The Enzyme Database

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EC 1.1.1.404     
Accepted name: tetrachlorobenzoquinone reductase
Reaction: 2,3,5,6-tetrachlorohydroquinone + NAD+ = 2,3,5,6-tetrachloro-1,4-benzoquinone + NADH + H+
Other name(s): pcpD (gene name); TCBQ reductase
Systematic name: 2,3,5,6-tetrachlorohydroquinone:NAD+ oxidoreductase
Comments: Contains FMN. The enzyme, characterized from the bacterium Sphingobium chlorophenolicum, participates in the degradation of pentachlorophenol.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Chen, L. and Yang, J. Biochemical characterization of the tetrachlorobenzoquinone reductase involved in the biodegradation of pentachlorophenol. Int. J. Mol. Sci. 9 (2008) 198–212. [PMID: 19325743]
2.  Yadid, I., Rudolph, J., Hlouchova, K. and Copley, S.D. Sequestration of a highly reactive intermediate in an evolving pathway for degradation of pentachlorophenol. Proc. Natl. Acad. Sci. USA 110 (2013) E2182–E2190. [DOI] [PMID: 23676275]
[EC 1.1.1.404 created 2017]
 
 
EC 1.1.2.3     
Accepted name: L-lactate dehydrogenase (cytochrome)
Reaction: (S)-lactate + 2 ferricytochrome c = pyruvate + 2 ferrocytochrome c + 2 H+
Other name(s): lactic acid dehydrogenase; cytochrome b2 (flavin-free derivative of flavocytochrome b2); flavocytochrome b2; L-lactate cytochrome c reductase; L(+)-lactate:cytochrome c oxidoreductase; dehydrogenase, lactate (cytochrome); L-lactate cytochrome c oxidoreductase; lactate dehydrogenase (cytochrome); lactic cytochrome c reductase
Systematic name: (S)-lactate:ferricytochrome-c 2-oxidoreductase
Comments: Identical with cytochrome b2; a flavohemoprotein (FMN).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9078-32-4
References:
1.  Appleby, C.A. and Morton, R.K. Lactic dehydrogenase and cytochrome b2 of baker's yeast. Purification and crystallization. Biochem. J. 71 (1959) 492–499. [PMID: 13638255]
2.  Appleby, C.A. and Morton, R.K. Lactic dehydrogenase and cytochrome b2 of baker's yeast. Enzymic and chemical properties of the crystalline enzyme. Biochem. J. 73 (1959) 539–550. [PMID: 13793977]
3.  Bach, S.G., Dixon, M. and Zerfas, L.G. Yeast lactic dehydrogenase and cytochrome b2. Biochem. J. 40 (1946) 229–239. [PMID: 16747991]
4.  Nygaard, A.P. Lactate dehydrogenases of yeast. In: Boyer, P.D., Lardy, H. and Myrbäck, K. (Ed.), The Enzymes, 2nd edn, vol. 7, Academic Press, New York, 1963, pp. 557–565.
[EC 1.1.2.3 created 1961]
 
 
EC 1.1.3.2     
Accepted name: L-lactate oxidase
Reaction: (S)-lactate + O2 = pyruvate + H2O2
Other name(s): lctO (gene name); LOX
Systematic name: (S)-lactate:oxygen 2-oxidoreductase
Comments: Contains flavin mononucleotide (FMN). The best characterized enzyme is that from the bacterium Aerococcus viridans. The enzyme is widely used in biosensors to measure the lactate concentration in blood and other tissues.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Duncan, J.D., Wallis, J.O. and Azari, M.R. Purification and properties of Aerococcus viridans lactate oxidase. Biochem. Biophys. Res. Commun. 164 (1989) 919–926. [DOI] [PMID: 2818595]
2.  Maeda-Yorita, K., Aki, K., Sagai, H., Misaki, H. and Massey, V. L-Lactate oxidase and L-lactate monooxygenase: mechanistic variations on a common structural theme. Biochimie 77 (1995) 631–642. [DOI] [PMID: 8589073]
3.  Gibello, A., Collins, M.D., Dominguez, L., Fernandez-Garayzabal, J.F. and Richardson, P.T. Cloning and analysis of the L-lactate utilization genes from Streptococcus iniae. Appl. Environ. Microbiol. 65 (1999) 4346–4350. [PMID: 10508058]
4.  Umena, Y., Yorita, K., Matsuoka, T., Kita, A., Fukui, K. and Morimoto, Y. The crystal structure of L-lactate oxidase from Aerococcus viridans at 2.1 Å resolution reveals the mechanism of strict substrate recognition. Biochem. Biophys. Res. Commun. 350 (2006) 249–256. [DOI] [PMID: 17007814]
5.  Furuichi, M., Suzuki, N., Dhakshnamoorhty, B., Minagawa, H., Yamagishi, R., Watanabe, Y., Goto, Y., Kaneko, H., Yoshida, Y., Yagi, H., Waga, I., Kumar, P.K. and Mizuno, H. X-ray structures of Aerococcus viridans lactate oxidase and its complex with D-lactate at pH 4.5 show an α-hydroxyacid oxidation mechanism. J. Mol. Biol. 378 (2008) 436–446. [DOI] [PMID: 18367206]
6.  Stoisser, T., Brunsteiner, M., Wilson, D.K. and Nidetzky, B. Conformational flexibility related to enzyme activity: evidence for a dynamic active-site gatekeeper function of Tyr215 in Aerococcus viridans lactate oxidase. Sci. Rep. 6:27892 (2016). [DOI] [PMID: 27302031]
[EC 1.1.3.2 created 1961, transferred 1972 to EC 1.13.12.4, reinstated 2018]
 
