Maltase-glucoamylase (MGA) is a brush border membrane enzyme that plays a role in the final steps of small intestinal digestion of linear regions of starch to glucose. Brush border sucrase-isomaltase (SI) serves a complementary function through digestion of branched starch linkages. Brush-border maltase-glucoamylase (MGA) activity serves as the final step of small intestinal digestion of linear regions of dietary starch to glucose.

Maltase-glucoamylase is synthesized as a single-chain polypeptide precursor, acquires N- and O-linked carbohydrates, and does not undergo intracellular or extracellular proteolytic cleavage. Maltase is an enzyme produced by the cells lining the small intestine that breaks down the disaccharide maltose. It comes under the enzyme category carbohydrase.