Transfer of electrons from ferrocytochrome C to cytochrome c oxidase is facilated by enzyme-substrate complexes stabilized by salt bridges. Computer simulations were employed to identify residues that participate in intermolecular salt bridges.

Cytochrome c oxidase (COX) employs electrons obtained from cytochrome c to reduce oxygen to water. Recently, we proposed that electrons travel from cytochrome c to CuA of COX, by a hydrogen/hydride ion relay. Now, on the basis of a similar computer study, we conclude that this hydride/hydrogen ion mechanism is common to other oxidases.