 
EC 1.1.3.15     
Accepted name: (S)-2-hydroxy-acid oxidase
Reaction: an (S)-2-hydroxy carboxylate + O2 = a 2-oxo carboxylate + H2O2
Other name(s): hydroxy-acid oxidase A; hydroxy-acid oxidase B; glycolate oxidase; L-2-hydroxy acid oxidase; hydroxyacid oxidase A; L-α-hydroxy acid oxidase
Systematic name: (S)-2-hydroxy carboxylate:oxygen 2-oxidoreductase
Comments: A flavoprotein (FMN). Exists as two major isoenzymes; the A form preferentially oxidizes short-chain aliphatic hydroxy acids, and was previously listed as EC 1.1.3.1, glycolate oxidase; the B form preferentially oxidizes long-chain and aromatic hydroxy acids. The rat isoenzyme B also acts as EC 1.4.3.2, L-amino-acid oxidase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9028-71-1
References:
1.  Blanchard, M., Green, D.E., Nocito-Carroll, V. and Ratner, S. l-Hydroxy acid oxidase. J. Biol. Chem. 163 (1946) 137–144. [PMID: 21023634]
2.  Frigerio, N.A. and Harbury, H.A. Preparation and some properties of crystalline glycolic acid oxidase of spinach. J. Biol. Chem. 231 (1958) 135–157. [PMID: 13538955]
3.  Kun, E., Dechary, J.M. and Pitot, H.C. The oxidation of glycolic acid by a liver enzyme. J. Biol. Chem. 210 (1954) 269–280. [PMID: 13201588]
4.  Nakano, M. and Danowski, T.S. Crystalline mammalian L-amino acid oxidase from rat kidney mitochondria. J. Biol. Chem. 241 (1966) 2075–2083. [PMID: 5946631]
5.  Nakano, M., Ushijima, Y., Saga, M., Tsutsumi, Y. and Asami, H. Aliphatic L-α-hydroxyacid oxidase from rat livers: purification and properties. Biochim. Biophys. Acta 167 (1968) 9–22. [DOI] [PMID: 5686300]
6.  Phillips, D.R., Duley, J.A., Fennell, D.J. and Holmes, R.S. The self-association of L-α hydroxyacid oxidase. Biochim. Biophys. Acta 427 (1976) 679–687. [DOI] [PMID: 1268224]
7.  Schuman, M. and Massey, V. Purification and characterization of glycolic acid oxidase from pig liver. Biochim. Biophys. Acta 227 (1971) 500–520. [DOI] [PMID: 5569122]
8.  Jones, J.M., Morrell, J.C. and Gould, S.J. Identification and characterization of HAOX1, HAOX2, and HAOX3, three human peroxisomal 2-hydroxy acid oxidases. J. Biol. Chem. 275 (2000) 12590–12597. [DOI] [PMID: 10777549]
[EC 1.1.3.15 created 1972 (EC 1.1.3.1 created 1961, incorporated 1984)]
 
