AMY2B

AMY2B
Identifiers
Aliases	AMY2B, AMY2, AMY3, HXA, amylase, alpha 2B (pancreatic), amylase alpha 2B (pancreatic), amylase alpha 2B
External IDs	OMIM: 104660; MGI: 3714985; GeneCards: AMY2B
Enzyme activity EC # BRENDA ExPASy KEGG MetaCyc 3.2.1.1 ↗ ↗ ↗ ↗
Gene location (Human) Chr. Chromosome 1 (human) Band 1p21.1 Start 103,553,815 bp End 103,579,534 bp
Gene location (Mouse) Chr. Chromosome 3 (mouse) Band 3 F3|3 Start 113,219,771 bp End 113,231,368 bp
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in body of pancreas right uterine tube cerebellar hemisphere right hemisphere of cerebellum gastric mucosa left lobe of thyroid gland tibial nerve right lobe of thyroid gland apex of heart Achilles tendon Top expressed in pancreas islet of Langerhans stomach colon esophagus duodenum jejunum quadriceps femoris muscle spermatid ileum More reference expression data BioGPS More reference expression data
Gene ontology Molecular function catalytic activity alpha-amylase activity hydrolase activity metal ion binding hydrolase activity, acting on glycosyl bonds cation binding Cellular component extracellular region extracellular exosome Biological process digestion metabolism carbohydrate metabolic process Sources:Amigo / QuickGO
Orthologs Databases NCBI: entry; OMA: entry Species Human Mouse Entrez 280 100043686 Ensembl ENSG00000240038 ENSMUSG00000093931 UniProt P19961 P00688 RefSeq (mRNA) NM_020978 NM_001386109 NM_001387437 NM_001160151 RefSeq (protein) NP_066188 NP_001036176 NP_001153622 NP_001153623 NP_001153624 Location (UCSC) Chr 1: 103.55 – 103.58 Mb Chr 3: 113.22 – 113.23 Mb PubMed search
Wikidata
View/Edit Human View/Edit Mouse

Alpha-amylase 2B is a digestive enzyme that in humans is encoded by the AMY2B gene. This enzyme functions to break down carbohydrates, especially large carbohydrates like starch. This enzyme (along with AMY2A) is one of the primary alpha-amylases secreted by the acinar cells of the pancreas into pancreatic juice, which is released into the small intestines.

Function

See also: α-Amylase

Amylases are secreted proteins that hydrolyze 1,4-alpha-glucoside bonds in oligosaccharides and polysaccharides, and thus catalyze the first step in digestion of dietary starch and glycogen. The human genome has a cluster of several amylase genes that are expressed at high levels in either the salivary glands (AMY1A, AMY1B, AMY1C) or pancreas (AMY2A, AMY2B). This gene encodes an amylase isoenzyme produced by the pancreas. Similar to AMY1, the number of AMY2-encoding genes varies from individual to individual, however the proteins encoded by AMY2A and AMY2B are not identical (though they are ~99% similar).

Promotor region

AMY2B is distinct from AMY2A and the AMY1 genes by a difference in its promotor region. All AMY1 and AMY2 genes have a γ-actin pseudogene located in their promotor region. In all but AMY2B, this pseudogene is interrupted by a retroviral-like sequence. This may impact the regulation of these genes, and has been cited as evidence for the claim that the (salivary) AMY1 genes originated as copies of an AMY2 gene (see Amylase § Evolution).

