Association of creatine kinase with rat heart mitochondria: high and low affinity binding sites and the involvement of phospholipids.

: Cleavage of mitochondrial phosphatidylethanolamine (PE), phosphatidylcholine (PC) and cardiolipin (CL) by phospholipase A2 but not selective degradation of PE and PC by phospholipase C dissociates creatine kinase from rat heart mitochondria. Creatine kinase exhibits a high resistance against Triton X-100 solubilization up to concentrations of 0.05-0.1%. Scatchard plot of rebinding experiments using mitoplasts revealed the presence of both low and high affinity binding sites; the latter may account for the originally bound creatine kinase activity. It is suggested that creatine kinase is specifically bound to a CL containing domain of the inner mitochondrial membrane.