Characteristics and nature of redox-linked proton transfer reactions in cytochrome c oxidase of mitochondria.

A discussion is presented of the characteristics of proton transfer reactions associated to redox catalysis in mitochondrial cytochrome c oxidase. These properties are examined in the light of the mechanisms proposed for the conversion of redox energy into a transmembrane proton gradient. It is concluded that this energy transfer process is first of all due to the anisotropic arrangement of the reduction of oxygen to H2O in the oxidase. The experimental observations available seem, on the other hand, to raise doubts on the capacity of cytochrome oxidase to function under steady-state conditions, in the native membrane, as a proton pump.