Mechanism of cobalt (II) ion inhibition of iron-supported phospholipid peroxidation.
Co2+ inhibited nonenzymatic iron chelate-dependent lipid peroxidation in dispersed lipids, such as ascorbate-supported lipid peroxidation, but not iron-independent lipid peroxidation. Histidine partially abolished the Co2+ inhibition of the iron-dependent lipid peroxidation. The affinity of iron for phosphatidylcholine liposomes in Fe(2+)-PPi-supported systems was enhanced by the addition of an anionic lipid, phosphatidylserine, and Co2+ competitively inhibited the peroxidation, while the inhibiting ability of Co2+ as well as the peroxidizing ability of Fe(2+)-PPi on liposomes to which other phospholipids, phosphatidylethanolamine, or phosphatidylinositol had been added was reduced. Co2+ inhibited microsomal NADPH-supported lipid peroxidation monitored in terms of malondialdehyde production and the peroxidation monitored in terms of oxygen consumption. The inhibitory action of Co2+ was not associated with iron reduction or NADPH oxidation in microsomes, suggesting that Co2+ does not affect the microsomal electron transport system responsible for lipid peroxidation. Fe(2+)-PPi-supported peroxidation of microsomal lipid liposomes was markedly inhibited by Co2+.
Tampo
Y
Y
Division of Environmental Hygiene, Hokkaido Institute of Pharmaceutical Sciences, Japan.
Yonaha
M
M
D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D001667:Binding, Competitive; D002413:Cations, Divalent; D003035:Cobalt / Q000494:pharmacology*; D006639:Histidine / Q000494:pharmacology; D007501:Iron / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects*; D008081:Liposomes / Q000378:metabolism; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008862:Microsomes, Liver / Q000378:metabolism; D009249:NADP / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects; D010713:Phosphatidylcholines / Q000378:metabolism; D010718:Phosphatidylserines / Q000494:pharmacology; D010743:Phospholipids / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D001095:Arachidonic Acids; D002413:Cations, Divalent; D008081:Liposomes; D010713:Phosphatidylcholines; D010718:Phosphatidylserines; D010743:Phospholipids; D016718:Arachidonic Acid; D003035:Cobalt; D006639:Histidine; D008315:Malondialdehyde; D009249:NADP; D007501:Iron