The Metabolism of Sphingomyelin

Abstract

A sphingomyelin-cleaving enzyme has been found in rat liver tissue. The enzyme, originally present in subcellular particulate fractions, could be released in a soluble form by treatment with appropriate detergents and was partially purified by conventional procedures. The most highly purified enzyme preparations catalyzed the hydrolysis of sphingomyelin, whereas lecithin and phosphatidylethanolamine were unaffected. The products of the reaction were identified as phosphorylcholine and ceramide. Lecithin was a competitive inhibitor of the reaction.