Specific inhibition of redox-linked proton pump activity of cytochrome oxidase by oleate hydroperoxide and involvement of ferrocytochrome c in the catabolism of hydroperoxide.
Both oleic acid and oleate hydroperoxide at concentrations below 200 nmol/mg asolectin remarkably depressed the proton pumping of cytochrome c oxidase reconstituted into liposomes but did not affect the respiratory control ratio. The inhibitory effect was comparable to that of N,N'-dicyclohexylcarbodiimide. Oleate hydroperoxide in the vesicles was reduced by ferrocytochrome c in the absence of cytochrome oxidase and converted to the hydroxy fatty acid. This non-enzymatic oxidation of ferrocytochrome c affected slightly the proton pumping and the cytochrome c oxidation by liposomal cytochrome oxidase. A physiological role of ferrocytochrome c in catabolism of the hydroperoxide of fatty acids is thus suggested.
Yoshida
S
S
Research Laboratory Center, Medical College of Oita, Japan.
Miki
T
T
Orii
Y
Y
Takeshita
M
M
D000818:Animals; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002417:Cattle; D003574:Cytochrome c Group / Q000378:metabolism*; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D008054:Lipid Peroxides / Q000378:metabolism / Q000494:pharmacology*; D019301:Oleic Acid; D009829:Oleic Acids / Q000494:pharmacology; D010084:Oxidation-Reduction; D011522:Protons
D003574:Cytochrome c Group; D007473:Ion Channels; D008054:Lipid Peroxides; D009829:Oleic Acids; D011522:Protons; D019301:Oleic Acid; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D004024:Dicyclohexylcarbodiimide; D006861:Hydrogen Peroxide; D003576:Electron Transport Complex IV