ExplorEnz: EC 1*

References:

1.	Estrada, A.F., Youssar, L., Scherzinger, D., Al-Babili, S. and Avalos, J. The ylo-1 gene encodes an aldehyde dehydrogenase responsible for the last reaction in the Neurospora carotenoid pathway. Mol. Microbiol. 69 (2008) 1207–1220. [DOI] [PMID: 18627463]
2.	Diaz-Sanchez, V., Estrada, A.F., Trautmann, D., Al-Babili, S. and Avalos, J. The gene carD encodes the aldehyde dehydrogenase responsible for neurosporaxanthin biosynthesis in Fusarium fujikuroi. FEBS J. 278 (2011) 3164–3176. [DOI] [PMID: 21749649]

[EC 1.2.1.82 created 2011, modified 2023]

1.2.1.83

Accepted name:

3-succinoylsemialdehyde-pyridine dehydrogenase

Reaction:

4-oxo-4-(pyridin-3-yl)butanal + NADP⁺ + H₂O = 4-oxo-4-(pyridin-3-yl)butanoate + NADPH + H⁺

Glossary:

4-oxo-4-(pyridin-3-yl)butanal = 3-succinoylsemialdehyde-pyridine
4-oxo-4-(3-pyridyl)-butanoate = 3-succinoyl-pyridine

Systematic name:

4-oxo-4-(pyridin-3-yl)butanal:NADP⁺ oxidoreductase

Comments:

The enzyme has been characterized from the soil bacterium Pseudomonas sp. HZN6. It participates in the nicotine degradation pathway.

Links to other databases:

References:

1.	Qiu, J., Ma, Y., Wen, Y., Chen, L., Wu, L. and Liu, W. Functional identification of two novel genes from Pseudomonas sp. strain HZN6 involved in the catabolism of nicotine. Appl. Environ. Microbiol. 78 (2012) 2154–2160. [DOI] [PMID: 22267672]

[EC 1.2.1.83 created 2012]

1.2.1.84

Accepted name:

alcohol-forming fatty acyl-CoA reductase (NADPH)

Reaction:

a long-chain acyl-CoA + 2 NADPH + 2 H⁺ = a long-chain alcohol + 2 NADP⁺ + CoA

Glossary:

a long-chain acyl-CoA = an acyl-CoA thioester where the acyl chain contains 13 to 22 carbon atoms.

Other name(s):

FAR (gene name); long-chain acyl-CoA:NADPH reductase

Systematic name:

NADPH:long-chain acyl-CoA reductase

Comments:

The enzyme has a wide distribution and is found in bacteria, plants, fungi, and animals. The alcohol is formed by a four-electron reduction of fatty acyl-CoA. Although the reaction proceeds through an aldehyde intermediate, a free aldehyde is not released. Enzymes from different sources vary in their chain-length preference. cf. EC 1.2.1.108, alcohol-forming fatty acyl-CoA reductase (NADH).

Links to other databases:

BRENDA, EXPASY, GENE, KEGG, MetaCyc, PDB

References:

1.	Metz, J.G., Pollard, M.R., Anderson, L., Hayes, T.R. and Lassner, M.W. Purification of a jojoba embryo fatty acyl-coenzyme A reductase and expression of its cDNA in high erucic acid rapeseed. Plant Physiol. 122 (2000) 635–644. [PMID: 10712526]
2.	Cheng, J.B. and Russell, D.W. Mammalian wax biosynthesis. I. Identification of two fatty acyl-Coenzyme A reductases with different substrate specificities and tissue distributions. J. Biol. Chem. 279 (2004) 37789–37797. [DOI] [PMID: 15220348]
3.	Doan, T.T., Carlsson, A.S., Hamberg, M., Bulow, L., Stymne, S. and Olsson, P. Functional expression of five Arabidopsis fatty acyl-CoA reductase genes in Escherichia coli. J. Plant Physiol. 166 (2009) 787–796. [DOI] [PMID: 19062129]
4.	Moto, K., Yoshiga, T., Yamamoto, M., Takahashi, S., Okano, K., Ando, T., Nakata, T. and Matsumoto, S. Pheromone gland-specific fatty-acyl reductase of the silkmoth, Bombyx mori. Proc. Natl. Acad. Sci. USA 100 (2003) 9156–9161. [DOI] [PMID: 12871998]

[EC 1.2.1.84 created 2012, modified 2025]

1.2.1.85

Accepted name:

2-hydroxymuconate-6-semialdehyde dehydrogenase

Reaction:

2-hydroxymuconate-6-semialdehyde + NAD⁺ + H₂O = (2Z,4E)-2-hydroxyhexa-2,4-dienedioate + NADH + 2 H⁺

For diagram of catechol catabolism (meta ring cleavage), click here

Glossary:

2-hydroxymuconate-6-semialdehyde = (2Z,4E)-2-hydroxy-6-oxohexa-2,4-dienoate

Other name(s):

xylG (gene name); praB (gene name)

Systematic name:

2-hydroxymuconate-6-semialdehyde:NAD⁺ oxidoreductase

Comments:

This substrate for this enzyme is formed by meta ring cleavage of catechol (EC 1.13.11.2, catechol 2,3-dioxygenase), and is an intermediate in the bacterial degradation of several aromatic compounds. Has lower activity with benzaldehyde [1]. Activity with NAD⁺ is more than 10-fold higher than with NADP⁺ [3]. cf. EC 1.2.1.32, aminomuconate-semialdehyde dehydrogenase.

Links to other databases:

References:

1.	Inoue, J., Shaw, J.P., Rekik, M. and Harayama, S. Overlapping substrate specificities of benzaldehyde dehydrogenase (the xylC gene product) and 2-hydroxymuconic semialdehyde dehydrogenase (the xylG gene product) encoded by TOL plasmid pWW0 of Pseudomonas putida. J. Bacteriol. 177 (1995) 1196–1201. [DOI] [PMID: 7868591]
2.	Orii, C., Takenaka, S., Murakami, S. and Aoki, K. Metabolism of 4-amino-3-hydroxybenzoic acid by Bordetella sp. strain 10d: A different modified meta-cleavage pathway for 2-aminophenols. Biosci. Biotechnol. Biochem. 70 (2006) 2653–2661. [DOI] [PMID: 17090920]
3.	Kasai, D., Fujinami, T., Abe, T., Mase, K., Katayama, Y., Fukuda, M. and Masai, E. Uncovering the protocatechuate 2,3-cleavage pathway genes. J. Bacteriol. 191 (2009) 6758–6768. [DOI] [PMID: 19717587]

[EC 1.2.1.85 created 2012]

1.2.1.86

Accepted name:

geranial dehydrogenase

Reaction:

geranial + H₂O + NAD⁺ = geranate + NADH + H⁺

For diagram of acyclic monoterpenoid biosynthesis, click here

Other name(s):

GaDH; geoB (gene name)

Systematic name:

geranial:NAD⁺ oxidoreductase

Comments:

Does not act on neral.

Links to other databases:

BRENDA, EAWAG-BBD, EXPASY, Gene, KEGG, MetaCyc

References:

1.	Wolken, W.A. and van der Werf, M.J. Geraniol biotransformation-pathway in spores of Penicillium digitatum. Appl. Microbiol. Biotechnol. 57 (2001) 731–737. [PMID: 11778886]
2.	Lüddeke, F., Wülfing, A., Timke, M., Germer, F., Weber, J., Dikfidan, A., Rahnfeld, T., Linder, D., Meyerdierks, A. and Harder, J. Geraniol and geranial dehydrogenases induced in anaerobic monoterpene degradation by Castellaniella defragrans. Appl. Environ. Microbiol. 78 (2012) 2128–2136. [DOI] [PMID: 22286981]

[EC 1.2.1.86 created 2012]

1.2.1.87

Accepted name:

propanal dehydrogenase (CoA-propanoylating)

Reaction:

propanal + CoA + NAD⁺ = propanoyl-CoA + NADH + H⁺

Other name(s):

BphJ

Systematic name:

propanal:NAD⁺ oxidoreductase (CoA-propanoylating)

Comments:

The enzyme forms a bifunctional complex with EC 4.1.3.43, 4-hydroxy-2-oxohexanoate aldolase, with a tight channel connecting the two subunits [1,2,3]. Also acts, more slowly, on glycolaldehyde and butanal. In Pseudomonas species the enzyme forms a bifunctional complex with EC 4.1.3.39, 4-hydroxy-2-oxovalerate aldolase. The enzymes from the bacteria Burkholderia xenovorans and Thermus thermophilus also perform the reaction of EC 1.2.1.10, acetaldehyde dehydrogenase (acetylating). NADP⁺ can replace NAD⁺ with a much slower rate [3].

