Submitted to: American Chemical Society National Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/30/2001
Publication Date: N/A
Technical Abstract: Alternansucrase synthesizes an alpha-(1-3),(1-6)-D-glucan via glucosyl transfer from sucrose. It also synthesizes oligosaccharides containing both types of linkages when acceptor sugars are present (Cote & Robyt, Carbohydr. Res. 111 (1982) 127-142). We have found that certain galactose-containing saccharides serve as good acceptors for alternansucrase. Melibiose was glucosylated mainly at position 3', giving rise to the trisaccharide alpha-D-Glcp(1-3)-alpha-D-Galp(1-6)-D-Glc. Dextransucrase also transfers glucosyl units to melibiose, although less efficiently. The product formed by dextransucrase is alpha-D-Glcp(1-4)- alpha-D-Galp(1-6)-D-Glc. Methyl alpha-D-galactopyranoside was glucosylated at positions 3 and 4 by alternansucrase, giving rise to a mixture of alpha-D-Glcp(1-3)-alpha-D-Galp-OMe and alpha-D-Glcp(1-4)-alpha-D-Galp-OMe. Higher saccharides were formed by glucosylation of these products, mainly at position 6'. Lactose and raffinose were also good acceptors for alternansucrase, but the product mixtures were complex and have not yet been separated.