THE SYNTHESIS OF β-GALACTO- AND β-GLUCO-PYRANOSYL DISACCHARIDES BY SPOROBOLOMYCES SINGULARIS

Abstract

Synthesis of β-D-galactopyranosyl disaccharides takes place in growing cultures of Sporobolomycessingularis containing lactose and a sugar acceptor. The products of galactosyl transfer using various acceptors arise mainly from substitution of secondary rather than primary hydroxyl groups. The minimal structural requirement for reaction with the acceptor appears to be a hydroxyl vicinal to the substituted hydroxyl group. A mechanism that accounts for the formation of secondary disaccharides is postulated.The organism also contains a β-glucosidase which transfers O-β-D-glucopyranosyl groups from cellobiose to sugar acceptors. The positions of the glycosidic linkages in the disaccharide products are identical with those formed in the corresponding galactosyl transfer reaction.