Inhibition of human intestinalα-glucosidehydrolases by a new complex oligosaccharide

Abstract

The effect of a new complex oligosaccharide (Bay g 5421) of microbial origin on human intestinalα-glucosidehydrolase activity was tested in mucosal homogenate from human small bowel biopsy specimens. Theα-glucosidehydrolase inhibitor (α-GHI) exerted a potent inhibitory effect on glucoamylase, sucrase, and maltase, was minimally effective on isomaltase, and did not affect trehalase and lactase activity. Kinetic analysis revealed a fully competitive type of inhibition with a Ki of 1.3 × 10⁻⁶M; thus the inhibitor had a 15 000-fold higher affinity to the enzyme sucrase than its natural substrate sucrose. The new compound may prove to be useful in the study of carbohydrate maldigestion and malabsorption and may possibly be of therapeutic benefit in diabetes and obesity.