Relative, quantitative effects of acceptors in the reaction of Leuconostoc mesenteroides B-512F dextransucrase

The acceptor reaction of dextransucrase consists of the transfer of d -glucosyl groups from sucrose to other carbohydrates, and occurs at the expense of dextran synthesis. In the present study, solutions of [ 14 C]sucrose and of each of seventeen acceptor sugars were digested with highly purified Leuconostoc mesenteroides B-512F dextransucrase. The products were separated by paper chromatography, and quantitated by liquid scintillation counting. Maltose was the most effective acceptor; its products, members of an isomaltodextrinyl-maltose series (d.p. 3 to 6), accounted for >75% of the d -glucosyl groups of sucrose. Other acceptors giving rise to a similar series of oligosaccharide products were (in order of decreasing effectiveness): isomaltose, nigerose, methyl α- d -glucoside, 1,5-anhydro- d -glucitol, d -glucose, turanose, methyl β- d -glucoside, cellobiose, and l -sorbose. Lactose, raffinose, melibiose, d -galactose, and d -xylose each gave a single, mono- d -glucosylated product; d -fructose and d -mannose each gave a pair of mono- d -glucosylated (disaccharide) products. Another series of digests contained sucrose and various proportions of maltose. As the level of maltose increased, the size of the largest oligosaccharide acceptor-product decreased, and less dextran was produced. The virtual absence of high-d.p. (8 to 13) oligosaccharide products in all acceptor digests is interpreted as evidence against a role for acceptors as primers of dextran synthesis.