Further reading

• Kaczmarek MJ, Rosenmund H (August 1977). "The action of human pancreatic and salivary isoamylases on starch and glycogen". Clinica Chimica Acta; International Journal of Clinical Chemistry. 79 (1): 69–73. doi:10.1016/0009-8981(77)90462-4. PMID 890964.
• Groot PC, Mager WH, Henriquez NV, Pronk JC, Arwert F, Planta RJ, Eriksson AW, Frants RR (September 1990). "Evolution of the human alpha-amylase multigene family through unequal, homologous, and inter- and intrachromosomal crossovers". Genomics. 8 (1): 97–105. doi:10.1016/0888-7543(90)90230-R. PMID 2081604.
• Yokouchi H, Horii A, Emi M, Tomita N, Doi S, Ogawa M, Mori T, Matsubara K (June 1990). "Cloning and characterization of a third type of human alpha-amylase gene, AMY2B". Gene. 90 (2): 281–6. doi:10.1016/0378-1119(90)90191-S. PMID 2401405.
• Gumucio DL, Wiebauer K, Caldwell RM, Samuelson LC, Meisler MH (March 1988). "Concerted evolution of human amylase genes". Molecular and Cellular Biology. 8 (3): 1197–205. doi:10.1128/mcb.8.3.1197. PMC 363264. PMID 2452973.
• Samuelson LC, Wiebauer K, Gumucio DL, Meisler MH (September 1988). "Expression of the human amylase genes: recent origin of a salivary amylase promoter from an actin pseudogene". Nucleic Acids Research. 16 (17): 8261–76. doi:10.1093/nar/16.17.8261. PMC 338557. PMID 2458567.
• Tomita N, Horii A, Doi S, Yokouchi H, Shiosaki K, Higashiyama M, Matsuura N, Ogawa M, Mori T, Matsubara K (March 1989). "A novel type of human alpha-amylase produced in lung carcinoid tumor". Gene. 76 (1): 11–8. doi:10.1016/0378-1119(89)90003-6. PMID 2701942.
• Groot PC, Bleeker MJ, Pronk JC, Arwert F, Mager WH, Planta RJ, Eriksson AW, Frants RR (July 1989). "The human alpha-amylase multigene family consists of haplotypes with variable numbers of genes". Genomics. 5 (1): 29–42. doi:10.1016/0888-7543(89)90083-9. PMID 2788608.
• Groot PC, Bleeker MJ, Pronk JC, Arwert F, Mager WH, Planta RJ, Eriksson AW, Frants RR (May 1988). "Human pancreatic amylase is encoded by two different genes". Nucleic Acids Research. 16 (10): 4724. doi:10.1093/nar/16.10.4724. PMC 336663. PMID 3260028.
• Tricoli JV, Shows TB (March 1984). "Regional assignment of human amylase (AMY) to p22----p21 of chromosome 1". Somatic Cell and Molecular Genetics. 10 (2): 205–10. doi:10.1007/BF01534909. PMID 6608795. S2CID 21230969.
• Nagase T, Nakayama M, Nakajima D, Kikuno R, Ohara O (April 2001). "Prediction of the coding sequences of unidentified human genes. XX. The complete sequences of 100 new cDNA clones from brain which code for large proteins in vitro". DNA Research. 8 (2): 85–95. doi:10.1093/dnares/8.2.85. PMID 11347906.
• Aughsteen AA (May 2001). "A comparative immunohistochemical study on amylase localization in the rat and human exocrine pancreas". Saudi Medical Journal. 22 (5): 410–5. PMID 11376382.
• Koyama I, Komine S, Iino N, Hokari S, Igarashi S, Alpers DH, Komoda T (July 2001). "alpha-Amylase expressed in human liver is encoded by the AMY-2B gene identified in tumorous tissues". Clinica Chimica Acta; International Journal of Clinical Chemistry. 309 (1): 73–83. doi:10.1016/S0009-8981(01)00501-0. PMID 11408008.
• Iafrate AJ, Feuk L, Rivera MN, Listewnik ML, Donahoe PK, Qi Y, Scherer SW, Lee C (September 2004). "Detection of large-scale variation in the human genome". Nature Genetics. 36 (9): 949–51. doi:10.1038/ng1416. PMID 15286789.

External links

• Human AMY2B genome location and AMY2B gene details page in the UCSC Genome Browser.