 
EC 1.1.3.46     
Accepted name: 4-hydroxymandelate oxidase
Reaction: (S)-4-hydroxymandelate + O2 = 2-(4-hydroxyphenyl)-2-oxoacetate + H2O2
Glossary: (S)-4-hydroxymandelate = (S)-2-hydroxy-2-(4-hydroxyphenyl)acetate
2-(4-hydroxyphenyl)-2-oxoacetate = 4-hydroxyphenylglyoxylate = (4-hydroxyphenyl)(oxo)acetate
L-(4-hydroxyphenyl)glycine = (S)-4-hydroxyphenylglycine
L-(3,5-dihydroxyphenyl)glycine = (S)-3,5-dihydroxyphenylglycine
Other name(s): 4HmO; HmO
Systematic name: (S)-4-hydroxymandelate:oxygen 1-oxidoreductase
Comments: A flavoprotein (FMN). The enzyme from the bacterium Amycolatopsis orientalis is involved in the biosynthesis of L-(4-hydroxyphenyl)glycine and L-(3,5-dihydroxyphenyl)glycine, two non-proteinogenic amino acids occurring in the vancomycin group of antibiotics.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Hubbard, B.K., Thomas, M.G. and Walsh, C.T. Biosynthesis of L-p-hydroxyphenylglycine, a non-proteinogenic amino acid constituent of peptide antibiotics. Chem. Biol. 7 (2000) 931–942. [DOI] [PMID: 11137816]
2.  Li, T.L., Choroba, O.W., Charles, E.H., Sandercock, A.M., Williams, D.H. and Spencer, J.B. Characterisation of a hydroxymandelate oxidase involved in the biosynthesis of two unusual amino acids occurring in the vancomycin group of antibiotics. Chem. Commun. (Camb.) (2001) 1752–1753. [PMID: 12240298]
[EC 1.1.3.46 created 2014]
 
 
EC 1.1.98.2     
Accepted name: glucose-6-phosphate dehydrogenase (coenzyme-F420)
Reaction: D-glucose 6-phosphate + oxidized coenzyme F420 = 6-phospho-D-glucono-1,5-lactone + reduced coenzyme F420
Other name(s): coenzyme F420-dependent glucose-6-phosphate dehydrogenase; F420-dependent glucose-6-phosphate dehydrogenase; FGD1; Rv0407; F420-dependent glucose-6-phosphate dehydrogenase 1
Systematic name: D-glucose-6-phosphate:F420 1-oxidoreductase
Comments: The enzyme is very specific for D-glucose 6-phosphate. No activity with NAD+, NADP+, FAD and FMN [1].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Purwantini, E. and Daniels, L. Purification of a novel coenzyme F420-dependent glucose-6-phosphate dehydrogenase from Mycobacterium smegmatis. J. Bacteriol. 178 (1996) 2861–2866. [DOI] [PMID: 8631674]
2.  Bashiri, G., Squire, C.J., Baker, E.N. and Moreland, N.J. Expression, purification and crystallization of native and selenomethionine labeled Mycobacterium tuberculosis FGD1 (Rv0407) using a Mycobacterium smegmatis expression system. Protein Expr. Purif. 54 (2007) 38–44. [DOI] [PMID: 17376702]
3.  Purwantini, E., Gillis, T.P. and Daniels, L. Presence of F420-dependent glucose-6-phosphate dehydrogenase in Mycobacterium and Nocardia species, but absence from Streptomyces and Corynebacterium species and methanogenic Archaea. FEMS Microbiol. Lett. 146 (1997) 129–134. [DOI] [PMID: 8997717]
[EC 1.1.98.2 created 2010 as EC 1.1.99.34, transferred 2011 to EC 1.1.98.2]
 
 
EC 1.1.99.27     
Accepted name: (R)-pantolactone dehydrogenase (flavin)
Reaction: (R)-pantolactone + acceptor = 2-dehydropantolactone + reduced acceptor
Other name(s): 2-dehydropantolactone reductase (flavin); 2-dehydropantoyl-lactone reductase (flavin); (R)-pantoyllactone dehydrogenase (flavin)
Systematic name: (R)-pantolactone:acceptor oxidoreductase (flavin-containing)
Comments: High specificity for (R)-pantolactone. Phenazine methosulfate (PMS) can act as acceptor. The enzyme has been studied in the bacterium Nocardia asteroides and shown to be membrane-bound and induced by 1,2-propanediol. The FMN cofactor is non-covalently bound.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 140879-14-7
References:
1.  Kataoka, M., Shimizu, S. and Yamada, H. Purification and characterization of a novel FMN-dependent enzyme. Membrane-bound L-(+)-pantoyl lactone dehydrogenase from Nocardia asteroides. Eur. J. Biochem. 204 (1992) 799–806. [DOI] [PMID: 1541293]
[EC 1.1.99.27 created 1999]
 
