Localization of some glycolipid glycosylating enzymes in the Golgi apparatus of rat kidney.

Cell fractions from rat kidney were isolated and studied for their ability to synthesize several possible intermediates in the biosynthesis of sulfatides and gangliosides. The enzymes studied include UDP-Gal:ceramide galactosyltransferase, UDP-Gal:glucosylceramide galactosyltransferase, UDP-Gal:galactosylceramide galactosyltransferase, and CMP-NAN:lactosylceramide sialytransferase activities. The initial glycosylation of ceramide was found to be present in all of the kidney cell fractions studied. The remaining glycosylating enzymes were largely localized in the Golgi apparatus of kidney. Thus, in addition to modifying glycoproteins for secretion, the Golgi apparatus in kidney is involved in the modification of a number of glycolipids which are destined to form cell membrane components.