophagy is a catabolic process via which superfluous or damaged proteins and organelles are delivered to the lysosome and degraded to release free amino acids into the cytoplasm. Furthermore, autophagy is specifically activated in response to amino acid starvation via two key signaling cascades: the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) and the general control nonderepressible 2 (GCN2) pathways. These pathways are key regulators of the integration between anabolic (amino acid depleting) and catabolic (such as autophagy which is amino acid replenishing) processes to ensure intracellular amino acid homeostasis. Here, we discuss the key roles that amino acids, along with energy (ATP, glucose) and oxygen, are playing in cellular growth and proliferation. We further explore how sophisticated methods are employed by cells to sense intracellular amino acid concentrations, how amino acids can act as a switch to dictate the temporal and spatial activation of anabolic and catabolic processes and how autophagy contributes to the replenishment of free amino acids, all to ensure cell survival. Relevance of these molecular processes to cellular and organismal physiology and pathology is also discussed.
Synthesis and antibacterial activity of thioglycolic amino acid derivatives and dipeptides containing the 2-methyl-3,4-dihydroquinazolin-4-one moiety.
Atta, F M
3-(2'-Chloroethyl)-2-methyl-3,4-dihydroquinazolin-4-one (I) was reacted with sodio (sodium thioglycolate) in dry dioxane and yielded compound II. By using thionyl chloride, this compound was converted to the corresponding acid chloride (III). The prepared acyl chloride (III) was allowed to interact with different alpha-amino acids such as Gly, L-Ala, L-B-Phe, DL-Asp, L-Glu, L-Thr and L-Val to give new amino acid derivatives (IVa-g). A selected C-terminal derivative of glycine (IVa) was converted into acid chloride (V). The acid chloride formed was reacted with L-Ala, L-B-Phe, DL-Asp, L-Glu, L-Thr and L-Val and yielded the new dipeptides VIa-f. The structures of the synthesized compounds were elucidated by elemental analysis and IR spectra. The prepared peptides were tested for their antimicrobial activities by comparison with tetra-cycline as a reference compound.
Synthesis of novel poly(ethylene glycol) derivatives having pendant amino groups and aggregating behavior of its mixture with fatty acid in water.
Koyama, Y; Umehara, M; Mizuno, A; Itaba, M; Yasukouchi, T; Natsume, K; Suginaka, A
Novel poly(ethylene glycol) (PEG) derivatives having pendant amino groups were prepared by copolymerization of allyl glycidyl ether with ethylene oxide followed by chemical modification of the double bond side chains. Dropwise addition of the mixture of monomers to the anionic initiator gave an almost monodisperse (Mw/Mn = 1.05) random copolymer. 1H NMR spectra showed that addition of 2-aminoethanethiol to the pendant allyl groups of the copolymer was completely carried out in methanol without catalyst, and an aminated PEG derivative with a definite structure was obtained. Acetylation of the pendant amino groups was readily performed by acetic anhydride with triethylamine. A gel permeation chromatogram of the acetylated polymer showed a very narrow molecular weight distribution (Mw/Mn = 1.06) of the polyamine. These cationic PEG derivatives make amphiphilic polyion complexes with fatty acids, and then aggregate in water. A fluorescence study using pyrene as a microenvironment probe revealed that the aminated PEG-lauric acid ion complex could take up the hydrophobic fluorescence probe into the lipophilic field inside, and they also had a critical aggregation concentration at [lauric acid] = 0.7 mM. It is much lower than the critical micelle concentration of the corresponding fatty acid sodium salts, indicating high stability of the polymer-fatty acid aggregate.
Postprandial fate of amino acids: adaptation to molecular forms
Nolles, J.A.
During the postprandial phase dietary proteins are digested to peptides and amino acids and absorbed. Once absorbed the peptides are further hydrolyzed to amino acids and transported to the tissues. These amino acids are largely incorporated into body proteins. Not all amino acids are, however,
Effect of supplementing grain amaranth diets with amino acids ...
African Journals Online (AJOL)
James Bond
145 impeding availability of its essential amino acids. Reduced availability of essential amino acids at the digestive stage would further be expected to adversely affect the concentration of amino acids in plasma. According to Hewitt & Lewis (1972a; b) plasma amino acid concentrations are a sensitive index of changes.
Amino Acid Profile of Biodegraded Brewers Spent Grains (BSG ...
African Journals Online (AJOL)
The amino acids profiles of biodegraded brewers spent grains (BSG) were determined. The analysis revealed the presence of 17 amino acids including the major amino acids (cysteine, lysine and methionine) required in poultry nutrition. The concentrations of the amino acids however varied with the microbial species used ...
Environmental roles of microbial amino acid racemases.
Hernández, Sara B; Cava, Felipe
Enzymes catalysing the stereo-chemical inter-conversion of amino acids are known as amino acid racemases. In bacteria, these enzymes are fundamental to synthesize the D-Ala and D-Glu that are critical components of the peptidoglycan. In addition to this structural function in cell wall assembly, D-amino acids produced by microbial amino acid racemases have been described as relevant constituents in other prokaryotic structures (e.g. capsule, non-ribosomal peptides) and have been associated to growth fitness and to processes such as biofilm development, spore germination and signalling. The recent discovery of broad spectrum racemases able to produce and release several D-amino acids to the environment suggests that these enzymes might have a great impact in microbial ecology. Consequently, new data on the biochemistry and regulation of racemases is key to understand the biological significance of D-enantiomers in nature, in particular their effect on microbial social networks. This review summarizes current knowledge on the environmental roles of bacterial racemases with an emphasis on the potential roles of the new broad spectrum enzymes in natural environments. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.
Amino acids profile of Serbian unifloral honeys.
Kečkeš, Jelena; Trifković, Jelena; Andrić, Filip; Jovetić, Milica; Tešić, Zivoslav; Milojković-Opsenica, Dušanka
The free amino acids profile of 192 samples of seven different floral types of Serbian honey (acacia, linden, sunflower, rape, basil, giant goldenrod, and buckwheat) from six different regions was analysed in order to distinguish honeys by their botanical origin. The most abundant amino acids were proline, alanine, phenylalanine, threonine and arginine. Based on the established amino acids profiles, some important differences have been identified among studied honey samples relying on the basic descriptive statistics data, and confirmed by multivariate chemometric methods. Principal component analysis revealed that basil honey samples form a well-defined cluster imposed with phenylalanine content. The model obtained by linear discriminant analysis might be used to distinguish basil honey from the rest of the samples, and has moderate predictive power to separate genuine acacia, linden, sunflower and rape honeys. New data for the amino acids profile of giant goldenrod and buckwheat honey samples are presented. The floral origin of honey could be successfully evaluated by its amino acids profile coupled with chemometric analysis. © 2013 Society of Chemical Industry.
Amino acid uptake in rust fungi
Directory of Open Access Journals (Sweden)
Christine eStruck
Full Text Available The plant pathogenic rust fungi colonize leaf tissue and feed off their host plants without killing them. Certain economically important species of different genera such as Melampsora, Phakopsora, Puccinia or Uromyces are extensively studied for resolving the mechanisms of the obligate biotrophy. As obligate parasites rust fungi only can complete their life cycle on living hosts where they grow through the leaf tissue by developing an extended network of intercellular hyphae from which intracellular haustoria are differentiated. Haustoria are involved in key functions of the obligate biotrophic lifestyle: suppressing host defense responses and acquiring nutrients. This review provides a survey of rust fungi nitrogen nutrition with special emphasis on amino acid uptake. A variety of sequences of amino acid transporter genes of rust fungi have been published; however, transport activity of only three in planta highly up-regulated amino acid permeases have been characterized. Functional and immunohistochemical investigations have shown the specificity and localization of these transporters. Sequence data of various genome projects allowed identification of numerous rust amino acid tranporter genes. An in silico analysis reveals that these genes can be classified into different transporter families. In addition, genetic and molecular data of amino acid transporters have provided new insights in the corresponding metabolic pathways.
Amino acid "little Big Bang": Representing amino acid substitution matrices as dot products of Euclidian vectors
Directory of Open Access Journals (Sweden)
Zimmermann Karel
Full Text Available Abstract Background Sequence comparisons make use of a one-letter representation for amino acids, the necessary quantitative information being supplied by the substitution matrices. This paper deals with the problem of finding a representation that provides a comprehensive description of amino acid intrinsic properties consistent with the substitution matrices. Results We present a Euclidian vector representation of the amino acids, obtained by the singular value decomposition of the substitution matrices. The substitution matrix entries correspond to the dot product of amino acid vectors. We apply this vector encoding to the study of the relative importance of various amino acid physicochemical properties upon the substitution matrices. We also characterize and compare the PAM and BLOSUM series substitution matrices. Conclusions This vector encoding introduces a Euclidian metric in the amino acid space, consistent with substitution matrices. Such a numerical description of the amino acid is useful when intrinsic properties of amino acids are necessary, for instance, building sequence profiles or finding consensus sequences, using machine learning algorithms such as Support Vector Machine and Neural Networks algorithms.
Amino acid "little Big Bang": representing amino acid substitution matrices as dot products of Euclidian vectors.
Zimmermann, Karel; Gibrat, Jean-François
Sequence comparisons make use of a one-letter representation for amino acids, the necessary quantitative information being supplied by the substitution matrices. This paper deals with the problem of finding a representation that provides a comprehensive description of amino acid intrinsic properties consistent with the substitution matrices. We present a Euclidian vector representation of the amino acids, obtained by the singular value decomposition of the substitution matrices. The substitution matrix entries correspond to the dot product of amino acid vectors. We apply this vector encoding to the study of the relative importance of various amino acid physicochemical properties upon the substitution matrices. We also characterize and compare the PAM and BLOSUM series substitution matrices. This vector encoding introduces a Euclidian metric in the amino acid space, consistent with substitution matrices. Such a numerical description of the amino acid is useful when intrinsic properties of amino acids are necessary, for instance, building sequence profiles or finding consensus sequences, using machine learning algorithms such as Support Vector Machine and Neural Networks algorithms.
Amino acids in the sedimentary humic and fulvic acids
Digital Repository Service at National Institute of Oceanography (India)
Sardessai, S.
Humic and fulvic acids isolated from a few sediment samples from Arabian Sea and Bay of Bengal were analysed for total hydrolysable amino acids concentration and their composition. The amono acids content of fulvic acids was higher than in the humic...
Reprogramming amino acid catabolism in CHO cells with CRISPR-Cas9 genome editing improves cell growth and reduces by-product secretion
DEFF Research Database (Denmark)
Ley, Daniel; Pereira, Sara; Pedersen, Lasse Ebdrup
CHO cells primarily utilize amino acids for three processes: biomass synthesis, recombinant protein production and catabolism. In this work, we disrupted 9 amino acid catabolic genes participating in 7 dierent catabolic pathways, to increase synthesis of biomass and recombinant protein, while...... reducing production of growth-inhibiting metabolic by-products from amino acid catabolism....
Economic aspects of amino acids production.
Mueller, Udo; Huebner, Susanna
Amino acids represent basic elements of proteins, which as a main source of nutrition themselves serve as a major reserve for maintaining essential functions of humans as well as animals. Taking the recent state of scientific knowledge into account, the industrial sector of amino acids is a priori "suitable" to a specific kind of an ecologically sound way of production, which is based on biotechnology. The following article may point out characteristics of this particular industrial sector and illustrates the applicability of the latest economic methods, founded on development of the discipline of bionics in order to describe economic aspects of amino acids markets. The several biochemical and technological fields of application of amino acids lead to specific market structures in high developed and permanently evolving systems. The Harvard tradition of industrial economics explains how market structures mould the behaviour of the participants and influences market results beyond that. A global increase in intensity of competition confirms the notion that the supply-side is characterised by asymmetric information in contrast to Kantzenbachs concept of "narrow oligopoly" with symmetrical shared knowledge about market information. Departing from this point, certain strategies of companies in this market form shall be derived. The importance of Research and Development increases rapidly and leads to innovative manufacturing methods which replace more polluting manufacturing processes like acid hydrolysis. In addition to these modifications within the production processes the article deals furthermore with the pricing based on product life cycle concept and introduces specific applications of tools like activity based costing and target costing to the field of amino acid production. The authors come to the conclusion that based on a good transferability of latest findings in bionics and ecological compatibility competitors in amino acids manufacturing are well advised
Effects of running the Bostom Marathon on plasma concentrations of large neutral amino acids
Conlay, L. A.; Wurtman, R. J.; Lopez G-Coviella, I.; Blusztajn, J. K.; Vacanti, C. A.; Logue, M.; During, M.; Caballero, B.; Maher, T. J.; Evoniuk, G.
Plasma large neutral amino acid concentrations were measured in thirty-seven subjects before and after completing the Boston Marathon. Concentrations of tyrosine, phenylalanine, and methionine increased, as did their 'plasma ratios' (i.e., the ratio of each amino acid's concentration to the summed plasma concentrations of the other large neutral amino acids which compete with it for brain uptake). No changes were noted in the plasma concentrations of tryptophan, leucine, isoleucine, nor valine; however, the 'plasma ratios' of valine, leucine, and isoleucine all decreased. These changes in plasma amino acid patterns may influence neurotransmitter synthesis.
Influence of nitrogen sources on amino acid production by aspergillus niger
International Nuclear Information System (INIS)
Almani, F.; Dahot, M.U.
The effect of different organic and inorganic nitrogen sources in 0.1% and 0.2% concentration on the production of amino acid was studied using a wild strain of Aspergillus niger. The rate of amino acid biosynthesis was found to be higher when 0.2% corn steep liquor was incorporated in the mineral medium. It was concluded from the study that the amino acid synthesis by wild strain depends not only on the nature and type of nitrogen sources used but the concentration of nitrogen source also play an important in the accumulation of free amino acids in the medium. (author)
Cometary Amino Acids from the STARDUST Mission
Cook, Jamie Elsila
NASA's Stardust spacecraft returned samples from comet 81 P/WiId 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a cometary amino acid.
Amino acid nutrition of fishes: requirements and supplementation of diets
Ketola, H.G.
The purpose of this paper is: (1) to make a concise review of the published dietary requirements of fishes for amino acids, (2) to describe recent findings at the Tunison Laboratory concerning amino acid nutrition of trout, (3) to review specific signs of deficiency of amino acids, and (4) to discuss use of the fish egg amino acid pattern as a guideline to formulating new feeds or studying amino acid requirements of fishes for which there is limited information on their quantitative requirements.
Unusual Amino Acids in Medicinal Chemistry.
Blaskovich, Mark A T
Unusual amino acids are fundamental building blocks of modern medicinal chemistry. The combination of readily functionalized amine and carboxyl groups attached to a chiral central core along with one or two potentially diverse side chains provides a unique three-dimensional structure with a high degree of functionality. This makes them invaluable as starting materials for syntheses of complex molecules, highly diverse elements for SAR campaigns, integral components of peptidomimetic drugs, and potential drugs on their own. This Perspective highlights the diversity of unnatural amino acid structures found in hit-to-lead and lead optimization campaigns and clinical stage and approved drugs, reflecting their increasingly important role in medicinal chemistry.
Indigenous Amino Acids in Iron Meteorites
Elsila, J. E.; Dworkin, J. P.; Glavin, D. P.; Johnson, N. M.
Understanding the organic content of meteorites and the potential delivery of molecules relevant to the origin of life on Earth is an important area of study in astrobiology. There have been many studies of meteoritic organics, with much focus on amino acids as monomers of proteins and enzymes essential to terrestrial life. The majority of these studies have involved analysis of carbonaceous chondrites, primitive meteorites containing approx. 3-5 wt% carbon. Amino acids have been observed in varying abundances and distributions in representatives of all eight carbonaceous chondrite groups, as well as in ungrouped carbonaceous chondrites, ordinary and R chondrites, ureilites, and planetary achondrites [1 and references therein].
Rigid nonproteinogenic cyclic amino acids as ligands for glutamate receptors: trans-tris(homoglutamic) acids
DEFF Research Database (Denmark)
Meyer, Udo; Bisel, Philippe; Bräuner-Osborne, Hans
of the trans-1S,2R-configured secondary alpha-amino amido-ester. In receptor binding assays and functional tests, trans-1S,2R-1-amino-2-carboxymethylcyclopentanecarboxylic acid hydrochloride was found to behave as a selective mGluR(2)-antagonist without relevant binding properties at iGluRs.......The second-generation asymmetric synthesis of the trans-tris(homoglutamic) acids reported herein proceeds via Strecker reaction of chiral ketimines, obtained from condensation of racemic 2-ethoxycarbonylmethylcyclopentanone and commercially available (S)- and (R)-1-phenylethylamine, respectively......) yielded diastereomeric mixtures of secondary alpha-amino amido-esters, which after separation were hydrogenolyzed and hydrolyzed each to the enantiomeric trans-1-amino-2-carboxymethylcyclopentanecarboxylic acids. Their configuration was completely established by NMR methods, CD spectra, and X-ray analysis...
Synthesis, structural characterization and Hirshfeld analysis studies of three novel co-crystals of trans-4-[(2-amino-3,5-dibrobenzyl) amino] cyclohexanol with hydroxyl benzoic acids
Ma, Yu-heng; Lou, Ming; Sun, Qing-yang; Ge, Shu-wang; Sun, Bai-wang
Combination of active pharmaceutical ingredients, trans-4-[(2-amino-3,5-dibrobenzyl) amino] cyclohexanol (AMB) and some organic acids, e.g., p-hydroxybenzoic acid (PHBA), m-hydroxybenzoic acid (MHBA), and 3,4-dihydroxy benzoic acid (DHBA), yield three novel co-crystals characterized by X-ray single-crystal, Fluorescence spectroscopy and thermal analysis (DSC and TGA), which included co-crystal 1 with 2:2: 1 stoichiometry of AMB, PHBA and H2O, co-crystal 2 with 1:1 stoichiometry of AMB and MHBA, and co-crystal 3 with 1:1:1 stoichiometry of AMB, DHBA and CH3OH. Constituents of the co-crystalline phase were also investigated in terms of Hirshfeld surfaces. In the crystal lattice, a three-dimensional hydrogen-bonded network is observed, including formation of a two-dimensional molecular scaffolding motif. Hirshfeld surfaces and fingerprint plots of three co-crystals show that structures are stabilized by H⋯H, N-H⋯O, H⋯Br and C⋯H intermolecular interactions. Besides, the studies of the solubility showed that this co-crystal strategy could promote the solubility of AMB and follow the order: co-crystal 1 < co-crystal 2 < co-crystal 3.
