The Metabolism of Ceramide Trihexosides

Abstract

An enzyme that catalyzes the hydrolysis of the terminal galactose molecule of galactosylgalactosylglucosylceramide has been demonstrated in brain, liver, kidney, spleen, and small intestine of the rat. The enzyme has been obtained in a highly enriched form from subcellular particles of small intestinal tissue. The purified enzyme is specific for galactosylgalactosylglucosylceramide and does not catalyze the hydrolysis of a number of related sphingolipids such as lactosylceramide, galactosylceramide, or glucosylceramide. The products of the reaction are galactose and lactosylceramide. The enzyme is noncompetitively inhibited by glucosylsphingosine (psychosine).