The Biosynthesis of Blood‐Group‐B Character on Human O‐Erythrocytes by a Soluble α‐Galactosyltransferase from Milk

The enzyme α-galactosyltransferase from human milk catalysed the synthesis of B-character on blood-group-O erythrocytes. Erythrocytes from secretors and nonsecretors participated in this reaction to the same extent. Substances possessing H-active structure inhibited the acquisition of B-character by erythrocytes when added to the reaction mixture. The enzyme also incorporated galactose into isolated, water-soluble substances of erythrocytes with H-activity from secretors.