A simple strategy for changing the regioselectivity of glycosidase-catalysed formation of disaccharides.
The regioselectivity of glycosidase-catalysed formation of disaccharides can be changed by using alpha- or beta-glycosyl acceptors with various aglycons. The preponderant formation of other than (1----6) linkages can be effected with glycosidases which normally give (1----6) linkages. Thus, an alpha-D-galactosidase can be induced to catalyse the formation mainly of alpha-(1----2)-, alpha-(1----3), or alpha-(1----6)-linked digalactosides. Both the structure of the aglycon and the configuration of the glycosidic linkage can have a pronounced influence on the regioselectivity of disaccharide formation. Enzymic syntheses, in yields of 20-30%, are described of alpha-D-Galp-(1----3)-alpha-D-Galp-OMe, beta-D-Galp-(1----3)-beta-D-Galp-OMe, beta-D-Galp-(1----6)-alpha-D-Galp-OMe, alpha-D-Manp-(1----2)-alpha-D-Manp-OMe, alpha-D-Manp-(1----6)-alpha-D-Manp-OMe, alpha-D-Galp-(1----2)-alpha-D-Galp-OPhNO2-o, alpha-D-Galp-(1----3)-alpha-D-Galp-OPhNO2-p, alpha-D-Manp-(1----2)-alpha-D-Manp-OPhNO2-p, and alpha-D-Manp-(1----2)-alpha-D-Manp-(1----2)-alpha-D-Manp+ ++-OMe. Soluble and immobilised enzymes have been used.
Nilsson
K G
KG
Swedish Sugar Co. Ltd., Arlöv.
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000138:chemical synthesis*; D006026:Glycoside Hydrolases; D007202:Indicators and Reagents; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D009904:Optical Rotation; D013329:Structure-Activity Relationship
D004187:Disaccharides; D007202:Indicators and Reagents; D006026:Glycoside Hydrolases