Aamy_C

 Aamy_C
SMART accession number:SM00632
Description:
Interpro abstract (IPR006048):

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 (PUBMED:7624375), (PUBMED:8535779). This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site. Because the fold of proteins is better conserved than their sequences, some of the families can be grouped in 'clans'.

Alpha-amylase is classified as family 13 of the glycosyl hydrolases and is present in archaea, bacteria, plants and animals. Alpha-amylase is an essential enzyme in alpha-glucan metabolism, acting to catalyse the hydrolysis of alpha-1,4-glucosidic bonds of glycogen, starch and related polysaccharides. Although all alpha-amylases possess the same catalytic function, they can vary with respect to sequence. In general, they are composed of three domains: a TIM barrel containing the active site residues and chloride ion-binding site (domain A), a long loop region inserted between the third beta strand and the alpha-helix of domain A that contains calcium-binding site(s) (domain B), and a C-terminal beta-sheet domain that appears to show some variability in sequence and length between amylases (domain C) (PUBMED:11141191). Amylases have at least one conserved calcium-binding site, as calcium is essential for the stability of the enzyme. The chloride-binding functions to activate the enzyme, which acts by a two-step mechanism involving a catalytic nucleophile base (usually an Asp) and a catalytic proton donor (usually a Glu) that are responsible for the formation of the beta-linked glycosyl-enzyme intermediate.

This entry represents the all-beta domain that is found in several alpha-amylases, usually at the C-terminus, and which forms a Greek key beta-barrel fold in these enzymes (PUBMED:7877175).

More information about this protein can be found at Protein of the Month: alpha-Amylase.

GO process:carbohydrate metabolic process (GO:0005975)
GO function:cation binding (GO:0043169), catalytic activity (GO:0003824)
Family alignment:
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There are 325 Aamy_C domains in 324 proteins in SMART's nrdb database.

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