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

Abstract

The disaccharide α- l-Fuc p-(1→2)-β- d-Gal p-(1→ O)-Octyl ( 1) is an acceptor for the human blood group A and B glycosyltransferases. Seven analogues of 1, containing deoxy, methoxy and arabino modifications of the Fuc residue, were chemically synthesized and kinetically evaluated in radioactive 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 acceptors by these enzymes. The arabino derivative was recognized as an acceptor by the A transferase ( K m of 200 μM), but not the B transferase and is the first synthetic acceptor capable of distinguishing between the two enzyme activities.