Carbon-11 and Fluorine-18 Labeled Amino Acid Tracers for Positron Emission Tomography Imaging of Tumors
Sun, Aixia; Liu, Xiang; Tang, Ganghua
Tumor cells have an increased nutritional demand for amino acids(AAs) to satisfy their rapid proliferation. Positron-emitting nuclide labeled AAs are interesting probes and are of great importance for imaging tumors using positron emission tomography (PET). Carbon-11 and fluorine-18 labeled AAs include the [1-11C] amino acids, labeling alpha-C- amino acids, the branched-chain of amino acids and N-substituted carbon-11 labeled amino acids. These tracers target protein synthesis or amino acid(AA) transport, and their uptake mechanism mainly involves AA transport. AA PET tracers have been widely used in clinical settings to image brain tumors, neuroendocrine tumors, prostate cancer, breast cancer, non–small cell lung cancer (NSCLC) and hepatocellular carcinoma. This review focuses on the fundamental concepts and the uptake mechanism of AAs, AA PET tracers and their clinical applications.
Diversity-oriented synthesis of azapeptides with basic amino acid residues: aza-lysine, aza-ornithine, and aza-arginine.
Traoré, Mariam; Doan, Ngoc-Duc; Lubell, William D
Aza-peptides with basic amino acid residues (lysine, ornithine, arginine) and derivatives were synthesized by an effective approach featuring alkylation of a hydrazone-protected aza-glycine residue with α-bromo ω-chloro propane and butane to provide the corresponding alkyl chloride side chains. Displacement of the chloride with azide and various amines gave entry to azaOrn, azaLys, and azaArg containing peptides as demonstrated by the solution and solid-phase syntheses of 29 examples, including an aza-library of Growth Hormone Releasing Peptide-6 analogs.
New entry for synthesis of N-acylhydrazones, pyridazinones, and 1,3,4-oxadiazin-6-ones from alpha-amino acid esters.
Yasui, Eiko; Wada, Masao; Takamura, Norio
Versatile electrophiles N-acylhydrazones are synthesized via diazotization, reduction, and acylation of alpha-amino acid esters. Reduction of diazo esters with L-selectride or tributylphosphine affords the corresponding hydrazones in good yields. Both reducing agents give anti-hydrazones as the major product although the reactivity of each reductant is slightly different. The resulting hydrazones are acylated to give N-acylhydrazones, which are subjected to further reactions to give 1,3,4-oxadiazin-6-ones that serve as useful synthetic intermediates for the Diels-Alder reaction.
Evaluation of methods to estimate the essential amino acids requirements of fish from the muscle amino acid profile
de Almeida Bicudo,Álvaro José; Possebon Cyrino,José Eurico
Many methods to estimate amino acid requirement based on amino acid profile of fish have been proposed. This study evaluates the methodology proposed by Meyer & Fracalossi (2005) and by Tacon (1989) to estimate amino acids requirement of fish, which do exempt knowledge on previous nutritional requirement of reference amino acid. Data on amino acid requirement of pacu, Piaractus mesopotamicus, were used to validate de accuracy of those methods. Meyer & Fracalossi's and Tacon's methodol...
Adsorption of aromatic amino acids in a fixed bed column
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Cremasco M.A.
Full Text Available Phenylalanine (Phe and tyrosine (Tyr are two of the twenty amino acids in proteins; they are classified as aromatic amino acids, because both have a benzene ring in their structures. These amino acids are important in the synthesis of several biologically active amines, such as beta-endorphin, a neurotransmitter. Amino acids can be separated by ion-exchange chromatography. In this case, it is important that fixed-bed adsorber design adequately predict the breakthrough curve. This work presents a mathematical model for both fluid and porous phases. In the solution proposed for this model the liquid-phase concentration inside the particles is solved analytically and is related to the liquid-phase concentration in the bed using Duhamel's theorem. The solution for liquid-phase concentration in the bed is then solved numerically instead of analytically. The basic mass transfer parameters are from the literature. The results from the model are compared with those obtained experimentally using Phe and Tyr diluted in aqueous solutions in a fixed bed of PVP (poly-4-vinylpyridine resin.
Regional amino acid transport into brain during diabetes: Effect of plasma amino acids
International Nuclear Information System (INIS)
Mans, A.M.; DeJoseph, M.R.; Davis, D.W.; Hawkins, R.A.
Transport of phenylalanine and lysine into the brain was measured in 4-wk streptozotocin-diabetic rats to assess the effect on the neutral and basic amino acid transport systems at the blood-brain barrier. Amino acid concentrations in plasma and brain were also measured. Regional permeability-times-surface area (PS) products and influx were determined using a continuous infusion method and quantitative autoradiography. The PS of phenylalanine was decreased by an average of 40% throughout the entire brain. Influx was depressed by 35%. The PS of lysine was increased by an average of 44%, but the influx was decreased by 27%. Several plasma neutral amino acids (branched chain) were increased, whereas all basic amino acids were decreased. Brain tryptophan, phenylalanine, tyrosine, methionine, and lysine contents were markedly decreased. The transport changes were almost entirely accounted for by the alterations in the concentrations of the plasma amino acids that compete for the neutral and basic amino acid carriers. The reduced influx could be responsible for the low brain content of some essential amino acids, with possibly deleterious consequences for brain functions
Characterization of N,N-dimethyl amino acids by electrospray ionization-tandem mass spectrometry.
Naresh Chary, V; Sudarshana Reddy, B; Kumar, Ch Dinesh; Srinivas, R; Prabhakar, S
Methylation is an essential metabolic process for a number of critical reactions in the body. Methyl groups are involved in the healthy function of the body life processes, by conducting methylation process involving specific enzymes. In these processes, various amino acids are methylated, and the occurrence of methylated amino acids in nature is diverse. Nowadays, mass-spectrometric-based identification of small molecules as biomarkers for diseases is a growing research. Although all dimethyl amino acids are metabolically important molecules, mass spectral data are available only for a few of them in the literature. In this study, we report synthesis and characterization of all dimethyl amino acids, by electrospray ionization-tandem mass spectrometry (MS/MS) experiments on protonated molecules. The MS/MS spectra of all the studied dimethyl amino acids showed preliminary loss of H2O + CO to form corresponding immonium ions. The other product ions in the spectra are highly characteristic of the methyl groups on the nitrogen and side chain of the amino acids. The amino acids, which are isomeric and isobaric with the studied dimethyl amino acids, gave distinctive MS/MS spectra. The study also included MS/MS analysis of immonium ions of dimethyl amino acids that provide information on side chain structure, and it is further tested to determine the N-terminal amino acid of the peptides. Copyright © 2015 John Wiley & Sons, Ltd.
Polymerization of amino acids containing nucleotide bases
Ben Cheikh, Azzouz; Orgel, Leslie E.
The nucleoamino acids 1-(3'-amino,3'-carboxypropyl)uracil (3) and 9-(3'-amino,3'-carboxypropyl)adenine (4) have been prepared as (L)-en-antiomers and as racemic mixtures. When 3 or 4 is suspended in water and treated with N,N'-carbon-yldiimidazole, peptides are formed in good yield. The products formed from the (L)-enantiomers are hydrolyzed to the monomeric amino acids by pronase. Attempts to improve the efficiency of these oligomerizations by including a polyuridylate template in the reaction mixture were not successful. Similarly, oligomers derived from the (L)-enantiomer of 3 did not act as templates to facilitate the oligomerization of 4.
DNA Synthesis and Viability of a mutT Derivative of Escherichia coli WP2 under Conditions of Amino Acid Starvation and Relation to Stationary-Phase (Adaptive) Mutation
Bridges, Bryn A.; Ereira, Sharon
Escherichia coli WP2 bacteria with an ochre amino acid auxotrophy show no evidence of growth during the first few days after plating at densities above 108 on plates lacking the required amino acid. They lose viability for some days, and then a subpopulation recovers and there is cell turnover. At very low plating densities (around 102 per plate), almost every cell will eventually form a small but visible colony. At intermediate plating densities (106 to 107 per plate), there is an immediate increase in the number of viable bacteria. The results are consistent with a model that assumes that growth is dependent on trace amounts of tryptophan or a tryptophan-complementing substance and that death is due to extracellular toxic species in the medium, including active oxygen species. Mutations in mutT bacteria under these conditions result from incorporation of 7,8-dihydro-8-oxo-dGTP into DNA and thus largely reflect DNA synthesis associated with the increase in the number of viable cells at the initial density used (107 per plate). We show that the increase in cell number and much of this DNA synthesis can be eliminated by the presence of 108 scavenger bacteria and by removal of early-arising mutant colonies that release the required amino acid. The synthesis that remains is equivalent to less than a quarter of a genome per day and is marginally reduced, if at all, in a polA derivative. We cannot exclude the possibility that this residual DNA synthesis is peculiar to mutT bacteria due to transcriptional leakiness, although there is no evidence that this is a major problem in this strain. If such DNA synthesis also occurs in wild-type bacteria, it may well be important for adaptive mutation since use of a more refined agar in selective plates both eliminated the initial increase in cell number seen at low density (107 per plate) and reduced the rate of appearance of mutants at plating densities above 108 per plate. PMID:9603880
Synthesis, structure and characterization of two copper(II) supramolecular coordination polymers based on a multifunctional ligand 2-amino-4-sulfobenzoic acid.
Wei, Yan; Zhang, Lei; Wang, Meng-Jie; Chen, Si-Chun; Wang, Zi-Hao; Zhang, Kou-Lin
Copper(II) coordination polymers have attracted considerable interest due to their catalytic, adsorption, luminescence and magnetic properties. The reactions of copper(II) with 2-amino-4-sulfobenzoic acid (H(2)asba) in the presence/absence of the auxiliary chelating ligand 1,10-phenanthroline (phen) under ambient conditions yielded two supramolecular coordination polymers, namely (3-amino-4-carboxybenzene-1-sulfonato-κO(1))bis(1,10-phenanthroline-κ(2)N,N')copper(II) 3-amino-4-carboxybenzene-1-sulfonate monohydrate, [Cu(C7H6N2O5S)(C12H8N2)2](C7H6N2O5S)·H2O, (1), and catena-poly[[diaquacopper(II)]-μ-3-amino-4-carboxylatobenzene-1-sulfonato-κ(2)O(4):O(4')], [Cu(C7H6N2O5S)(H2O)2]n, (2). The products were characterized by FT-IR spectroscopy, thermogravimetric analysis (TGA), solid-state UV-Vis spectroscopy and single-crystal X-ray diffraction analysis, as well as by variable-temperature powder X-ray diffraction analysis (VT-PXRD). Intermolecular π-π stacking interactions in (1) link the mononuclear copper(II) cation units into a supramolecular polymeric chain, which is further extended into a supramolecular double chain through interchain hydrogen bonds. Supramolecular double chains are then extended into a two-dimensional supramolecular double layer through hydrogen bonds between the lattice Hasba(-) anions, H2O molecules and double chains. Left- and right-handed 21 helices formed by the Hasba(-) anions are arranged alternately within the two-dimensional supramolecular double layers. Complex (2) exhibits a polymeric chain which is further extended into a three-dimensional supramolecular network through interchain hydrogen bonds. Complex (1) shows a reversible dehydration-rehydration behaviour, while complex (2) shows an irreversible dehydration-rehydration behaviour.
Proximate composition, amino acid profile and phytochemical ...
African Journals Online (AJOL)
The objective of this study was to evaluate Lophira lanceolata (false shea or meni oil tree) seeds with the aim of qualifying and quantifying chemical and biological information that might serve as a guide to exploit its potentials and benefits for human and animal nutrition .The chemical composition, amino acid profile and ...
Treatment of Amino Acid Metabolism Disorders
... of amino acids. Babies with TYR I may need vitamin D, a vitamin that can help babies who ... Rickets is a condition in which too little vitamin D causes a child's bones to be ... condition, he may need to take certain medicines. For example: Babies with ...
Large neutral amino acids in daily practice
DEFF Research Database (Denmark)
Ahring, Kirsten Kiær
At the Kennedy Centre for Phenylketonuria, Denmark, large neutral amino acids (LNAAs) are being used to treat adult and adolescent patients who are nonadherent to dietary treatment for phenylketonuria (PKU). At the start of treatment, a patient must undergo dietary analysis and regular blood...
Optimization of short amino acid sequences classifier
Barcz, Aleksy; Szymański, Zbigniew
This article describes processing methods used for short amino acid sequences classification. The data processed are 9-symbols string representations of amino acid sequences, divided into 49 data sets - each one containing samples labeled as reacting or not with given enzyme. The goal of the classification is to determine for a single enzyme, whether an amino acid sequence would react with it or not. Each data set is processed separately. Feature selection is performed to reduce the number of dimensions for each data set. The method used for feature selection consists of two phases. During the first phase, significant positions are selected using Classification and Regression Trees. Afterwards, symbols appearing at the selected positions are substituted with numeric values of amino acid properties taken from the AAindex database. In the second phase the new set of features is reduced using a correlation-based ranking formula and Gram-Schmidt orthogonalization. Finally, the preprocessed data is used for training LS-SVM classifiers. SPDE, an evolutionary algorithm, is used to obtain optimal hyperparameters for the LS-SVM classifier, such as error penalty parameter C and kernel-specific hyperparameters. A simple score penalty is used to adapt the SPDE algorithm to the task of selecting classifiers with best performance measures values.
Side Chain Cyclized Aromatic Amino Acids
DEFF Research Database (Denmark)
Van der Poorten, Olivier; Knuhtsen, Astrid; Sejer Pedersen, Daniel
Constraining the conformation of flexible peptides is a proven strategy to increase potency, selectivity, and metabolic stability. The focus has mostly been on constraining the backbone dihedral angles; however, the correct orientation of the amino acid side chains (χ-space) that constitute the p...
[Plasma amino acid concentrations in aggressive dogs].
Juhr, Norbert-Christian; Brand, Ulrike; Riedel, Eberhard
Following the hypothesis that metabolic screens may be useful tools in the diagnosis of canine aggression we have investigated the blood plasma amino acid levels of dogs which have been found aggressive (N = 10) against dogs or men in comparison to non-aggressive dogs (N = 10). In summary, the aggressive dogs showed elevated plasma concentrations of the neurophysiological active aromatic amino acids tryptophan (46/171 micromol/l, p urea-cycle in the conversion of ornithine (17/34 micromol/l, p < 0.01) to citrulline (64/47 micromol/l). Higher levels of branched chain amino acids, especially leucine (122/150 micromol/l, p < 0.01), mainly metabolized in muscles, and isoleucin (60/71 micromol/l, p < 0.05) show a high energy potential. The acidose-stimulator methionine (48/78 micromol/l, p < 0.01) proved elevated. The results show that the changed behavior in the aggressive dogs is also reflected in their free amino acid plasma concentrations, independent of the question whether these data are the cause or the result of the aggressivity.
Functional amino acids in fish nutrition, health and welfare.
Andersen, Synne M; Waagbø, Rune; Espe, Marit
Protein is the most expensive part of fish diets and supplies amino acids (AA) for energy, growth, protein synthesis and as substrates for key metabolic pathways. Functional AA is a term used to describe AA that are involved in cellular processes apart from protein synthesis. A deficiency, or imbalance, in functional AA may impair body metabolism and homeostasis. Recent years have seen an increased interest in AA to increase disease resistance, immune response, reproduction, behavior and more. This has led to a boost of commercially available functional fish feeds that aim to optimize fish performance and quality of the product. This review aim to collect recent findings of functional AA and of how they may improve fish health and welfare. It will focus on functional properties of some of the most studied AA, namely arginine, glutamine, glutamate, tryptophan, sulfur amino acids (methionine, cysteine and taurine), histidine and branched chain amino acids. Where information is not available in fish, we will point towards functions known in animals and humans, with possible translational functions to fish.
Present Global Situation of Amino Acids in Industry.
Tonouchi, Naoto; Ito, Hisao
At present, amino acids are widely produced and utilized industrially. Initially, monosodium glutamate (MSG) was produced by extraction from a gluten hydrolysate. The amino acid industry started using the residual of the lysate. The discovery of the functions of amino acids has led to the expansion of their field of use. In addition to seasoning and other food use, amino acids are used in many fields such as animal nutrients, pharmaceuticals, and cosmetics. On the other hand, the invention of the glutamate fermentation process, followed by the development of fermentation methods for many other amino acids, is no less important. The supply of these amino acids at a low price is very essential for their industrial use. Most amino acids are now produced by fermentation. The consumption of many amino acids such as MSG or feed-use amino acids is still rapidly increasing.
Amino acid code of protein secondary structure.
Shestopalov, B V
The calculation of protein three-dimensional structure from the amino acid sequence is a fundamental problem to be solved. This paper presents principles of the code theory of protein secondary structure, and their consequence--the amino acid code of protein secondary structure. The doublet code model of protein secondary structure, developed earlier by the author (Shestopalov, 1990), is part of this theory. The theory basis are: 1) the name secondary structure is assigned to the conformation, stabilized only by the nearest (intraresidual) and middle-range (at a distance no more than that between residues i and i + 5) interactions; 2) the secondary structure consists of regular (alpha-helical and beta-structural) and irregular (coil) segments; 3) the alpha-helices, beta-strands and coil segments are encoded, respectively, by residue pairs (i, i + 4), (i, i + 2), (i, i = 1), according to the numbers of residues per period, 3.6, 2, 1; 4) all such pairs in the amino acid sequence are codons for elementary structural elements, or structurons; 5) the codons are divided into 21 types depending on their strength, i.e. their encoding capability; 6) overlappings of structurons of one and the same structure generate the longer segments of this structure; 7) overlapping of structurons of different structures is forbidden, and therefore selection of codons is required, the codon selection is hierarchic; 8) the code theory of protein secondary structure generates six variants of the amino acid code of protein secondary structure. There are two possible kinds of model construction based on the theory: the physical one using physical properties of amino acid residues, and the statistical one using results of statistical analysis of a great body of structural data. Some evident consequences of the theory are: a) the theory can be used for calculating the secondary structure from the amino acid sequence as a partial solution of the problem of calculation of protein three
Amino acid quality indices of the leaves of Clerodendrum volubile
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Ochuko Lucky Erukainure
Full Text Available Objective: To evaluate the amino acid profile and quality indices of Clerodendrum volubile (C. volubile leaves. Methods: Dried leaves of C. volubile were blended, defatted and subjected to amino acid analysis using the technicon sequential multi-sample amino acid analyzer. The amino acid quality indices which covers for chemical score, essential amino acid index, nutritional index, true digestibility, protein digestibility corrected amino acid score, and digestible indispensable amino acid score were evaluated using standard formulas. Results: Amino acid analysis revealed glutamic acid to have the highest concentration, with cysteine having the least. Aspartic acid had the highest chemical score, this was followed by glycine, histidine and arginine, respectively. The least scores were observed in serine and methionine. Glutamic acid had the highest value for true digestibility and protein digestibility corrected amino acid score, with the least observed in cysteine. Digestible indispensable amino acid score evaluation showed histidine to have the highest value for infants (birth to 6 months, threonine for children (6 months to 3 years, while isoleucine was observed to have the highest value for older children, adolescents and adults. The essential amino acid index value was less than 4, while nutritional index value was less than 0.5. Conclusions: These results indicated the leaves of C. volubile as a potential source of amino acids in the human diet as portrayed by its amino acids profile and qualities.
