Effect of maltotriitol on the action pattern of porcine pancreatic alpha-amylase using amylose as a substrate.

The effect of the oligosaccharide analog maltotriitol (G3OH) on the action pattern of porcine pancreatic alpha-amylase (PPA) was examined using amylose as a substrate. Fluorescence titration indicated that two molecules of G3OH can bind to one molecule of PPA. The slope in the blue value versus extent-of-reaction plot was shifted by G3OH from that for multiple attack in the direction of that for random attack as the G3OH concentration increased. From these it is inferred that at least one molecule of G3OH can bind at the active site of the enzyme so as to inhibit the sliding of the retained-product fragment after the initial cleavage of an amylose molecule.