 
EC 1.1.99.31     
Accepted name: (S)-mandelate dehydrogenase
Reaction: (S)-mandelate + acceptor = phenylglyoxylate + reduced acceptor
For diagram of reaction, click here
Glossary: (S)-mandelate = (S)-2-hydroxy-2-phenylacetate
phenylglyoxylate = benzoylformate = 2-oxo-2-phenylacetate
Other name(s): MDH (ambiguous)
Systematic name: (S)-mandelate:acceptor 2-oxidoreductase
Comments: This enzyme is a member of the FMN-dependent α-hydroxy-acid oxidase/dehydrogenase family [1]. While all enzymes of this family oxidize the (S)-enantiomer of an α-hydroxy acid to an α-oxo acid, the ultimate oxidant (oxygen, intramolecular heme or some other acceptor) depends on the particular enzyme. This enzyme transfers the electron pair from FMNH2 to a component of the electron transport chain, most probably ubiquinone [1,2]. It is part of a metabolic pathway in Pseudomonads that allows these organisms to utilize mandelic acid, derivatized from the common soil metabolite amygdalin, as the sole source of carbon and energy [2]. The enzyme has a large active-site pocket and preferentially binds substrates with longer sidechains, e.g. 2-hydroxyoctanoate rather than 2-hydroxybutyrate [1]. It also prefers substrates that, like (S)-mandelate, have β unsaturation, e.g. (indol-3-yl)glycolate compared with (indol-3-yl)lactate [1]. Esters of mandelate, such as methyl (S)-mandelate, are also substrates [3].
Links to other databases: BRENDA, EAWAG-BBD, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9067-95-2
References:
1.  Lehoux, I.E. and Mitra, B. (S)-Mandelate dehydrogenase from Pseudomonas putida: mechanistic studies with alternate substrates and pH and kinetic isotope effects. Biochemistry 38 (1999) 5836–5848. [DOI] [PMID: 10231535]
2.  Dewanti, A.R., Xu, Y. and Mitra, B. Role of glycine 81 in (S)-mandelate dehydrogenase from Pseudomonas putida in substrate specificity and oxidase activity. Biochemistry 43 (2004) 10692–10700. [DOI] [PMID: 15311930]
3.  Dewanti, A.R., Xu, Y. and Mitra, B. Esters of mandelic acid as substrates for (S)-mandelate dehydrogenase from Pseudomonas putida: implications for the reaction mechanism. Biochemistry 43 (2004) 1883–1890. [DOI] [PMID: 14967029]
[EC 1.1.99.31 created 2006]
 
 
EC 1.3.1.14     
Accepted name: dihydroorotate dehydrogenase (NAD+)
Reaction: (S)-dihydroorotate + NAD+ = orotate + NADH + H+
Other name(s): orotate reductase (NADH); orotate reductase (NADH2); DHOdehase (ambiguous); DHOD (ambiguous); DHODase (ambiguous); dihydroorotate oxidase, pyrD (gene name)
Systematic name: (S)-dihydroorotate:NAD+ oxidoreductase
Comments: Binds FMN, FAD and a [2Fe-2S] cluster. The enzyme consists of two subunits, an FMN binding catalytic subunit and a FAD and iron-sulfur binding electron transfer subunit [4]. The reaction, which takes place in the cytosol, is the only redox reaction in the de-novo biosynthesis of pyrimidine nucleotides. Other class 1 dihydroorotate dehydrogenases use either fumarate (EC 1.3.98.1) or NADP+ (EC 1.3.1.15) as electron acceptor. The membrane bound class 2 dihydroorotate dehydrogenase (EC 1.3.5.2) uses quinone as electron acceptor.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 37255-26-8
References:
1.  Friedmann, H.C. and Vennesland, B. Purification and properties of dihydroorotic acid dehydrogenase. J. Biol. Chem. 233 (1958) 1398–1406. [PMID: 13610849]
2.  Friedmann, H.C. and Vennesland, B. Crystalline dihydroorotic dehydrogenase. J. Biol. Chem. 235 (1960) 1526–1532. [PMID: 13825167]
3.  Lieberman, I. and Kornberg, A. Enzymic synthesis and breakdown of a pyrimidine, orotic acid. I. Dihydro-orotic dehydrogenase. Biochim. Biophys. Acta 12 (1953) 223–234. [DOI] [PMID: 13115431]
4.  Nielsen, F.S., Andersen, P.S. and Jensen, K.F. The B form of dihydroorotate dehydrogenase from Lactococcus lactis consists of two different subunits, encoded by the pyrDb and pyrK genes, and contains FMN, FAD, and [FeS] redox centers. J. Biol. Chem. 271 (1996) 29359–29365. [DOI] [PMID: 8910599]
5.  Rowland, P., Nørager, S., Jensen, K.F. and Larsen, S. Structure of dihydroorotate dehydrogenase B: electron transfer between two flavin groups bridged by an iron-sulphur cluster. Structure 8 (2000) 1227–1238. [DOI] [PMID: 11188687]
6.  Kahler, A.E., Nielsen, F.S. and Switzer, R.L. Biochemical characterization of the heteromeric Bacillus subtilis dihydroorotate dehydrogenase and its isolated subunits. Arch. Biochem. Biophys. 371 (1999) 191–201. [DOI] [PMID: 10545205]
7.  Marcinkeviciene, J., Tinney, L.M., Wang, K.H., Rogers, M.J. and Copeland, R.A. Dihydroorotate dehydrogenase B of Enterococcus faecalis. Characterization and insights into chemical mechanism. Biochemistry 38 (1999) 13129–13137. [DOI] [PMID: 10529184]
[EC 1.3.1.14 created 1972, modified 2011]
 