Genetic regulation by amino acids of specific membrane protein biosynthesis in isolated rat hepatocytes
International Nuclear Information System (INIS)
Chiles, T.C.; Handlogten, M.E.; Kilberg, M.S.
Rat Hepatocytes in primary culture were incubated in amino acid-free (AAF) medium or amino acid-supplemented (AAS) medium for 2-6 hr. The effect of amino acid starvation on the synthesis of specific membrane proteins was monitored by including 3 H-leucine during the incubation. A crude plasma membrane fraction was prepared and then analyzed by 2-D gel electrophoresis followed by fluorography. Amino acid deprivation caused an induction of the synthesis of 5 of the 30 proteins studied. The ratio (AAF/-AAS) of cpm incorporated into the remaining 25 proteins was 0.8 +/- 0.2, whereas the ratio for the 5 proteins that showed amino acid-dependent synthesis ranged from 1.5 to 2.5. The presence of 4 μM actinomycin in the AAF medium completely blocked the starvation-induced synthesis of the 5 proteins tested, but did not alter significantly the ratio of cpm incorporated into the other 25 proteins. Binding studies involving ConA suggested a plasma membrane location for the 5 proteins. The molecular weight values of the starvation-induced proteins are 70, 66, 66, 67, and 45kD. Surface-labelling of intact cells and preparation of antibodies against the 5 proteins will be used to establish the subcellular location and to describe the amino acid-dependent synthesis of each in more detail
Plasma free amino acid kinetics in rainbow trout (Oncorhynchus mykiss) using a bolus injection of 15N-labeled amino acids.
Robinson, Jacob William; Yanke, Dan; Mirza, Jeff; Ballantyne, James Stuart
To gain insight into the metabolic design of the amino acid carrier systems in fish, we injected a bolus of (15)N amino acids into the dorsal aorta in mature rainbow trout (Oncorhynchus mykiss). The plasma kinetic parameters including concentration, pool size, rate of disappearance (R(d)), half-life and turnover rate were determined for 15 amino acids. When corrected for metabolic rate, the R(d) values obtained for trout for most amino acids were largely comparable to human values, with the exception of glutamine (which was lower) and threonine (which was higher). R(d) values ranged from 0.9 μmol 100 g(-1) h(-1) (lysine) to 22.1 μmol 100 g(-1) h(-1) (threonine) with most values falling between 2 and 6 μmol 100 g(-1) h(-1). There was a significant correlation between R(d) and the molar proportion of amino acids in rainbow trout whole body protein hydrolysate. Other kinetic parameters did not correlate significantly with whole body amino acid composition. This indicates that an important design feature of the plasma-free amino acids system involves proportional delivery of amino acids to tissues for protein synthesis.
A Propensity for n-omega-Amino Acids in Thermally-Altered Antarctic Meteorites
Burton, Aaron S.; Elsila, Jamie E.; Callahan, Michael P.; Martin, Mildred G.; Glavin, Daniel P.; Johnson, Natasha M.; Dworkin, Jason P.
Carbonaceous meteorites are known to contain a wealth of indigenous organic molecules, including amino acids, which suggests that these meteorites could have been an important source of prebiotic organic material during the origins of life on Earth and possibly elsewhere. We report the detection of extraterrestrial amino acids in thermally-altered type 3 CV and CO carbonaceous chondrites and ureilites recovered from Antarctica. The amino acid concentrations of the thirteen Antarctic meteorites were generally less abundant than in more amino acid-rich CI, CM, and CR carbonaceous chondrites that experienced much lower temperature aqueous alteration on their parent bodies. In contrast to low-temperature aqueously-altered meteorites that show complete structural diversity in amino acids formed predominantly by Strecker-cyanohydrin synthesis, the thermally-altered meteorites studied here are dominated by small, straight-chain, amine terminal (n-omega-amino) amino acids that are not consistent with Strecker formation. The carbon isotopic ratios of two extraterrestrial n-omega-amino acids measured in one of the CV chondrites are consistent with C-13-depletions observed previously in hydrocarbons produced by Fischer-Tropsch type reactions. The predominance of n-omega-amino acid isomers in thermally-altered meteorites hints at cosmochemical mechanisms for the preferential formation and preservation of a small subset of the possible amino acids.
Evidence from Meteorites for Multiple Possible Amino Acid Alphabets for the Origins of Life
Burton, A. S.; Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Dworkin, J. P.
A key question for the origins of life is understanding which amino acids made up the first proteins synthesized during the origins of life. The canonical set of 20 - 22 amino acids used in proteins are all alpha-amino, alpha-hydrogen isomers that, nevertheless, show considerable variability in properties including size, hydrophobicity, and ionizability. Abiotic amino acid synthesis experiments such as Miller-Urey spark discharge reactions produce a set of up to 23 amino acids, depending on starting materials and reaction conditions, with significant abundances of both alpha- and non-alpha-amino acid isomers. These two sets of amino acids do not completely overlap; of the 23 spark discharge amino acids, only 11 are used in modern proteins. Furthermore, because our understanding of conditions on the early Earth are limited, it is unclear which set(s) of conditions employed in spark discharge or hydrothermal reactions are correct, leaving us with significant uncertainty about the amino acid alphabet available for the origins of life on Earth. Meteorites, the surviving remnants of asteroids and comets that fall to the Earth, offer the potential to study authentic samples of naturally-occurring abiotic chemistry, and thus can provide an alternative approach to constraining the amino acid library during the origins of life.
Inititation and termination of chromosome replication in Escherichia coli subjected to amino acid starvation.
Marsh, R C; Hepburn, M L
Initiation and termination of chromosome replication in an Escherichia coli auxotroph subjected to amino acid starvation were examined by following the incorporation of [3H]thymidine into the EcoRI restriction fragments of the chromosome. The pattern of incorporation observed upon restoration of the amino acid showed that starvation blocks the process of initiation prior to deoxyribonucleic acid synthesis within any significant portion of the EcoRI fragment which contains the origin of replic...
Biliary amino acid and glutathione secretion in response to amino acid infusion in the isolated rat liver.
Shattuck, K E; Grinnell, C D; Rassin, D K
The intravenous infusion of amino acid solutions has been associated with cholestatic liver injury in hospitalized patients and in laboratory animals. In the isolated rat liver, we recently showed that the acute decrease in bile flow, previously reported by other investigators, is dose related, reversible, and associated with dose-related increases in total biliary amino acid concentrations. In the present study, we characterized the effects of graded infusions of amino acid solutions, with and without taurocholate, on biliary secretion of individual amino acids and glutathione, an important regulator of bile flow. Livers from young adult male rats were perfused with an amino acid solution for 1 hour and allowed to recover for 30 minutes. Infusion of the amino acid solution was associated with dose-related increases in biliary concentrations of most amino acids included in the amino acid solution. Infusion of amino acid solutions resulted in a decreased bile/perfusate ratio of most amino acids, which were secreted into bile in amounts approximating their calculated uptake from the infusate. The inclusion of taurocholate in the infusate was associated with lower biliary concentrations of each individual amino acid and significant decreases in biliary total, reduced, and oxidized glutathione. Further investigation of the relationship between these changes in biliary amino acids and glutathione concentrations and the cholestasis associated with infusion of amino acid solutions may provide insights into the mechanism by which amino acids induce such cholestasis.
Nonconventional techniques for separation of biosynthetic amino acids.
Kloetzer, Lenuţa; Poştaru, Mădălina; Cheptea, Corina; Caşcaval, D; Galaction, Anca-Irina
Amino acids can be obtained by biosynthesis, by protein hydrolysis or by extraction from natural sources. The most efficient methods are the first two, but the separation of amino acids from fermentation broths or protein hydrolysates is rather difficult. Amino acids dissociate in aqueous solutions, forming characteristic ionic species depending on the solution pH-value. These properties make amino acids to be hydrophilic at any pH-value. This paper presents a review of the separation studies of some amino acids by nonconventional methods, namely individual or selective reactive extraction. Separation of some amino acids from their mixture obtained either by fermentation or protein hydrolysis by reactive extraction with different extractants indicated the possibility of the amino acids selective separation as a function of the pH-value of aqueous solution correlated with the acidic or basic character of each amino acid.
Dynamic kinetic resolution of amino acid amide catalyzed by D-aminopeptidase and alpha-amino-epsilon-caprolactam racemase.
Asano, Yasuhisa; Yamaguchi, Shigenori
Amino acid amide racemizing activity was discovered in alpha-amino-epsilon-caprolactam (ACL) racemase (EC 5. 1. 1. 15) from Achromobacter obae. The enzymatic synthesis of d-alanine from l-alanine amide has been demonstrated by use of d-aminopeptidase (DAP; EC 3. 4. 11. 19) from Ochrobactrum anthropi C1-38 and ACL racemase. The conversion of 45 mM l-alanine amide was carried out at 30 degrees C for 7 h; l-alanine amide was completely converted to d-alanine, and no l-alanine was detected. The result of successive enzymatic reaction shows that the combination of ACL racemase and DAP can be applied for dynamic kinetic resolution of dl-amino acid amides to yield d-amino acids.
Synthesis of Biobased Succinonitrile from Glutamic Acid and Glutamine
Lammens, T.M.; Nôtre, Le J.; Franssen, M.C.R.; Scott, E.L.; Sanders, J.P.M.
Succinonitrile is the precursor of 1,4-diaminobutane, which is used for the industrial production of polyamides. This paper describes the synthesis of biobased succinonitrile from glutamic acid and glutamine, amino acids that are abundantly present in many plant proteins. Synthesis of the
Amino acids analysis during lactic acid fermentation by single strain ...
African Journals Online (AJOL)
Jul 9, 2014 ... Amino acids analysis during lactic acid fermentation by single strain cultures of lactobacilli and mixed culture starter made from them. KiBeom Lee1*, Ho-Jin Kim1 and Sang-Kyu Park2. 1Bio Center Technopark, 7-50 Songdo, Yeonsu-Gu, Incheon 406-840, Republic of Korea. 2Nambu University, Chumdan ...
Synthesis of enantiomerically pure (purin-6-yl)phenylalanines and their nucleosides, a novel type of purine-amino acid conjugates.
Capek, Petr; Pohl, Radek; Hocek, Michal
[Chemical reaction: See text] Enantiomerically or diastereomerically pure 4-(purin-6-yl)phenylalanines, a novel type of stable amino acid-purine conjugates, were synthesized by palladium-catalyzed cross-coupling reactions of protected 4-boronophenylalanines or 4-(trimethylstanyl)phenylalanines with diverse 6-halopurines (9-benzyl-6-halopurines and 9-(tetrahydropyran-2-yl)-6-halopurines as well as acyl- and silyl-protected 6-halopurine ribonucleosides and 2-deoxyribonucleosides). Free purine bases and nucleosides bearing (S)- or (R)-phenylalanine in position 6 were obtained after complete deprotection of the products of cross-coupling reactions. Reactivity trends for both of these cross-coupling and deprotection protocols have been compared in terms of practicability, efficiency, and stereoselectivity.
An Assay of Selected Serum Amino Acids in Patients with Type 2 Diabetes Mellitus.
Drábková, Petra; Šanderová, Jana; Kovařík, Jakub; kanďár, Roman
Amino acids are the building blocks of proteins. In case of insulin resistance, which is typical for type 2 diabetes mellitus (T2DM), proteolysis is increased and protein synthesis is decreased; therefore, we can observe changes in the levels of amino acids in diabetics vs. non-diabetics. The aim of this study was to find differences in the levels of selected amino acids between patients with diabetes (type 2) and a control group. Amino acids were derivatized with naphthalene-2,3-dicarboxaldehyde in the presence of potassium cyanide to form fluorescent 1-cyanobenz(f)isoindole product. Amino acids derivatives were measured using a high-performance liquid chromatography with fluorescence detection. The serum levels of glucose were determined using an automatic biochemistry analyzer, glycated hemoglobin HbA1c was measured by cation exchange chromatography. A total of 19 serum amino acids in T2DM patients and non-diabetics were measured. There were 9 amino acids, which were significantly different in these groups (pdiabetics were found. Significant difference in metabolism of amino acids between diabetics and non-diabetics were observed. The altered levels of amino acids in diabetic patients could be a suitable predictor of diabetes.
Change in amino acids content during germination and seedling ...
African Journals Online (AJOL)
presence of histidine (His) and phenylalanine (Phe), but also to amide amino acids asparagine (Asn), glutamine (Gln) and Arg contents. In Cola sp., free amino acids varied significantly during these two processes indicating their high utilization.
Effects of Supplementation of Branched-Chain Amino Acids to Reduced-Protein Diet on Skeletal Muscle Protein Synthesis and Degradation in the Fed and Fasted States in a Piglet Model
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Liufeng Zheng
Full Text Available Supplementation of branched-chain amino acids (BCAA has been demonstrated to promote skeletal muscle mass gain, but the mechanisms underlying this observation are still unknown. Since the regulation of muscle mass depends on a dynamic equilibrium (fasted losses–fed gains in protein turnover, the aim of this study was to investigate the effects of BCAA supplementation on muscle protein synthesis and degradation in fed/fasted states and the related mechanisms. Fourteen 26- (Experiment 1 and 28-day-old (Experiment 2 piglets were fed reduced-protein diets without or with supplemental BCAA. After a four-week acclimation period, skeletal muscle mass and components of anabolic and catabolic signaling in muscle samples after overnight fasting were determined in Experiment 1. Pigs in Experiment 2 were implanted with carotid arterial, jugular venous, femoral arterial and venous catheters, and fed once hourly along with the intravenous infusion of NaH13CO3 for 2 h, followed by a 6-h infusion of [1-13C]leucine. Muscle leucine kinetics were measured using arteriovenous difference technique. The mass of most muscles was increased by BCAA supplementation. During feeding, BCAA supplementation increased leucine uptake, protein synthesis, protein degradation and net transamination. The greater increase in protein synthesis than in protein degradation resulted in elevated protein deposition. Protein synthesis was strongly and positively correlated with the intramuscular net production of α-ketoisocaproate (KIC and protein degradation. Moreover, BCAA supplementation enhanced the fasted-state phosphorylation of protein translation initiation factors and inhibited the protein-degradation signaling of ubiquitin-proteasome and autophagy-lysosome systems. In conclusion, supplementation of BCAA to reduced-protein diet increases fed-state protein synthesis and inhibits fasted-state protein degradation, both of which could contribute to the elevation of skeletal muscle
Effects of Supplementation of Branched-Chain Amino Acids to Reduced-Protein Diet on Skeletal Muscle Protein Synthesis and Degradation in the Fed and Fasted States in a Piglet Model.
Zheng, Liufeng; Wei, Hongkui; He, Pingli; Zhao, Shengjun; Xiang, Quanhang; Pang, Jiaman; Peng, Jian
Supplementation of branched-chain amino acids (BCAA) has been demonstrated to promote skeletal muscle mass gain, but the mechanisms underlying this observation are still unknown. Since the regulation of muscle mass depends on a dynamic equilibrium (fasted losses-fed gains) in protein turnover, the aim of this study was to investigate the effects of BCAA supplementation on muscle protein synthesis and degradation in fed/fasted states and the related mechanisms. Fourteen 26- (Experiment 1) and 28-day-old (Experiment 2) piglets were fed reduced-protein diets without or with supplemental BCAA. After a four-week acclimation period, skeletal muscle mass and components of anabolic and catabolic signaling in muscle samples after overnight fasting were determined in Experiment 1. Pigs in Experiment 2 were implanted with carotid arterial, jugular venous, femoral arterial and venous catheters, and fed once hourly along with the intravenous infusion of NaH 13 CO₃ for 2 h, followed by a 6-h infusion of [1- 13 C]leucine. Muscle leucine kinetics were measured using arteriovenous difference technique. The mass of most muscles was increased by BCAA supplementation. During feeding, BCAA supplementation increased leucine uptake, protein synthesis, protein degradation and net transamination. The greater increase in protein synthesis than in protein degradation resulted in elevated protein deposition. Protein synthesis was strongly and positively correlated with the intramuscular net production of α-ketoisocaproate (KIC) and protein degradation. Moreover, BCAA supplementation enhanced the fasted-state phosphorylation of protein translation initiation factors and inhibited the protein-degradation signaling of ubiquitin-proteasome and autophagy-lysosome systems. In conclusion, supplementation of BCAA to reduced-protein diet increases fed-state protein synthesis and inhibits fasted-state protein degradation, both of which could contribute to the elevation of skeletal muscle mass in
Diverse characteristics of the urinary excretion of amino acids in humans and the use of amino acid supplementation to reduce fatigue and sub-health in adults.
