alphaglucosidase

Alpha-glucosidase refers to a family of enzymes that catalyze the hydrolysis of alpha-glucosidic linkages, removing terminal glucose residues from oligosaccharides and related carbohydrates to yield glucose. These enzymes are found in a range of organisms and cellular contexts, where they participate in carbohydrate digestion or in the breakdown of glycogen within lysosomes.

In humans, several forms of alpha-glucosidase have distinct roles and locations. Lysosomal acid alpha-glucosidase, produced by the GAA gene, digests glycogen inside lysosomes and is active in acidic environments. In the small intestine, brush-border enzymes including maltase-glucoamylase and sucrase-isomaltase provide alpha-glucosidase activities that complete the breakdown of dietary starch-derived oligosaccharides into glucose. These intestinal enzymes are anchored to the enterocyte surface and act on alpha-1,4 and related linkages, generating absorbable glucose for the body.

Medical relevance includes Pompe disease, caused by deficiency of lysosomal acid alpha-glucosidase. This leads to accumulation of glycogen in lysosomes, primarily affecting muscle tissue and causing progressive weakness. Diagnosis involves enzyme activity assays and genetic testing, and treatment options include enzyme replacement therapy with recombinant human GAA.

Inhibitors of intestinal alpha-glucosidases, such as acarbose, miglitol, and voglibose, slow carbohydrate digestion and can help manage postprandial blood glucose in type 2 diabetes. Beyond medicine, alpha-glucosidases are also used in research and biotechnology to study carbohydrate metabolism and to modify starch-derived substrates.