Selenoprotein P (SeP) is an extracellular glycoprotein with 8-10 selenocysteines per molecule, containing approximately 50% of total selenium in human serum. An antioxidant function of SeP has been postulated. In the present study, we show that SeP protects low-density lipoproteins (LDL) against oxidation in a cell-free in-vitro system. LDL were isolated from human blood plasma and oxidized with CuCl2, 2,2'-azobis(2-amidinopropane) (AAPH) or peroxynitrite in the presence or absence of SeP, using the formation of conjugated dienes as parameter for lipid peroxidation. SeP delayed the CuCl2- and AAPH-induced LDL oxidation significantly and more efficiently than bovine serum albumin used as control. In contrast, SeP was not capable of inhibiting peroxynitrite-induced LDL oxidation. The protection of LDL against CuCl2- and AAPH-induced oxidation provides evidence for the antioxidant capacity of SeP. Because SeP associates with endothelial membranes, it may act in vivo as a protective factor inhibiting the oxidation of LDL by reactive oxygen species.
Selenoprotein P ( SeP ) is an extracellular glycoprotein with 8 - 10 selenocysteines per molecule , containing approximately 50 % of total selenium in human serum . An antioxidant function of SeP has been postulated . In the present study , we show that SeP protects low - density lipoproteins ( LDL ) against oxidation in a cell - free in - vitro system . LDL were isolated from human blood plasma and oxidized with CuCl2 , 2,2'-azobis(2-amidinopropane ) ( AAPH ) or peroxynitrite in the presence or absence of SeP , using the formation of conjugated dienes as parameter for lipid peroxidation . SeP delayed the CuCl2- and AAPH - induced LDL oxidation significantly and more efficiently than bovine serum albumin used as control . In contrast , SeP was not capable of inhibiting peroxynitrite - induced LDL oxidation . The protection of LDL against CuCl2- and AAPH - induced oxidation provides evidence for the antioxidant capacity of SeP. Because SeP associates with endothelial membranes , it may act in vivo as a protective factor inhibiting the oxidation of LDL by reactive oxygen species .
Which is the human selenoprotein that contains several Se-Cys residues?
Which is the human selenoprotein that contains several Se - Cys residues ?
Selenoprotein P
Selenoprotein P