 
EC 1.3.1.15     
Accepted name: dihydroorotate dehydrogenase (NADP+)
Reaction: (S)-dihydroorotate + NADP+ = orotate + NADPH + H+
Other name(s): orotate reductase; dihydro-orotic dehydrogenase; L-5,6-dihydro-orotate:NAD+ oxidoreductase; orotate reductase (NADPH)
Systematic name: (S)-dihydroorotate:NADP+ oxidoreductase
Comments: Binds FMN and FAD [2]. Other class 1 dihydroorotate dehydrogenases use either fumarate (EC 1.3.98.1) or NAD+ (EC 1.3.1.14) as electron acceptor. The membrane bound class 2 dihydroorotate dehydrogenase (EC 1.3.5.2) uses quinone as electron acceptor .
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 37255-27-9
References:
1.  Taylor, W.H., Taylor, M.L. and Eames, D.F. Two functionally different dihydroorotic dehydrogenases in bacteria. J. Bacteriol. 91 (1966) 2251–2256. [PMID: 4380263]
2.  Udaka, S. and Vennesland, B. Properties of triphosphopyridine nucleotide-linked dihydroorotic dehydrogenase. J. Biol. Chem. 237 (1962) 2018–2024. [PMID: 13923427]
[EC 1.3.1.15 created 1972, modified 2011]
 
 
EC 1.3.1.34     
Accepted name: 2,4-dienoyl-CoA reductase [(2E)-enoyl-CoA-producing]
Reaction: (1) a (2E)-2-enoyl-CoA + NADP+ = a (2E,4E)-2,4-dienoyl-CoA + NADPH + H+
(2) a (2E)-2-enoyl-CoA + NADP+ = a (2E,4Z)-2,4-dienoyl-CoA + NADPH + H+
Other name(s): fadH (gene name); 4-enoyl-CoA reductase (NADPH) (ambiguous); 4-enoyl coenzyme A (reduced nicotinamide adenine dinucleotide phosphate) reductase (ambiguous); 4-enoyl-CoA reductase (ambiguous); 2,4-dienoyl-CoA reductase (NADPH) (ambiguous); trans-2,3-didehydroacyl-CoA:NADP+ 4-oxidoreductase
Systematic name: (2E)-2-enoyl-CoA:NADP+ 4-oxidoreductase
Comments: This bacterial enzyme catalyses the reduction of either (2E,4E)-2,4-dienoyl-CoA or (2E,4Z)-2,4-dienoyl-CoA to (2E)-2-enoyl-CoA. The enzyme from Escherichia coli contains FAD, FMN, and an [4Fe-4S] iron sulfur cluster. cf. EC 1.3.1.124, 2,4-dienoyl-CoA reductase [(3E)-enoyl-CoA-producing].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 82869-38-3
References:
1.  Dommes, V., Luster, W., Cvetanovic, M. and Kunau, W.-H. Purification by affinity chromatography of 2,4-dienoyl-CoA reductases from bovine liver and Escherichia coli. Eur. J. Biochem. 125 (1982) 335–341. [DOI] [PMID: 6749495]
2.  Dommes, V. and Kunau, W.H. 2,4-Dienoyl coenzyme A reductases from bovine liver and Escherichia coli. Comparison of properties. J. Biol. Chem. 259 (1984) 1781–1788. [PMID: 6363415]
3.  You, S.Y., Cosloy, S. and Schulz, H. Evidence for the essential function of 2,4-dienoyl-coenzyme A reductase in the β-oxidation of unsaturated fatty acids in vivo. Isolation and characterization of an Escherichia coli mutant with a defective 2,4-dienoyl-coenzyme A reductase. J. Biol. Chem. 264 (1989) 16489–16495. [PMID: 2506179]
4.  He, X.Y., Yang, S.Y. and Schulz, H. Cloning and expression of the fadH gene and characterization of the gene product 2,4-dienoyl coenzyme A reductase from Escherichia coli. Eur. J. Biochem. 248 (1997) 516–520. [PMID: 9346310]
5.  Liang, X., Thorpe, C. and Schulz, H. 2,4-Dienoyl-CoA reductase from Escherichia coli is a novel iron-sulfur flavoprotein that functions in fatty acid β-oxidation. Arch. Biochem. Biophys. 380 (2000) 373–379. [PMID: 10933894]
6.  Hubbard, P.A., Liang, X., Schulz, H. and Kim, J.J. The crystal structure and reaction mechanism of Escherichia coli 2,4-dienoyl-CoA reductase. J. Biol. Chem. 278 (2003) 37553–37560. [PMID: 12840019]
7.  Tu, X., Hubbard, P.A., Kim, J.J. and Schulz, H. Two distinct proton donors at the active site of Escherichia coli 2,4-dienoyl-CoA reductase are responsible for the formation of different products. Biochemistry 47 (2008) 1167–1175. [PMID: 18171025]
[EC 1.3.1.34 created 1984, modified 1986, modified 2020]
 
