Novel Quantitative Method for the Degree of Branching in Dextran

摘要

A novel quantitative method for the determination of degree of branching in Leuconostoc mesenteroides B-512F dextran was developed by using the combination of 3 dextran-degrading enzymes. First, Paenibacillus sp. endo-dextranase was randomly degraded B-512F dextran into linear or branched isomalto-oligosaccharides with various degree of polymerization (2-8). Second, Streptococcus mutans dextran glucosidase hydrolyzed linear or branched isomalto-oligosaccharides into glucose and branched isomalto-penta-saccharides. Third, the branched isomalto-penta-saccharide was degraded into glucose by using Bacteroides thetaimicron a-glucosidase. The number of branching points in B-512F dextran (5.42%) was determined by the difference in the amount of glucose in the reaction digest between BTGase-PDex and DGase-PDex treatments.