Antioxidant activity of albumin-bound bilirubin.
Bilirubin, when bound to human albumin and at concentrations present in normal human plasma, protects albumin-bound linoleic acid from peroxyl radical-induced oxidation in vitro. Initially, albumin-bound bilirubin (Alb-BR) is oxidized at the same rate as peroxyl radicals are formed and biliverdin is produced stoichiometrically as the oxidation product. On an equimolar basis, Alb-BR successfully competes with uric acid for peroxyl radicals but is less efficient in scavenging these radicals than vitamin C. These results show that 1 mol of Alb-BR can scavenge 2 mol of peroxyl radicals and that small amounts of plasma bilirubin are sufficient to prevent oxidation of albumin-bound fatty acids as well as of the protein itself. The data indicate a role for Alb-BR as a physiological antioxidant in plasma and the extravascular space.
D000975:Antioxidants / Q000097:blood*; D001663:Bilirubin / Q000097:blood*; D001664:Biliverdine / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D005609:Free Radicals; D006801:Humans; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000097:blood; D010084:Oxidation-Reduction; D012709:Serum Albumin; D013696:Temperature
D000975:Antioxidants; D005609:Free Radicals; D008041:Linoleic Acids; D012709:Serum Albumin; D019787:Linoleic Acid; D001664:Biliverdine; D001663:Bilirubin