Reconstitution studies on the involvement of radiation-induced lipid peroxidation in damage to membrane enzymes.
The effect of radiation on the drug-metabolizing enzyme system of microsomes, reconstituted with liposomes of microsomal phospholipids, NADPH-cytochrome P-450 reductase and cytochrome P-450, was examined to elucidate the role of lipid peroxidation of membranes in radiation-induced damage to membrane-bound enzymes. The reconstituted system of non-irradiated enzymes with irradiated liposomes showed a low activity of hexobarbital hydroxylation, whereas irradiated enzymes combined with non-irradiated liposomes exhibited an activity equal to that of unirradiated controls. Irradiation of liposomes caused a decrease in cytochrome P-450 content by destruction of the haem of cytochrome P-450 and also inhibited the binding capacity of cytochrome P-450 for hexobarbital. The relationship between radiation-induced lipid peroxidation and membrane-bound enzymes is discussed.
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D006591:Hexobarbital / Q000378:metabolism; D008054:Lipid Peroxides / Q000378:metabolism; D008081:Liposomes / Q000528:radiation effects; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism; D008862:Microsomes, Liver / Q000201:enzymology / Q000528:radiation effects*; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism / Q000528:radiation effects; D051381:Rats; D011919:Rats, Inbred Strains
D008054:Lipid Peroxides; D008081:Liposomes; D008563:Membrane Lipids; D003577:Cytochrome P-450 Enzyme System; D006591:Hexobarbital; D009251:NADPH-Ferrihemoprotein Reductase