Abstract
Action patterns of dextranase from P. funiculosum on the substrate were investigated. Isomaltodextrins and their reduced derivatives (isomaltodextrinols) were used as the substrate. Comparison of the enzymatic digestion products did lead the conclusion that the attack points of the dextranase on isomaltodextrin were primarily at second and third glucosidic linkage from the non-reducing end of the substrate. On the increase of polymerization degree of substrate, the enzyme hydrolyzed also at fourth or fifth glucosidic linkage from the non-reducing end. The inhibition of dextranase hydrolysis reaction by some mono-and disaccharides was also investigated. It was found that C-2 and C-6 positions of glucosidic residue were primary positions to effect the binding to active center of the enzyme ; C-2 position was likely to effect the binding affinity and C-6 position was to exert the binding site.