 
EC 1.3.1.100     
Accepted name: chanoclavine-I aldehyde reductase
Reaction: dihydrochanoclavine-I aldehyde + NADP+ = chanoclavine-I aldehyde + NADPH + H+
For diagram of fumigaclavin alkaloid biosynthesis, click here
Glossary: chanoclavine-I aldehyde = (1E)-2-methyl-3-[(4R,5R)-4-(methylamino)-1,3,4,5-tetrahydrobenz[cd]indol-5-yl]prop-2-enal
Other name(s): FgaOx3; easA (gene name)
Systematic name: chanoclavine-I aldehyde:NAD+ oxidoreductase
Comments: Contains FMN. The enzyme participates in the biosynthesis of fumigaclavine C, an ergot alkaloid produced by some fungi of the Trichocomaceae family. The enzyme catalyses the reduction of chanoclavine-I aldehyde to dihydrochanoclavine-I aldehyde. This hydrolyses spontaneously to form 6,8-dimethyl-6,7-didehydroergoline, which is converted to festuclavine by EC 1.5.1.44, festuclavine dehydrogenase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Coyle, C.M., Cheng, J.Z., O'Connor, S.E. and Panaccione, D.G. An old yellow enzyme gene controls the branch point between Aspergillus fumigatus and Claviceps purpurea ergot alkaloid pathways. Appl. Environ. Microbiol. 76 (2010) 3898–3903. [DOI] [PMID: 20435769]
2.  Cheng, J.Z., Coyle, C.M., Panaccione, D.G. and O'Connor, S.E. A role for Old Yellow Enzyme in ergot alkaloid biosynthesis. J. Am. Chem. Soc. 132 (2010) 1776–1777. [DOI] [PMID: 20102147]
3.  Wallwey, C., Matuschek, M., Xie, X.L. and Li, S.M. Ergot alkaloid biosynthesis in Aspergillus fumigatus: Conversion of chanoclavine-I aldehyde to festuclavine by the festuclavine synthase FgaFS in the presence of the old yellow enzyme FgaOx3. Org. Biomol. Chem. 8 (2010) 3500–3508. [DOI] [PMID: 20526482]
4.  Xie, X., Wallwey, C., Matuschek, M., Steinbach, K. and Li, S.M. Formyl migration product of chanoclavine-I aldehyde in the presence of the old yellow enzyme FgaOx3 from Aspergillus fumigatus: a NMR structure elucidation. Magn. Reson. Chem. 49 (2011) 678–681. [DOI] [PMID: 21898587]
[EC 1.3.1.100 created 2013]
 
 
EC 1.3.1.116     
Accepted name: 7β-hydroxy-3-oxochol-24-oyl-CoA 4-desaturase
Reaction: 7β-hydroxy-3-oxochol-24-oyl-CoA + NAD+ = 7β-hydroxy-3-oxochol-4-en-24-oyl-CoA + NADH + H+
Other name(s): baiH (gene name)
Systematic name: 7β-hydroxy-3-oxochol-24-oyl-CoA Δ4-oxidoreductase
Comments: Contains FAD and FMN. The enzyme, characterized from the bacterium Clostridium scindens, participates in the bile acid 7α-dehydroxylation pathway. The enzyme catalyses the stereo-specific oxidation of its substrate and has no activity with the 7α anomer. cf. EC 1.3.1.115, 3-oxocholoyl-CoA 4-desaturase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Baron, S.F. and Hylemon, P.B. Expression of the bile acid-inducible NADH:flavin oxidoreductase gene of Eubacterium sp. VPI 12708 in Escherichia coli. Biochim. Biophys. Acta 1249 (1995) 145–154. [PMID: 7599167]
2.  Franklund, C.V., Baron, S.F. and Hylemon, P.B. Characterization of the baiH gene encoding a bile acid-inducible NADH:flavin oxidoreductase from Eubacterium sp. strain VPI 12708. J. Bacteriol. 175 (1993) 3002–3012. [PMID: 8491719]
3.  Kang, D.J., Ridlon, J.M., Moore, D.R., 2nd, Barnes, S. and Hylemon, P.B. Clostridium scindens baiCD and baiH genes encode stereo-specific 7α/7β-hydroxy-3-oxo-Δ4-cholenoic acid oxidoreductases. Biochim. Biophys. Acta 1781 (2008) 16–25. [PMID: 18047844]
[EC 1.3.1.116 created 2018]
 
