RESUMEN
Remarakable advances in glycobiology in recent years have stimulated a resurgence of interest in carbohydrate chemistry. The challenge of producing the complex glycosides and oligosaccharides needed for research in glycobiology has led to the development of enzymatic methods that are now firmly established as part of the synthetic repertoire of the carbohydrate chemist.
Asunto(s)
Glicósido Hidrolasas/química , Glicósidos/síntesis química , Glicosiltransferasas/química , Oligosacáridos/síntesis química , Catálisis , Humanos , HidrólisisRESUMEN
Alkyl beta-D-glucosides were synthesized from D-glucose and alcohols by reverse hydrolysis using the commercially available almond beta-D-glucosidase in 9:1 (v/v) acetonitrile-water medium. The main characteristics of this enzyme-catalyzed glucosylation were established by using 2-hydroxybenzyl alcohol. The reaction is entirely regio- and stereoselective. The solvent plays a fundamental role because, by decreasing the water concentration in the medium, the shift of the reaction equilibrium toward synthesis is realized without using an excessive amount of alcohol. Nevertheless, a minimum amount of water is necessary to maintain the enzyme activity. In contrast to the use of the enzyme in aqueous medium, the pH of the added water in acetonitrile did not influence the synthesis. Using this procedure, we have conducted systematic glucosylation of numerous alcohols and we have investigated enzyme specificity and alcohol reactivity. The enzyme has a pronounced affinity for the alcohols containing a phenyl group, and enantioselectivity for the aglycon is obtained with 1-phenylethyl alcohol. Moreover, by using almond beta-D-glucosidase it was also possible to synthesize alkyl beta-D-galactosides. (c) 1995 John Wiley & Sons, Inc.