Dunstan, R H; Sparkes, D L; Macdonald, M M; De Jonge, X Janse; Dascombe, B J; Gottfries, J; Gottfries, C-G; Roberts, T K
The excretion of amino acids in urine represents an important avenue for the loss of key nutrients. Some amino acids such as glycine and histidine are lost in higher abundance than others. These two amino acids perform important physiological functions and are required for the synthesis of key proteins such as haemoglobin and collagen. Stage 1 of this study involved healthy subjects (n = 151) who provided first of the morning urine samples and completed symptom questionnaires. Urine was analysed for amino acid composition by gas chromatography. Stage 2 involved a subset of the initial cohort (n = 37) who completed a 30 day trial of an amino acid supplement and subsequent symptom profile evaluation. Analyses of urinary amino acid profiles revealed that three groups could be objectively defined from the 151 participants using k-means clustering. The amino acid profiles were significantly different between each of the clusters (Wilks' Lambda = 0.13, p amino acids with histidine being the most abundant component. Cluster 2 had glycine present as the most abundant urinary amino acid and cluster 3 had equivalent abundances of glycine and histidine. Strong associations were observed between urinary proline concentrations and fatigue/pain scores (r = .56 to .83) for females in cluster 1, with several other differential sets of associations observed for the other clusters. Different phenotypic subsets exist in the population based on amino acid excretion characteristics found in urine. Provision of the supplement resulted in significant improvements in reported fatigue and sleep for 81% of the trial cohort with all females reporting improvements in fatigue. The study was registered on the 18th April 2011 with the Australian New Zealand Clinical Trials Registry ( ACTRN12611000403932 ).
African Journals Online (AJOL)
B. S. Chandravanshi
As can be expected this correspond with the higher content of total amino acids in the fresh samples. The following ranges were observed for fresh and commercial samples 14.7–17.3 and 12.5–14.9 mg/g, respectively. The mean values were 16.1±0.8 and 13.2±1.0%. According to Pavel et al. [15] there is no difference in ...
Conformational Interconversions of Amino Acid Derivatives
Czech Academy of Sciences Publication Activity Database
Kaminský, Jakub; Jensen, F.
Roč. 12, č. 2 (2016), s. 694-705 ISSN 1549-9618 R&D Projects: GA ČR GA13-03978S; GA ČR(CZ) GA14-03564S; GA ČR(CZ) GA16-00270S Institutional support: RVO:61388963 Keywords : amino acids * force fields * transition states Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.245, year: 2016
Branched-chain amino acids for hepatic encephalopathy
DEFF Research Database (Denmark)
Als-Nielsen, B; Koretz, R L; Kjaergard, L L
Hepatic encephalopathy may be caused by a decreased plasma ratio of branched-chain amino acids (BCAA) to aromatic amino acids. Treatment with BCAA may therefore have a beneficial effect on patients with hepatic encephalopathy.......Hepatic encephalopathy may be caused by a decreased plasma ratio of branched-chain amino acids (BCAA) to aromatic amino acids. Treatment with BCAA may therefore have a beneficial effect on patients with hepatic encephalopathy....
Differential utilization of blood meal amino acids in mosquitoes
Miesfeld, Roger
Guoli Zhou, Roger MiesfeldDepartment of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USAAbstract: Amino acids in the mosquito blood meal have two forms, protein-bound and plasma-free amino acids. To determine if the metabolic fate and flux of these two forms of blood meal amino acids are distinct, we fed mosquitoes eight [14C]-labeled amino acids, seven of which are essential for mosquitoes (leucine, valine, isoleucine, phenylalanine, lysine, arginine, histidine), and one th...
Dietary amino acids budget for juvenile yellowtail (Seriola quinqueradiata)
Masumoto, Toshiro; Itoh, Yoshiaki; Ruchimat, Toni; Hosokawa, Hidetsuyo; Shimeno, Sadao
Yellowtail weighing 31.7g was fed 4 levels of fish meal diet for 21 days. Based on the amino acid intake and gain data from the best growth exhibited crude protein content 52% fed fish, the amino acid budget was estimated. Average of each amino acid value showed that about 32% and 57% of intake amino acids were utilized for growth and for as an energy source and maintenance, respectively.
Genetics of Amino Acid Taste and Appetite123
Bachmanov, Alexander A; Bosak, Natalia P; Glendinning, John I; Inoue, Masashi; Li, Xia; Manita, Satoshi; McCaughey, Stuart A; Murata, Yuko; Reed, Danielle R; Tordoff, Michael G; Beauchamp, Gary K
The consumption of amino acids by animals is controlled by both oral and postoral mechanisms. We used a genetic approach to investigate these mechanisms. Our studies have shown that inbred mouse strains differ in voluntary amino acid consumption, and these differences depend on sensory and nutritive properties of amino acids. Like humans, mice perceive some amino acids as having a sweet (sucrose-like) taste and others as having an umami (glutamate-like) taste. Mouse strain differences in the ...
Green Route for Efficient Synthesis of Novel Amino Acid Schiff Bases as Potent Antibacterial and Antifungal Agents and Evaluation of Cytotoxic Effects
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Harshita Sachdeva
Full Text Available Green chemical one-pot multicomponent condensation reaction of substituted 1H-indole-2,3-diones (1, various amino acids (2, and thiosemicarbazide (3 is found to be catalyzed by lemon juice as natural acid using water as a green solvent to give the corresponding Schiff bases (4 in good to excellent yields. This method is experimentally simple, clean, high yielding, and green, with reduced reaction times. The product is purified by simple filtration followed by washing with water and drying process. The synthesized compounds are characterized by FT-IR, 13CNMR, and 1HNMR spectroscopy and are screened for their antifungal activity against Aspergillus niger, Penicillium notatum, Fusarium oxysporum, Alternaria brassicicola, Chaetomium orium, and Lycopodium sp. and antibacterial activity against Gram-positive bacteria, Bacillus licheniformis, Staphylococcus aureus, and Micrococcus luteus, and Gram-negative bacteria, Pseudomonas aeruginosa and Escherichia coli. Compounds have also been evaluated for cytotoxic effects against human colon cancer cell line Colo205.
Synthesis of a polymer-bound galactosylamine and its application as an immobilized chiral auxiliary in stereoselective syntheses of piperidine and amino acid derivatives.
Zech, Gernot; Kunz, Horst
A 2,3,4-tri-O-pivaloylated beta-D-galactopyranosyl azide bearing a hydroxy-functionalized spacer unit at the C-6 position of the galactose was synthesized and immobilized on the solid phase by using a polymer-bound chlorosilane. The azide was reduced to the corresponding galactopyranosylamine, which served as a versatile chiral auxiliary in highly diastereoselective Ugi four-component condensation reactions at ambient temperature. Fluoride-induced cleavage from the polymeric support furnished N-glycosylated N-acylated alpha-amino acid amides. The reaction of the immobilized galactosylamine with aldehydes gave rise to the corresponding aldimines, which underwent a domino Mannich-Michael condensation reaction with Danishefsky's diene at ambient temperature to yield 2-substituted 5,6-didehydropiperidin-4-ones on the solid phase. Subsequent cleavage with tetra-n-butylammonium fluoride delivered the N-glycosylated products in high yields, purities, and diastereoselectivities. A chemoselective 1,4-hydride addition to the polymer-bound dehydropiperidinones was achieved in the presence of the bulky oxygenophilic Lewis acid methylaluminum [bis(2,6-di-tert-butyl-4-methylphenoxide)]. The conjugate addition of cyano-modified Gilman reagents to the immobilized dehydropiperidinones furnished 2,6-cis-substituted piperidine derivatives as the major diastereomers that were isolated after cleavage from the support.
Enzymatically and reductively degradable α-amino acid-based poly(ester amide)s: synthesis, cell compatibility, and intracellular anticancer drug delivery.
Sun, Huanli; Cheng, Ru; Deng, Chao; Meng, Fenghua; Dias, Aylvin A; Hendriks, Marc; Feijen, Jan; Zhong, Zhiyuan
A novel and versatile family of enzymatically and reductively degradable α-amino acid-based poly(ester amide)s (SS-PEAs) were developed from solution polycondensation of disulfide-containing di-p-toluenesulfonic acid salts of bis-l-phenylalanine diesters (SS-Phe-2TsOH) with di-p-nitrophenyl adipate (NA) in N,N-dimethylformamide (DMF). SS-PEAs with Mn ranging from 16.6 to 23.6 kg/mol were obtained, depending on NA/SS-Phe-2TsOH molar ratios. The chemical structures of SS-PEAs were confirmed by (1)H NMR and FTIR spectra. Thermal analyses showed that the obtained SS-PEAs were amorphous with a glass transition temperature (Tg) in the range of 35.2-39.5 °C. The in vitro degradation studies of SS-PEA films revealed that SS-PEAs underwent surface erosion in the presence of 0.1 mg/mL α-chymotrypsin and bulk degradation under a reductive environment containing 10 mM dithiothreitol (DTT). The preliminary cell culture studies displayed that SS-PEA films could well support adhesion and proliferation of L929 fibroblast cells, indicating that SS-PEAs have excellent cell compatibility. The nanoparticles prepared from SS-PEA with PVA as a surfactant had an average size of 167 nm in phosphate buffer (PB, 10 mM, pH 7.4). SS-PEA nanoparticles while stable under physiological environment undergo rapid disintegration under an enzymatic or reductive condition. The in vitro drug release studies showed that DOX release was accelerated in the presence of 0.1 mg/mL α-chymotrypsin or 10 mM DTT. Confocal microscopy observation displayed that SS-PEA nanoparticles effectively transported DOX into both drug-sensitive and -resistant MCF-7 cells. MTT assays revealed that DOX-loaded SS-PEA nanoparticles had a high antitumor activity approaching that of free DOX in drug-sensitive MCF-7 cells, while more than 10 times higher than free DOX in drug-resistant MCF-7/ADR cells. These enzymatically and reductively degradable α-amino acid-based poly(ester amide)s have provided an appealing platform for
Origin, Microbiology, Nutrition, and Pharmacology of D-Amino Acids
Exposure of food proteins to certain processing conditions induces two major chemical changes: racemization of all L-amino acids (LAA) to D-amino acids (DAA) and concurrent formation of crosslinked amino acids such as lysinoalanine (LAL). The diet contains both processing-induced and naturally-form...
Metabolism of amino acid amides in Pseudomonas putida ATCC 12633
Hermes, H.F.M.; Croes, L.M.; Peeters, W.P.H.; Peters, P.J.H.; Dijkhuizen, L.
The metabolism of the natural amino acid L-valine, the unnatural amino acids D-valine, and D-, L-phenylglycine (D-, L-PG), and the unnatural amino acid amides D-, L-phenylglycine amide (D, L-PG-NH2) and L-valine amide (L-Val-NH2) was studied in Pseudomonas putida ATCC 12633. The organism possessed
Evaluation of Mineral and Amino Acid Composition of Leaves of ...
African Journals Online (AJOL)
The study was conducted to determine the mineral and amino acid composition of the leave of Ocimum gratissimum. The mineral composition showed major minerals such as Na, K, Ca and Mg should essential and non-essential amino acids. The amino acids compared favorably with FAO reference protein. The leave were ...
Proximate and Amino Acid Composition of Celosia argentea Leaves ...
African Journals Online (AJOL)
The proximate, trace metals and amino acids composition of Celosia argentea were determined. The crude fat, fibre and protein contents were moderate with 1.10, 3.53 and 5.17% respectively while high in the ash content (22.43%). Results of the amino acid analysis revealed high contents of the essential amino acids with ...
40 Oil Characterization, Amino Acid and Vitamin A and C ...
African Journals Online (AJOL)
email: email@example.com. ABSTRACT. Oil characterization, amino acid and vitamin A and C composition of Cucurbita maxima seeds was carried out using standard analytical methods. The amino acid profile was determined using Techno sequential multi sample amino acid analyser and except phenylalanine which ...
Regulation of autophagy by mTOR and amino acids
Ruf, Stefanie
Amino acids are the molecular building blocks for proteins, which form the molecular framework of every cell. In addition, amino acids are also needed for the production of nucleotides and lipids to make DNA and membranes. Amino acids are essential biomolecules and without them cellular growth would
Radiolabeled amino acids : Basic aspects and clinical applications in oncology
Jager, PL; Vaalburg, W; Pruim, J; de Vries, EGE; Langen, KJ; Piers, DA
As the applications of metabolic imaging are expanding, radiolabeled amino acids may gain increased clinical interest, This review first describes the basic aspects of amino acid metabolism, then continues with basic aspects of radiolabeled amino acids, and finally describes clinical applications,
Determination and stability constants of Manganese (II) amino acid ...
African Journals Online (AJOL)
Determination and stability constants of Manganese (II) amino acid complexes. HN Aliyu, J Na'aliya. Abstract. The stepwise and the overall stability constants of the complexes formed by manganese (II) ion and twelve (12) amino acids have been determined. The dissociation constants, pKa, of the amino acids determined ...
Metabolic regulation of amino acid uptake in marine waters
International Nuclear Information System (INIS)
Kirchman, D.L.; Hodson, R.E.
To determine the relationships among the processes of uptake, intracellular pool formation, and incorporation of amino acids into protein, the authors measured the uptake of dipeptides and free amino acids by bacterial assemblages in estuarine and coastal waters of the southeast US. The dipeptide phenylalanyl-phenylalanine (phe-phe) lowered V/sub max/ of phenylalanine uptake when the turnover rate of phenylalanine was relatively high. When the turnover rate was relatively low, phe-phe either had no effect or increased V/sub max/ of phenylalanine uptake. An analytical model was developed and tested to measure the turnover time of the intracellular pool of phenylalanine. The results suggested that the size of the intracellular pool is regulated, which precludes high assimilation rates of both phenylalanine and phe-phe. In waters with relatively low phenylalanine turnover rates, bacterial assemblages appear to have a greater capacity to assimilate phenylalanine and phe-phe simultaneously. Marine bacterial assemblages do not substantially increase the apparent respiration of amino acids when concentrations increase. The authors conclude that sustained increases in uptake rates and mineralization by marine bacterial assemblages in response to an increase in the concentrations of dissolved organic nitrogen is determined by the rate of protein synthesis
Nutritional and medicinal aspects of D-amino acids.
Friedman, Mendel; Levin, Carol E
This paper reviews and interprets a method for determining the nutritional value of D-amino acids, D-peptides, and amino acid derivatives using a growth assay in mice fed a synthetic all-amino acid diet. A large number of experiments were carried out in which a molar equivalent of the test compound replaced a nutritionally essential amino acid such as L-lysine (L-Lys), L-methionine (L-Met), L-phenylalanine (L-Phe), and L-tryptophan (L-Trp) as well as the semi-essential amino acids L-cysteine (L-Cys) and L-tyrosine (L-Tyr). The results show wide-ranging variations in the biological utilization of test substances. The method is generally applicable to the determination of the biological utilization and safety of any amino acid derivative as a potential nutritional source of the corresponding L-amino acid. Because the organism is forced to use the D-amino acid or amino acid derivative as the sole source of the essential or semi-essential amino acid being replaced, and because a free amino acid diet allows better control of composition, the use of all-amino-acid diets for such determinations may be preferable to protein-based diets. Also covered are brief summaries of the widely scattered literature on dietary and pharmacological aspects of 27 individual D-amino acids, D-peptides, and isomeric amino acid derivatives and suggested research needs in each of these areas. The described results provide a valuable record and resource for further progress on the multifaceted aspects of D-amino acids in food and biological samples.
Neighbor Preferences of Amino Acids and Context-Dependent Effects of Amino Acid Substitutions in Human, Mouse, and Dog
Directory of Open Access Journals (Sweden)
Mingchuan Fu
Full Text Available Amino acids show apparent propensities toward their neighbors. In addition to preferences of amino acids for their neighborhood context, amino acid substitutions are also considered to be context-dependent. However, context-dependence patterns of amino acid substitutions still remain poorly understood. Using relative entropy, we investigated the neighbor preferences of 20 amino acids and the context-dependent effects of amino acid substitutions with protein sequences in human, mouse, and dog. For 20 amino acids, the highest relative entropy was mostly observed at the nearest adjacent site of either N- or C-terminus except C and G. C showed the highest relative entropy at the third flanking site and periodic pattern was detected at G flanking sites. Furthermore, neighbor preference patterns of amino acids varied greatly in different secondary structures. We then comprehensively investigated the context-dependent effects of amino acid substitutions. Our results showed that nearly half of 380 substitution types were evidently context dependent, and the context-dependent patterns relied on protein secondary structures. Among 20 amino acids, P elicited the greatest effect on amino acid substitutions. The underlying mechanisms of context-dependent effects of amino acid substitutions were possibly mutation bias at a DNA level and natural selection. Our findings may improve secondary structure prediction algorithms and protein design; moreover, this study provided useful information to develop empirical models of protein evolution that consider dependence between residues.
The multifaceted role of amino acids in chemical evolution
Strasdeit, Henry; Fox, Stefan; Dalai, Punam
We present an overview of recent ideas about α-amino acids on the Hadean / early Archean Earth and Noachian Mars. Pertinent simulation experiments are discussed. Electrical dis-charges in early Earth's bulk, probably non-reducing atmosphere [1, 2] and in volcanic ash-gas clouds [3] are likely to have synthesized amino acids abiotically. In principle, this may have been followed by the synthesis of peptides. Different kinds of laboratory simulations have, however, revealed severe difficulties with the condensation process under presumed prebiotic conditions. It therefore appears that peptides on the early Earth were mainly di-, tri-and tetramers and slightly longer only in the case of glycine homopeptides. But even such short peptides may have shown primitive catalytic activity after complexation of metal ions to form proto-metalloenzymes. L-enantiomeric excesses (L-ee) of meteoritic amino acids were possibly involved in the origin of biohomochirality [4, 5]. This idea also faces some problems, mainly dilution of the amino acids on Earth and a resulting low overall L-ee. However, as yet unknown reactions might exist that are highly enantioselective even under such unfavorable conditions, perhaps by a combination of autocatalysis and inhibition (compare the Soai reaction). Primor-dial volcanic islands are prebiotically interesting locations. At their hot coasts, solid sea salt probably embedded amino acids [6]. Our laboratory experiments showed that further heating of the salt crusts, simulating the vicinity of lava streams, produced pyrroles among other prod-ucts. Pyrroles are building blocks of biomolecules such as bilins, chlorophylls and heme. Thus, an abiotic route from amino acids to the first photoreceptor and electron-transfer molecules might have existed. There is no reason to assume that the chemical evolutionary processes described above were singular events restricted to Earth and Mars. In fact, they might take place even today on terrestrial exoplanets
Neuroexcitatory amino acids: 4-methylene glutamic acid derivatives : Short Communication.
Receveur, J M; Roumestant, M L; Viallefont, P
A short synthesis of 4-methylene glutamic acid was achieved. Under thermal conditions the corresponding anhydride reacted with 2,3 dimethylbutadiene to afford the corresponding DIELS-ALDER adduct in good yield. L-4-methylene glutamic acid essentially acts on glutamate metabotropic receptors and is as potent as L-Glu in producing IPs.
New branched amino acids for high affinity dendrimeric DC-SIGN ligands.