 
EC 1.3.3.1      
Transferred entry: dihydroorotate oxidase. Now EC 1.3.98.1 [dihydroorotate dehydrogenase (fumarate)]
[EC 1.3.3.1 created 1961, deleted 2011]
 
 
EC 1.3.3.7     
Accepted name: dihydrouracil oxidase
Reaction: 5,6-dihydrouracil + O2 = uracil + H2O2
Systematic name: 5,6-dihydrouracil:oxygen oxidoreductase
Comments: Also oxidizes dihydrothymine to thymine. A flavoprotein (FMN).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 104327-11-9
References:
1.  Owaki, J., Uzura, K., Minami, Z. and Kusai, K. Partial-purification and characterization of dihydrouracil oxidase, a flavoprotein from Rhodotorula glutinis. J. Ferment. Technol. 64 (1986) 205–210.
[EC 1.3.3.7 created 1989]
 
 
EC 1.3.3.16     
Accepted name: oxazoline dehydrogenase
Reaction: (1) a [protein]-(1S,4R)-2-(C-substituted-aminomethyl)-4-acyl-2-thiazoline + O2 = a [protein]-(S)-2-(C-substituted-aminomethyl)-4-acyl-1,3-thiazole + H2O2
(2) a [protein]-(S,S)-2-(C-substituted-aminomethyl)-4-acyl-2-oxazoline + O2 = a [protein]-(S)-2-(C-substituted-aminomethyl)-4-acyl-1,3-oxazole + H2O2
(3) a [protein]-(S,S)-2-(C-substituted-aminomethyl)-4-acyl-5-methyl-2-oxazoline + O2 = a [protein]-(S)-2-(C-substituted-aminomethyl)-4-acyl-5-methyl-1,3-oxazole + H2O2
Other name(s): azoline oxidase; thiazoline oxidase; cyanobactin oxidase; patG (gene name); mcaG (gene name); artG (gene name); lynG (gene name); tenG (gene name)
Systematic name: a [protein]-2-oxazoline:oxygen oxidoreductase (2-oxazole-forming)
Comments: Contains FMN. This enzyme oxidizes 2-oxazoline, 5-methyl-2-oxazoline, and 2-thiazoline within peptides, which were formed by EC 6.2.2.2, oxazoline synthase, and EC 6.2.2.3, thiazoline synthase, to the respective pyrrole-type rings. The enzyme is found as either a stand-alone protein or as a domain within a multifunctional protein (the G protein) that also functions as a peptidase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Li, Y.M., Milne, J.C., Madison, L.L., Kolter, R. and Walsh, C.T. From peptide precursors to oxazole and thiazole-containing peptide antibiotics: microcin B17 synthase. Science 274 (1996) 1188–1193. [PMID: 8895467]
2.  Schmidt, E.W., Nelson, J.T., Rasko, D.A., Sudek, S., Eisen, J.A., Haygood, M.G. and Ravel, J. Patellamide A and C biosynthesis by a microcin-like pathway in Prochloron didemni, the cyanobacterial symbiont of Lissoclinum patella. Proc. Natl. Acad. Sci. USA 102 (2005) 7315–7320. [PMID: 15883371]
3.  Bent, A.F., Mann, G., Houssen, W.E., Mykhaylyk, V., Duman, R., Thomas, L., Jaspars, M., Wagner, A. and Naismith, J.H. Structure of the cyanobactin oxidase ThcOx from Cyanothece sp. PCC 7425, the first structure to be solved at Diamond Light Source beamline I23 by means of S-SAD. Acta Crystallogr D Struct Biol 72 (2016) 1174–1180. [PMID: 27841750]
4.  Ghilarov, D., Stevenson, C.EM., Travin, D.Y., Piskunova, J., Serebryakova, M., Maxwell, A., Lawson, D.M. and Severinov, K. Architecture of microcin B17 synthetase: an octameric protein complex converting a ribosomally synthesized peptide into a DNA gyrase poison. Mol. Cell 73 (2019) 749–762.e5. [PMID: 30661981]
[EC 1.3.3.16 created 2020]
 
