[Theoretical analysis of redox-dependent protonation of hema a and Cu(A) in cytochrome c oxidase and CO-inhibited binuclear center].

One of the proposed mechanisms of functioning of cytochrome c oxidase (COX) postulates that heme a is the element pumping protons across the membrane. It is generally believed that, to support this mechanism, a substantial proton uptake/release should exist upon heme a reduction/oxidation. Two direct measurements of proton uptake/release in oxidation/reduction of heme a in CO-bound mixed-valence COX were recently reported.