Alpha-amylase/4-alpha-glucanotransferase, central domain (IPR015178)

Short name: A-amylase/a-glucTrfase_central

Overlapping homologous superfamilies

Domain relationships



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) [PMID: 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 a domain found in prokaryotic alpha-amylase (EC: and 4-alpha-glucanotransferase (EC: It is adjacent to the C-terminal domain (see IPR015179). The exact function of this domain is, as yet, unknown.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.