The mechanistic H+ O ejection stoichiometry of the cytochrome c oxidase reaction in rat liver miloplasts is close to 4 at level flow when the reduced oxidase is pulsed with O2. Dicyclohexylcarbodiimide (DCCD) up to 30 nmol mg protein fails to influence the rate of electron flow through the mitoplast oxidase, but inhibits H+ ejection. The inhibition of H+ ejection appears to be biphasic; ejection of 2-3 H+ per O is completely inhibited by very low DCCD, whereas inhibition of the remaining H+ ejection requires very much higher concentrations of DCCD. This effect suggests the occurrence of two types of H+ pumps in the native cytochrome oxidase of mitoplasts.
ASJC Scopus subject areas
- Inorganic Chemistry