|PDB structures||RCSB PDB PDBe PDBsum|
|Gene Ontology||AmiGO / QuickGO|
β-Amylase (EC 22.214.171.124 , saccharogen amylase, glycogenase) is an enzyme with the systematic name 4-α-D-glucan maltohydrolase. It catalyses the following reaction:
This enzyme acts on starch, glycogen and related polysaccharides and oligosaccharides producing beta-maltose by an inversion. Beta-amylase is found in bacteria, fungi, and plants; bacteria and cereal sources are the most heat stable. Working from the non-reducing end, β-amylase catalyzes the hydrolysis of the second α-1,4 glycosidic bond, cleaving off two glucose units (maltose) at a time. During the ripening of fruit, β-amylase breaks starch into maltose, resulting in the sweet flavor of ripe fruit.
β-amylase is present in an inactive form prior to seed germination. Many microbes also produce amylase to degrade extracellular starches. Animal tissues do not contain β-amylase, although it may be present in microorganisms contained within the digestive tract. The optimum pH for β-amylase is 4.0–5.0 They belong to Glycoside hydrolase family 14.