Enzymatic synthesis of disaccharides by β-galactosidase-catalyzed glycosylation of a glycocluster

The synthesis of disaccharides by galactosylation of a glucose-containing cluster has been studied using β-galactosidases from different sources. Galactosylation of the cluster could be detected by ESI-MS. After size-exclusion chromatography of the reaction mixtures and subsequent cleavage of the linker, galactopyranosyl-glucose disaccharides were obtained with yield and regioselectivity dependent on the origin of the enzyme. The possibility of using this method for the synthesis of multivalent glycoconjugates is discussed.