Glycosyl hydrolase, family 13, catalytic domain <p>O-Glycosyl hydrolases <db_xref db="EC" dbkey="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 [<cite idref="PUB00004870"/>, <cite idref="PUB00005266"/>]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site.</p><p> Enzymes containing this domain, such as alpha-amylase, belong to family 13 (<db_xref db="CAZY" dbkey="GH13"/>) of the glycosyl hydrolases. The maltogenic alpha-amylase is an enzyme which catalyses hydrolysis of (1-4)-alpha-D-glucosidic linkages in polysaccharides so as to remove successive alpha-maltose residues from the non-reducing ends of the chains in the conversion of starch to maltose. Other enzymes include neopullulanase, which hydrolyses pullulan to panose, and cyclomaltodextrinase, which hydrolyses cyclodextrins.</p><p>This entry represents the catalytic domain found in several protein members of this family. It has a structure consisting of an 8 stranded alpha/beta barrel that contains the active site, interrupted by a ~70 amino acid calcium-binding domain protruding between beta strand 3 and alpha helix 3, and a carboxyl-terminal Greek key beta-barrel domain [<cite idref="PUB00027665"/>].</p><p>More information about this protein can be found at Protein of the Month: alpha-Amylase [<cite idref="PUB00027661"/>].</p>