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB

References:

1.	Baker, P., Pan, D., Carere, J., Rossi, A., Wang, W. and Seah, S.Y.K. Characterization of an aldolase-dehydrogenase complex that exhibits substrate channeling in the polychlorinated biphenyls degradation pathway. Biochemistry 48 (2009) 6551–6558. [DOI] [PMID: 19476337]
2.	Carere, J., Baker, P. and Seah, S.Y.K. Investigating the molecular determinants for substrate channeling in BphI-BphJ, an aldolase-dehydrogenase complex from the polychlorinated biphenyls degradation pathway. Biochemistry 50 (2011) 8407–8416. [DOI] [PMID: 21838275]
3.	Baker, P., Hillis, C., Carere, J. and Seah, S.Y.K. Protein-protein interactions and substrate channeling in orthologous and chimeric aldolase-dehydrogenase complexes. Biochemistry 51 (2012) 1942–1952. [DOI] [PMID: 22316175]

[EC 1.2.1.87 created 2013]

1.2.1.88

Accepted name:

L-glutamate γ-semialdehyde dehydrogenase

Reaction:

L-glutamate 5-semialdehyde + NAD⁺ + H₂O = L-glutamate + NADH + H⁺

For diagram of reaction, click here

Glossary:

L-glutamate 5-semialdehyde = L-glutamate γ-semialdehyde = (S)-2-amino-5-oxopentanoate

Other name(s):

1-pyrroline-5-carboxylate dehydrogenase; Δ¹-pyrroline-5-carboxylate dehydrogenase; 1-pyrroline dehydrogenase; pyrroline-5-carboxylate dehydrogenase; pyrroline-5-carboxylic acid dehydrogenase; L-pyrroline-5-carboxylate-NAD⁺ oxidoreductase; 1-pyrroline-5-carboxylate:NAD⁺ oxidoreductase; Δ¹-pyrroline-5-carboxylic acid dehydrogenase

Systematic name:

L-glutamate γ-semialdehyde:NAD⁺ oxidoreductase

Comments:

This enzyme catalyses the irreversible oxidation of glutamate-γ-semialdehyde to glutamate as part of the proline degradation pathway. (S)-1-pyrroline-5-carboxylate, the product of the first enzyme of the pathway (EC 1.5.5.2, proline dehydrogenase) is in spontaneous equilibrium with its tautomer L-glutamate γ-semialdehyde. In many bacterial species, both activities are carried out by a single bifunctional enzyme [3,4].The enzyme can also oxidize other 1-pyrrolines, e.g. 3-hydroxy-1-pyrroline-5-carboxylate is converted into 4-hydroxyglutamate and (R)-1-pyrroline-5-carboxylate is converted into D-glutamate. NADP⁺ can also act as acceptor, but with lower activity [5].

Links to other databases:

BRENDA, EXPASY, Gene, KEGG, MetaCyc, PDB, CAS registry number: 9054-82-4

References:

1.	Adams, E. and Goldstone, A. Hydroxyproline metabolism. IV. Enzymatic synthesis of γ-hydroxyglutamate from Δ¹-pyrroline-3-hydroxy-5-carboxylate. J. Biol. Chem. 235 (1960) 3504–3512. [PMID: 13681370]
2.	Strecker, H.J. The interconversion of glutamic acid and proline. III. Δ¹-Pyrroline-5-carboxylic acid dehydrogenase. J. Biol. Chem. 235 (1960) 3218–3223.
3.	Forlani, G., Scainelli, D. and Nielsen, E. Δ¹-Pyrroline-5-carboxylate dehydrogenase from cultured cells of potato (purification and properties). Plant Physiol. 113 (1997) 1413–1418. [PMID: 12223682]
4.	Brown, E.D. and Wood, J.M. Redesigned purification yields a fully functional PutA protein dimer from Escherichia coli. J. Biol. Chem. 267 (1992) 13086–13092. [PMID: 1618807]
5.	Inagaki, E., Ohshima, N., Sakamoto, K., Babayeva, N.D., Kato, H., Yokoyama, S. and Tahirov, T.H. New insights into the binding mode of coenzymes: structure of Thermus thermophilus Δ¹-pyrroline-5-carboxylate dehydrogenase complexed with NADP⁺. Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun. 63 (2007) 462–465. [DOI] [PMID: 17554163]

[EC 1.2.1.88 created 1972 as EC 1.5.1.12, modified 2008, transferred 2013 to EC 1.2.1.88]

1.2.1.89

Accepted name:

D-glyceraldehyde dehydrogenase (NADP⁺)

Reaction:

D-glyceraldehyde + NADP⁺ + H₂O = D-glycerate + NADPH + H⁺

Other name(s):

glyceraldehyde dehydrogenase; GADH

Systematic name:

D-glyceraldehyde:NADP⁺ oxidoreductase

Comments:

The enzyme from the archaea Thermoplasma acidophilum and Picrophilus torridus is involved in the non-phosphorylative Entner-Doudoroff pathway. cf. EC 1.2.99.8, glyceraldehyde dehydrogenase (FAD-containing).

Links to other databases:

References:

1.	Jung, J.H. and Lee, S.B. Identification and characterization of Thermoplasma acidophilum glyceraldehyde dehydrogenase: a new class of NADP⁺-specific aldehyde dehydrogenase. Biochem. J. 397 (2006) 131–138. [DOI] [PMID: 16566751]
2.	Reher, M. and Schonheit, P. Glyceraldehyde dehydrogenases from the thermoacidophilic euryarchaeota Picrophilus torridus and Thermoplasma acidophilum, key enzymes of the non-phosphorylative Entner-Doudoroff pathway, constitute a novel enzyme family within the aldehyde dehydrogenase superfamily. FEBS Lett. 580 (2006) 1198–1204. [DOI] [PMID: 16458304]

[EC 1.2.1.89 created 2014]

1.2.1.90

Accepted name:

glyceraldehyde-3-phosphate dehydrogenase [NAD(P)⁺]

Reaction:

D-glyceraldehyde 3-phosphate + NAD(P)⁺ + H₂O = 3-phospho-D-glycerate + NAD(P)H + 2 H⁺

Other name(s):

non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase (ambiguous); GAPN

Systematic name:

D-glyceraldehyde-3-phosphate:NAD(P)⁺ oxidoreductase

Comments:

The enzyme is part of the modified Embden-Meyerhof-Parnas pathway of the archaeon Thermoproteus tenax. cf. EC 1.2.1.9 [glyceraldehyde-3-phosphate dehydrogenase (NADP⁺)].

Links to other databases:

References:

1.	Brunner, N.A., Brinkmann, H., Siebers, B. and Hensel, R. NAD⁺-dependent glyceraldehyde-3-phosphate dehydrogenase from Thermoproteus tenax. The first identified archaeal member of the aldehyde dehydrogenase superfamily is a glycolytic enzyme with unusual regulatory properties. J. Biol. Chem. 273 (1998) 6149–6156. [DOI] [PMID: 9497334]
2.	Brunner, N.A., Siebers, B. and Hensel, R. Role of two different glyceraldehyde-3-phosphate dehydrogenases in controlling the reversible Embden-Meyerhof-Parnas pathway in Thermoproteus tenax: regulation on protein and transcript level. Extremophiles 5 (2001) 101–109. [PMID: 11354453]
3.	Pohl, E., Brunner, N., Wilmanns, M. and Hensel, R. The crystal structure of the allosteric non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic archaeum Thermoproteus tenax. J. Biol. Chem. 277 (2002) 19938–19945. [DOI] [PMID: 11842090]
4.	Lorentzen, E., Hensel, R., Knura, T., Ahmed, H. and Pohl, E. Structural basis of allosteric regulation and substrate specificity of the non-phosphorylating glyceraldehyde 3-phosphate dehydrogenase from Thermoproteus tenax. J. Mol. Biol. 341 (2004) 815–828. [DOI] [PMID: 15288789]

[EC 1.2.1.90 created 2014]

1.2.1.91

Accepted name:

3-oxo-5,6-dehydrosuberyl-CoA semialdehyde dehydrogenase

Reaction:

3-oxo-5,6-dehydrosuberyl-CoA semialdehyde + NADP⁺ + H₂O = 3-oxo-5,6-dehydrosuberyl-CoA + NADPH + H⁺

For diagram of aerobic phenylacetate catabolism, click here

Glossary:

3-oxo-5,6-dehydrosuberyl-CoA semialdehyde = 3,8-dioxooct-5-enoyl-CoA

Other name(s):

paaZ (gene name)

Systematic name:

3-oxo-5,6-dehydrosuberyl-CoA semialdehyde:NADP⁺ oxidoreductase

Comments:

The enzyme from Escherichia coli is a bifunctional fusion protein that also catalyses EC 3.3.2.12, oxepin-CoA hydrolase. Combined the two activities result in a two-step conversion of oxepin-CoA to 3-oxo-5,6-dehydrosuberyl-CoA, part of an aerobic phenylacetate degradation pathway.