Cattiaux, Laurent; Porkolab, Vanessa; Fieschi, Franck; Mallet, Jean-Maurice
A branched amino acid was synthesized from methyl glucopyranoside; this amino acid presents three amino groups protected by Fmoc and one acid group and can be used in classic peptide synthesis. In parallel, similar azido terminated blocks were synthesized. Successive coupling reaction and deprotection afforded dendrimers with up to 27 azido functional groups. As an example of application, d-mannose and l-fucose residues were linked through CuAAC coupling and resulting glycodendrimers were evaluated in their interaction with DC-SIGN using SPR competition assay. Copyright © 2017 Elsevier Ltd. All rights reserved.
Azide- and Alkyne-Functionalised α- and β3-Amino Acids
DEFF Research Database (Denmark)
Sminia, T.J.; Pedersen, Daniel Sejer
The synthesis and full characterisation of bifunctional β -amino acids that have side chains functionalised with terminal azides (S)-4 and (R)-4 or acetylenes 5 and 6 is reported for the first time. The building blocks incorporate a turn-inducing β -segment and a side chain that can...... be functionalised further, for example, through copper-catalysed Huisgen cycloaddition. Moreover, the corresponding α-amino acids 1 and 3 have been synthesised and characterised. All amino acid building blocks were of high optical purity as demonstrated by derivatisation and subsequent NMR analysis....
Labeling of unnatural amino acids with sup(99m)Tc and tissue distribution of the labeled products in mice
International Nuclear Information System (INIS)
Tamemasa, Osamu; Goto, Rensuke; Takeda, Atsushi
The selective affinity of amino acids for pancreas, due to its high rate of protein synthesis, has prompted us to synthesize new radio-labeled amino acids for pancreatic imaging. Labeling of 19 unnatural amino acids with sup(99m)Tc was tried in the usual way, and 10 labeled products were obtained with low yields. The highest distribution of radioactivity from all these labeled amino acids, which had been injected intravenously into mice, was found in the kidney, whereas little activity was found in the pancreas. Their low distributions in stomach suggest little dissociation of the labeled amino acids into sup(99m)TcO 4 - in mice. It is presumed that these labeled amino acids behave unlike their original amino acids in the body. (author)
Synthesis of nitrogen-doped and amino acid-functionalized graphene quantum dots from glycine, and their application to the fluorometric determination of ferric ion
International Nuclear Information System (INIS)
Li, Linbo; Li, Lin; Wang, Chao; Liu, Kangyu; Zhu, Ruohua; Qiang, Hong; Lin, Yuqing
We report on a single-step thermolysis strategy to prepare highly luminescent nitrogen-doped and amino acid-functionalized graphene quantum dots (NA-GQDs) by using glycine as both carbon and nitrogen source. The NA-GQDs display an excitation wavelength-dependent fluorescence with maximum excitation and emission wavelengths of 380 and 450 nm, respectively, and a quantum yield of ∼16 %. Fluorescence is quenched by Fe(III) and Hg(II), and the effect was used to develop a method for the determination of Fe(III). Quenching by Fe(III) is attributed to its higher thermodynamic affinity (compared to other transition-metal ions) for the ligands on the GQDs in which nitrogen atoms mainly act as the chelating atoms. A linear relationship was observed between fluorescence intensity and the concentration of Fe(III) over the 0.5 μM to 0.5 mM range. The detection limit is 0.1 μM. (author)
Synthesis of new poly(ether-urethane-urea)s based on amino acid cyclopeptide and PEG: study of their environmental degradation.
Rafiemanzelat, Fatemeh; Fathollahi Zonouz, Abolfazl; Emtiazi, Giti
Conventional polyurethanes (PUs) are among biomaterials not intended to degrade but are susceptible to hydrolytic, oxidative and enzymatic degradation in vivo. Biodegradable PUs are typically prepared from polyester polyols, aliphatic diisocyanates and chain extenders. In this work we have developed a degradable monomer based on α-amino acid to accelerate hard segment degradation. Thus a new class of degradable poly(ether-urethane-urea)s (PEUUs) was synthesized via direct reaction of 4,4'-methylene-bis(4-phenylisocyanate) (MDI), L-leucine anhydride (LA) and polyethylene glycol with molecular weight of 1,000 (PEG-1000) as polyether soft segment. The resulting polymers are environmentally biodegradable and thermally stable. Decomposition temperatures for 5 % weight loss occurred above 300 °C by TGA in nitrogen atmospheres. Some structural characterization and physical properties of these polymers before and after degradation in soil, river water and sludge are reported. The environmental degradation of the polymer films was investigated by SEM, FTIR, TGA, DSC, GPC and XRD techniques. A significant rate of degradation occurred in PEUU samples under river water and sludge condition. The polymeric films were not toxic to E. coli (Gram negative), Staphylococcus aureus and Micrococcus (Gram positive) bacteria and showed good biofilm formation on polymer surface. Our results show that hard segment degraded selectively as much as soft segment and these polymers are susceptible to degradation in soil and water. Thus our study shows that new environment-friendly polyurethane, which can degrade in soil, river water and sludge, is synthesized.
Amino acids (L-arginine and L-alanine) passivated CdS nanoparticles: Synthesis of spherical hierarchical structure and nonlinear optical properties
Talwatkar, S. S.; Tamgadge, Y. S.; Sunatkari, A. L.; Gambhire, A. B.; Muley, G. G.
CdS nanoparticles (NPs) passivated with amino acids (L-alanine and L-arginine) having spherical hierarchical morphology were synthesized by room temperature wet chemical method. Synthesized NPs were characterized by ultraviolet-visible (UV-vis) spectroscopy to study the variation of band gaps with concentration of surface modifying agents. Increase in band gap has been observed with the increase in concentration of surface modifying agents and was found more prominent for CdS NPs passivated with L-alanine. Powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis were carried out for the study of crystal structure and morphology of CdS NPs. The average particle size of CdS NPs calculated from Debye-Scherer formula was found to less than 5 nm and agrees well with those determined from UV-vis spectra and TEM data. Fourier transform infrared (FT-IR) spectroscopy was performed to know the functional groups of the grown NPs. Peaks in FT-IR spectra indicate the formation of CdS NPs and capping with L-alanine and L-arginine. Photoluminescence spectra of these NPs were also studied. Finally, colloidal solution of CdS-PVAc was subjected to Z-scan experiment under low power cw laser illumination to characterize them for third order nonlinear optical properties. CdS-PVAc colloidal solution shows enhanced nonlinear absorption due to RSA and weak FCA on account of two photon absorption processes triggered by thermal effect.
Incretin effect after oral amino Acid ingestion in humans
DEFF Research Database (Denmark)
Lindgren, Ola; Pacini, Giovanni; Tura, Andrea
) was administered orally or iv at a rate resulting in matching total amino acid concentrations to 12 male volunteers with age 22.5 ± 1.4 years and a body mass index 22.4 ± 1.4 kg/m(2), who had no history of diabetes. MAIN OUTCOME MEASURES: Main outcome measures were area under the 120-minute curve for insulin, C...... is also present after amino acid ingestion is not known. OBJECTIVE: The objective of the study was to explore insulin secretion and incretin hormones after oral and iv amino acid administration at matched total amino acid concentrations in healthy subjects. DESIGN: An amino acid mixture (Vaminolac...... after oral than after iv amino acid challenges (P = .006), whereas there was no significant difference in the glucagon response. Intact and total GIP rose after oral but not after iv amino acid administration, whereas intact and total GLP-1 levels did not change significantly in either test. CONCLUSION...
Effects of infusion of branched chain amino-acids enriched TPN solutions on plasma amino-acid profiles in sepsis and trauma patients
Vente, J. P.; von Meyenfeldt, M. F.; van Eijk, H. M.; van Berlo, C. L.; Gouma, D. J.; van der Linden, C. J.; Soeters, P. B.
Total parenteral nutrition with branched chain amino-acids enriched solutions has been advocated in patients with sepsis and stress because of favourable effects on nitrogen balance, protein synthesis and immune competence. The rationale for the use of BCAA-enriched solutions is based on their
Amino Acid Uptake and Metabolism of Legionella pneumophila Hosted by Acanthamoeba castellanii.
Schunder, Eva; Gillmaier, Nadine; Kutzner, Erika; Eisenreich, Wolfgang; Herrmann, Vroni; Lautner, Monika; Heuner, Klaus
Legionella pneumophila survives and replicates within a Legionella-containing vacuole (LCV) of amoebae and macrophages. Less is known about the carbon metabolism of the bacteria within the LCV. We have now analyzed the transfer and usage of amino acids from the natural host organism Acanthamoeba castellanii to Legionella pneumophila under in vivo (LCV) conditions. For this purpose, A. castellanii was 13C-labeled by incubation in buffer containing [U-(13)C(6)]glucose. Subsequently, these 13C-prelabeled amoebae were infected with L. pneumophila wild type or some mutants defective in putative key enzymes or regulators of carbon metabolism. 13C-Isotopologue compositions of amino acids from bacterial and amoebal proteins were then determined by mass spectrometry. In a comparative approach, the profiles documented the efficient uptake of Acanthamoeba amino acids into the LCV and further into L. pneumophila where they served as precursors for bacterial protein biosynthesis. More specifically, A. castellanii synthesized from exogenous [U-13C6]glucose unique isotopologue mixtures of several amino acids including Phe and Tyr, which were also observed in the same amino acids from LCV-grown L. pneumophila. Minor but significant differences were only detected in the isotopologue profiles of Ala, Asp, and Glu from the amoebal or bacterial protein fractions, respectively, indicating partial de novo synthesis of these amino acids by L. pneumophila. The similar isotopologue patterns in amino acids from L. pneumophila wild type and the mutants under study reflected the robustness of amino acid usage in the LCV of A. castellannii.
Kinetics of oxidation of acidic amino acids by sodium N
Indian Academy of Sciences (India)
Asp)) by sodium N-bromobenzenesulphonamide (bromamine-B or BAB) has been carried out in aqueous HClO4 medium at 30°C. The rate shows firstorder dependence each on [BAB]o and [amino acid]o and inverse first-order on [H+]. At [H+] > ...
Amino acids analysis during lactic acid fermentation by single strain ...
African Journals Online (AJOL)
L. salivarius alone showed relatively good assimilation of various amino acids that existed at only a little amounts in MRS media (Asn, Asp, Cit, Cys, Glu, His, Lys, Orn, Phe, Pro, Tyr, Arg, Ile, Leu, Met, Ser, Thr, Trp and Val), whereas Ala and Gly accumulated in L. salivarius cultures. P. acidilactici, in contrast, hydrolyzed the ...
Kinetics of oxidation of acidic amino acids by sodium N ...
Indian Academy of Sciences (India)
Asp)) by sodium N-bromobenzenesulphonamide (bromamine-B or BAB) has been carried out in aqueous HClO4 medium at 30°C. The rate shows firstorder dependence each on [BAB]o and [amino acid]o and inverse first-order on [H+]. At [H+] > ...
Fatty acid composition and amino acid profile of two freshwater ...
African Journals Online (AJOL)
The proximate, fatty and amino acids composition of two commercially important freshwater fish species Clarias gariepinus and Tilapia zillii. purchased from local fishermen in two landing sites in Lagos State, Nigeria were determined. Live specimens of C. gariepinus were purchased while samples of T. zillii were stored in ...
Fatty acids and amino acids contents in Scomber scombrus fillets ...
African Journals Online (AJOL)
The highest rates were noted for phenylalanine, valine, threonine, isoleucine, leucine and methionine. It was concluded that Atlantic Mackerel was high in interesting human feeding nutriments, mainly PUFA and essential amino Acids. Even when significant, differences between seasons were not drastic and S. scombrus ...
Adsorption of amino acids and nucleic acid bases onto minerals: a few suggestions for prebiotic chemistry experiments
Zaia, Dimas A. M.
Amino acids and nucleic acid bases are very important for the living organisms. Thus, their protection from decomposition, selection, pre-concentration and formation of biopolymers are important issues for understanding the origin of life on the Earth. Minerals could have played all of these roles. This paper discusses several aspects involving the adsorption of amino acids and nucleic acid bases onto minerals under conditions that could have been found on the prebiotic Earth; in particular, we recommend the use of minerals, amino acids, nucleic acid bases and seawater ions in prebiotic chemistry experiments. Several experiments involving amino acids, nucleic acid bases, minerals and seawater ions are also suggested, including: (a) using well-characterized minerals and the standardization of the mineral synthesis methods; (b) using primary chondrite minerals (olivine, pyroxene, etc.) and clays modified with metals (Cu, Fe, Ni, Mo, Zn, etc.); (c) determination of the possible products of decomposition due to interactions of amino acids and nucleic acid bases with minerals; (d) using minerals with more organophilic characteristics; (e) using seawaters with different concentrations of ions (i.e. Na+, Ca2+, Mg2+, SO4 2- and Cl-) (f) using non-protein amino acids (AIB, α-ABA, β-ABA, γ-ABA and β-Ala and g) using nucleic acid bases other than adenine, thymine, uracil and cytosine. These experiments could be useful to clarify the role played by minerals in the origin of life on the Earth.
Extraterrestrial Amino Acids in the Almahata Sitta Meteorite
Glavin, Daniel P.; Aubrey, Andrew D.; Callahan, Michael P.; Dworkin, Jason P.; Elsila, Jamie E.; Parker, Eric T.; Bada, Jeffrey L.
Amino acid analysis of a meteorite fragment of asteroid 2008 TC3 called Almahata Sitta was carried out using reverse-phase liquid chromatography coupled with UV fluorescence detection and time-of-flight mass spectrometry (LC-FD/ToF-MS) as part of a sample analysis consortium. LC-FD/ToF-MS analyses of hot-water extracts from the meteorite revealed a complex distribution of two- to seven-carbon aliphatic amino acids and one- to three-carbon amines with abundances ranging from 0.5 to 149 parts-per-billion (ppb). The enantiomeric ratios of the amino acids alanine, R-amino-n-butyric acid (beta-ABA), 2-amino-2-methylbutanoic acid (isovaline), and 2-aminopentanoic acid (norvaline) in the meteorite were racemic (D/L approximately 1), indicating that these amino acids are indigenous to the meteorite and not terrestrial contaminants. Several other non-protein amino acids were also identified in the meteorite above background levels including alpha-aminoisobutyric acid (alpha-AIB), 4-amino-2- methylbutanoic acid, 4-amino-3-methylbutanoic acid, and 3-, 4-, and 5-aminopentanoic acid. The total abundances of isovaline and alpha-AIB in Almahata Sitta are 1000 times lower than the abundances of these amino acids found in the CM carbonaceous chondrite Murchison. The extremely low abundances and unusual distribution of five carbon amino acids in Almahata Sitta compared to Cl, CM, and CR carbonaceous chondrites may reflect extensive thermal alteration of amino acids on the parent asteroid by partial melting during formation or subsequent impact shock heating. It is also possible that amino acids were synthesized by catalytic reactions on the parent body after asteroid 2008 TC3 cooled to lower temperatures.
D-Amino Acids Trigger Biofilm Disassembly
Kolodkin-Gal, Illana; Romero, Diego; Cao, Shugeng; Clardy, Jon; Kolter, Roberto; Losick, Richard
Bacteria form communities known as biofilms, which disassemble over time. Here we found that prior to biofilm disassembly Bacillus subtilis produced a factor that prevented biofilm formation and could break down existing biofilms. The factor was shown to be a mixture of D-leucine, D-methionine, D-tyrosine and D-tryptophan that could act at nanomolar concentrations. D-amino acid treatment caused the release of amyloid fibers that linked cells in the biofilm together. Mutants able to form biofi...
A multi-enzymatic cascade reaction for the stereoselective production of γ-oxyfunctionalyzed amino acids
Directory of Open Access Journals (Sweden)
Junichi eEnoki
Full Text Available A stereoselective three-enzyme cascade for synthesis of diasteromerically pure γ-oxyfunctionalized α-amino acids was developed. By coupling a dynamic kinetic resolution using an N-acylamino acid racemase and an L-selective aminoacylase from Geobacillus thermoglucosidasius with a stereoselective isoleucine dioxygenase from Bacillus thuringiensis, diastereomerically pure oxidized amino acids were produced from racemic N-acetylamino acids. The three enzymes differ in their optimal temperature and pH-spectra. Their different metal cofactor dependencies lead to inhibitory effects. Under optimized conditions, racemic N-acetylmethionine was quantitatively converted into L-methionine-(S-sulfoxide with 97% conversion and 95% de. The combination of these three different biocatalysts allows the direct synthesis of diastereopure oxyfunctionalized amino acids from inexpensive racemic starting material.
Sugar amino acids and related molecules: Some recent developments
Indian Academy of Sciences (India)
Sugar amino acids constitute an important class of such polyfunctional scaffolds where the carboxyl, amino and hydroxyl termini provide an excellent opportunity to organic chemists to create structural diversities akin to Nature's molecular arsenal. In recent years, sugar amino acids have been used extensively in the area of ...
Design, synthesis, and characterization of a 39 amino acid peptide mimic of the main immunogenic region of the Torpedo acetylcholine receptor.
