Instruct: Given a question, retrieve documents that answer the question.
Query: Is oxidative phosphorylation new?
The field of oxidative phosphorylation began with the report in 1906 by Arthur Harden of a vital role for phosphate in cellular fermentation, but initially only sugar phosphates were known to be involved. However, in the early 1940s, the link between the oxidation of sugars and the generation of ATP was firmly established by Herman Kalckar, confirming the central role of ATP in energy transfer that had been proposed by Fritz Albert Lipmann in 1941. Later, in 1949, Morris Friedkin and Albert L. Lehninger proved that the coenzyme NADH linked metabolic pathways such as the citric acid cycle and the synthesis of ATP. The term "oxidative phosphorylation" was coined by in 1939.
The term "biochemistry" itself is derived from a combination of biology and chemistry. In 1877, Felix Hoppe-Seyler used the term ("biochemie" in German) as a synonym for physiological chemistry in the foreword to the first issue of "Zeitschrift für Physiologische Chemie" (Journal of Physiological Chemistry) where he argued for the setting up of institutes dedicated to this field of study. The German chemist Carl Neuberg however is often cited to have coined the word in 1903, while some credited it to Franz Hofmeister.
It was once generally believed that life and its materials had some essential property or substance (often referred to as the "vital principle") distinct from any found in non-living matter, and it was thought that only living beings could produce the molecules of life. Then, in 1828, Friedrich Wöhler published a paper on the synthesis of urea, proving that organic compounds can be created artificially. Since then, biochemistry has advanced, especially since the mid-20th century, with the development of new techniques such as chromatography, X-ray diffraction, dual polarisation interferometry, NMR spectroscopy, radioisotopic labeling, electron microscopy, and molecular dynamics simulations. These techniques allowed for the discovery and detailed analysis of many molecules and metabolic pathways of the cell, such as glycolysis and the Krebs cycle (citric acid cycle), and led to an understanding of biochemistry on a molecular level. Philip Randle is well-known for his discovery in diabetes research is possibly the glucose-fatty acid cycle in 1963.He confirmed that fatty acids reduce oxidation of sugar by the muscle. High fat oxidation was responsible for the insulin resistance.
NADH-coenzyme Q oxidoreductase, also known as "NADH dehydrogenase" or "complex I", is the first protein in the electron transport chain. Complex I is a giant enzyme with the mammalian complex I having 46 subunits and a molecular mass of about 1,000 kilodaltons (kDa). The structure is known in detail only from a bacterium; in most organisms the complex resembles a boot with a large "ball" poking out from the membrane into the mitochondrion. The genes that encode the individual proteins are contained in both the cell nucleus and the mitochondrial genome, as is the case for many enzymes present in the mitochondrion.
Christian de Duve coined the term autophagy in 1963 whereas Ohsumi began his work in 1988. Prior to that time, less than 20 papers per year were published on this subject. During the 1990s, Ohsumi's group described the morphology of autophagy in yeast, and performed mutational screening on yeast cells that identified essential genes for cells to be capable of autophagy.
Mitophagy is the selective degradation of mitochondria by autophagy. It often occurs to defective mitochondria following damage or stress. The process of mitophagy was first described over a hundred years ago by Lewis and Lewis. Ashford and Porter used electron microscopy to observe mitochondrial fragments in liver lysosomes by 1962, and a 1977 report suggested that "mitochondria develop functional alterations which would activate autophagy." The term "mitophagy" was in use by 1998.
The above figure illustrates the proposed mechanism for oxidation by the White–Chen catalyst. The reaction proceeds in conjunction with hydrogen peroxide oxidant and acetic acid. The catalyst quickly reacts with hydrogen peroxide, believed to be catalyzed by the acetic acid, and forms and iron-oxo intermediate. The iron-oxo intermediate is then thought to abstract a hydrogen on the carbon to be oxidized to generate a short-lived carbon centered radical. The iron-hydroxide then quickly rebounds onto the carbon centered radical to form the oxidized compound. Recently, direct evidence was obtained for a carbon-centered radical intermediate in this reaction using a Taxane-based radical trap. It is important to note that these reactions (both directed and non-directed) proceed with complete retention of stereochemistry, as is often observed in reactions where radical rebound is rapid enough that epimerization does not happen.
