An essential requirement of cardiolipin for mitochondrial carnitine acylcarnitine translocase activity. Lipid requirement of carnitine acylcarnitine translocase.

The phospholipid requirement for the optimal solubilization of carnitine acylcarnitine translocase from the inner membrane vesicles of rat liver mitochondria and for its reconstitution in liposomes was investigated. At the octylglucoside-solubilization step, the presence of cardiolipin proved superior to the other lipids tested. For reconstitution, a mixture having phosphatidylcholine, phosphatidylethanolamine and cardiolipin was found to be particularly effective. The requirement of cardiolipin at this step was met less effectively by other anionic phospholipids. Moreover, in intact mitochondria of rat liver and heart, the translocase activity was markedly inhibited by micromolar concentrations of doxorubicin, a specific cardiolipin-binding agent.