Cytochrome c oxidase depleted of subunit III: proton-pumping, respiratory control, and pH dependence of the midpoint potential of cytochrome a.


An examination of respiratory control, proton pumping, and the pH dependence of the redox potential of cytochrome a is reported for subunit III-depleted rat liver cytochrome oxidase prepared by chromatography in laurylmaltoside. The results indicate a facilitating rather than essential role for subunit III in these properties related to energy conservation.