This computer based study leads to the conclusion that electrons arriving at the surface of cytochrome c oxidase migrate to the enzyme’s first active centre by a hydride ion relay system similar to that seen at the active site of chymotrypsin.

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.