Ectogalactosyltransferase. Presence of enzyme and acceptors on the rat lymphocyte cell surface.

Experiments are described to demonstrate the existence of ectogalactosyltransferase activity on the lymphocyte surface. The procedures described enable us to exclude the possibility of misleading results due to precursor hydrolysis and intracellular utilization of the free galactose. This depicted transferase is able to catalyse the transfer of a galactosyl residue from UDP-galactose to a nonphagocytosable exogenous acceptor and to endogenous membrane acceptors. The cells galactosylated in this way acquired new agglutinating properties with soybean agglutinin, which proves the external position of the galactosyl residues incorporated on the cell surface.