Escherichia coli K-12 substr. MG1655 Enzyme: α-amylase

Gene: amyA Accession Numbers: EG11387 (EcoCyc), b1927, ECK1926

Synonyms: yedC

Regulation Summary Diagram: ?

Regulation summary diagram for amyA

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.

Locations: cytosol

Map Position: [2,004,180 -> 2,005,667] (43.2 centisomes, 156°)
Length: 1488 bp / 495 aa

Molecular Weight of Polypeptide: 56.639 kD (from nucleotide sequence), 56 kD (experimental) [Raha92 ]

pI: 4.71

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

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

GO Terms:

Biological Process: GO:0005975 - carbohydrate metabolic process Inferred by computational analysis [UniProtGOA11a, GOA01a]
GO:0008152 - metabolic process Inferred by computational analysis [UniProtGOA11a]
Molecular Function: GO:0004556 - alpha-amylase activity Inferred from experiment Inferred by computational analysis [GOA01, Raha92]
GO:0003824 - catalytic activity Inferred by computational analysis [GOA01a]
GO:0004553 - hydrolase activity, hydrolyzing O-glycosyl compounds Inferred by computational analysis [GOA01a]
GO:0005509 - calcium ion binding Inferred by computational analysis [GOA01a]
GO:0016787 - hydrolase activity Inferred by computational analysis [UniProtGOA11a]
GO:0016798 - hydrolase activity, acting on glycosyl bonds Inferred by computational analysis [UniProtGOA11a]
GO:0043169 - cation binding Inferred by computational analysis [GOA01a]
GO:0046872 - metal ion binding Inferred by computational analysis [UniProtGOA11a]
Cellular Component: GO:0005737 - cytoplasm Inferred from experiment Inferred by computational analysis [UniProtGOA11, UniProtGOA11a, Raha92]
GO:0005829 - cytosol Inferred by computational analysis [DiazMejia09, Raha92]

MultiFun Terms: metabolism carbon utilization carbon compounds
metabolism degradation of macromolecules polysaccharides

Essentiality data for amyA knockouts: ?

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB enriched Yes 37 Aerobic 6.95   Yes [Gerdes03, Comment 1]
LB Lennox Yes 37 Aerobic 7   Yes [Baba06, Comment 2]
M9 medium with 1% glycerol Yes 37 Aerobic 7.2 0.35 Yes [Joyce06, Comment 3]
MOPS medium with 0.4% glucose Yes 37 Aerobic 7.2 0.22 Yes [Baba06, Comment 2]
Yes [Feist07, Comment 4]

Last-Curated ? 30-Mar-2011 by Keseler I , SRI International

Enzymatic reaction of: α-amylase

Synonyms: 1,4-α-D-glucan glucanohydrolase

EC Number:

a 1,4-α-D-glucan + n H2O <=> n a 1,4-α-D-glucan

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 5]:

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 Features

Protein sequence of alpha-amylase with features indicated

Feature Class Location Citations Comment
Sequence-Conflict 19 -> 20
[Raha92, UniProt10]
UniProt: (in Ref. 1; AAA23810);
Metal-Binding-Site 104
UniProt: Calcium; Non-Experimental Qualifier: by similarity;
Sequence-Conflict 109
[Raha92, UniProt10]
UniProt: (in Ref. 1; AAA23810);
Sequence-Conflict 149
[Raha92, UniProt10]
UniProt: (in Ref. 1; AAA23810);
Sequence-Conflict 234
[Raha92, UniProt10]
UniProt: (in Ref. 1; AAA23810);
Active-Site 235
UniProt: Nucleophile; Non-Experimental Qualifier: by similarity;
Metal-Binding-Site 239
UniProt: Calcium; via carbonyl oxygen; Non-Experimental Qualifier: by similarity;
Active-Site 265
UniProt: Proton donor; Non-Experimental Qualifier: by similarity;
Active-Site 332
UniProt: Non-Experimental Qualifier: by similarity;

Gene Local Context (not to scale): ?

Gene local context diagram

Transcription Unit:

Transcription-unit diagram


10/20/97 Gene b1927 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG11387; confirmed by SwissProt match.


Baba06: Baba T, Ara T, Hasegawa M, Takai Y, Okumura Y, Baba M, Datsenko KA, Tomita M, Wanner BL, Mori H (2006). "Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection." Mol Syst Biol 2;2006.0008. PMID: 16738554

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

Feist07: Feist AM, Henry CS, Reed JL, Krummenacker M, Joyce AR, Karp PD, Broadbelt LJ, Hatzimanikatis V, Palsson BO (2007). "A genome-scale metabolic reconstruction for Escherichia coli K-12 MG1655 that accounts for 1260 ORFs and thermodynamic information." Mol Syst Biol 3;121. PMID: 17593909

Gerdes03: Gerdes SY, Scholle MD, Campbell JW, Balazsi G, Ravasz E, Daugherty MD, Somera AL, Kyrpides NC, Anderson I, Gelfand MS, Bhattacharya A, Kapatral V, D'Souza M, Baev MV, Grechkin Y, Mseeh F, Fonstein MY, Overbeek R, Barabasi AL, Oltvai ZN, Osterman AL (2003). "Experimental determination and system level analysis of essential genes in Escherichia coli MG1655." J Bacteriol 185(19);5673-84. PMID: 13129938

GOA01: GOA, MGI (2001). "Gene Ontology annotation based on Enzyme Commission mapping." Genomics 74;121-128.

GOA01a: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

Joyce06: Joyce AR, Reed JL, White A, Edwards R, Osterman A, Baba T, Mori H, Lesely SA, Palsson BO, Agarwalla S (2006). "Experimental and computational assessment of conditionally essential genes in Escherichia coli." J Bacteriol 188(23);8259-71. PMID: 17012394

Raha92: Raha M, Kawagishi I, Muller V, Kihara M, Macnab RM (1992). "Escherichia coli produces a cytoplasmic alpha-amylase, AmyA." J Bacteriol 1992;174(20);6644-52. PMID: 1400215

UniProt10: UniProt Consortium (2010). "UniProt version 2010-11 released on 2010-11-02 00:00:00." Database.

UniProt10a: UniProt Consortium (2010). "UniProt version 2010-07 released on 2010-06-15 00:00:00." Database.

UniProtGOA11: UniProt-GOA (2011). "Gene Ontology annotation based on the manual assignment of UniProtKB Subcellular Location terms in UniProtKB/Swiss-Prot entries."

UniProtGOA11a: UniProt-GOA (2011). "Gene Ontology annotation based on manual assignment of UniProtKB keywords in UniProtKB/Swiss-Prot entries."

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Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
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