Intestinal alpha-amylase

Intestinal alpha-amylase is a digestive enzyme classified as an endo-amylase, responsible for catalyzing the hydrolysis of internal α-1,4-glycosidic bonds in starch and glycogen to produce maltose, maltotriose, and alpha-limit dextrins[1][3][7]. It is primarily secreted by the pancreas into the intestinal tract (duodenum), operating optimally in the slightly alkaline environment of the small intestine[2][6][7]. Human alpha-amylase is a single polypeptide chain enzyme with three domains (A, B, and C), containing a calcium ion crucial for structural stability and catalytic activity[1][3]. Pancreatic and, to a much lesser extent, epithelial sources contribute to intestinal alpha-amylase[2][7]. It plays a central role in carbohydrate digestion and is a therapeutic target in the management of diabetes and obesity through pharmacological inhibition, which slows the conversion of dietary starch into absorbable monosaccharides[5]. Serum amylase levels serve as clinical biomarkers for pancreatic and some intestinal disorders[2]. Medications targeting this enzyme may cause gastrointestinal disturbances due to unabsorbed carbohydrates in the colon.

Other names

Alpha-amylaseα-amylase1,4-α-D-glucan-glucanohydrolaseAmylaseEC 3.2.1.1

Competitive inhibition of active site to prevent starch hydrolysis (e.g., acarbose and related drugs inhibit breakdown of complex carbohydrates to glucose, reducing postprandial blood glucose spikes)