Links to other databases:

References:

1.	Ferrandez, A., Minambres, B., Garcia, B., Olivera, E.R., Luengo, J.M., Garcia, J.L. and Diaz, E. Catabolism of phenylacetic acid in Escherichia coli. Characterization of a new aerobic hybrid pathway. J. Biol. Chem. 273 (1998) 25974–25986. [DOI] [PMID: 9748275]
2.	Ismail, W., El-Said Mohamed, M., Wanner, B.L., Datsenko, K.A., Eisenreich, W., Rohdich, F., Bacher, A. and Fuchs, G. Functional genomics by NMR spectroscopy. Phenylacetate catabolism in Escherichia coli. Eur. J. Biochem. 270 (2003) 3047–3054. [DOI] [PMID: 12846838]
3.	Teufel, R., Mascaraque, V., Ismail, W., Voss, M., Perera, J., Eisenreich, W., Haehnel, W. and Fuchs, G. Bacterial phenylalanine and phenylacetate catabolic pathway revealed. Proc. Natl. Acad. Sci. USA 107 (2010) 14390–14395. [DOI] [PMID: 20660314]

[EC 1.2.1.91 created 2011 as EC 1.17.1.7, transferred 2014 to EC 1.2.1.91]

1.2.1.92

Accepted name:

3,6-anhydro-α-L-galactose dehydrogenase

Reaction:

3,6-anhydro-α-L-galactopyranose + NAD(P)⁺ + H₂O = 3,6-anhydro-L-galactonate + NAD(P)H + H⁺

Systematic name:

3,6-anhydro-α-L-galactopyranose:NAD(P)⁺ 1-oxidoredutase

Comments:

The enzyme, characterized from the marine bacterium Vibrio sp. EJY3, is involved in a degradation pathway for 3,6-anhydro-α-L-galactose, a major component of the polysaccharides produced by red macroalgae, such as agarose and porphyran.

Links to other databases:

References:

1.	Yun, E.J., Lee, S., Kim, H.T., Pelton, J.G., Kim, S., Ko H,-J., Choi I,-G. and Kim, K.H. The novel catabolic pathway of 3,6-anhydro-L-galactose, the main component of red macroalgae, in a marine bacterium. Environ. Microbiol. 17 (2014) 1677–1688. [DOI] [PMID: 25156229]

[EC 1.2.1.92 created 2014]

1.2.1.93

Transferred entry:

formate dehydrogenase (NAD⁺, ferredoxin). Now EC 1.17.1.11, formate dehydrogenase (NAD⁺, ferredoxin)

[EC 1.2.1.93 created 2015, deleted 2017]

1.2.1.94

Accepted name:

farnesal dehydrogenase

Reaction:

(2E,6E)-farnesal + NAD⁺ + H₂O = (2E,6E)-farnesoate + NADH + 2 H⁺

For diagram of juvenile hormone biosynthesis, click here

Glossary:

farnesal = 3,7,11-trimethyldodeca-2,6,10-trienal
farnesoate = 3,7,11-trimethyldodeca-2,6,10-trienoate

Other name(s):

AaALDH3

Systematic name:

farnesal:NAD⁺ oxidoreductase

Comments:

Invoved in juvenile hormone production in insects. The enzyme was described from the corpora allata of Drosophila melanogaster (fruit fly), Manduca sexta (tobacco hornworm) and Aedes aegypti (dengue mosquito).

Links to other databases:

References:

1.	Madhavan, K., Conscience-Egli, M., Sieber, F. and Ursprung, H. Farnesol metabolism in Drosophila melanogaster: ontogeny and tissue distribution of octanol dehydrogenase and aldehyde oxidase. J. Insect Physiol. 19 (1973) 235–241. [DOI] [PMID: 4631837]
2.	Baker, F.C., Mauchamp, B., Tsai, L.W. and Schooley, D.A. Farnesol and farnesal dehydrogenase(s) in corpora allata of the tobacco hornworm moth, Manduca sexta. J. Lipid Res. 24 (1983) 1586–1594. [PMID: 6366103]
3.	Rivera-Perez, C., Nouzova, M., Clifton, M.E., Garcia, E.M., LeBlanc, E. and Noriega, F.G. Aldehyde dehydrogenase 3 converts farnesal into farnesoic acid in the corpora allata of mosquitoes. Insect Biochem. Mol. Biol. 43 (2013) 675–682. [DOI] [PMID: 23639754]

[EC 1.2.1.94 created 2015]

1.2.1.95

Accepted name:

L-2-aminoadipate reductase

Reaction:

(S)-2-amino-6-oxohexanoate + NADP⁺ + AMP + diphosphate = L-2-aminoadipate + NADPH + H⁺ + ATP (overall reaction)
(1a) L-2-aminoadipyl-[LYS2 peptidyl-carrier-protein] + AMP + diphosphate = L-2-aminoadipate + holo-[LYS2 peptidyl-carrier-protein] + ATP
(1b) (S)-2-amino-6-oxohexanoate + holo-[LYS2 peptidyl-carrier-protein] + NADP⁺ = L-2-aminoadipyl-[LYS2 peptidyl-carrier-protein] + NADPH + H⁺

Glossary:

L-2-aminoadipate = (2S)-2-aminohexanedioate

Other name(s):

LYS2; α-aminoadipate reductase

Systematic name:

(S)-2-amino-6-oxohexanoate:NADP⁺ oxidoreductase (ATP-forming)

Comments:

This enzyme, characterized from the yeast Saccharomyces cerevisiae, catalyses the reduction of L-2-aminoadipate to (S)-2-amino-6-oxohexanoate during L-lysine biosynthesis. An adenylation domain activates the substrate at the expense of ATP hydrolysis, and forms L-2-aminoadipate adenylate, which is attached to a peptidyl-carrier protein (PCP) domain. Binding of NADPH results in reductive cleavage of the acyl-S-enzyme intermediate, releasing (S)-2-amino-6-oxohexanoate. Different from EC 1.2.1.31, L-aminoadipate-semialdehyde dehydrogenase, which catalyses a similar transformation in the opposite direction without ATP hydrolysis.

Links to other databases:

References:

1.	Ehmann, D.E., Gehring, A.M. and Walsh, C.T. Lysine biosynthesis in Saccharomyces cerevisiae: mechanism of α-aminoadipate reductase (Lys²) involves posttranslational phosphopantetheinylation by Lys⁵. Biochemistry 38 (1999) 6171–6177. [DOI] [PMID: 10320345]

[EC 1.2.1.95 created 2015]

1.2.1.96

Accepted name:

4-hydroxybenzaldehyde dehydrogenase (NADP⁺)

Reaction:

4-hydroxybenzaldehyde + NADP⁺ + H₂O = 4-hydroxybenzoate + NADPH + 2 H⁺

Other name(s):

p-hydroxybenzaldehyde dehydrogenase (ambiguous); pchA (gene name)

Systematic name:

4-hydroxybenzaldehyde:NADP⁺ oxidoreductase

Comments:

Involved in the aerobic pathway for degradation of toluene, 4-methylphenol, and 2,4-xylenol by several Pseudomonas strains. The enzyme is also active with 4-hydroxy-3-methylbenzaldehyde. cf. EC 1.2.1.64, 4-hydroxybenzaldehyde dehydrogenase (NAD⁺).

