Characterization of α-(1→3) Branched Oligosaccharides Synthesized by Acceptor Reaction with the Extracellular Glucosyltransferases fromL. MesenteroidesNRRL B-742

Abstract

Abstract The glucosyltransferases from L. mesenteroides are known to catalyze the transfer of the D-glucosyl group of sucrose onto sugars, now commonly named acceptors. We investigated in the present work, the acceptor reaction catalyzed by the extracellular glucosyltransferases from L. mesenteroides NRRL B-742. The enzymes of the culture supernatant, purified by aqueous two-phase partition between dextran and polyethylene glycol solutions, were found to efficiently transfer the glucose moiety of sucrose onto maltose acceptor. By increasing the sucrose/maltose ratio (S/M), it was possible to catalyze the synthesis of oligosaccharides of increasing degree of polymerisation (d.p.). For an S/M ratio of 7, both linear oligosaccharides (only composed of α-(1→6) linkages and a maltose residue at the reducing end) and branched oligosaccharides were produced. A glucanase treatment permitted isolation of the branched products which were then analyzed by carbon 13 NMR spectroscopy. The chemical shifts arising from ...