PRODUCTION AND USE OF GLUCOSYLTRANSFERASES FROM LEUCONOSTOC-MESENTEROIDES NRRL B-1299 FOR THE SYNTHESIS OF OLIGOSACCHARIDES CONTAINING ALPHA-(1-]2) LINKAGES

Glucosyltransferase activities, produced by batch culture of Leuconost oc mesenteroides NRRL B-1299, were recovered both in the culture super natant (SGT) and associated with the insoluble part of the culture (IG T). A total glucosyltransferase activity of 3.5 U/mL was measured in b atch culture. The enzymes from the supernatant were purified 313 times using aqueous two-phase partition between dextran and PEG phases, yie lding a preparation with 18.8 U/mg protein. It was shown that both SGT and IGT preparations catalyze acceptor reactions and transfer the glu cose unit from sucrose onto maltose to produce glucooligosaccharides. Some of the glucooligosaccharides synthesized (L(n) series) contain al pha-(1-->6) osidic linkages and a maltose residue at the reducing end. They were completely hydrolyzed by glucoamylas e and dextranase. The other glucooligosaccharides synthesized (Bn series) resisted the actio n of these enzymes. The tetrasaccharide of this series has been charac terized by C-13 NMR. Its Structure was determined as 2-O-alpha-D-gluco sylpanose. The oligosaccharides synthesized by the maltose acceptor re action with the SGT and IGT preparations only differed in the relative amounts in which they were produced. The difference may arise from di ffusional limitations appearing when the insoluble catalyst is used. U nder the assay conditions, the glucanase resistant oligosaccharide yie ld was 35% with both glucosyltransferase preparations.