Autophagy was first observed by Keith R. Porter and his student Thomas Ashford at the Rockefeller Institute. In January 1962 they reported an increased number of lysosomes in rat liver cells after the addition of glucagon, and that some displaced lysosomes towards the centre of the cell contained other cell organelles such as mitochondria. They called this autolysis after Christian de Duve and Alex B. Novikoff. However Porter and Ashford wrongly interpreted their data as lysosome formation (ignoring the pre-existing organelles). Lysosomes could not be cell organelles, but part of cytoplasm such as mitochondria, and that hydrolytic enzymes were produced by microbodies. In 1963 Hruban, Spargo and colleagues published a detailed ultrastructural description of "focal cytoplasmic degradation," which referenced a 1955 German study of injury-induced sequestration. Hruban, Spargo and colleagues recognized three continuous stages of maturation of the sequestered cytoplasm to lysosomes, and that the process was not limited to injury states that functioned under physiological conditions for "reutilization of cellular materials," and the "disposal of organelles" during differentiation. Inspired by this discovery, de Duve christened the phenomena "autophagy". Unlike Porter and Ashford, de Duve conceived the term as a part of lysosomal function while describing the role of glucagon as a major inducer of cell degradation in the liver. With his student Russell Deter, he established that lysosomes are responsible for glucagon-induced autophagy. This was the first time the fact that lysosomes are the sites of intracellular autophagy are established.
The name "autophagy" was coined by Belgian biochemist Christian de Duve in 1963 based on his discovery of the functions of lysosome. The identification of autophagy-related genes in yeast in the 1990s let researchers figure out the mechanisms of autophagy, which eventually led to the award of the 2016 Nobel Prize in Physiology or Medicine to Japanese researcher Yoshinori Ohsumi.
5("S")-HETE may also be made in combination with 5("R")-HETE along with numerous other "(S,R)"-hydroxy polyunsaturated fatty acids as a consequence of the non-enzymatic oxidation reactions. Formation of these products can occur in any tissue subjected to oxidative stress.
The processes of oxidation and reduction occur simultaneously and cannot happen independently of one another, similar to the acid–base reaction. The oxidation alone and the reduction alone are each called a "half-reaction", because two half-reactions always occur together to form a whole reaction. When writing half-reactions, the gained or lost electrons are typically included explicitly in order that the half-reaction be balanced with respect to electric charge.
In 1967, it was discovered that mitochondria contained ribosomes. In 1968, methods were developed for mapping the mitochondrial genes, with the genetic and physical map of yeast mitochondrial DNA being completed in 1976.
ERRα regulates genes involved in mitochondrial biogenesis, gluconeogenesis, oxidative phosphorylation, and fatty acid metabolism, and brown adipose tissue thermogenesis. It was recently identified as an important regulator of the mammalian circadian clock, and its output pathways at both transcriptional and physiological levels regulated the expression of transcription factors involved in metabolic homeostasis. It has been demonstrated that ERRα is required for the maintenance of diurnal cholesterol, glucose, insulin, bile acid, and trygliceride levels as well as locomotor rhythms in mice. ERRα is related to mitochondrial function but studies involving ERRα knockout mice suggested that this receptor, while dispensable for basal cellular function, is definitely necessary to provide the levels of energy necessary to respond to physiological and pathological insults in diverse tissues, the lack of that nuclear receptor leading to impaired fat metabolism and absorption.
This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O2 with 2-oxoglutarate as one donor, and incorporation of one atom o oxygen into each donor. The systematic name of this enzyme class is taurine, 2-oxoglutarate:O2 oxidoreductase (sulfite-forming). Other names in common use include 2-aminoethanesulfonate dioxygenase, and alpha-ketoglutarate-dependent taurine dioxygenase. This enzyme participates in taurine and hypotaurine metabolism. It has 3 cofactors: iron, Ascorbate, and Fe2+.
Mitochondrial DNA was discovered in the 1960s by Margit M. K. Nass and Sylvan Nass by electron microscopy as DNase-sensitive threads inside mitochondria, and by Ellen Haslbrunner, Hans Tuppy and Gottfried Schatz by biochemical assays on highly purified mitochondrial fractions.
Fatty acid synthesis is an anabolic process that starts from the conversion of acetyl-CoA to malonyl-CoA by acetyl-CoA carboxylase. Malonyl CoA leads to fatty acid synthesis (FAS) and is involved in the elongation of fatty acids through Fatty acid synthase (FASN). Although aerobic glycolysis is the best documented metabolic phenotype of tumor cells, it is not a universal feature of all human cancers. Amino acids and fatty acids have been shown to function as fuels for tumor cells to proliferate. The carnitine palmitoyltransferase enzymes that regulate the β-oxidation of fatty acids may have a key role in determining some of these phenotypes. Enhanced fatty acid synthesis provides lipids for membrane biogenesis to tumor cells and hence, it gives advantage in both growth and survival of the cell.
The oxygenator was first conceptualized in the 17th century by Robert Hooke and developed into practical extracorporeal oxygenators by French and German experimental physiologists in the 19th century. Bubble oxygenators have no intervening barrier between blood and oxygen, these are called 'direct contact' oxygenators. Membrane oxygenators introduce a gas-permeable membrane between blood and oxygen that decreases the blood trauma of direct-contact oxygenators. Much work since the 1960s focused on overcoming the gas exchange handicap of the membrane barrier, leading to the development of high-performance microporous hollow-fibre oxygenators that eventually replaced direct-contact oxygenators in cardiac theatres.
