DUF1926

• PFAM accession number: PF09095
• Interpro abstract (IPR015179):

  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 a domain found in prokaryotic alpha-amylase ( EC 3.2.1.1 ) and 4-alpha-glucanotransferase ( EC 2.4.1.25 ). This domain adopts a beta-sandwich fold, in which two layers of anti-parallel beta-sheets are arranged in a nearly parallel fashion. The exact function of this domain is, as yet, unknown, however it has been proposed that it may play a role in transglycosylation reactions [ (PUBMED:12618437) ].

• GO process: carbohydrate metabolic process (GO:0005975)
• GO function: carbohydrate binding (GO:0030246), catalytic activity (GO:0003824)

This is a PFAM domain. For full annotation and more information, please see the PFAM entry DUF1926