Zur Spaltung und Resorption von Oligosacchariden im Dünndarm, III. Die Bedeutung glucosidatischer Enzyme bei der Zerlegung von Maltooligosacchariden und Stärke

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Abstract
Comparative studies are reported on the glucosidic and [alpha]-amylolytic hydrolysis of malto-oligosaccharides (maltose, maltotriose, maltotetraose, maltopentaose) and starch by pancreatic [alpha]-amylase, mucosal gluco-amylase, and homogenates of the mucosa and intestinal contents of rat and pig. [alpha]-Amylase produces glucose from the tri-, tetra-, and penta-saccharides. Its glucosidic activity is, however, too low to be significant, especially in the region of the mucosa. Taking the [alpha]-amylase activity of each source as 100, the activities of glucoamylase are: rat mucosa, 3; pig mucosa, 2.5; intestinal contents of rat and pig, 0.5. In the lumen and in the mucosal region, maltotriose is hydrolyzed exclusively by glucosidic enzymes (chiefly glucoamylase). The tetra-and pentasaccharides are hydrolyzed both from the center ([alpha]-amylolytic) and terminally (glucosidic). The glucosidase activities of the mucosal homogenate are predominantly of the glucoamylase type. The glucosidase activities measured in the intestinal contents consist of about equal proportions of [alpha]-amylase and glucoamylase.