Efficient Enzymatic Synthesis of Disaccharide, .ALPHA.-D-Galactosyl .ALPHA.-D-Glucoside, by Trehalose Phosphorylase from Thermoanaerobacter brockii.

Abstract

A non-reducing disaccharide was synthesized by trehalose phosphorylase from a thermophilic anaerobe, Thermoanaerobacter brockii, using trehalose as a glucosyl donor and D-galactose as an acceptor. This disaccharide was efficiently isolated from the reaction mixture by glucose elimination using baker's yeast, trehalase digestion, alkaline treatment and preparative HPLC. The chemical structure of the disaccharide was determined to be a-D-galactopyranosyl a-D-glucopyranoside by acid hydrolysis, methylation analysis, and by 13C-NMR spectrometry. This saccharide was only minimally hydrolyzed by a-galactosidase, but not hydrolyzed by a- or j9-glucosidase, j9- galactosidase and trehalase.