InterPro domain: IPR006046

O-Glycosyl hydrolases ( 3.2.1. ) are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycosyl hydrolases, based on sequence similarity, has led to the definition of 85 different families [ 1 , 2 ]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) website.

Alpha-amylases, which belong to glycoside hydrolase family 13, are 1,4-alpha-D-glucan glucanohydrolases, which degrade both the branched and unbranched forms of starch by cleaving theinternal alpha-1,4 bonds connecting the glucose monomers. The products ofthese reactions are maltose and maltotriose, which are further degraded toglucose by maltases. One atom of calcium is required to bind to each proteinmolecule to allow it to function, but excess calcium can inhibit activityby binding to amino acids that are required for the catalytic activityof the enzyme.

1. Conserved catalytic machinery and the prediction of a common fold for several families of glycosyl hydrolases. Proc. Natl. Acad. Sci. U.S.A. 92, 7090-4
2. Structures and mechanisms of glycosyl hydrolases. Structure 3, 853-9