β-amylase | |||||||||
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Identifiers | |||||||||
EC no. | 3.2.1.2 | ||||||||
CAS no. | 9000-91-3 | ||||||||
Databases | |||||||||
IntEnz | IntEnz view | ||||||||
BRENDA | BRENDA entry | ||||||||
ExPASy | NiceZyme view | ||||||||
KEGG | KEGG entry | ||||||||
MetaCyc | metabolic pathway | ||||||||
PRIAM | profile | ||||||||
PDB structures | RCSB PDB PDBe PDBsum | ||||||||
Gene Ontology | AmiGO / QuickGO | ||||||||
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β-Amylase ( EC 3.2.1.2, saccharogen amylase, glycogenase) is an enzyme with the systematic name 4-α-D-glucan maltohydrolase. [2] [3] [4] 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 [5] They belong to Glycoside hydrolase family 14.