Links to other databases:

BRENDA, EAWAG-BBD, EXPASY, Gene, KEGG, MetaCyc, CAS registry number: 61229-72-9

References:

1.	Whited, G.M. and Gibson, D.T. Separation and partial characterization of the enzymes of the toluene-4-monooxygenase catabolic pathway in Pseudomonas mendocina KR1. J. Bacteriol. 173 (1991) 3017–3020. [DOI] [PMID: 2019564]
2.	Chen, Y.F., Chao, H. and Zhou, N.Y. The catabolism of 2,4-xylenol and p-cresol share the enzymes for the oxidation of para-methyl group in Pseudomonas putida NCIMB 9866. Appl. Microbiol. Biotechnol. 98 (2014) 1349–1356. [DOI] [PMID: 23736872]

[EC 1.2.1.96 created 2015]

1.2.1.97

Accepted name:

3-sulfolactaldehyde dehydrogenase

Reaction:

(2S)-3-sulfolactaldehyde + NAD(P)⁺ + H₂O = (2S)-3-sulfolactate + NAD(P)H + H⁺

For diagram of sulphoglycolysis of sulfoquinovose, click here

Glossary:

(2S)-3-sulfolactaldehyde = (2S)-2-hydroxy-3-oxopropane-1-sulfonate

Other name(s):

SLA dehydrogenase

Systematic name:

(2S)-3-sulfolactaldehyde:NAD(P)⁺ oxidoreductase

Comments:

The enzyme, characterized from the bacterium Pseudomonas putida SQ1, participates in a sulfoquinovose degradation pathway. Also acts on succinate semialdehyde.

Links to other databases:

References:

1.	Felux, A.K., Spiteller, D., Klebensberger, J. and Schleheck, D. Entner-Doudoroff pathway for sulfoquinovose degradation in Pseudomonas putida SQ1. Proc. Natl. Acad. Sci. USA 112 (2015) E4298–E4305. [DOI] [PMID: 26195800]

[EC 1.2.1.97 created 2015]

1.2.1.98

Accepted name:

2-hydroxy-2-methylpropanal dehydrogenase

Reaction:

2-hydroxy-2-methylpropanal + NAD⁺ + H₂O = 2-hydroxy-2-methylpropanoate + NADH + H⁺

Other name(s):

mpdC (gene name)

Systematic name:

2-hydroxy-2-methylpropanal:NAD⁺ oxidoreductase

Comments:

This bacterial enzyme is involved in the degradation pathways of the alkene 2-methylpropene and the fuel additive tert-butyl methyl ether (MTBE), a widely occurring groundwater contaminant.

Links to other databases:

References:

1.	Lopes Ferreira, N., Labbe, D., Monot, F., Fayolle-Guichard, F. and Greer, C.W. Genes involved in the methyl tert-butyl ether (MTBE) metabolic pathway of Mycobacterium austroafricanum IFP 2012. Microbiology 152 (2006) 1361–1374. [DOI] [PMID: 16622053]

[EC 1.2.1.98 created 2016]

1.2.1.99

Accepted name:

4-(γ-glutamylamino)butanal dehydrogenase

Reaction:

4-(γ-L-glutamylamino)butanal + NAD(P)⁺ + H₂O = 4-(γ-L-glutamylamino)butanoate + NAD(P)H + H⁺

Other name(s):

puuC (gene name)

Systematic name:

4-(γ-L-glutamylamino)butanal:NAD(P)⁺ oxidoreductase

Comments:

The enzyme, characterized from the bacterium Escherichia coli, is involved in a putrescine catabolic pathway. It has a broad substrate range, and can also catalyse the activities of EC 1.2.1.19, aminobutyraldehyde dehydrogenase, and EC 1.2.1.24, succinate-semialdehyde dehydrogenase (NAD⁺).

Links to other databases:

References:

1.	Kurihara, S., Oda, S., Kato, K., Kim, H.G., Koyanagi, T., Kumagai, H. and Suzuki, H. A novel putrescine utilization pathway involves γ-glutamylated intermediates of Escherichia coli K-12. J. Biol. Chem. 280 (2005) 4602–4608. [DOI] [PMID: 15590624]
2.	Jo, J.E., Mohan Raj, S., Rathnasingh, C., Selvakumar, E., Jung, W.C. and Park, S. Cloning, expression, and characterization of an aldehyde dehydrogenase from Escherichia coli K-12 that utilizes 3-hydroxypropionaldehyde as a substrate. Appl. Microbiol. Biotechnol. 81 (2008) 51–60. [DOI] [PMID: 18668238]
3.	Schneider, B.L. and Reitzer, L. Pathway and enzyme redundancy in putrescine catabolism in Escherichia coli. J. Bacteriol. 194 (2012) 4080–4088. [DOI] [PMID: 22636776]

[EC 1.2.1.99 created 2017]

1.2.1.100

Accepted name:

5-formyl-3-hydroxy-2-methylpyridine 4-carboxylic acid 5-dehydrogenase

Reaction:

5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate + NAD⁺ + H₂O = 3-hydroxy-2-methylpyridine-4,5-dicarboxylate + NADH + H⁺

For diagram of pyridoxal catabolism, click here

Other name(s):

mlr6793 (locus name)

Systematic name:

5-formyl-3-hydroxy-2-methylpyridine-4-carboxylate:NAD⁺ 5-oxidoreductase

Comments:

The enzyme, characterized from the bacteria Pseudomonas sp. MA-1 and Mesorhizobium loti, participates in the degradation of pyridoxine (vitamin B₆).

Links to other databases:

References:

1.	Lee, Y.C., Nelson, M.J. and Snell, E.E. Enzymes of vitamin B₆ degradation. Purification and properties of isopyridoxal dehydrogenase and 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylic-acid dehydrogenase. J. Biol. Chem. 261 (1986) 15106–15111. [PMID: 3533936]
2.	Yokochi, N., Yoshikane, Y., Matsumoto, S., Fujisawa, M., Ohnishi, K. and Yagi, T. Gene identification and characterization of 5-formyl-3-hydroxy-2-methylpyridine 4-carboxylic acid 5-dehydrogenase, an NAD⁺-dependent dismutase. J. Biochem. 145 (2009) 493–503. [DOI] [PMID: 19218190]
3.	Mugo, A.N., Kobayashi, J., Mikami, B., Yoshikane, Y., Yagi, T. and Ohnishi, K. Crystal structure of 5-formyl-3-hydroxy-2-methylpyridine 4-carboxylic acid 5-dehydrogenase, an NAD(+)-dependent dismutase from Mesorhizobium loti. Biochem. Biophys. Res. Commun. 456 (2015) 35–40. [DOI] [PMID: 25446130]

[EC 1.2.1.100 created 2018]

1.2.1.101

Accepted name:

L-tyrosine reductase

Reaction:

L-tyrosinal + NADP⁺ + AMP + diphosphate = L-tyrosine + NADPH + H⁺ + ATP

Glossary:

L-tyrosinal = (2S)-2-amino-3-(4-hydroxyphenyl)propanal

Other name(s):

lnaA (gene name); lnbA (gene name)

Systematic name:

(2S)-2-amino-3-(4-hydroxyphenyl)propanal:NADP⁺ oxidoreductase (ATP-forming)

Comments:

The enzyme, characterized from the ascomycete fungus Aspergillus flavus, is specific for L-tyrosine. It contains three domains - an adenylation domain, a peptidyl-carrier protein (PCP) domain, and a reductase domain, and requires activation by attachment of a phosphopantetheinyl group. The enzyme activates its substrate to an adenylate form, followed by a transfer to the PCP domain. The resulting thioester is subsequently transferred to the reductase domain, where it is reduced to the aldehyde.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 9074-94-6

References:

1.	Forseth, R.R., Amaike, S., Schwenk, D., Affeldt, K.J., Hoffmeister, D., Schroeder, F.C. and Keller, N.P. Homologous NRPS-like gene clusters mediate redundant small-molecule biosynthesis in Aspergillus flavus. Angew. Chem. Int. Ed. Engl. 52 (2013) 1590–1594. [PMID: 23281040]

[EC 1.2.1.101 created 2018]

1.2.1.102

Accepted name:

isopyridoxal dehydrogenase (5-pyridoxate-forming)

Reaction:

isopyridoxal + NAD⁺ + H₂O = 5-pyridoxate + NADH + H⁺

Glossary:

isopyridoxal = 5-hydroxy-4-(hydroxymethyl)-6-methylpyridine-3-carbaldehyde
5-pyridoxate = 3-hydroxy-4-hydroxymethyl-2-methylpyridine-5-carboxylate

Systematic name:

isopyridoxal:NAD⁺ oxidoreductase (5-pyridoxate-forming)

Comments:

The enzyme, characterized from the bacterium Arthrobacter sp. Cr-7, participates in the degradation of pyridoxine. The enzyme also catalyses the activity of EC 1.1.1.416, isopyridoxal dehydrogenase (5-pyridoxolactone-forming).

