Escherichia coli K-12 substr. MG1655 Enzyme: aldehyde reductase, NADPH-dependent

Gene: ahr Accession Numbers: EG11436 (EcoCyc), b4269, ECK4262

Synonyms: yjgB, AdhZ3

Regulation Summary Diagram: ?

Regulation summary diagram for ahr

Ahr is a member of the zinc-containing medium-chain dehydrogenase/reductase family. The enzyme is a source of NADPH-dependent aldehyde reductase activity in the cell. Catalytic activity of the purified enzyme was measured with a variety of aldehyde substrates [Pick13].

Unpurified Ahr was previously shown to have acetaldehyde and isobutyraldehyde reductase activity, with a preference for the NADPH co-substrate. This activity contributes to the conversion of isobutyraldehyde to isobutanol in an engineered strain [Rodriguez12]. In a metabolically engineered strain, phenylacetaldehyde and 4-hydroxyphenylacetaldehyde are reduced to 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol by the endogenous aldehyde reductases YqhD, Ahr, and YahK [Koma12].

Mutants that change the preference of the enzyme for the NADPH cosubstrate towards NADH have been constructed [Pick14].

The yjgB gene of Salmonella enterica serovar Typhimurium is part of the RpoS regulon [IbanezRuiz00].

Ahr: "aldehyde reductase" [Akhtar13]

Locations: cytosol

Map Position: [4,493,213 <- 4,494,232] (96.84 centisomes, 349°)
Length: 1020 bp / 339 aa

Molecular Weight of Polypeptide: 36.502 kD (from nucleotide sequence)

Unification Links: ASAP:ABE-0013982 , EchoBASE:EB1406 , EcoGene:EG11436 , EcoliWiki:b4269 , ModBase:P27250 , OU-Microarray:b4269 , PortEco:yjgB , Pride:P27250 , Protein Model Portal:P27250 , RefSeq:NP_418690 , RegulonDB:EG11436 , SMR:P27250 , String:511145.b4269 , UniProt:P27250

Relationship Links: InterPro:IN-FAMILY:IPR002085 , InterPro:IN-FAMILY:IPR002328 , InterPro:IN-FAMILY:IPR011032 , InterPro:IN-FAMILY:IPR013149 , InterPro:IN-FAMILY:IPR013154 , InterPro:IN-FAMILY:IPR016040 , InterPro:IN-FAMILY:IPR029752 , Panther:IN-FAMILY:PTHR11695 , Pfam:IN-FAMILY:PF00107 , Pfam:IN-FAMILY:PF08240 , Prosite:IN-FAMILY:PS00059

In Paralogous Gene Group: 582 (3 members)

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Instance reaction of [an aldehyde + NADP+ + H2O → a carboxylate + NADPH + 2 H+] (
i3: acetaldehyde + NADP+ + H2O → acetate + NADPH + 2 H+ (

Instance reactions of [an alcohol + NADP+ = an aldehyde + NADPH + H+] (
i1: (S)-propane-1,2-diol + NADP+ = (S)-lactaldehyde + NADPH + H+ (1.1.1.-)

i2: (R)-propane-1,2-diol + NADP+ = (R)-lactaldehyde + NADPH + H+ (1.1.1.-)

GO Terms:

Biological Process: GO:0006629 - lipid metabolic process Inferred by computational analysis [UniProtGOA11]
GO:0006631 - fatty acid metabolic process Inferred by computational analysis [UniProtGOA11]
GO:0055114 - oxidation-reduction process Inferred by computational analysis [UniProtGOA11, GOA01]
Molecular Function: GO:0008106 - alcohol dehydrogenase (NADP+) activity Inferred from experiment Inferred by computational analysis [GOA01a, Pick13, Rodriguez12]
GO:0008270 - zinc ion binding Inferred from experiment Inferred by computational analysis [GOA01, Sevcenco11]
GO:0016491 - oxidoreductase activity Inferred by computational analysis [UniProtGOA11, GOA01]
GO:0046872 - metal ion binding Inferred by computational analysis [UniProtGOA11]
Cellular Component: GO:0005829 - cytosol Inferred by computational analysis [DiazMejia09]


Essentiality data for ahr 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]

Last-Curated ? 05-Sep-2014 by Keseler I , SRI International

Enzymatic reaction of: aldehyde reductase

EC Number:

an alcohol + NADP+ <=> an aldehyde + NADPH + H+

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

Reversibility of this reaction is unspecified.

Alternative Substrates for an alcohol: geraniol [Zhou14 ]

Alternative Substrates for an aldehyde: geranial [Zhou14 ] , butanal [Pick13 ] , furfural [Pick13 ]

Kinetic parameters for a range of substrates were measured in [Pick13]. The substrate specificity of the enzyme from E. coli BL21(DE3), which differs in a single amino acid from the K-12 enzyme, was characterized in [Akhtar13]; the enzyme primarily utilizes C4, C6 and C8 aldehydes. The initial rate of alcohol oxidation is two orders of magnitude lower than the initial rate of aldehyde reduction.

