β-Amylase (EC 3.2.1.2, saccharogen amylase, glycogenase) is an enzyme with the systematic name4-α-D-glucan maltohydrolase.[2][3][4] It catalyses the following reaction:
Hydrolysis of (1→4)-α-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[5] They belong to Glycoside hydrolase family 14.
^Rejzek M, Stevenson CE, Southard AM, Stanley D, Denyer K, Smith AM, Naldrett MJ, Lawson DM, Field RA (March 2011). "Chemical genetics and cereal starch metabolism: structural basis of the non-covalent and covalent inhibition of barley β-amylase". Molecular BioSystems. 7 (3): 718–30. doi:10.1039/c0mb00204f. PMID 21085740.
^Balls AK, Walden MK, Thompson RR (March 1948). "A crystalline β-amylase from sweet potatoes". The Journal of Biological Chemistry. 173 (1): 9–19. doi:10.1016/S0021-9258(18)35550-9. PMID 18902365.
^French D (1960). "β-Amylases". In Boyer PD, Lardy H, Myrbaumlck K (eds.). The Enzymes. Vol. 4 (2nd ed.). New York: Academic Press. pp. 345–368.
^Manners DJ (1962). "Enzymic synthesis and degradation of starch and glycogen". Advances in Carbohydrate Chemistry. 17: 371–430. doi:10.1016/s0096-5332(08)60139-3. ISBN9780120072170.
Friedberg F, Rhodes C (March 1986). "Cloning and characterization of the β-amylase gene from Bacillus polymyxa". Journal of Bacteriology. 165 (3): 819–24. doi:10.1128/JB.165.3.819-824.1986. PMC214501. PMID 2419310.
Rhodes C, Strasser J, Friedberg F (May 1987). "Sequence of an active fragment of B. polymyxa β amylase". Nucleic Acids Research. 15 (9): 3934. doi:10.1093/nar/15.9.3934. PMC340808. PMID 2438660.
amylase, saccharogen, amylase, glycogenase, enzyme, with, systematic, name, glucan, maltohydrolase, catalyses, following, reaction, amylasestructure, barley, beta, amylase, 2xfr, identifiersec, 2cas, 9000, 3databasesintenzintenz, viewbrendabrenda, entryexpasyn. b Amylase EC 3 2 1 2 saccharogen amylase glycogenase is an enzyme with the systematic name 4 a D glucan maltohydrolase 2 3 4 It catalyses the following reaction b amylaseStructure of barley beta amylase PDB 2xfr 1 IdentifiersEC no 3 2 1 2CAS no 9000 91 3DatabasesIntEnzIntEnz viewBRENDABRENDA entryExPASyNiceZyme viewKEGGKEGG entryMetaCycmetabolic pathwayPRIAMprofilePDB structuresRCSB PDB PDBe PDBsumGene OntologyAmiGO QuickGOSearchPMCarticlesPubMedarticlesNCBIproteins Hydrolysis of 1 4 a D glucosidic linkages in polysaccharides so as to remove successive maltose units from the non reducing ends of the chainsThis 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 b amylase catalyzes the hydrolysis of the second a 1 4 glycosidic bond cleaving off two glucose units maltose at a time During the ripening of fruit b amylase breaks starch into maltose resulting in the sweet flavor of ripe fruit b 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 b amylase although it may be present in microorganisms contained within the digestive tract The optimum pH for b amylase is 4 0 5 0 5 They belong to Glycoside hydrolase family 14 Contents 1 See also 2 References 3 Further reading 4 External links 5 External linksSee also editAmylase Alpha amylaseReferences edit Rejzek M Stevenson CE Southard AM Stanley D Denyer K Smith AM Naldrett MJ Lawson DM Field RA March 2011 Chemical genetics and cereal starch metabolism structural basis of the non covalent and covalent inhibition of barley b amylase Molecular BioSystems 7 3 718 30 doi 10 1039 c0mb00204f PMID 21085740 Balls AK Walden MK Thompson RR March 1948 A crystalline b amylase from sweet potatoes The Journal of Biological Chemistry 173 1 9 19 doi 10 1016 S0021 9258 18 35550 9 PMID 18902365 French D 1960 b Amylases In Boyer PD Lardy H Myrbaumlck K eds The Enzymes Vol 4 2nd ed New York Academic Press pp 345 368 Manners DJ 1962 Enzymic synthesis and degradation of starch and glycogen Advances in Carbohydrate Chemistry 17 371 430 doi 10 1016 s0096 5332 08 60139 3 ISBN 9780120072170 Amylase Alpha I U B 3 2 1 11 4 a D Glucan glucanohydrolase Further reading editFriedberg F Rhodes C March 1986 Cloning and characterization of the b amylase gene from Bacillus polymyxa Journal of Bacteriology 165 3 819 24 doi 10 1128 JB 165 3 819 824 1986 PMC 214501 PMID 2419310 Rhodes C Strasser J Friedberg F May 1987 Sequence of an active fragment of B polymyxa b amylase Nucleic Acids Research 15 9 3934 doi 10 1093 nar 15 9 3934 PMC 340808 PMID 2438660 External links edit Amylase Alpha I U B 3 2 1 11 4 a D Glucan glucanohydrolase Amylase Alpha I U B 3 2 1 11 4 a D Glucan glucanohydrolase External links editBeta amylase at the U S National Library of Medicine Medical Subject Headings MeSH Portal nbsp Biology Retrieved from https en wikipedia org w index php title B Amylase amp oldid 1172366227, wikipedia, wiki, book, books, library,