Trinh, Vu B; Foster, Alex J; Fairclough, Robert H
We have designed a 39 amino acid peptide mimic of the conformation-dependent main immunogenic region (MIR) of the Torpedo acetylcholine receptor (TAChR) that joins three discontinuous segments of the Torpedo α-subunit, α(1-12), α(65-79), and α(110 - 115) with two GS linkers: This 39MIR-mimic was expressed in E. coli as a fusion protein with an intein-chitin-binding domain (IChBD) to permit affinity collection on chitin beads. Six MIR-directed monoclonal antibodies (mAbs) bind to this complex and five agonist/antagonist site directed mAbs do not. The complex of MIR-directed mAb-132A with 39MIR has a Kd of (2.11±0.11)×10(-10)M, which is smaller than (7.13±1.20)×10(-10)M for the complex of mAb-132A with α(1-161) and about the same as 3.4×10(-10)M for that of mAb-132A with TAChR. Additionally, the 39MIR-IChBD adsorbs all MIR-directed antibodies (Abs) from an experimental autoimmune myasthenia gravis (EAMG) rat serum. Hence, the 39MIR-mimic has the potential to inactivate or remove pathogenic Torpedo MIR-directed Abs from EAMG sera and to direct a magic bullet to the memory B-cells that produce those pathogenic Abs. The hope is to use this as a guide to produce a mimic of the human MIR on the way to an antigen specific therapeutic agent to treat MG. Copyright © 2014 Elsevier Ltd. All rights reserved.
l-Arginine Uptake by Cationic Amino Acid Transporter Promotes Intra-Macrophage Survival of Leishmania donovani by Enhancing Arginase-Mediated Polyamine Synthesis
Mandal, Abhishek; Das, Sushmita; Kumar, Ajay; Roy, Saptarshi; Verma, Sudha; Ghosh, Ayan Kumar; Singh, Ruby; Abhishek, Kumar; Saini, Savita; Sardar, Abul Hasan; Purkait, Bidyut; Kumar, Ashish; Mandal, Chitra; Das, Pradeep
The survival of intracellular protozoan parasite, Leishmania donovani, the causative agent of Indian visceral leishmaniasis (VL), depends on the activation status of macrophages. l-Arginine, a semi-essential amino acid plays a crucial regulatory role for activation of macrophages. However, the role of l-arginine transport in VL still remains elusive. In this study, we demonstrated that intra-macrophage survival of L. donovani depends on the availability of extracellular l-arginine. Infection of THP-1-derived macrophage/human monocyte-derived macrophage (hMDM) with Leishmania, resulted in upregulation of l-arginine transport. While investigating the involvement of the transporters, we observed that Leishmania survival was greatly impaired when the transporters were blocked either using inhibitor or siRNA-mediated downregulation. CAT-2 was found to be the main isoform associated with l-arginine transport in L. donovani-infected macrophages. l-arginine availability and its transport regulated the host arginase in Leishmania infection. Arginase and inducible nitric oxide synthase (iNOS) expression were reciprocally regulated when assayed using specific inhibitors and siRNA-mediated downregulation. Interestingly, induction of iNOS expression and nitric oxide production were observed in case of inhibition of arginase in infected macrophages. Furthermore, inhibition of l-arginine transport as well as arginase resulted in decreased polyamine production, limiting parasite survival inside macrophages. l-arginine availability and transport regulated Th1/Th2 cytokine levels in case of Leishmania infection. Upregulation of l-arginine transport, induction of host arginase, and enhanced polyamine production were correlated with increased level of IL-10 and decreased level of IL-12 and TNF-α in L. donovani-infected macrophages. Our findings provide clear evidence for targeting the metabolism of l-arginine and l-arginine-metabolizing enzymes as an important therapeutic and
The Role of Microbial Amino Acid Metabolism in Host Metabolism
Neis, Evelien P. J. G.; Dejong, Cornelis H. C.; Rensen, Sander S.
Disruptions in gut microbiota composition and function are increasingly implicated in the pathogenesis of obesity, insulin resistance, and type 2 diabetes mellitus. The functional output of the gut microbiota, including short-chain fatty acids and amino acids, are thought to be important modulators underlying the development of these disorders. Gut bacteria can alter the bioavailability of amino acids by utilization of several amino acids originating from both alimentary and endogenous protei...
Large neutral amino acids in daily practice.
Ahring, Kirsten Kiær
At the Kennedy Centre for Phenylketonuria, Denmark, large neutral amino acids (LNAAs) are being used to treat adult and adolescent patients who are nonadherent to dietary treatment for phenylketonuria (PKU). At the start of treatment, a patient must undergo dietary analysis and regular blood sampling to measure plasma amino acid (AA) concentrations. The aim of this analysis and treatment is that the patient receives 25-30% of the daily protein requirement from LNAA supplementation and the remaining 70-75% from natural, low-phenylalanine proteins (although some patients have difficulties in maintaining this level of protein intake). Patients are therefore able to follow a more "normal" diet than those adhering to a PKU diet with AA supplementation (in which only 20% of the daily protein requirement is provided from the diet and 80% from AA supplementation). LNAAs have also been used to treat older patients with untreated/late-diagnosed PKU who show profound intellectual, psychological, and behavioral impairments. Treatment with LNAAs has been shown to improve measures of concentration and awareness of external stimuli in some of these patients and thus enhance their socialization, emotionality, frustration tolerance, and mood.
Turkey-hen amino acid composition of brain and eyes
International Nuclear Information System (INIS)
Adeyeye, E.I.
The amino acids composition of the brain and eyes of the mature Turkey-hen (Meleagris gallopavo L.), were determined on dry weight basis. Total essential amino acids ranged from 35.1-36.0 g/100 g as 49.5-49.8% of the total amino acids. The amino acid score showed that lysine ranged from 0.76-0.91 (on whole hen.s egg comparison), 0.85-1.03 (on provisional essential amino acid scoring pattern), and 0.81-0.98 (on suggested requirement of the essential amino acid of a preschool child). The predicted protein efficiency ratio was 1.94-2.41, whilst essential amino acid index range was 1.06-1.08 and the calculated isoelectric point range was 3.97-4.18. The correlation coefficient (rxy) was positively high and significant at r = 0.01 for the total amino acids, amino acid scores (on the whole hen.s egg comparisons made) and the isoelectric point. On the whole, the eyes were better in 12/18 or 66.7% parameters of the amino acids than the brain of Turkey-Hen. (author)
Transfer of Asymmetry between Proteinogenic Amino Acids under Harsh Conditions
Tarasevych, Arkadii V.; Vives, Thomas; Snytnikov, Valeriy N.; Guillemin, Jean-Claude
The heating above 400 °C of serine, cysteine, selenocysteine and threonine leads to a complete decomposition of the amino acids and to the formation in low yields of alanine for the three formers and of 2-aminobutyric acid for the latter. At higher temperature, this amino acid is observed only when sublimable α-alkyl-α-amino acids are present, and with an enantiomeric excess dependent on several parameters. Enantiopure or enantioenriched Ser, Cys, Sel or Thr is not able to transmit its enantiomeric excess to the amino acid formed during its decomposition. The presence during the sublimation-decomposition of enantioenriched valine or isoleucine leads to the enantioenrichment of all sublimable amino acids independently of the presence of many decomposition products coming from the unstable derivative. All these studies give information on a potentially prebiotic key-reaction of abiotic transformations between α-amino acids and their evolution to homochirality.
Amino acid chirality breaking by N-phosphorylation
International Nuclear Information System (INIS)
Zhao Yufen; Yan Qingjin.
The chirality breaking of amino acid is a focus issue in the origin of life. For chemists, there are some interesting chemical approaches to solve the symmetry breaking problem. Our previous experiments indicated that when amino acids were phosphorylated, there were many bio-mimic reactions happened. In this paper, it was found that there had significant difference between the N-phosphoryl L- and D- amino acids such as serine and threonine. The optical rotation tracing experiments of the racemic N-phosphoamino acids also showed the similar results. The chirality breaking of amino acids by N-phosphorylation was a novel phenomena. (author). 3 refs, 1 fig. Abstract only
[Amino acid level in pastry with low caloric value].
Barkhatov, V Iu; Vyskubova, N K; Felipas, T B; Pshemurzova, R M; Kamenetskaia, E V
The effect of fruit paste additives on amino acid composition of farinaceous and decorative confectionery semifinished products was studied to decrease their fuel value. It was found that a partial replacement of sugar and fat for apple and quince pastes in apple biscuit and apple shortbread semiproducts led to an increase in the content of essential and sulfur-containing amino acids. Cream prepared from egg albumin and quince paste had reduced content of amino acids (except for glutamic acid) due to the diminished content of egg albumin, however, the balance of amino acid composition was improved.
Solid-phase route to Fmoc-protected cationic amino acid building blocks
DEFF Research Database (Denmark)
Clausen, Jacob Dahlqvist; Linderoth, Lars; Nielsen, Hanne Mørck
Diamino acids are commonly found in bioactive compounds, yet only few are commercially available as building blocks for solid-phase peptide synthesis. In the present work a convenient, inexpensive route to multiple-charged amino acid building blocks with varying degree of hydrophobicity was devel...... of simple neutral amino acids as well as analogs displaying high bulkiness or polycationic side chains was prepared. Two building blocks were incorporated into peptide sequences using microwave-assisted solid-phase peptide synthesis confirming their general utility.......Diamino acids are commonly found in bioactive compounds, yet only few are commercially available as building blocks for solid-phase peptide synthesis. In the present work a convenient, inexpensive route to multiple-charged amino acid building blocks with varying degree of hydrophobicity...... was developed. A versatile solid-phase protocol leading to selectively protected amino alcohol intermediates was followed by oxidation to yield the desired di- or polycationic amino acid building blocks in gram-scale amounts. The synthetic sequence comprises loading of (S)-1-(p-nosyl)aziridine-2-methanol onto...
Synthesis of aminoaldonic acids
DEFF Research Database (Denmark)
Jørgensen, Christel Thea
With the aim of synthesising aminoaldonic acids, two 2-acetamido-2-deoxyaldonolactones with D-galacto (6) and D-arabino (11) configuration were prepared from acetylated sugar formazans in analogy with a known procedure. Empolying the same procedure to acetylated sugar phenylhydrazones gave mixtures......,4-lactone, respectively. A 2,3-aziridino-2,3-dideoxypentonamide 70 was also prepared from D-glucono-1,5-lactone. The lactones were converted into methyl 3,4-O-isopropylidene-2-O-sulfonyl esters 42, 50, 62 and 68, which upon treatment with concentrated aqueous ammonia yielded the aziridino compounds...... and 82, respectively. The aminolactone 84 was converted into the corresponding amino sugar 89.With the aim of synthesising substrates for the Pictet-Spengler reaction three 4-aldehydo acetamidodideoxytetronolactones 92, 97 and 103 were prepared by periodate cleavage of the corresponding hexonolactones...
gamma-Glutamyl amino acids. Transport and conversion to 5-oxoproline in the kidney
International Nuclear Information System (INIS)
Bridges, R.J.; Meister, A.
Transport of gamma-glutamyl amino acids, a step in the proposed glutathione-gamma-glutamyl transpeptidase-mediated amino acid transport pathway, was examined in mouse kidney. The transport of gamma-glutamyl amino acids was demonstrated in vitro in studies on kidney slices. Transport was followed by measuring uptake of 35 S after incubation of the slices in media containing gamma-glutamyl methionine [ 35 S]sulfone. The experimental complication associated with extracellular conversion of the gamma-glutamyl amino acid to amino acid and uptake of the latter by slices was overcome by using 5-oxoproline formation (catalyzed by intracellular gamma-glutamyl-cyclotransferase) as an indicator of gamma-glutamyl amino acid transport. This method was also successfully applied to studies on transport of gamma-glutamyl amino acids in vivo. Transport of gamma-glutamyl amino acids in vitro and in vivo is inhibited by several inhibitors of gamma-glutamyl transpeptidase and also by high extracellular levels of glutathione. This seems to explain urinary excretion of gamma-glutamylcystine by humans with gamma-glutamyl transpeptidase deficiency and by mice treated with inhibitors of this enzyme. Mice depleted of glutathione by treatment with buthionine sulfoximine (which inhibits glutathione synthesis) or by treatment with 2,6-dimethyl-2,5-heptadiene-4-one (which effectively interacts with tissue glutathione) exhibited significantly less transport of gamma-glutamyl amino acids than did untreated controls. The findings suggest that intracellular glutathione functions in transport of gamma-glutamyl amino acids. Evidence was also obtained for transport of gamma-glutamyl gamma-glutamylphenylalanine into kidney slices
Application of cyanuric chloride-based six new chiral derivatizing reagents having amino acids and amino acid amides as chiral auxiliaries for enantioresolution of proteinogenic amino acids by reversed-phase high-performance liquid chromatography.
Bhushan, Ravi; Dixit, Shuchi
Six dichloro-s-triazine (DCT) reagents having L-Leu, D-Phg, L-Val, L-Met, L-Ala and L-Met-NH(2) as chiral auxiliaries in cyanuric chloride were introduced for enantioseparation of 13 proteinogenic amino acids. Four other DCTs and six monochloro-s-triazine (MCT) reagents having amino acid amides as chiral auxiliaries were also synthesized. These 16 chiral derivatizing reagents (CDRs) were used for synthesis of diastereomers of all the 13 analytes using microwave irradiation, which were resolved by reversed-phase high-performance liquid chromatography (RP-HPLC) using C18 column and gradient eluting mixture of aqueous TFA and acetonitrile with UV detection at 230 nm. It required only 60-90 s for derivatization using microwave irradiation. Better resolution and lower retention times were observed for the diastereomers prepared with CDRs having amino acids as chiral auxiliaries as compared to counterparts prepared with reagents having amino acid amides as chiral auxiliaries. As the best resolution of all the 13 analytes was observed for their diastereomers prepared using the DCT reagent having L-Leu as chiral auxiliary, this CDR was further employed for derivatization of Lys, Tyr, His and Arg followed by RP-HPLC analysis of resulting diastereomers. The results are discussed in light of acid and amide groups of chiral auxiliaries constituting CDRs, electronegativities of the atoms of achiral moieties constituting CDRs and hydrophobicities of side chains of amino acids constituting CDRs and analytes.
Levulinic acid in organic synthesis
International Nuclear Information System (INIS)
Timokhin, Boris V; Baransky, V A; Eliseeva, G D
Data concerning the methods of synthesis, chemical transformations and application of levulinic acid are analysed and generalised. The wide synthetic potential of levulinic acid, particularly as a key compound in the synthesis of various heterocyclic systems, saturated and unsaturated ketones and diketones, difficultly accessible acids and other compounds is demonstrated. The accessibility of levulinic acid from hexose-containing wood-processing and agricultural wastes is noted. The bibliography includes 260 references.
Indispensable amino acid concentrations decrease in tissues of stomachless fish, common carp in response to free amino acid- or peptide-based diets.
Zhang, Y; Dabrowski, K; Hliwa, P; Gomulka, P
The premise that free amino acid or dipeptide based diets will resolve the nutritional inadequacy of formulated feeds for larval and juvenile fish and improve utilization of nitrogen in comparison to protein-based diets was tested in stomachless fish, common carp (Cyprinus carpio L.) larvae. We examined the postprandial whole body free amino acid (FAA) pool in fish that were offered a FAA mixture based diet for the duration of 2 or 4 weeks. We found that the total amount and all indispensable amino acids concentrations in the whole body decreased after a meal. We then fed juvenile carp with dietary amino acids provided in the FAA, dipeptide (PP), or protein (live feed organisms; brine shrimp Artemia salina nauplii, AS) forms. Histidine concentrations in the whole fish body increased in all dietary groups after feeding whereas all other indispensable amino acids decreased in FAA and PP groups in comparison to the AS group. Taurine appears to be the major osmotic pressure balancing free amino acid in larval freshwater fish which may indicate a conditional requirement. We present the first evidence in larval fish that in response to synthetic FAA and PP diets, the whole body indispensable free AA concentrations decreased after feeding. This study shows that amino acids given entirely as FAA or PP cannot sustain stomachless larval fish growth, and may result in depletion of body indispensable AA and most of dispensable AA. The understanding of these responses will determine necessary changes in diet formulations that prevent accelerated excretion of amino acids without protein synthesis.
Amino Acid Bound Surfactants: A New Synthetic Family of Polymeric Monoliths Open Up Possibilities for Chiral Separations in Capillary Electrochromatography
He, Jun; Wang, Xiaochun; Morrill, Mike; Shamsi, Shahab A.
By combining a novel chiral amino-acid surfactant containing acryloyl amide tail, carbamate linker and leucine head group of different chain lengths with a conventional cross linker and a polymerization technique, a new "one-pot", synthesis for the generation of amino-acid based polymeric monolith is realized. The method promises to open up the discovery of amino-acid based polymeric monolith for chiral separations in capillary electrochromatography (CEC). Possibility of enhanced chemoselectivity for simultaneous separation of ephedrine and pseudoephedrine containing multiple chiral centers, and the potential use of this amino-acid surfactant bound column for CEC and CEC coupled to mass spectrometric detection is demonstrated. PMID:22607448
Signaling Pathways Related to Protein Synthesis and Amino Acid Concentration in Pig Skeletal Muscles Depend on the Dietary Protein Level, Genotype and Developmental Stages.
Liu, Yingying; Li, Fengna; Kong, Xiangfeng; Tan, Bie; Li, Yinghui; Duan, Yehui; Blachier, François; Hu, Chien-An A; Yin, Yulong
Muscle growth is regulated by the homeostatic balance of the biosynthesis and degradation of muscle proteins. To elucidate the molecular interactions among diet, pig genotype, and physiological stage, we examined the effect of dietary protein concentration, pig genotype, and physiological stages on amino acid (AA) pools, protein deposition, and related signaling pathways in different types of skeletal muscles. The study used 48 Landrace pigs and 48 pure-bred Bama mini-pigs assigned to each of 2 dietary treatments: lower/GB (Chinese conventional diet)- or higher/NRC (National Research Council)-protein diet. Diets were fed from 5 weeks of age to respective market weights of each genotype. Samples of biceps femoris muscle (BFM, type I) and longissimus dorsi muscle (LDM, type II) were collected at nursery, growing, and finishing phases according to the physiological stage of each genotype, to determine the AA concentrations, mRNA levels for growth-related genes in muscles, and protein abundances of mechanistic target of rapamycin (mTOR) signaling pathway. Our data showed that the concentrations of most AAs in LDM and BFM of pigs increased (Prelated AA, including Met, Phe, Tyr, Pro, and Ser, compared with Landrace pigs. The mRNA levels for myogenic determining factor, myogenin, myocyte-specific enhancer binding factor 2 A, and myostatin of Bama mini-pigs were higher (P<0.05) than those of Landrace pigs, while total and phosphorylated protein levels for protein kinase B, mTOR, and p70 ribosomal protein S6 kinases (p70S6K), and ratios of p-mTOR/mTOR, p-AKT/AKT, and p-p70S6K/p70S6K were lower (P<0.05). There was a significant pig genotype-dependent effect of dietary protein on the levels for mTOR and p70S6K. When compared with the higher protein-NRC diet, the lower protein-GB diet increased (P<0.05) the levels for mTOR and p70S6K in Bama mini-pigs, but repressed (P<0.05) the level for p70S6K in Landrace pigs. The higher protein-NRC diet increased ratio of p-mTOR/mTOR in
Silicon-Containing Amino Acids: Synthetic Aspects, Conformational Studies, and Applications to Bioactive Peptides.
