Efficient Enzymatic Synthesis of Disaccharide, α-D-Galactosyl α-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 eliminationusing baker's yeast, trehalase digestion, alkaline treatment and preparative HPLC. The chemicalstructure of the disaccharide was determined to be α-D-galactopyranosyl α-D-glucopyranoside byacid hydrolysis, methylation analysis, and by ¹³C-NMR spectrometry. This saccharide was onlyminimally hydrolyzed by α-galactosidase, but not hydrolyzed by α- or β-glucosidase, β-galactosidase and trehalase.