Glycosyltransferase Activities in Normal and Polyoma-transformed BHK Cells

Normal (BHK 21-C13) and polyoma-transformed (BHK 21-C13/PyH3) baby hamster kidney fibroblasts were assayed for several glycosyltransferases involved in the synthesis of glycoproteins and gangliosides. Glycosyltransferase activities in the polyoma-transformed cells were generally reduced to between 36 and 87% of those of normal cells; however, the activity of the sialyltransferase catalyzing the formation of hematoside (N-acetylneuraminylgalactosylglucosylceramide) from lactosylceramide and cytidine monophospho-N-acetylneuraminic acid (CMP-NAN) was reduced to about 15%. Activity of this sialyltransferase from normal cells was considerably enhanced by the addition of phosphatidyl-glycerol or cardiolipin to the incubation medium, whereas these lipids showed little or no effect on the sialyltransferase from transformed cells.