Links to other databases:

References:

1.	Lee, Y.C., Nelson, M.J. and Snell, E.E. Enzymes of vitamin B₆ degradation. Purification and properties of isopyridoxal dehydrogenase and 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylic-acid dehydrogenase. J. Biol. Chem. 261 (1986) 15106–15111. [PMID: 3533936]

[EC 1.2.1.102 created 2018]

1.2.1.103

Accepted name:

[amino-group carrier protein]-6-phospho-L-2-aminoadipate reductase

Reaction:

an [amino-group carrier protein]-C-terminal-[N-(1-carboxy-5-oxopentyl)-L-glutamine] + phosphate + NADP⁺ = an [amino-group carrier protein]-C-terminal-[N-(1-carboxy-5-phosphooxy-5-oxopentyl)-L-glutamine] + NADPH + H⁺

Other name(s):

lysY (gene name)

Systematic name:

[amino-group carrier protein]-C-terminal-[N-(1-carboxy-5-oxopentyl)-L-glutamine]:NADP⁺ 5-oxidoreductase (phosphorylating)

Comments:

The enzyme participates in an L-lysine biosynthesis in certain species of archaea and bacteria.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB

References:

1.	Nishida, H., Nishiyama, M., Kobashi, N., Kosuge, T., Hoshino, T. and Yamane, H. A prokaryotic gene cluster involved in synthesis of lysine through the amino adipate pathway: a key to the evolution of amino acid biosynthesis. Genome Res. 9 (1999) 1175–1183. [PMID: 10613839]
2.	Horie, A., Tomita, T., Saiki, A., Kono, H., Taka, H., Mineki, R., Fujimura, T., Nishiyama, C., Kuzuyama, T. and Nishiyama, M. Discovery of proteinaceous N-modification in lysine biosynthesis of Thermus thermophilus. Nat. Chem. Biol. 5 (2009) 673–679. [DOI] [PMID: 19620981]
3.	Shimizu, T., Tomita, T., Kuzuyama, T. and Nishiyama, M. Crystal Structure of the LysY.LysW Complex from Thermus thermophilus. J. Biol. Chem. 291 (2016) 9948–9959. [PMID: 26966182]

[EC 1.2.1.103 created 2019]

1.2.1.104

Accepted name:

pyruvate dehydrogenase system

Reaction:

pyruvate + CoA + NAD⁺ = acetyl-CoA + CO₂ + NADH

Other name(s):

pyruvate dehydrogenase complex; PDH

Systematic name:

pyruvate:NAD⁺ 2-oxidoreductase (CoA-acetylating)

Comments:

The pyruvate dehydrogenase system (PDH) is a large enzyme complex that belongs to the 2-oxoacid dehydrogenase system family, which also includes EC 1.2.1.25, branched-chain α-keto acid dehydrogenase system, EC 1.2.1.105, 2-oxoglutarate dehydrogenase system, EC 1.4.1.27, glycine cleavage system, and EC 2.3.1.190, acetoin dehydrogenase system. With the exception of the glycine cleavage system, which contains 4 components, the 2-oxoacid dehydrogenase systems share a common structure, consisting of three main components, namely a 2-oxoacid dehydrogenase (E1), a dihydrolipoamide acyltransferase (E2), and a dihydrolipoamide dehydrogenase (E3). The reaction catalysed by this system is the sum of three activities: EC 1.2.4.1, pyruvate dehydrogenase (acetyl-transferring) (E1), EC 2.3.1.12, dihydrolipoyllysine-residue acetyltransferase (E2), and EC 1.8.1.4, dihydrolipoyl dehydrogenase (E3). The mammalian system also includes E3 binding protein, which is involved in the interaction between the E2 and E3 subunits.

Links to other databases:

References:

1.	Reed, L.J., Pettit, F.H., Eley, M.H., Hamilton, L., Collins, J.H. and Oliver, R.M. Reconstitution of the Escherichia coli pyruvate dehydrogenase complex. Proc. Natl. Acad. Sci. USA 72 (1975) 3068–3072. [DOI] [PMID: 1103138]
2.	Bates, D.L., Danson, M.J., Hale, G., Hooper, E.A. and Perham, R.N. Self-assembly and catalytic activity of the pyruvate dehydrogenase multienzyme complex of Escherichia coli. Nature 268 (1977) 313–316. [DOI] [PMID: 329143]
3.	Stanley, C.J., Packman, L.C., Danson, M.J., Henderson, C.E. and Perham, R.N. Intramolecular coupling of active sites in the pyruvate dehydrogenase multienzyme complexes from bacterial and mammalian sources. Biochem. J. 195 (1981) 715–721. [DOI] [PMID: 7032507]
4.	Yang, H.C., Hainfeld, J.F., Wall, J.S. and Frey, P.A. Quaternary structure of pyruvate dehydrogenase complex from Escherichia coli. J. Biol. Chem. 260 (1985) 16049–16051. [PMID: 3905803]
5.	Patel, M.S. and Roche, T.E. Molecular biology and biochemistry of pyruvate dehydrogenase complexes. FASEB J. 4 (1990) 3224–3233. [DOI] [PMID: 2227213]

[EC 1.2.1.104 created 2020]

1.2.1.105

Accepted name:

2-oxoglutarate dehydrogenase system

Reaction:

2-oxoglutarate + CoA + NAD⁺ = succinyl-CoA + CO₂ + NADH

Other name(s):

2-oxoglutarate dehydrogenase complex

Systematic name:

2-oxoglutarate:NAD⁺ 2-oxidoreductase (CoA-succinylating)

Comments:

The 2-oxoglutarate dehydrogenase system is a large enzyme complex that belongs to the 2-oxoacid dehydrogenase system family, which also includes EC 1.2.1.25, branched-chain α-keto acid dehydrogenase system, EC 1.2.1.104, pyruvate dehydrogenase system, EC 1.4.1.27, glycine cleavage system, and EC 2.3.1.190, acetoin dehydrogenase system. With the exception of the glycine cleavage system, which contains 4 components, the 2-oxoacid dehydrogenase systems share a common structure, consisting of three main components, namely a 2-oxoacid dehydrogenase (E1), a dihydrolipoamide acyltransferase (E2), and a dihydrolipoamide dehydrogenase (E3). This enzyme system converts 2-oxoglutarate to succinyl-CoA and produces NADH and CO₂ in a complicated series of irreversible reactions. The reaction catalysed by this system is the sum of three activities: EC 1.2.4.2, oxoglutarate dehydrogenase (succinyl-transferring) (E1), EC 2.3.1.61, dihydrolipoyllysine-residue succinyltransferase (E2) and EC 1.8.1.4, dihydrolipoyl dehydrogenase (E3).

Links to other databases:

References:

1.	Robien, M.A., Clore, G.M., Omichinski, J.G., Perham, R.N., Appella, E., Sakaguchi, K. and Gronenborn, A.M. Three-dimensional solution structure of the E3-binding domain of the dihydrolipoamide succinyltransferase core from the 2-oxoglutarate dehydrogenase multienzyme complex of Escherichia coli. Biochemistry 31 (1992) 3463–3471. [DOI] [PMID: 1554728]
2.	Knapp, J.E., Mitchell, D.T., Yazdi, M.A., Ernst, S.R., Reed, L.J. and Hackert, M.L. Crystal structure of the truncated cubic core component of the Escherichia coli 2-oxoglutarate dehydrogenase multienzyme complex. J. Mol. Biol. 280 (1998) 655–668. [DOI] [PMID: 9677295]
3.	Reed, L.J. A trail of research from lipoic acid to α-keto acid dehydrogenase complexes. J. Biol. Chem. 276 (2001) 38329–38336. [DOI] [PMID: 11477096]
4.	Murphy, G.E. and Jensen, G.J. Electron cryotomography of the E. coli pyruvate and 2-oxoglutarate dehydrogenase complexes. Structure 13 (2005) 1765–1773. [DOI] [PMID: 16338405]
5.	Frank, R.A., Price, A.J., Northrop, F.D., Perham, R.N. and Luisi, B.F. Crystal structure of the E1 component of the Escherichia coli 2-oxoglutarate dehydrogenase multienzyme complex. J. Mol. Biol. 368 (2007) 639–651. [DOI] [PMID: 17367808]
6.	Bunik, V.I. and Degtyarev, D. Structure-function relationships in the 2-oxo acid dehydrogenase family: substrate-specific signatures and functional predictions for the 2-oxoglutarate dehydrogenase-like proteins. Proteins 71 (2008) 874–890. [DOI] [PMID: 18004749]
7.	Shim da, J., Nemeria, N.S., Balakrishnan, A., Patel, H., Song, J., Wang, J., Jordan, F. and Farinas, E.T. Assignment of function to histidines 260 and 298 by engineering the E1 component of the Escherichia coli 2-oxoglutarate dehydrogenase complex; substitutions that lead to acceptance of substrates lacking the 5-carboxyl group. Biochemistry 50 (2011) 7705–7709. [DOI] [PMID: 21809826]

