Glycosyl hydrolase family 13, catalytic domain
IPR006047
Definition
Enzymes containing this domain, such as alpha-amylase, belong to family 13 ([cazy:GH13]) of the glycosyl hydrolases. The maltogenic alpha-amylase is an enzyme that catalyses the 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. This entry represents the catalytic domain found in several protein members of this family. It has a structure consisting of an 8-stranded α/β barrel that contains the active site, interrupted by a ~70 amino acid calcium-binding domain protruding between β-strand 3 and α-helix 3, and a carboxyl-terminal β-barrel domain PMID:16302977. Family GH13 is the major glycoside hydrolase family acting on substrates containing α-glucoside linkages. GH13 contains hydrolases, transglycosidases, and isomerases PMID:17724034; noticeably, animal amino acid transporters PMID:9302327, which have no glycosidase activity PMID:19878315, are also GH13 members. The enzymes are found in a very wide range of organisms from all kingdoms. The GH13 enzymes have a wide range of different preferred substrates and products. For example, the α-amylases prefer polysaccharides of the α-1,4-glucan type, such as amylose and amylopectin, but are also able to attack the supramolecular structures represented by starch granules and glycogen particles. Among thousands of sequences and ~30 different enzyme specificities PMID:17085431 many are closely related to each other; GH13 therefore has officially been subdivided into almost 40 subfamilies PMID:18838391. In general, the GH13 members are multidomain proteins with catalytic (β/α)8-barrel (i.e. TIM-barrel) domain (called domain A) having a small domain B (usually varying in length and of irregular structure) PMID:17724034. Some of these enzymes include: α-amylase [ec:3.2.1.1] oligo-1,6-glucosidase [ec:3.2.1.10] α-glucosidase [ec:3.2.1.20] pullulanase [ec:3.2.1.4] cyclomaltodextrinase [ec:3.2.1.54] maltotetraose-forming α-amylase [ec:3.2.1.60] isoamylase [ec:3.2.1.68] dextran glucosidase [ec:3.2.1.70] trehalose-6-phosphate hydrolase [ec:3.2.1.93] maltohexaose-forming α-amylase [ec:3.2.1.9]) maltotriose-forming α-amylase [ec:3.2.1.116] maltogenic amylase [ec:3.2.1.133] neopullulanase [ec:3.2.1.135] malto-oligosyltrehalose trehalohydrolase [ec:3.2.1.141] limit dextrinase [ec:3.2.1.142] amylosucrase [ec:2.4.1.4] sucrose phosphorylase [ec:2.4.1.7] cyclomaltodextrin glucanotransferase (CGTase) [ec:2.4.1.19] 4-α-glucanotransferase [ec:2.4.1.25] isomaltulose synthase [ec:5.4.99.11] trehalose synthase [ec:5.4.99.16] O-Glycosyl hydrolases ([ec: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:PMID:7624375], [cite:PMID:8535779]]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) website.
8 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
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