β-galactosidase catalysed transglycosylation in aqueous organic media using glycosylasparagine mimics as novel acceptors

beta-1-N-acetamido-D-glucopyranose (2), a model of N-glycoprotein linkage region, and its benzamido analogue were explored as novel accepters in transglycosylation catalysed by beta-galactosidase from Bacillus circulans. Acceptor ability of 2 was shown to be as good as or better than several O-glycosides employed earlier. Systematic variation of reaction conditions led to improvement of yield from 5% to 41%. Interestingly, use of aqueous organic media has led to increased yield of transglycosylation and the 1,3-linked disaccharide was formed in considerable amounts under all the conditions examined. (C) 1999 Elsevier Science Ltd. All rights reserved.