[EC 1.2.1.105 created 2020]

1.2.1.106

Accepted name:

[amino-group carrier protein]-5-phospho-L-glutamate reductase

Reaction:

an [amino-group carrier protein]-C-terminal-γ-(L-glutamate 5-semialdehyde-2-yl)-L-glutamate + phosphate + NADP⁺ = an [amino-group carrier protein]-C-terminal-γ-(5-phospho-L-glutamyl)-L-glutamate + NADPH + H⁺

Other name(s):

lysY (gene name)

Systematic name:

[amino-group carrier protein]-C-terminal-γ-(L-glutamate 5-semialdehyde-2-yl)-L-glutamate:NADP⁺ 5-oxidoreductase (phosphorylating)

Comments:

The enzyme participates in an L-arginine biosynthesis pathway in certain species of archaea and bacteria. In some organisms the enzyme is bifunctional and also catalyses the activity of EC 1.2.1.103, [amino-group carrier protein]-6-phospho-L-2-aminoadipate reductase.

Links to other databases:

References:

1.	Ouchi, T., Tomita, T., Horie, A., Yoshida, A., Takahashi, K., Nishida, H., Lassak, K., Taka, H., Mineki, R., Fujimura, T., Kosono, S., Nishiyama, C., Masui, R., Kuramitsu, S., Albers, S.V., Kuzuyama, T. and Nishiyama, M. Lysine and arginine biosyntheses mediated by a common carrier protein in Sulfolobus. Nat. Chem. Biol. 9 (2013) 277–283. [DOI] [PMID: 23434852]
2.	Yoshida, A., Tomita, T., Atomi, H., Kuzuyama, T. and Nishiyama, M. Lysine biosynthesis of Thermococcus kodakarensis with the capacity to function as an ornithine biosynthetic system. J. Biol. Chem. 291 (2016) 21630–21643. [DOI] [PMID: 27566549]

[EC 1.2.1.106 created 2021]

1.2.1.107

Accepted name:

glyceraldehyde-3-phosphate dehydrogenase (arsenate-transferring)

Reaction:

D-glyceraldehyde 3-phosphate + arsenate + NAD⁺ = 1-arsono-3-phospho-D-glycerate + NADH + H⁺

Glossary:

1-arsono-3-phosphoglycerate = [(2R)-2-hydroxy-3-phosphopropanoyl]oxyarsonate

Systematic name:

D-glyceraldehyde-3-phosphate:NAD⁺ oxidoreductase (arsenate-transferring)

Comments:

The enzyme, discovered in bacteria, is very similar to EC 1.2.1.12, glyceraldehyde-3-phosphate dehydrogenase (phosphorylating). However, the gene encoding it is located in arsenic resistance islands in the chromosome, next to a gene (arsJ) that encodes a transporter that removes the product, 1-arsono-3-phosphoglycerate, from the cell. Together the two proteins form an arsenic detoxification system.

Links to other databases:

References:

1.	Chen, J., Yoshinaga, M., Garbinski, L.D. and Rosen, B.P. Synergistic interaction of glyceraldehydes-3-phosphate dehydrogenase and ArsJ, a novel organoarsenical efflux permease, confers arsenate resistance. Mol. Microbiol. 100 (2016) 945–953. [DOI] [PMID: 26991003]
2.	Wu, S., Wang, L., Gan, R., Tong, T., Bian, H., Li, Z., Du, S., Deng, Z. and Chen, S. Signature arsenic detoxification pathways in Halomonas sp. strain GFAJ-1. mBio 9 (2018) . [DOI] [PMID: 29717010]

[EC 1.2.1.107 created 2021]

1.2.1.108

Accepted name:

alcohol-forming fatty acyl-CoA reductase (NADH)

Reaction:

a long-chain acyl-CoA + 2 NADH + 2 H⁺ = a long-chain alcohol + 2 NAD⁺ + CoA

Glossary:

a long-chain acyl-CoA = an acyl-CoA thioester where the acyl chain contains 13 to 22 carbon atoms.

Other name(s):

FAR (gene name); long-chain acyl-CoA:NADH reductase

Systematic name:

NADH:long-chain acyl-CoA reductase

Comments:

The enzyme has been characterized from the photosynthetic flagellate Euglena gracilis. The alcohol is formed by a four-electron reduction of fatty acyl-CoA by NADH. Although the reaction proceeds through an aldehyde intermediate, a free aldehyde is not released. cf. EC 1.2.1.84, alcohol-forming fatty acyl-CoA reductase (NADPH).

Links to other databases:

BRENDA, EXPASY, GENE, KEGG, MetaCyc, PDB

References:

1.	Kolattukudy, P.E. Reduction of fatty acids to alcohols by cell-free preparations of Euglena gracilis. Biochemistry 9 (1970) 1095–1102. [DOI] [PMID: 4313936]
2.	Teerawanichpan, P. and Qiu, X. Fatty acyl-CoA reductase and wax synthase from Euglena gracilis in the biosynthesis of medium-chain wax esters. Lipids 45 (2010) 263–273. [DOI] [PMID: 20195781]

[EC 1.2.1.108 created 2025]

1.2.2.1

Accepted name:

formate dehydrogenase (cytochrome)

Reaction:

formate + 2 ferricytochrome b₁ = CO₂ + 2 ferrocytochrome b₁ + 2 H⁺

Other name(s):

formate dehydrogenase; formate:cytochrome b₁ oxidoreductase

Systematic name:

formate:ferricytochrome-b₁ oxidoreductase

Links to other databases:

BRENDA, EXPASY, Gene, KEGG, MetaCyc, CAS registry number: 37251-01-7

References:

1.	Gale, E.F. Formic dehydrogenase of Bacterium coli: its inactivation by oxygen and its protection in the bacterial cell. Biochem. J. 33 (1939) 1012–1027. [PMID: 16746983]

[EC 1.2.2.1 created 1961]

1.2.2.2

Deleted entry:

pyruvate dehydrogenase (cytochrome). Now covered by EC 1.2.5.1, pyruvate dehydrogenase (quinone)

[EC 1.2.2.2 created 1961, deleted 2010]

1.2.2.3

Transferred entry:

formate dehydrogenase (cytochrome-c-553). Now EC 1.17.2.3, formate dehydrogenase (cytochrome-c-553)

[EC 1.2.2.3 created 1981, deleted 2017]

1.2.2.4

Deleted entry:

carbon-monoxide dehydrogenase (cytochrome b-561). Now classified as EC 1.2.5.3, aerobic carbon monoxide dehydrogenase

[EC 1.2.2.4 created 1999 (EC 1.2.3.10 created 1990, incorporated 2003), modified 2003, deleted 2020]

1.2.3.1

Accepted name:

aldehyde oxidase

Reaction:

an aldehyde + H₂O + O₂ = a carboxylate + H₂O₂

Other name(s):

quinoline oxidase; retinal oxidase

Systematic name:

aldehyde:oxygen oxidoreductase

Comments:

Contains molybdenum, [2Fe-2S] centres and FAD. The enzyme from liver exhibits a broad substrate specificity, and is involved in the metabolism of xenobiotics, including the oxidation of N-heterocycles and aldehydes and the reduction of N-oxides, nitrosamines, hydroxamic acids, azo dyes, nitropolycyclic aromatic hydrocarbons, and sulfoxides [4,6].The enzyme is also responsible for the oxidation of retinal, an activity that was initially attributed to a distinct enzyme, retinal oxidase (formerly EC 1.2.3.11) [5,7].

