THE SPECIFICITY OF AN ALPHA-(1-]2)-L-GALACTOSYLTRANSFERASE FROM ALBUMIN GLANDS OF THE SNAIL HELIX-POMATIA

The specificity of an L-galactosyltransferase (L-Gal-T) from albumen g lands of the snail Helix pomatia has been studied. This enzyme transfe rs L-Gal from GDP-L-Gal to various disaccharides with beta-linked D-Ga l in terminal non-reducing position, forming an alpha-(1 --> 2) linkag e. The subterminal residue and the type of interglycosidic linkage pro ved to be of minor importance. However, the branched trisaccharide bet a-D-Gal-(1 --> 3)-[beta-D-Gal-(1 --> 6)]-beta-D-Gal-(1 --> O)Me is a v ery poor acceptor. The specificity of the L-Gal-T correlates well with the equimolar occurrence of L-Gal and the structural element --> 2)-G al-(1 --> found in the storage polysaccharide of this snail. Since L-F uc is also transferred from its GDP-activated form, the membrane prepa rations of the albumen glands can be used to synthesize fucosylated ol igosaccharides. (C) 1997 Elsevier Science Ltd.