Kinetic Parameters:

Km (μM)

T(opt): 37-50 °C [Pick13]

pH(opt): 7-8 [Pick14]

Sequence Features

Protein sequence of aldehyde reductase, NADPH-dependent with features indicated

Feature Class Location Citations Comment
Metal-Binding-Site 38
UniProt: Zinc 1; catalytic; Non-Experimental Qualifier: by similarity;
Metal-Binding-Site 63
UniProt: Zinc 1; catalytic; Non-Experimental Qualifier: by similarity;
Metal-Binding-Site 96
UniProt: Zinc 2; Non-Experimental Qualifier: by similarity;
Metal-Binding-Site 99
UniProt: Zinc 2; Non-Experimental Qualifier: by similarity;
Metal-Binding-Site 102
UniProt: Zinc 2; Non-Experimental Qualifier: by similarity;
Metal-Binding-Site 110
UniProt: Zinc 2; Non-Experimental Qualifier: by similarity;
Metal-Binding-Site 152
UniProt: Zinc 1; catalytic; Non-Experimental Qualifier: by similarity;
Sequence-Conflict 331 -> 339
[Pucci92a, UniProt15]
UniProt: (in Ref. 1; AAA72122).

Gene Local Context (not to scale): ?

Gene local context diagram

Transcription Unit:

Transcription-unit diagram


Peter D. Karp on Wed Jan 18, 2006:
Gene right-end position adjusted based on analysis performed in the 2005 E. coli annotation update [Riley06 ].
10/20/97 Gene b4269 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG11436; confirmed by SwissProt match.


Akhtar13: Akhtar MK, Turner NJ, Jones PR (2013). "Carboxylic acid reductase is a versatile enzyme for the conversion of fatty acids into fuels and chemical commodities." Proc Natl Acad Sci U S A 110(1);87-92. PMID: 23248280

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

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

GOA01a: GOA, MGI (2001). "Gene Ontology annotation based on Enzyme Commission mapping." Genomics 74;121-128.

IbanezRuiz00: Ibanez-Ruiz M, Robbe-Saule V, Hermant D, Labrude S, Norel F (2000). "Identification of RpoS (sigma(S))-regulated genes in Salmonella enterica serovar typhimurium." J Bacteriol 182(20);5749-56. PMID: 11004173

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

Koma12: Koma D, Yamanaka H, Moriyoshi K, Ohmoto T, Sakai K (2012). "Production of aromatic compounds by metabolically engineered Escherichia coli with an expanded shikimate pathway." Appl Environ Microbiol 78(17);6203-16. PMID: 22752168

Pick13: Pick A, Ruhmann B, Schmid J, Sieber V (2013). "Novel CAD-like enzymes from Escherichia coli K-12 as additional tools in chemical production." Appl Microbiol Biotechnol 97(13);5815-24. PMID: 23093176

Pick14: Pick A, Ott W, Howe T, Schmid J, Sieber V (2014). "Improving the NADH-cofactor specificity of the highly active AdhZ3 and AdhZ2 from Escherichia coli K-12." J Biotechnol. PMID: 24992211

Pucci92a: Pucci M.J., Discotto L.F., Dougherty T.J. (1992). Data submission to EMBL/GenBank/DDBJ databases on 1992-09.

Riley06: Riley M, Abe T, Arnaud MB, Berlyn MK, Blattner FR, Chaudhuri RR, Glasner JD, Horiuchi T, Keseler IM, Kosuge T, Mori H, Perna NT, Plunkett G, Rudd KE, Serres MH, Thomas GH, Thomson NR, Wishart D, Wanner BL (2006). "Escherichia coli K-12: a cooperatively developed annotation snapshot--2005." Nucleic Acids Res 34(1);1-9. PMID: 16397293

Rodriguez12: Rodriguez GM, Atsumi S (2012). "Isobutyraldehyde production from Escherichia coli by removing aldehyde reductase activity." Microb Cell Fact 11(1);90. PMID: 22731523

Sevcenco11: Sevcenco AM, Pinkse MW, Wolterbeek HT, Verhaert PD, Hagen WR, Hagedoorn PL (2011). "Exploring the microbial metalloproteome using MIRAGE." Metallomics 3(12);1324-30. PMID: 22094925

UniProt10: UniProt Consortium (2010). "UniProt version 2010-07 released on 2010-06-15 00:00:00." Database.

UniProt15: UniProt Consortium (2015). "UniProt version 2015-01 released on 2015-01-16 00:00:00." Database.

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

Zhou14: Zhou J, Wang C, Yoon SH, Jang HJ, Choi ES, Kim SW (2014). "Engineering Escherichia coli for selective geraniol production with minimized endogenous dehydrogenation." J Biotechnol 169;42-50. PMID: 24269531

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Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
Page generated by SRI International Pathway Tools version 19.0 on Mon Mar 30, 2015, BIOCYC13A.