Synthesis and enzymatic evaluation of modified accepters of recombinant blood group A and B glycosyltransferases

The disaccharide alpha-L-Fucp-(1 --> 2)-beta-D-Galp-(1 --> 0)-Octyl (1) is an acceptor for the human blood group A and B glycosyltransferases. Seven a nalogues of 1, containing deoxy, methoxy and arabino modifications of the F uc residue, were chemically synthesized and kinetically evaluated in radioa ctive enzymatic assays. Both the enzymes tolerate modification of the 3'-OH on the fucose residue. The 2'-OH was found to be key to the recognition of the accepters by these enzymes. The arabine derivative was recognized as a n acceptor by the A transferase (K-m of 200 mu M), but not the B transferas e and is the first synthetic acceptor capable of distinguishing between the two enzyme activities. (C) 2000 Elsevier Science Ltd. All rights reserved.