METHYL -(1-]4)-2-ACETAMIDO-2-DEOXY-BETA-D-GLUCOPYRANOSIDE - AN INHIBITOR OF ACTOPYRANOSYL-(1-]4)-2-ACETAMIDO-2-DEOXY-D-GLUCOSE (1-]3)-ALPHA-D-GALACTOPYRANOSYLTRANSFERASE

UDP-D-galactose: beta-D-galactopyranosyl-(1 --> 4)-2-acetamido-2-deoxy -D-glucose alpha(1 --> 3)-D-galactopyranosyltransferase [E.C. 2.4.1.15 1] transfers D-galactosyl-residues from the sugar nucleotide with rete ntion of configuration. We report here that synthetic methyl 3'-amino- 3'-deoxy-N-acetyllactosaminide (9), where the hydroxyl group normally undergoing galactosylation has been replaced by amino group, is an inh ibitor for this enzyme with K-i = 104 mu M. The mode of inhibition is not competitive, but appears to be specific, since other glycosyltrans ferases were not affected by 9.