|Gene:||amyA||Accession Numbers: EG11387 (MetaCyc), b1927, ECK1926|
Species: Escherichia coli K-12 substr. MG1655
AmyA is a cytoplasmic α-amylase. Amylose, a linear α-glucan, is the most effective substrate in vitro; starch and amylopectin, a lightly branched α-glucan, can serve as good substrates, while the highly branched α-glucan glycogen is a poor substrate. Linear oligomeric α-glucans of six or more glucose moieties are good substrates of AmyA [Raha92].
The physiological role of AmyA is uncertain. Although under experimental conditions glycogen is a poor substrate for the enzyme, it is the most likely natural substrate since it is the only polysaccharide present in appreciable amounts in the cytoplasm. It has been hypothesized that in the absence of exogenous oligosaccharides that could act as primers for glycogen synthesis, the cytoplasmic amylase might provide oligosaccharides through catabolism of existing cellular glycogen, which would then act as the source of primers for the synthesis of more molecules of glycogen [Raha92].
AmyA is one of two α-amylases present in E. coli. The second enzyme, MalS, is periplasmic.
|Map Position: [2,004,180 -> 2,005,667]|
Molecular Weight of Polypeptide: 56.639 kD (from nucleotide sequence), 56 kD (experimental) [Raha92 ]
Unification Links: ASAP:ABE-0006414 , CGSC:30745 , DIP:DIP-9108N , EchoBASE:EB1360 , EcoGene:EG11387 , EcoliWiki:b1927 , Mint:MINT-1279253 , ModBase:P26612 , OU-Microarray:b1927 , PortEco:amyA , PR:PRO_000022101 , Pride:P26612 , Protein Model Portal:P26612 , RefSeq:NP_416437 , RegulonDB:EG11387 , SMR:P26612 , String:511145.b1927 , UniProt:P26612
Relationship Links: CAZy:IN-FAMILY:GH13 , InterPro:IN-FAMILY:IPR006047 , InterPro:IN-FAMILY:IPR006589 , InterPro:IN-FAMILY:IPR013776 , InterPro:IN-FAMILY:IPR013780 , InterPro:IN-FAMILY:IPR013781 , InterPro:IN-FAMILY:IPR015902 , InterPro:IN-FAMILY:IPR017853 , Panther:IN-FAMILY:PTHR10357 , Pfam:IN-FAMILY:PF00128 , Smart:IN-FAMILY:SM00642
|Biological Process:||GO:0005975 - carbohydrate metabolic process
GO:0008152 - metabolic process [UniProtGOA11a]
|Molecular Function:||GO:0004556 - alpha-amylase activity
GO:0003824 - catalytic activity [GOA01a]
GO:0004553 - hydrolase activity, hydrolyzing O-glycosyl compounds [GOA01a]
GO:0005509 - calcium ion binding [GOA01a]
GO:0016787 - hydrolase activity [UniProtGOA11a]
GO:0016798 - hydrolase activity, acting on glycosyl bonds [UniProtGOA11a]
GO:0043169 - cation binding [GOA01a]
GO:0046872 - metal ion binding [UniProtGOA11a]
|Cellular Component:||GO:0005737 - cytoplasm
[UniProtGOA11, UniProtGOA11a, Raha92]
GO:0005829 - cytosol [DiazMejia09, Raha92]
|MultiFun Terms:||metabolism → carbon utilization → carbon compounds|
|metabolism → degradation of macromolecules → polysaccharides|
Enzymatic reaction of: α-amylase
Synonyms: 1,4-α-D-glucan glucanohydrolase
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.
The reaction is physiologically favored in the direction shown.
Alternative Substrates [Comment 1]:
Various reaction products, such as maltopentaose, maltotetraose, maltotriose, and maltose have been observed [Raha92].
T(opt): 45 °C [Raha92]
pH(opt): 7.2 [Raha92]
|Sequence-Conflict||19 -> 20|
10/20/97 Gene b1927 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG11387; confirmed by SwissProt match.
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
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