Long-chain Carnitine Acyltransferase and the Role of Acylcarnitine Derivatives in the Catalytic Increase of Fatty Acid Oxidation Induced by Carnitine.

Carnitine-H3 or palmitate-U4 incubated with heart muscle preparations waa incorporated into a compound that had chromatographic behavior in several systems identical to that of palmitylcarnitine chemically synthesized from palmityl chloride and carnitine. Palmitylcarnitine biosynthesis from palmitic acid and carnitine was dependent upon ATP and CoA in addition to substrates and an enzyme preparation. In contrast, palmityl carnitine formation from palmityl CoA and carnitine did not require ATP or CoA. The following reaction, catalyzed by palmitylcarnitine transferase, was shown to be reversible: Palmitylcarnitine + Cod S palmityl CoA + carnitine.