Structural Studies of the Intestinal α-Glucosidases, Maltase-glucoamylase and Sucrase-isomaltase.

OBJECTIVES: Maltase-glucoamylase and sucrase-isomaltase are enzymes in the brush-border membrane of the small intestinal lumen responsible for the breakdown of postamylase starch polysaccharides to release monomeric glucose. As such, they are critical players in healthy nutrition and their malfunction can lead to severe disorders.

METHODS: This review covers investigations of the structures and functions of these enzymes.

RESULTS: Each consists of 2 enzyme domains of the glycoside hydrolase family GH31 classification, yet with somewhat differing enzymatic properties.

CONCLUSIONS: Crystallographic structures of 3 of the domains have been published. Insights into substrate binding and specificity will be discussed, along with future lines of inquiry related to the enzymes' roles in disease and potential avenues for therapeutics.