Thyroxine deiodination associated with NADPH-dependent lipid peroxidation in a submicrosomal system.
A lipoprotein present in trypsin-treated microsomes can be oxidized with formation of malondialdehyde in a system which contains NADPH, ferric ion-ADP complex, NADPH-cytochrome c reductase and a factor. This factor, a mixture of peptides, can be isolated from hepatic microsomes by trypsin digestion and successive gel filtration through Sephadex G-100 and G-25 columns. Lipid peroxidation in this system catalyzes the deiodination of thyroxine, as does NADPH-dependent lipid peroxidation in fresh hepatic microsomes. Thyroxine inhibits lipid peroxidation as it is deiodinated in this system.
D000818:Animals; D002845:Chromatography; D002850:Chromatography, Gel; D007455:Iodine / Q000378:metabolism; D008074:Lipoproteins / Q000378:metabolism; D008862:Microsomes, Liver / Q000032:analysis / Q000201:enzymology / Q000378:metabolism*; D009249:NADP / Q000378:metabolism; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D010455:Peptides / Q000032:analysis; D051381:Rats; D013974:Thyroxine / Q000378:metabolism*
D008074:Lipoproteins; D010455:Peptides; D009249:NADP; D007455:Iodine; D009251:NADPH-Ferrihemoprotein Reductase; D013974:Thyroxine