Reconstituted microsomal lipid peroxidation: ADP-Fe3+-dependent peroxidation of phospholipid vesicles containing NADPH-cytochrome P450 reductase and cytochrome P450.
A reconstituted lipid peroxidation system consisting of rat liver microsomal NADPH-cytochrome P450 reductase and cytochrome P450 incorporated into phospholipid vesicles was developed and characterized. Peroxidation of the vesicles required NADPH and ADP-Fe3+, just as in the NADPH-dependent peroxidation of microsomes. The peroxidation of the vesicles was inhibited 30-50% by superoxide dismutase, depending upon their cytochrome P450 content: those with higher cytochrome P450 contents exhibited greater rates of malondialdehyde formation which were less sensitive to inhibition by superoxide dismutase. When cytochrome P450 was incorporated into vesicles, EDTA-Fe3+ was not required for lipid peroxidation, distinguishing this system from the one previously described by Pederson and Aust [Biochem. Biophys. Res. Comm. 48, 789; 1972]. Since at least 50% of the malondialdehyde formation in the vesicular system was not inhibited by superoxide dismutase, alternative means of iron reduction (O2-.-independent) were examined. It was found that rat liver microsomes or a reconstituted mixed function oxidase system consisting of NADPH-cytochrome P450 reductase and cytochrome P450 in dilauroylphosphatidylcholine micelles reduced ADP-Fe3+ under anaerobic conditions.
D000244:Adenosine Diphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004492:Edetic Acid / Q000494:pharmacology; D004579:Electron Transport; D005290:Ferric Compounds / Q000494:pharmacology; D008054:Lipid Peroxides / Q000378:metabolism*; D008081:Liposomes / Q000378:metabolism*; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008862:Microsomes, Liver / Q000378:metabolism*; D009249:NADP / Q000494:pharmacology; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism*; D010084:Oxidation-Reduction; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013482:Superoxide Dismutase / Q000494:pharmacology
D005290:Ferric Compounds; D008054:Lipid Peroxides; D008081:Liposomes; D010743:Phospholipids; C029936:adenosine diphosphate-ferric chelate; D008315:Malondialdehyde; D009249:NADP; D000244:Adenosine Diphosphate; D003577:Cytochrome P-450 Enzyme System; D004492:Edetic Acid; D013482:Superoxide Dismutase; D009251:NADPH-Ferrihemoprotein Reductase; C019179:Fe(III)-EDTA