Rémond, Emmanuelle; Martin, Charlotte; Martinez, Jean; Cavelier, Florine
Unnatural α-amino acids form a family of essential molecules used for, among other applications, the synthesis of modified peptides, to improve resistance to proteolytic enzyme degradation, and to modulate physico- and biochemical properties of bioactive peptides as well as chiral inducers in asymmetric synthesis. Among them, silicon-containing unnatural amino acids are becoming an interesting new class of building blocks. The replacement of carbon atoms in bioactive substances with silicon is becoming increasingly popular. Peptides containing silyl amino acids hold great promise for maintaining or reinforcing the biological activity of active compounds, while they simultaneously enhance their resistance to enzyme degradation. In addition, the lipophilicity of the silicon atom facilitates their membrane crossing and their bioavailability. Nowadays, the interest of the pharmaceutical industry in peptide- and protein-based therapies is increasing. In this respect, silicon-containing amino acids and peptides are likely to be a significant part of future innovations in this area, and more generally in the area of biomolecules. In this process, commercial availability of silicon-containing amino acids is necessary: new syntheses have been developed, and work in this area is ongoing. This review aims to be a comprehensive and general summary of the different methods used to prepare silicon-containing amino acids and their implications on conformational structures and biological applications when they are incorporated into bioactive molecules.
Geochemistry of amino acids in shells of the clam Saxidomus
Kvenvolden, K.A.; Blunt, D.J.; McMenamin, M.A.; Straham, S.E.
Concentrations of amino acids and their corresponding d l enantiomeric ratios have been measured in shells of the bivalve mollusk Saxidomus from eleven localities, ranging in age from modern to probably more than 500,000 yr, along the Pacific coast of North America. Natural logarithms of amino acid concentrations correlate well with d l ratios, and the relationship provides a possible guide to the selection of fossils for use in amino acid dating. The relative order of the extents of racemization of amino acids at any given time appears to change with increasing sample age. Application of the amino acid dating method to shells from Whidbey Island, Washington, yields an age of about 80,000 yr, in contrast to the previously determined radiocarbon age of 36,000 yr which was measured on some shell carbonate and considered a minimum age. The amino acid age is compatible with the geologic record in the area. ?? 1980.
Distribution and Origin of Amino Acids in Lunar Regolith Samples
Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Dworkin, J. P.; McLain, H. L.; Noble, S. K.; Gibson, E. K., Jr.
The existence of organic compounds on the lunar surface has been a question of interest from the Apollo era to the present. Investigations of amino acids immediately after collection of lunar samples yielded inconclusive identifications, in part due to analytical limitations including insensitivity to certain compounds, an inability to separate enantiomers, and lack of compound-specific isotopic measurements. It was not possible to determine if the detected amino acids were indigenous to the lunar samples or the result of terrestrial contamination. Recently, we presented initial data from the analysis of amino acid abundances in 12 lunar regolith samples and discussed those results in the context of four potential amino acid sources [5]. Here, we expand on our previous work, focusing on amino acid abundances and distributions in seven regolith samples and presenting the first compound-specific carbon isotopic ratios measured for amino acids in a lunar sample.
Twenty natural amino acids identification by a photochromic sensor chip.
Qin, Meng; Li, Fengyu; Huang, Yu; Ran, Wei; Han, Dong; Song, Yanlin
All 20 natural amino acids identification shows crucial importance in biochemistry and clinical application while it is still a challenge due to highly similarity in molecular configuration of the amino acids. Low efficiency, complicated sensing molecules and environment hindered the successful identification. Here, we developed a facile sensor chip composed of one photochromic molecule with metal ions spotted to form spirooxazine-metallic complexes, and successfully recognized all the 20 natural amino acids as well as their mixtures. The sensor chip gives distinct fluorescent fingerprint pattern of each amino acid, based on multistate of spirooxazine under different light stimulations and discriminated interaction between various metal ions and amino acids. The sensor chip demonstrates powerful capability of amino acids identification, which promotes sensing of biomolecules.
Diversity of amino acids in a typical chernozem of Moldova
Frunze, N. I.
The content and composition of the amino acids in typical chernozems were studied. The objects of the study included a reference soil under an old fallow and three variants under fodder crop rotations: not fertilized, with mineral fertilizers, and with organic fertilizers. The contents of 18 amino acids were determined in these soils. The amino acids were extracted by the method of acid hydrolysis and identified by the method of ion-exchange chromatography. The total content of most of the amino acids was maximal in the reference soil; it was much lower in the cultivated soils and decreased in the following sequence: organic background > mineral background > no fertilization. The diversity of amino acids was evaluated quantitatively using different parameters applied in ecology for estimating various aspects of the species composition of communities (Simpson, Margalef, Menhinick, and Shannon's indices). The diversity and contribution of different amino acids to the total pool of amino acids also varied significantly in the studied variants. The maximum diversity of amino acids and maximum evenness of their relative abundance indices were typical of the reference chernozem; these parameters were lower in the cultivated soils. It was concluded that the changes in the structure of the amino acids under the impact of agricultural loads are similar to those that are usually observed under stress conditions.
The Origin of Amino Acids in Lunar Regolith Samples
Cook, Jamie E.; Callahan, Michael P.; Dworkin, Jason P.; Glavin, Daniel P.; McLain, Hannah L.; Noble, Sarah K.; Gibson, Everett K., Jr.
We analyzed the amino acid content of seven lunar regolith samples returned by the Apollo 16 and Apollo 17 missions and stored under NASA curation since collection using ultrahigh-performance liquid chromatography with fluorescence detection and time-of-flight mass spectrometry. Consistent with results from initial analyses shortly after collection in the 1970s, we observed amino acids at low concentrations in all of the curated samples, ranging from 0.2 parts-per-billion (ppb) to 42.7 ppb in hot-water extracts and 14.5 ppb to 651.1 ppb in 6M HCl acid-vapor-hydrolyzed, hot-water extracts. Amino acids identified in the Apollo soil extracts include glycine, D- and L-alanine, D- and L-aspartic acid, D- and L-glutamic acid, D- and L-serine, L-threonine, and L-valine, all of which had previously been detected in lunar samples, as well as several compounds not previously identified in lunar regoliths: -aminoisobutyric acid (AIB), D-and L-amino-n-butyric acid (-ABA), DL-amino-n-butyric acid, -amino-n-butyric acid, -alanine, and -amino-n-caproic acid. We observed an excess of the L enantiomer in most of the detected proteinogenic amino acids, but racemic alanine and racemic -ABA were present in some samples.
Amino acid composition and protein quality of white melon ...
African Journals Online (AJOL)
Amino acid composition of the seed flour and its protein fractions were determined using standard analytical techniques in the laboratory. Protein quality of the seed flour was evaluated using the invitro techniques. Results showed that glutamic acid is the most abundant amino acid (128.2 156.4 mg/g protein) while leucine ...
Non-protein amino acids in peptide design
Indian Academy of Sciences (India)
protein amino acids in peptide design ... illustrate the use -aminoisobutyric acid (Aib) in the construction of helices, D-amino acids in the design of helix termination segments and DPro-Xxx segments for nucleating of -hairpin structures. - and ...
Interactive Hangman teaches amino acid structures and abbreviations
Pennington, BO; Sears, D; Clegg, DO
© 2014 by The International Union of Biochemistry and Molecular Biology, 42(6):495-500, 2014. We developed an interactive exercise to teach students how to draw the structures of the 20 standard amino acids and to identify the one-letter abbreviations by modifying the familiar game of "Hangman." Amino acid structures were used to represent single letters throughout the game. To provide additional practice in identifying structures, hints to the answers were written in "amino acid sentences" f...
Peripheral Amino Acid Levels in Schizophrenia and Antipsychotic Treatment
De Luca, Vincenzo; Viggiano, Emanuela; Messina, Giovanni; Viggiano, Alessandro; Borlido, Carol; Viggiano, Andrea; Monda, Marcellino
Abnormal levels of amino acids have been reported in patients with schizophrenia and have also been investigated as a biomarker to monitor antipsychotic treatment, however results have been inconsistent. The purpose of the present review is to summarize the evidence in the literature of whether amino acid levels can be a biomarker and predict the treatment outcome in schizophrenia. The current review does not support amino acid concentration as a useful biomarker for monitoring antipsychotic ...
Organotin(IV) complexes derived from proteinogenic amino acid: synthesis, structure and evaluation of larvicidal efficacy on Anopheles stephensi mosquito larvae
Basu Baul, Tushar S; Kehie, Pelesakuo; Höpfl, Herbert; Duthie, Andrew; Eng, George; Linden, Anthony
Five new organotin(IV) complexes of composition [Bz2SnL1]n (), [Bz3SnL1H⋅H2O] (), [Me2SnL2⋅H2O] (), [Me2SnL3] () and [Bz3SnL3H]n () (where L1 = (2S)-2-{[(E)-(4-hydroxypentan-2-ylidene)]amino}-4-methylpentanoate, L2 = (rac)-2-{[(E)-1-(2-hydroxyphenyl)methylidene]amino}-4-methylpentanoate and L3 = (2S)- or (rac)-2-{[(E)-1-(2-hydroxyphenyl)ethylidene]amino}-4-methylpentanoate) were synthesized and characterized using 1H NMR, 13C NMR, 119Sn NMR and infrared spectroscopic techniques. The crystal s...
Metabolic Effects of Dietary Proteins, Amino Acids and The Other Amine Consisting Compounds on Cardiovascular System.
Directory of Open Access Journals (Sweden)
Elif Uğur
Full Text Available During the prevention and treatment of cardiovascular diseases, first cause of deaths in the world, diet has a vital role. While nutrition programs for the cardiovascular health generally focus on lipids and carbohydrates, effects of proteins are not well concerned. Thus this review is written in order to examine effect of proteins, amino acids, and the other amine consisting compounds on cardiovascular system. Because of that animal or plant derived proteins have different protein composition in different foods such as dairy products, egg, meat, chicken, fish, pulse and grains, their effects on blood pressure and regulation of lipid profile are unlike. In parallel amino acids made up proteins have different effect on cardiovascular system. From this point, sulfur containing amino acids, branched chain amino acids, aromatic amino acids, arginine, ornithine, citrulline, glycine, and glutamine may affect cardiovascular system in different metabolic pathways. In this context, one carbon metabolism, synthesis of hormone, stimulation of signaling pathways and effects of intermediate and final products that formed as a result of amino acids metabolism is determined. Despite the protein and amino acids, some other amine consisting compounds in diet include trimethylamine N-oxide, heterocyclic aromatic amines, polycyclic aromatic hydrocarbons and products of Maillard reaction. These amine consisting compounds generally increase the risk for cardiovascular diseases by stimulating oxidative stress, inflammation, and formation of atherosclerotic plaque.
Filling gaps in bacterial amino acid biosynthesis pathways with high-throughput genetics.
Directory of Open Access Journals (Sweden)
Morgan N Price
Full Text Available For many bacteria with sequenced genomes, we do not understand how they synthesize some amino acids. This makes it challenging to reconstruct their metabolism, and has led to speculation that bacteria might be cross-feeding amino acids. We studied heterotrophic bacteria from 10 different genera that grow without added amino acids even though an automated tool predicts that the bacteria have gaps in their amino acid synthesis pathways. Across these bacteria, there were 11 gaps in their amino acid biosynthesis pathways that we could not fill using current knowledge. Using genome-wide mutant fitness data, we identified novel enzymes that fill 9 of the 11 gaps and hence explain the biosynthesis of methionine, threonine, serine, or histidine by bacteria from six genera. We also found that the sulfate-reducing bacterium Desulfovibrio vulgaris synthesizes homocysteine (which is a precursor to methionine by using DUF39, NIL/ferredoxin, and COG2122 proteins, and that homoserine is not an intermediate in this pathway. Our results suggest that most free-living bacteria can likely make all 20 amino acids and illustrate how high-throughput genetics can uncover previously-unknown amino acid biosynthesis genes.
Genetic incorporation of recycled unnatural amino acids.
Ko, Wooseok; Kim, Sanggil; Jo, Kyubong; Lee, Hyun Soo
The genetic incorporation of unnatural amino acids (UAAs) into proteins has been a useful tool for protein engineering. However, most UAAs are expensive, and the method requires a high concentration of UAAs, which has been a drawback of the technology, especially for large-scale applications. To address this problem, a method to recycle cultured UAAs was developed. The method is based on recycling a culture medium containing the UAA, in which some of essential nutrients were resupplemented after each culture cycle, and induction of protein expression was controlled with glucose. Under optimal conditions, five UAAs were recycled for up to seven rounds of expression without a decrease in expression level, cell density, or incorporation fidelity. This method can generally be applied to other UAAs; therefore, it is useful for reducing the cost of UAAs for genetic incorporation and helpful for expanding the use of the technology to industrial applications.
Study of Stationary Phase Metabolism Via Isotopomer Analysis of Amino Acids from an Isolated Protein
Energy Technology Data Exchange (ETDEWEB)
Shaikh, AfshanS.; Tang, YinjieJ.; Mukhopadhyay, Aindrila; Martin, Hector Garcia; Gin, Jennifer; Benke, Peter; Keasling, Jay D.
Microbial production of many commercially important secondary metabolites occurs during stationary phase, and methods to measure metabolic flux during this growth phase would be valuable. Metabolic flux analysis is often based on isotopomer information from proteinogenic amino acids. As such, flux analysis primarily reflects the metabolism pertinent to the growth phase during which most proteins are synthesized. To investigate central metabolism and amino acids synthesis activity during stationary phase, addition of fully 13C-labeled glucose followed by induction of green fluorescent protein (GFP) expression during stationary phase was used. Our results indicate that Escherichia coli was able to produce new proteins (i.e., GFP) in the stationary phase, and the amino acids in GFP were mostly from degraded proteins synthesized during the exponential growth phase. Among amino acid biosynthetic pathways, only those for serine, alanine, glutamate/glutamine, and aspartate/asparagine had significant activity during the stationary phase.
Amino acids grafting of Ar+ ions modified PE
International Nuclear Information System (INIS)
Svorcik, V.; Hnatowicz, V.; Stopka, P.; Bacakova, L.; Heitz, J.; Oechsner, R.; Ryssel, H.
Polyethylene (PE) was irradiated with 63 keV Ar + ions to the fluences from 1x10 12 to 3x10 15 cm -2 and then grafted at room temperature from water solution with amino acids (alanine, leucine). Using various spectroscopic techniques (UV-VIS, FTIR, RBS and EPR) it was shown that the amino acids penetrate into PE where they are eventually captured either on double bonds or on free radicals created by the ion irradiation. Grafting with amino acids in the whole specimen layer modified by irradiation is observed. The ion-beam-modified and amino-acid grafted PE is supposed to exhibit increased biocompatibility. (author)
Electronic-state control of amino acids on semiconductor surfaces
International Nuclear Information System (INIS)
Oda, Masato; Nakayama, Takashi
Electronic structures of amino acids on the Si(1 1 1) surfaces are investigated by using ab initio Hartree-Fock calculations. It is shown that among various polar amino acids, a histidine is the only one that can be positively ionized when hole carriers are supplied in the Si substrate, by transferring the hole charge from Si substrate to an amino acid. This result indicates that the ionization of a histidine, which will activate the protein functions, can be controlled electrically by producing amino acid/Si junctions
Amino acids in the cultivation of mammalian cells.
Salazar, Andrew; Keusgen, Michael; von Hagen, Jörg
Amino acids are crucial for the cultivation of mammalian cells. This importance of amino acids was realized soon after the development of the first cell lines, and a solution of a mixture of amino acids has been supplied to cultured cells ever since. The importance of amino acids is further pronounced in chemically defined mammalian cell culture media, making the consideration of their biological and chemical properties necessary. Amino acids concentrations have been traditionally adjusted to their cellular consumption rates. However, since changes in the metabolic equilibrium of amino acids can be caused by changes in extracellular concentrations, metabolomics in conjunction with flux balance analysis is being used in the development of culture media. The study of amino acid transporters is also gaining importance since they control the intracellular concentrations of these molecules and are influenced by conditions in cell culture media. A better understanding of the solubility, stability, dissolution kinetics, and interactions of these molecules is needed for an exploitation of these properties in the development of dry powdered chemically defined media for mammalian cells. Due to the complexity of these mixtures however, this has proven to be challenging. Studying amino acids in mammalian cell culture media will help provide a better understanding of how mammalian cells in culture interact with their environment. It would also provide insight into the chemical behavior of these molecules in solutions of complex mixtures, which is important in the understanding of the contribution of individual amino acids to protein structure.
Corrosion control of vanadium in aqueous solutions by amino acids
International Nuclear Information System (INIS)
El-Rabiee, M.M.; Helal, N.H.; El-Hafez, Gh.M. Abd; Badawy, W.A.
The electrochemical behavior of vanadium in amino acid free and amino acid containing aqueous solutions of different pH was studied using open-circuit potential measurements, polarization techniques and electrochemical impedance spectroscopy (EIS). The corrosion current density, i corr , the corrosion potential, E corr and the corrosion resistance, R corr , were calculated. A group of amino acids, namely, glycine, alanine, valine, histidine, glutamic and cysteine has been investigated as environmentally safe inhibitors. The effect of Cl - on the corrosion inhibition efficiency especially in acid solutions was investigated. In neutral and basic solutions, the presence of amino acids increases the corrosion resistance of the metal. The electrochemical behavior of V before and after the corrosion inhibition process has shown that some amino acids like glutamic acid and histidine have promising corrosion inhibition efficiency at low concentration (≅25 mM). The inhibition efficiency (η) was found to depend on the structure of the amino acid and the constituents of the corrosive medium. The corrosion inhibition process is based on the adsorption of the amino acid molecules on the metal surface and the adsorption process follows the Freundlich isotherm. The adsorption free energy for valine on V in acidic solutions was found to be -9.4 kJ/mol which reveals strong physical adsorption of the amino acid molecules on the vanadium surface
D-Amino acids and D-Tyr-tRNA(Tyr) deacylase: stereospecificity of the translation machine revisited.
Yang, Hongbo; Zheng, Gen; Peng, Xiaozhong; Qiang, Boqin; Yuan, Jiangang
Until 30 years ago, it had been considered that D-amino acids were excluded from living systems except for D-amino acids in the cell wall of microorganisms. However, D-amino acids, in the form of free amino acids, peptides and proteins, were recently detected in various living organisms from bacteria to mammals. The extensive distribution of bio-functional D-amino acids challenges the current concept of protein synthesis: more attention should be paid to the stereospecificity of the translation machine. Besides aminoacyl-tRNA synthetases, elongation factor Tu and some other mechanisms, D-Tyr-tRNA(Tyr) deacylases provide a novel checkpoint since they specifically recycle misaminoacylated D-Tyr-tRNA(Tyr) and some other D-aminoacyl-tRNAs. Their unique structure represents a new class of tRNA-dependent hydrolase. These unexpected findings have far-reaching implications for our understanding of protein synthesis and its origin.