Links to other databases:

BRENDA, EAWAG-BBD, EXPASY, Gene, KEGG, MetaCyc, PDB, CAS registry number: 9029-07-6

References:

1.	Gordon, A.H., Green, D.E. and Subrahmanyan, V. Liver aldehyde oxidase. Biochem. J. 34 (1940) 764–774. [PMID: 16747217]
2.	Knox, W.E. The quinine-oxidizing enzyme and liver aldehyde oxidase. J. Biol. Chem. 163 (1946) 699–711. [PMID: 20985642]
3.	Mahler, H.R., Mackler, B., Green, D.E. and Bock, R.M. Studies on metalloflavoproteins. III. Aldehyde oxidase: a molybdoflavoprotein. J. Biol. Chem. 210 (1954) 465–480. [PMID: 13201608]
4.	Krenitsky, T.A., Neil, S.M., Elion, G.B. and Hitchings, G.H. A comparison of the specificities of xanthine oxidase and aldehyde oxidase. Arch. Biochem. Biophys. 150 (1972) 585–599. [DOI] [PMID: 5044040]
5.	Tomita, S., Tsujita, M. and Ichikawa, Y. Retinal oxidase is identical to aldehyde oxidase. FEBS Lett. 336 (1993) 272–274. [DOI] [PMID: 8262244]
6.	Yoshihara, S. and Tatsumi, K. Purification and characterization of hepatic aldehyde oxidase in male and female mice. Arch. Biochem. Biophys. 338 (1997) 29–34. [DOI] [PMID: 9015384]
7.	Huang, D.-Y., Furukawa, A. and Ichikawa, Y. Molecular cloning of retinal oxidase/aldehyde oxidase cDNAs from rabbit and mouse livers and functional expression of recombinant mouse retinal oxidase cDNA in Escherichia coli. Arch. Biochem. Biophys. 364 (1999) 264–272. [DOI] [PMID: 10190983]
8.	Uchida, H., Kondo, D., Yamashita, A., Nagaosa, Y., Sakurai, T., Fujii, Y., Fujishiro, K., Aisaka, K. and Uwajima, T. Purification and characterization of an aldehyde oxidase from Pseudomonas sp. KY 4690. FEMS Microbiol. Lett. 229 (2003) 31–36. [DOI] [PMID: 14659539]

[EC 1.2.3.1 created 1961, modified 2002, modified 2004, modified 2012]

1.2.3.2

Transferred entry:

xanthine oxidase. Now EC 1.17.3.2, xanthine oxidase

[EC 1.2.3.2 created 1961, deleted 1984]

1.2.3.3

Accepted name:

pyruvate oxidase

Reaction:

pyruvate + phosphate + O₂ = acetyl phosphate + CO₂ + H₂O₂

Glossary:

thiamine diphosphate = 3-[(4-amino-2-methylpyrimidin-5-yl)methyl]-5-(2-diphosphoethyl)-4-methyl-1,3-thiazolium

Other name(s):

pyruvic oxidase; phosphate-dependent pyruvate oxidase

Systematic name:

pyruvate:oxygen 2-oxidoreductase (phosphorylating)

Comments:

A flavoprotein (FAD) requiring thiamine diphosphate. Two reducing equivalents are transferred from the resonant carbanion/enamine forms of 2-hydroxyethyl-thiamine-diphosphate to the adjacent flavin cofactor, yielding 2-acetyl-thiamine diphosphate (AcThDP) and reduced flavin. FADH₂ is reoxidized by O₂ to yield H₂O₂ and FAD and AcThDP is cleaved phosphorolytically to acetyl phosphate and thiamine diphosphate [2].

Links to other databases:

BRENDA, EXPASY, Gene, KEGG, MetaCyc, PDB, CAS registry number: 9001-96-1

References:

Williams, F.R. and Hager, L.P. Crystalline flavin pyruvate oxidase from Escherichia coli. I. Isolation and properties of the flavoprotein. Arch. Biochem. Biophys. 116 (1966) 168–176. [PMID: 5336022]

Tittmann, K., Wille, G., Golbik, R., Weidner, A., Ghisla, S. and Hübner, G. Radical phosphate transfer mechanism for the thiamin diphosphate- and FAD-dependent pyruvate oxidase from Lactobacillus plantarum. Kinetic coupling of intercofactor electron transfer with phosphate transfer to acetyl-thiamin diphosphate via a transient FAD semiquinone/hydroxyethyl-ThDP radical pair. Biochemistry 44 (2005) 13291–13303. [DOI] [PMID: 16201755]

[EC 1.2.3.3 created 1961]

1.2.3.4

Accepted name:

oxalate oxidase

Reaction:

oxalate + O₂ + 2 H⁺ = 2 CO₂ + H₂O₂

Other name(s):

aero-oxalo dehydrogenase; oxalic acid oxidase

Systematic name:

oxalate:oxygen oxidoreductase

Comments:

Contains Mn²⁺ as a cofactor. The enzyme is not a flavoprotein as had been thought [3].

Links to other databases:

BRENDA, EXPASY, Gene, KEGG, MetaCyc, PDB, CAS registry number: 9031-79-2

References:

1.	Datta, P.K., Meeuse, B.J.D., Engstrom-Heg, V. and Hilal, S.H. Moss oxalic acid oxidase - a flavoprotein. Biochim. Biophys. Acta 17 (1955) 602–603. [PMID: 13250021]
2.	Kotsira, V.P. and Clonis, Y.D. Oxalate oxidase from barley roots: purification to homogeneity and study of some molecular, catalytic, and binding properties. Arch. Biochem. Biophys. 340 (1997) 239–249. [DOI] [PMID: 9143327]
3.	Requena, L. and Bornemann, S. Barley (Hordeum vulgare) oxalate oxidase is a manganese-containing enzyme. Biochem. J. 343 (1999) 185–190. [PMID: 10493928]

[EC 1.2.3.4 created 1961]

1.2.3.5

Accepted name:

glyoxylate oxidase

Reaction:

glyoxylate + H₂O + O₂ = oxalate + H₂O₂

Systematic name:

glyoxylate:oxygen oxidoreductase

Links to other databases:

BRENDA, EXPASY, Gene, KEGG, MetaCyc, PDB, CAS registry number: 37251-03-9

References:

1.	Kasai, T., Suzuki, I. and Asai, T. [Glyoxylic oxidase system in Acetobacter.] Koso Kagaku Shimpojiumu 17 (1962) 77–81. (in Japanese)

[EC 1.2.3.5 created 1972]

1.2.3.6

Accepted name:

pyruvate oxidase (CoA-acetylating)

Reaction:

pyruvate + CoA + O₂ = acetyl-CoA + CO₂ + H₂O₂

Systematic name:

pyruvate:oxygen 2-oxidoreductase (CoA-acetylating)

Comments:

A flavoprotein (FAD). May be identical with EC 1.2.7.1 pyruvate synthase.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 62213-57-4

References:

1.	Reeves, R.E., Warren, L.G., Susskind, B. and Lo, H.-S. An energy-conserving pyruvate-to-acetate pathway in Entamoeba histolytica. Pyruvate synthase and a new acetate thiokinase. J. Biol. Chem. 252 (1977) 726–731. [PMID: 13076]
2.	Takeuchi, T., Weinbach, E.C. and Diamond, L.S. Pyruvate oxidase (CoA acetylating) in Entamoeba histolytica. Biochem. Biophys. Res. Commun. 65 (1975) 591–596. [DOI] [PMID: 167776]

[EC 1.2.3.6 created 1976]

1.2.3.7

Accepted name:

indole-3-acetaldehyde oxidase

Reaction:

(indol-3-yl)acetaldehyde + H₂O + O₂ = (indol-3-yl)acetate + H₂O₂

Other name(s):

indoleacetaldehyde oxidase; IAAld oxidase; AO1; indole-3-acetaldehyde:oxygen oxidoreductase

Systematic name:

(indol-3-yl)acetaldehyde:oxygen oxidoreductase

Comments:

A hemoprotein. This enzyme is an isoform of aldehyde oxidase (EC 1.2.3.1). It has a preference for aldehydes having an indole-ring structure as substrate [6,7]. It may play a role in plant hormone biosynthesis as its activity is higher in the auxin-overproducing mutant, super-root1, than in wild-type Arabidopsis thaliana [7]. While (indol-3-yl)acetaldehyde is the preferred substrate, it also oxidizes indole-3-carbaldehyde and acetaldehyde, but more slowly. The enzyme from maize contains FAD, iron and molybdenum [4].

