Beta-amylase (EC 126.96.36.199, β-amylase, saccharogen amylase, glycogenase) is an enzyme with the systematic name 4-alpha-D-glucan maltohydrolase. 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. 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
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- "Amylase, Alpha" , I.U.B.: 188.8.131.52,4-α-D-Glucan glucanohydrolase.