A Novel Synthetic Pathway Enables Microbial Production of Polyphenols Independent from the Endogenous Aromatic Amino Acid Metabolism.
Kallscheuer, Nicolai; Vogt, Michael; Marienhagen, Jan
Numerous plant polyphenols have potential applications as pharmaceuticals or nutraceuticals. Stilbenes and flavonoids as most abundant polyphenols are synthesized from phenylpropanoids, which are exclusively derived from aromatic amino acids in nature. Several microorganisms were engineered for the synthesis of biotechnologically interesting plant polyphenols; however, low activity of heterologous ammonia lyases, linking endogenous microbial aromatic amino acid biosynthesis to phenylpropanoid synthesis, turned out to be the limiting step during microbial synthesis. We here developed an alternative strategy for polyphenol production from cheap benzoic acids by reversal of a β-oxidative phenylpropanoid degradation pathway avoiding any ammonia lyase activity. The synthetic pathway running in the non-natural direction is feasible with respect to thermodynamics and involved reaction mechanisms. Instantly, product titers of 5 mg/L resveratrol could be achieved in recombinant Corynebacterium glutamicum strains indicating that phenylpropanoid synthesis from 4-hydroxybenzoic acid can in principle be implemented independently from aromatic amino acids and ammonia lyase activity.
Amino Acid Transporters and Release of Hydrophobic Amino Acids in the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120
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Rafael Pernil
Full Text Available Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that can use inorganic compounds such as nitrate or ammonium as nitrogen sources. In the absence of combined nitrogen, it can fix N2 in differentiated cells called heterocysts. Anabaena also shows substantial activities of amino acid uptake, and three ABC-type transporters for amino acids have been previously characterized. Seven new loci encoding predicted amino acid transporters were identified in the Anabaena genomic sequence and inactivated. Two of them were involved in amino acid uptake. Locus alr2535-alr2541 encodes the elements of a hydrophobic amino acid ABC-type transporter that is mainly involved in the uptake of glycine. ORF all0342 encodes a putative transporter from the dicarboxylate/amino acid:cation symporter (DAACS family whose inactivation resulted in an increased uptake of a broad range of amino acids. An assay to study amino acid release from Anabaena filaments to the external medium was set up. Net release of the alanine analogue α-aminoisobutyric acid (AIB was observed when transport system N-I (a hydrophobic amino acid ABC-type transporter was engaged in the uptake of a specific substrate. The rate of AIB release was directly proportional to the intracellular AIB concentration, suggesting leakage from the cells by diffusion.
Signaling Pathways Related to Protein Synthesis and Amino Acid Concentration in Pig Skeletal Muscles Depend on the Dietary Protein Level, Genotype and Developmental Stages.
Directory of Open Access Journals (Sweden)
Yingying Liu
Full Text Available Muscle growth is regulated by the homeostatic balance of the biosynthesis and degradation of muscle proteins. To elucidate the molecular interactions among diet, pig genotype, and physiological stage, we examined the effect of dietary protein concentration, pig genotype, and physiological stages on amino acid (AA pools, protein deposition, and related signaling pathways in different types of skeletal muscles. The study used 48 Landrace pigs and 48 pure-bred Bama mini-pigs assigned to each of 2 dietary treatments: lower/GB (Chinese conventional diet- or higher/NRC (National Research Council-protein diet. Diets were fed from 5 weeks of age to respective market weights of each genotype. Samples of biceps femoris muscle (BFM, type I and longissimus dorsi muscle (LDM, type II were collected at nursery, growing, and finishing phases according to the physiological stage of each genotype, to determine the AA concentrations, mRNA levels for growth-related genes in muscles, and protein abundances of mechanistic target of rapamycin (mTOR signaling pathway. Our data showed that the concentrations of most AAs in LDM and BFM of pigs increased (P<0.05 gradually with increasing age. Bama mini-pigs had generally higher (P<0.05 muscle concentrations of flavor-related AA, including Met, Phe, Tyr, Pro, and Ser, compared with Landrace pigs. The mRNA levels for myogenic determining factor, myogenin, myocyte-specific enhancer binding factor 2 A, and myostatin of Bama mini-pigs were higher (P<0.05 than those of Landrace pigs, while total and phosphorylated protein levels for protein kinase B, mTOR, and p70 ribosomal protein S6 kinases (p70S6K, and ratios of p-mTOR/mTOR, p-AKT/AKT, and p-p70S6K/p70S6K were lower (P<0.05. There was a significant pig genotype-dependent effect of dietary protein on the levels for mTOR and p70S6K. When compared with the higher protein-NRC diet, the lower protein-GB diet increased (P<0.05 the levels for mTOR and p70S6K in Bama mini-pigs, but
Sites That Can Produce Left-Handed Amino Acids in the Supernova Neutrino Amino Acid Processing Model
Boyd, Richard N.; Famiano, Michael A.; Onaka, Takashi; Kajino, Toshitaka
The Supernova Neutrino Amino Acid Processing model, which uses electron anti-neutrinos and the magnetic field from a source object such as a supernova to selectively destroy one amino acid chirality, is studied for possible sites that would produce meteoroids having partially left-handed amino acids. Several sites appear to provide the requisite magnetic field intensities and electron anti-neutrino fluxes. These results have obvious implications for the origin of life on Earth.
Sites that Can Produce Left-handed Amino Acids in the Supernova Neutrino Amino Acid Processing Model
Boyd, Richard N.; Famiano, Michael A.; Onaka, Takashi; Kajino, Toshitaka
The Supernova Neutrino Amino Acid Processing model, which uses electron anti-neutrinos and the magnetic field from a source object such as a supernova to selectively destroy one amino acid chirality, is studied for possible sites that would produce meteoroids with partially left-handed amino acids. Several sites appear to provide the requisite magnetic field intensities and electron anti-neutrino fluxes. These results have obvious implications for the origin of life on Earth.
New Insights into Effects of Aromatic Amino Acids on Hydroxyapatite.
Guo, Y R; Yang, X; Feng, X W; Sa, Y; Wang, M; Li, P; Jiang, T
Biomimetics inspired by superstructures and extraordinary properties of teeth have resulted in tooth repair and the generation of novel materials. However, little attention has been paid to tooth color, whose origin remains unknown. Based on recent studies, fluorophores-mainly aromatic amino acids (AAAs) in proteins-might be responsible for tooth color. We synthesized carbonated hydroxyapatite (HA; the mineral phase of teeth) in the presence of different amino acids (AAs; the basic units of protein matrix of teeth) as a simplified model of teeth to explore the color source at the AA level. After measuring the fluorescence and color characteristics of HA-AAs before and after bleaching treatment, we found that only HA, synthesized in the presence of AAAs, exhibited remarkable fluorescence and color property. Furthermore, linearly increased fluorescence intensity and deeper color were observed with an increase in AAA content in HA-AAAs. Similarly, significantly decreased absorbance of HA-AAAs between 250 and 300 nm in ultraviolet spectra, declined fluorescence intensity, and decolored performance of HA-AAAs were observed after bleaching treatment. The results showed that AAAs contributed to the fluorescence and color properties of HA and that hydrogen peroxide might whiten HA-AAAs by oxidizing the benzene ring in AAAs. These findings are of great significance in promoting the synthesis of advanced tooth-colored materials and furthering our understanding of the possible mechanisms of hydrogen peroxide. Moreover, our study shed light on the importance of AAAs and might provide new ideas for investigations of biomineralization and biomimetics.
Amino acid catabolism by Lactobacillus helveticus in cheese
DEFF Research Database (Denmark)
Kananen, Soila Kaarina
and aromatic amino acids. After transamination of amino acids the formed a-keto acids may be dehydrogenased to hydroxy acids or converted to flavour compounds such as aldehydes, alcohols and carboxylic acids. The highest hydroxy acid dehydrogenase activities were detected towards central metabolites......Amino acid catabolism is the final step in the conversion of caseins to flavour compounds and a part of a complex combination of biochemical pathways in cheese flavour formation. Lactobacillus helveticus is a thermophilic lactic acid bacterium that is used in cheese manufacture as a primary starter...... culture or as an adjunct culture. It has shown high proteolytic activities in conversion of caseins to peptides and further to amino acids and flavour compounds. Better understanding of the enzyme activity properties and the influence of different properties on final cheese flavour is favourable...
Activation of mTORC1 by leucine is potentiated by branched-chain amino acids and even more so by essential amino acids following resistance exercise
DEFF Research Database (Denmark)
Moberg, Marcus; Apró, William; Ekblom, Björn
Protein synthesis is stimulated by resistance exercise and intake of amino acids, in particular leucine. Moreover, activation of mammalian target of rapamycin complex 1 (mTORC1) signaling by leucine is potentiated by the presence of other essential amino acids (EAA). However, the contribution...... of the branched-chain amino acids (BCAA) to this effect is yet unknown. Here we compare the stimulatory role of leucine, BCAA, and EAA ingestion on anabolic signaling following exercise. Accordingly, eight trained volunteers completed four sessions of resistance exercise during which they ingested either placebo......, leucine, BCAA, or EAA (including the BCAA) in random order. Muscle biopsies were taken at rest, immediately after exercise, and following 90 and 180 min of recovery. Following 90 min of recovery the activity of S6 kinase 1 (S6K1) was greater than at rest in all four trials (PlaceboLeucine
Teaching old NCATs new tricks: using non-canonical amino acid tagging to study neuronal plasticity
Hinz, FI; Dieterich, DC; Schuman, EM
The non-canonical amino acid labeling techniques BONCAT (bioorthogonal non-canonical amino acid tagging) and FUNCAT (fluorescent non-canonical amino acid tagging) enable the specific identification and visualization of newly synthesized proteins. Recently, these techniques have been applied to neuronal systems to elucidate protein synthesis dynamics during plasticity, identify stimulation-induced proteomes and subproteomes and to investigate local protein synthesis in specific subcellular compartments. The next generation of tools and applications, reviewed here, includes the development of new tags, the quantitative identification of newly synthesized proteins, the application of NCAT to whole animals, and the ability to genetically restrict NCAT labeling. These techniques will enable not only improved detection but also allow new scientific questions to be tackled. PMID:23938204
Amino Acid compositions of 27 food fishes and their importance in clinical nutrition.
Mohanty, Bimal; Mahanty, Arabinda; Ganguly, Satabdi; Sankar, T V; Chakraborty, Kajal; Rangasamy, Anandan; Paul, Baidyanath; Sarma, Debajit; Mathew, Suseela; Asha, Kurukkan Kunnath; Behera, Bijay; Aftabuddin, Md; Debnath, Dipesh; Vijayagopal, P; Sridhar, N; Akhtar, M S; Sahi, Neetu; Mitra, Tandrima; Banerjee, Sudeshna; Paria, Prasenjit; Das, Debajeet; Das, Pushpita; Vijayan, K K; Laxmanan, P T; Sharma, A P
Proteins and amino acids are important biomolecules which regulate key metabolic pathways and serve as precursors for synthesis of biologically important substances; moreover, amino acids are building blocks of proteins. Fish is an important dietary source of quality animal proteins and amino acids and play important role in human nutrition. In the present investigation, crude protein content and amino acid compositions of important food fishes from different habitats have been studied. Crude protein content was determined by Kjeldahl method and amino acid composition was analyzed by high performance liquid chromatography and information on 27 food fishes was generated. The analysis showed that the cold water species are rich in lysine and aspartic acid, marine fishes in leucine, small indigenous fishes in histidine, and the carps and catfishes in glutamic acid and glycine. The enriched nutrition knowledge base would enhance the utility of fish as a source of quality animal proteins and amino acids and aid in their inclusion in dietary counseling and patient guidance for specific nutritional needs.
Amino Acid Compositions of 27 Food Fishes and Their Importance in Clinical Nutrition
Directory of Open Access Journals (Sweden)
Bimal Mohanty
Full Text Available Proteins and amino acids are important biomolecules which regulate key metabolic pathways and serve as precursors for synthesis of biologically important substances; moreover, amino acids are building blocks of proteins. Fish is an important dietary source of quality animal proteins and amino acids and play important role in human nutrition. In the present investigation, crude protein content and amino acid compositions of important food fishes from different habitats have been studied. Crude protein content was determined by Kjeldahl method and amino acid composition was analyzed by high performance liquid chromatography and information on 27 food fishes was generated. The analysis showed that the cold water species are rich in lysine and aspartic acid, marine fishes in leucine, small indigenous fishes in histidine, and the carps and catfishes in glutamic acid and glycine. The enriched nutrition knowledge base would enhance the utility of fish as a source of quality animal proteins and amino acids and aid in their inclusion in dietary counseling and patient guidance for specific nutritional needs.
Photolabile protection for amino acids: studies on the release from novel benzoquinolone cages.
Fonseca, Andrea S C; Soares, Ana M S; Gonçalves, M Sameiro T; Costa, Susana P G
The synthesis of a novel fused nitrogen heterocycle, benzoquinolone, for evaluation as a photocleavable protecting group is described for the first time by coupling to model amino acids (alanine, phenylalanine and glutamic acid). Conversion of the phenylalanine ester conjugate to the thionated derivative was accomplished by reaction with Lawesson's reagent. Photocleavage studies of the carbonyl and thiocarbonyl benzoquinolone conjugates in various solvents and at different wavelengths (300, 350 and 419 nm) showed that the most interesting result was obtained at 419 nm for the thioconjugate, revealing that the presence of the thiocarbonyl group clearly improved the photolysis rates, giving practicable irradiations times for the release of the amino acids (less than 1 min).
Free amino acids in botanicals and botanical preparations.
Carratù, B; Boniglia, C; Giammarioli, S; Mosca, M; Sanzini, E
Numerous studies were carried out about aminoacidic composition of vegetable proteins, but information about the free amino acid pool and the role of these substances is very incomplete. The aim of this paper was to contribute to the scarce knowledge concerning the composition of free amino acids in botanicals and botanical preparations widely used as food, in dietary supplements, and in pharmaceutical products. This work studied the composition of free amino acids, identified the major components of 19 species of plants, and evaluated the influence of different types of extraction on the amino acid profile. Amino acids were determined using an automatic precolumn derivatization with fluorenylmethyl-chloroformate and reversed-phase liquid chromatography with fluorescence and ultraviolet detection. The amounts of total free amino acids varied widely between plants, from approximately 12 g in 100 g of Echinacea pallida extract to less than 60 mg in the same amount of Coleus forskohlii, Garcinia cambogia, and Glycine max. In 13 plants arginine, asparagine, glutamine, proline, and gamma-aminobutyric acid were the free amino acids found in preponderant quantities. The levels of free amino acids above the quantification limit in 36 assayed samples of botanicals, extracts, and supplements are shown.
Study of the chemistry of amino acids with respect to their utility in isotopic syntheses using 14C labelled compounds
International Nuclear Information System (INIS)
The paper deals with studies on amino acid chemistry from the point of their usefulness in the preparation of compounds having similar carbon skeleton with modification in functional groups. With the help of (U- 14 C) labelled amino acids, the following reactions were studied: (1) nitrous acid deamination, (2) reduction using hydriodic acid, (3) cleavage of β-hydroxy α-amino acid using periodate and (4) oxidation of proline by pyridine chloro chromate. The paper also highlights the advantages of chemical synthesis when combined with biologically produced labelled substrates. (author)
1,2,3-triazolyl amino acids as AMPA receptor ligands
DEFF Research Database (Denmark)
Stanley, Nathan J.; Pedersen, Daniel Sejer; Nielsen, Birgitte
The central nervous system glutamate receptors are an important target for drug discovery. Herein we report initial investigations into the synthesis and glutamate receptor activity of 1,2,3-triazolyl amino acids. Two compounds were found to be selective AMPA receptor ligands, which warrant further...
Novel 3-carboxy- and 3-phosphonopyrazoline amino acids as potent and selective NMDA receptor antagonists
DEFF Research Database (Denmark)
Conti, Paola; Pinto, Andrea; Tamborini, Lucia
The design and synthesis of new N1-substituted 3-carboxy- and 3-phosphonopyrazoline and pyrazole amino acids that target the glutamate binding site of NMDA receptors are described. An analysis of the stereochemical requirements for high-affinity interaction with these receptors was performed. We...
Amino acids, independent of insulin, attenuate skeletal muscle autophagy in neonatal pigs during endotoxemia
Sepsis induces loss of skeletal muscle mass by activating the ubiquitin proteasome (UPS) and autophagy systems. Although muscle protein synthesis in healthy neonatal piglets is responsive to amino acids (AA) stimulation, it is not known if AA can prevent the activation of muscle protein degradation ...
Penicillin-insensitive incorporation of D-amino acids into cell wall peptidoglycan influences the amount of bound lipoprotein in Escherichia coli.
Tsuruoka, T; Tamura, A; Miyata, A; Takei, T; Iwamatsu, K; Inouye, S; Matsuhashi, M
Certain D-amino acids, such as D-methionine and D-cystine, were incorporated into cells of Escherichia coli under conditions inhibiting protein and cell wall synthesis. Part of the radioactivity of D-14C-amino acids incorporated into the cells was found in the isolated cell wall peptidoglycan. A covalent linkage between the amino group of the D-amino acids and the peptidoglycan was presumed to be the main cause of the binding of the D-amino acids to peptidoglycan, because the amino group of t...
Synthesis of 2-amino-4-chromene derivatives under microwave ...
Indian Academy of Sciences (India)
... amount of ammonium acetate under microwave irradiation. The protocol offers rapid synthesis of structurally diverse 2-amino-4-chromenes for biological screening. All the synthesized compounds were evaluated for their antimicrobial activity, and several compounds exhibited moderate to potent antimicrobial activity.
Genetic analysis of amino acid content in wheat grain
Indian Academy of Sciences (India)
Aug 22, 2014 ... Therefore, it is important to enhance the level of nutrition in food by increasing the protein content of wheat, especially improving the amino acid composition of protein. Contents of wheat grain amino acids are quantitative traits, controlled by many genes, and their genetic basis was. ∗For correspondence.

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