Links to other databases:

BRENDA, EXPASY, Gene, KEGG, MetaCyc, CAS registry number: 66082-22-2

References:

1.	Bower, P.J., Brown, H.M. and Purves, W.K. Cucumber seedling indoleacetaldehyde oxidase. Plant Physiol. 61 (1978) 107–110. [PMID: 16660220]
2.	Miyata, S., Suzuki, Y., Kamisaka, S. and Masuda, Y. Indole-3-acetaldehyde oxidase of pea-seedlings. Physiol. Plant. 51 (1981) 402–406.
3.	Rajagopal, R. Metabolism of indole-3-acetaldehyde. III. Some characteristics of the aldehyde oxidase of Avena coleoptiles. Physiol. Plant. 24 (1971) 272–281.
4.	Koshiba, T., Saito, E., Ono, N., Yamamoto, N. and Sato, M. Purification and properties of flavin- and molybdenum-containing aldehyde oxidase from coleoptiles of maize. Plant Physiol. 110 (1996) 781–789. [PMID: 12226218]
5.	Koshiba, T. and Matsuyama, H. An in vitro system of indole-3-acetic acid formation from tryptophan in maize (Zea mays) coleoptile extracts. Plant Physiol. 102 (1993) 1319–1324. [PMID: 12231908]
6.	Sekimoto, H., Seo, M., Kawakami, N., Komano, T., Desloire, S., Liotenberg, S., Marion-Poll, A., Caboche, M., Kamiya, Y. and Koshiba, T. Molecular cloning and characterization of aldehyde oxidases in Arabidopsis thaliana. Plant Cell Physiol. 39 (1998) 433–442. [PMID: 9615466]
7.	Seo, M., Akaba, S., Oritani, T., Delarue, M., Bellini, C., Caboche, M. and Koshiba, T. Higher activity of an aldehyde oxidase in the auxin-overproducing superroot1 mutant of Arabidopsis thaliana. Plant Physiol. 116 (1998) 687–693. [PMID: 9489015]

[EC 1.2.3.7 created 1984, modified 2004, modified 2006]

1.2.3.8

Accepted name:

pyridoxal oxidase

Reaction:

pyridoxal + H₂O + O₂ = 4-pyridoxate + (?)

For diagram of pyridoxal catabolism, click here

Systematic name:

pyridoxal:oxygen 4-oxidoreductase

Comments:

A molybdenum protein.

Links to other databases:

BRENDA, EAWAG-BBD, EXPASY, Gene, KEGG, MetaCyc, PDB, CAS registry number: 76415-81-1

References:

1.	Hanly, E.W. Preliminary characterization and physical properties of pyridoxal oxidase activity from Drosophila melanogaster. Mol. Gen. Genet. 180 (1980) 455–462.
2.	Warner, C.K., Watts, D.T. and Finnerty, V. Molybdenum hydroxylases in Drosophila. I. Preliminary studies of pyridoxal oxidase. Mol. Gen. Genet. 180 (1980) 449–453.

[EC 1.2.3.8 created 1984]

1.2.3.9

Accepted name:

aryl-aldehyde oxidase

Reaction:

an aromatic aldehyde + O₂ + H₂O = an aromatic carboxylate + H₂O₂

Systematic name:

aryl-aldehyde:oxygen oxidoreductase

Comments:

Acts on benzaldehyde, vanillin and a number of other aromatic aldehydes, but not on aliphatic aldehydes or sugars.

Links to other databases:

BRENDA, EXPASY, Gene, KEGG, MetaCyc, CAS registry number: 82657-93-0

References:

1.	Crawford, D.L., Sutherland, J.B., Pometto, A.L., III and Miller, J.M. Production of an aromatic aldehyde oxidase by Streptomyces viridosporus. Arch. Microbiol. 131 (1982) 351–355.

[EC 1.2.3.9 created 1986, modified 2002]

1.2.3.10

Deleted entry:

carbon-monoxide oxidase. Activity due to EC 1.2.2.4 carbon-monoxide dehydrogenase (cytochrome b-561)

[EC 1.2.3.10 created 1990, deleted 2003]

1.2.3.11

Deleted entry:

retinal oxidase. Now included with EC 1.2.3.1, aldehyde oxidase

[EC 1.2.3.11 created 1990, modified 2002, deleted 2011]

1.2.3.12

Transferred entry:

vanillate demethylase. Now EC 1.14.13.82, vanillate monooxygenase

[EC 1.2.3.12 created 2000, deleted 2003]

1.2.3.13

Accepted name:

4-hydroxyphenylpyruvate oxidase

Reaction:

2 4-hydroxyphenylpyruvate + O₂ = 2 4-hydroxyphenylacetate + 2 CO₂

For diagram of 4-hydroxyphenylpyruvate metabolites, click here

Systematic name:

4-hydroxyphenylpyruvate:oxygen oxidoreductase (decarboxylating)

Comments:

Involved in tyrosine degradation pathway in Arthrobacter sp.

Links to other databases:

BRENDA, EAWAG-BBD, EXPASY, KEGG, MetaCyc, CAS registry number: 78213-74-8

References:

1.	Blakley, E.R. The catabolism of L-tyrosine by an Arthrobacter sp. Can. J. Microbiol. 23 (1977) 1128–1139. [PMID: 20216]

[EC 1.2.3.13 created 2000]

1.2.3.14

Accepted name:

abscisic-aldehyde oxidase

Reaction:

abscisic aldehyde + H₂O + O₂ = abscisate + H₂O₂

For diagram of abscisic acid biosynthesis, click here

Other name(s):

abscisic aldehyde oxidase; AAO3; AOd; AOδ

Systematic name:

abscisic-aldehyde:oxygen oxidoreductase

Comments:

Acts on both (+)- and (–)-abscisic aldehyde. Involved in the abscisic-acid biosynthesis pathway in plants, along with EC 1.1.1.288, (xanthoxin dehydrogenase), EC 1.13.11.51 (9-cis-epoxycarotenoid dioxygenase) and EC 1.14.14.137 [(+)-abscisic acid 8′-hydroxylase]. While abscisic aldehyde is the best substrate, the enzyme also acts with indole-3-aldehyde, 1-naphthaldehyde and benzaldehyde as substrates, but more slowly [3].

Links to other databases:

BRENDA, EXPASY, Gene, KEGG, MetaCyc, CAS registry number: 129204-36-0

References:

1.	Sagi, M., Fluhr, R. and Lips, S.H. Aldehyde oxidase and xanthin dehydrogenase in a flacca tomato mutant with deficient abscisic acid and wilty phenotype. Plant Physiol. 120 (1999) 571–577. [PMID: 10364409]
2.	Seo, M., Peeters, A.J., Koiwai, H., Oritani, T., Marion-Poll, A., Zeevaart, J.A., Koornneef, M., Kamiya, Y. and Koshiba, T. The Arabidopsis aldehyde oxidase 3 (AAO3) gene product catalyzes the final step in abscisic acid biosynthesis in leaves. Proc. Natl. Acad. Sci. USA 97 (2000) 12908–12913. [DOI] [PMID: 11050171]
3.	Seo, M., Koiwai, H., Akaba, S., Komano, T., Oritani, T., Kamiya, Y. and Koshiba, T. Abscisic aldehyde oxidase in leaves of Arabidopsis thaliana. Plant J. 23 (2000) 481–488. [DOI] [PMID: 10972874]

[EC 1.2.3.14 created 2005]

1.2.3.15

Accepted name:

(methyl)glyoxal oxidase

Reaction:

(1) glyoxal + H₂O + O₂ = glyoxylate + H₂O₂
(2) 2-oxopropanal + H₂O + O₂ = pyruvate + H₂O₂

Glossary:

2-oxopropanal = methylglyoxal

Other name(s):

glx1 (gene name); glx2 (gene name)

Systematic name:

(methyl)glyoxal:oxygen oxidoreductase

Comments:

The enzyme, originally characterized from the white rot fungus Phanerochaete chrysosporium, utilizes a free radical-coupled copper complex for catalysis.

Links to other databases: