B-amylase
| Beta-amylase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
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| Identifiers | |||||||||
| EC number | 3.2.1.2 | ||||||||
| CAS number | Template:CAS | ||||||||
| 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 / EGO | ||||||||
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Beta-amylase (EC 3.2.1.2, saccharogen amylase, glycogenase, beta amylase, 1,4-alpha-D-glucan maltohydrolase) is an enzyme with systematic name 4-alpha-D-glucan maltohydrolase.[2][3][4] This enzyme catalyses the following chemical reaction
- Hydrolysis of (1->4)-alpha-D-glucosidic linkages in polysaccharides so as to remove successive maltose units from the non-reducing ends of the chains
This enzyme acts on starch, glycogen and related polysaccharides and oligosaccharides producing beta-maltose by an inversion. Alpha-amylase is found in bacteria, fungi, and plants and 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]
See also
References
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- ↑ "Amylase, Alpha" , I.U.B.: 3.2.1.11,4-α-D-Glucan glucanohydrolase.
External links
- Beta-amylase at the US National Library of Medicine Medical Subject Headings (MeSH)