In the early 1950s, Alexander Todd’s group pioneered H-phosphonate and phosphate triester methods of oligonucleotide synthesis. The reaction of compounds 1 and 2 to form H-phosphonate diester 3 is an H-phosphonate coupling in solution while that of compounds 4 and 5 to give 6 is a phosphotriester coupling (see phosphotriester synthesis below).
The primary structure (amino acid sequence) is highly conserved among OCP sequences, and the full-length protein is usually co-located on the chromosome with the FRP at an adjacent locus. Often, biosynthetic genes for ketocarotenoid synthesis (e.g., CrtW) are nearby. These conserved functional linkages underscore the evolutionary importance of the OCP style of photoprotection for many cyanobacteria.
The first model known as the "syntrophic model" proposes that a symbiotic relationship between the archaea and bacteria created the nucleus-containing eukaryotic cell. (Organisms of the Archaea and Bacteria domain have no cell nucleus.) It is hypothesized that the symbiosis originated when ancient archaea, similar to modern methanogenic archaea, invaded and lived within bacteria similar to modern myxobacteria, eventually forming the early nucleus. This theory is analogous to the accepted theory for the origin of eukaryotic mitochondria and chloroplasts, which are thought to have developed from a similar endosymbiotic relationship between proto-eukaryotes and aerobic bacteria. The archaeal origin of the nucleus is supported by observations that archaea and eukarya have similar genes for certain proteins, including histones. Observations that myxobacteria are motile, can form multicellular complexes, and possess kinases and G proteins similar to eukarya, support a bacterial origin for the eukaryotic cell.
Organophosphates inhibit AChE, causing OP poisoning by phosphorylating the serine hydroxyl residue on AChE, which inactivates AChE. AChE is critical for nerve function, so the irreversible blockage of this enzyme, which causes acetylcholine accumulation, results in muscle overstimulation. This causes disturbances across the cholinergic synapses and can only be reactivated very slowly, if at all. Paraoxonase (PON1) is a key enzyme involved in OP pesticides and has been found to be critical in determining an organism's sensitivity to OP exposure.
Cell theory led biologists to re-envision individual organisms as interdependent assemblages of individual cells. Scientists in the rising field of cytology, armed with increasingly powerful microscopes and new staining methods, soon found that even single cells were far more complex than the homogeneous fluid-filled chambers described by earlier microscopists. Robert Brown had described the nucleus in 1831, and by the end of the 19th century cytologists identified many of the key cell components: chromosomes, centrosomes mitochondria, chloroplasts, and other structures made visible through staining. Between 1874 and 1884 Walther Flemming described the discrete stages of mitosis, showing that they were not artifacts of staining but occurred in living cells, and moreover, that chromosomes doubled in number just before the cell divided and a daughter cell was produced. Much of the research on cell reproduction came together in August Weismann's theory of heredity: he identified the nucleus (in particular chromosomes) as the hereditary material, proposed the distinction between somatic cells and germ cells (arguing that chromosome number must be halved for germ cells, a precursor to the concept of meiosis), and adopted Hugo de Vries's theory of pangenes. Weismannism was extremely influential, especially in the new field of experimental embryology.
Oxidative phosphorylation (UK , US ) is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing energy which is used to produce adenosine triphosphate (ATP). In most eukaryotes, this takes place inside mitochondria. Almost all aerobic organisms carry out oxidative phosphorylation. This pathway is probably so pervasive because it is a highly efficient way of releasing energy, compared to alternative fermentation processes such as anaerobic glycolysis.
The encoded protein (PHC) catalyzes the transport of phosphate from the cytosol into the mitochondrial matrix, either by proton cotransport or in exchange for hydroxyl ions. In the final steps of oxidative phosphorylation, this protein catalyzes the uptake of a phosphate ion with a proton across the mitochondrial inner membrane. The availability of inorganic phosphate for oxidative phosphorylation is mainly dependent on PHC activity. To substantially affect oxidative phosphorylation, PHC depletion must be severe, exceeding 85%. This protein may be involved in regulation of the mitochondrial permeability transition pore (mPTP).
Unlike oxidative phosphorylation, oxidation and phosphorylation are not coupled in the process of substrate-level phosphorylation, and reactive intermediates are most often gained in the course of oxidation processes in catabolism. Most ATP is generated by oxidative phosphorylation in aerobic or anaerobic respiration while substrate-level phosphorylation provides a quicker, less efficient source of ATP, independent of external electron acceptors. This is the case in human erythrocytes, which have no mitochondria, and in oxygen-depleted muscle.
Oxidative phosphorylation produces 26 of the 30 equivalents of ATP generated in cellular respiration by transferring electrons from NADH or FADH2 to O2 through electron carriers. The energy released when electrons are passed from higher-energy NADH or FADH2 to the lower-energy O2 is required to phosphorylate ADP and once again generate ATP. It is this energy coupling and phosphorylation of ADP to ATP that gives the electron transport chain the name oxidative phosphorylation.