Structural analyses of new tri- and tetrasaccharides produced from disaccharides by transglycosylation of purified Trichoderma viride beta-glucosidase

A new beta-glucosidase was partially purified from Trichoderma viride cellu lase. This beta-glucosidase catalyzed a transglycosylation reaction of cell obiose to give beta-D-Glc-(1 --> 6)-beta-D-Glc-(1 --> 4)-D-Glc (1, yield: 1 8.8%) and beta-D-Glc-(1 --> 6)-beta-D-Glc-(1 --> 6)-beta-D-Glc-(1 --> 4)-D- Glc (2, 3.7%), regioselectively. Furthermore, the enzyme regioselectively c onverted laminaribiose and gentiobiose into beta-D-Glc-(1 --> 6)-beta-D-Glc -(1 --> 3)-D-Glc (3, 15.3%) and beta-D-Glc-(1 --> 6)-beta-D-Glc-(1 --> 6)-D -Glc (4, 20.2%), respectively. The structures (1-4) of the products were de termined by H-1 and C-13 NMR spectroscopies. This high regio- and stereosel ectively of the beta-glucosidase could be applied for oligosaccharide synth esis. [GRAPHICS]