Specific inhibition of redox-linked proton pump activity of cytochrome oxidase by oleate hydroperoxide and involvement of ferrocytochrome c in the catabolism of hydroperoxide. |
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Authors: | S Yoshida T Miki Y Orii M Takeshita |
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Institution: | Research Laboratory Center, Medical College of Oita, Japan. |
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Abstract: | 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. |
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