Glycosyltransferase activities of Ehrlich ascites tumor cells: Detection, isolation, and characterization using oligosaccharide-Synsorb beads

Abstract

Detergent extracts of Ehrlich tumor cell membranes exhibit a host of glycosyltransferase activities which have been investigated using oligosaccharides immobilized to Synsorb beads as acceptors. Glycosidase digestions in combination with methylation analysis of the insoluble products have demonstrated the presence of an [alpha](1,3)-galactosyltransferase and a [beta](1,3)-N-acetylglucosaminyltransferase, enzymes that utilize N-acetyllactosamine as their acceptor substrate. The two enzymes are presumably involved in the biosynthesis of [alpha]--galactosyl-terminated poly-N-acetyllactosamine glycans that occur on the surface of Ehrlich cells. In addition, a [beta]-galactosyltransferase acting on N-acetylglucosamine and a separate [beta]-N-acetylglucosaminyltransferase that is capable of incorporating GlcNAc into the trisaccharide [beta]--GlcNAc(1,3)-[beta]--Gal(1,4)-[beta]--Glc-Synsorb have been identified. The Ehrlich cell [alpha]- and [beta]-galactosyltransferases have been separated by chromatography on [beta]-GlcNAc-Synsorb beads. In the presence of MnCl2 and UDP the [beta]-galactosyltransferase is specifically adsorbed to the monosaccharide column whereas the [alpha]-galactosyltransferase passes through unretarded.