 
EC 1.3.5.2     
Accepted name: dihydroorotate dehydrogenase (quinone)
Reaction: (S)-dihydroorotate + a quinone = orotate + a quinol
Other name(s): dihydroorotate:ubiquinone oxidoreductase; (S)-dihydroorotate:(acceptor) oxidoreductase; (S)-dihydroorotate:acceptor oxidoreductase; DHOdehase (ambiguous); DHOD (ambiguous); DHODase (ambiguous); DHODH
Systematic name: (S)-dihydroorotate:quinone oxidoreductase
Comments: This Class 2 dihydroorotate dehydrogenase enzyme contains FMN [4]. The enzyme is found in eukaryotes in the mitochondrial membrane, in cyanobacteria, and in some Gram-negative and Gram-positive bacteria associated with the cytoplasmic membrane [2,5,6]. The reaction is the only redox reaction in the de-novo biosynthesis of pyrimidine nucleotides [2,4]. The best quinone electron acceptors for the enzyme from bovine liver are ubiquinone-6 and ubiquinone-7, although simple quinones, such as benzoquinone, can also act as acceptor at lower rates [2]. Methyl-, ethyl-, tert-butyl and benzyl (S)-dihydroorotates are also substrates, but methyl esters of (S)-1-methyl and (S)-3-methyl and (S)-1,3-dimethyldihydroorotates are not [2]. Class 1 dihydroorotate dehydrogenases use either fumarate (EC 1.3.98.1), NAD+ (EC 1.3.1.14) or NADP+ (EC 1.3.1.15) as electron acceptor.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 59088-23-2
References:
1.  Forman, H.J. and Kennedy, J. Mammalian dihydroorotate dehydrogenase: physical and catalytic properties of the primary enzyme. Arch. Biochem. Biophys. 191 (1978) 23–31. [DOI] [PMID: 216313]
2.  Hines, V., Keys, L.D., III and Johnston, M. Purification and properties of the bovine liver mitochondrial dihydroorotate dehydrogenase. J. Biol. Chem. 261 (1986) 11386–11392. [PMID: 3733756]
3.  Bader, B., Knecht, W., Fries, M. and Löffler, M. Expression, purification, and characterization of histidine-tagged rat and human flavoenzyme dihydroorotate dehydrogenase. Protein Expr. Purif. 13 (1998) 414–422. [DOI] [PMID: 9693067]
4.  Fagan, R.L., Nelson, M.N., Pagano, P.M. and Palfey, B.A. Mechanism of flavin reduction in Class 2 dihydroorotate dehydrogenases. Biochemistry 45 (2006) 14926–14932. [DOI] [PMID: 17154530]
5.  Björnberg, O., Grüner, A.C., Roepstorff, P. and Jensen, K.F. The activity of Escherichia coli dihydroorotate dehydrogenase is dependent on a conserved loop identified by sequence homology, mutagenesis, and limited proteolysis. Biochemistry 38 (1999) 2899–2908. [DOI] [PMID: 10074342]
6.  Nara, T., Hshimoto, T. and Aoki, T. Evolutionary implications of the mosaic pyrimidine-biosynthetic pathway in eukaryotes. Gene 257 (2000) 209–222. [DOI] [PMID: 11080587]
[EC 1.3.5.2 created 1983 as EC 1.3.99.11, transferred 2009 to EC 1.3.5.2, modified 2011]
 
 
EC 1.3.5.3     
Accepted name: protoporphyrinogen IX dehydrogenase (quinone)
Reaction: protoporphyrinogen IX + 3 quinone = protoporphyrin IX + 3 quinol
Other name(s): HemG; protoporphyrinogen IX dehydrogenase (menaquinone)
Systematic name: protoporphyrinogen IX:quinone oxidoreductase
Comments: Contains FMN. The enzyme participates in heme b biosynthesis. In the bacterium Escherichia coli it interacts with either ubiquinone or menaquinone, depending on whether the organism grows aerobically or anaerobically.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Boynton, T.O., Daugherty, L.E., Dailey, T.A. and Dailey, H.A. Identification of Escherichia coli HemG as a novel, menadione-dependent flavodoxin with protoporphyrinogen oxidase activity. Biochemistry 48 (2009) 6705–6711. [DOI] [PMID: 19583219]
2.  Möbius, K., Arias-Cartin, R., Breckau, D., Hännig, A.L., Riedmann, K., Biedendieck, R., Schroder, S., Becher, D., Magalon, A., Moser, J., Jahn, M. and Jahn, D. Heme biosynthesis is coupled to electron transport chains for energy generation. Proc. Natl. Acad. Sci. USA 107 (2010) 10436–10441. [PMID: 20484676]
[EC 1.3.5.3 created 2010, modified 2020]
 
 
EC 1.3.8.16     
Accepted name: 2-amino-4-deoxychorismate dehydrogenase
Reaction: (2S)-2-amino-4-deoxychorismate + FMN = 3-(1-carboxyvinyloxy)anthranilate + FMNH2
For diagram of enediyne antitumour antibiotic biosynthesis, click here
Glossary: (2S)-2-amino-4-deoxychorismate = (2S,3S)-3-(1-carboxyvinyloxy)-2,3-dihydroanthranilate
3-enolpyruvoylanthranilate = 3-(1-carboxyvinyloxy)anthranilate
Other name(s): ADIC dehydrogenase; 2-amino-2-deoxyisochorismate dehydrogenase; SgcG
Systematic name: (2S)-2-amino-4-deoxychorismate:FMN oxidoreductase
Comments: The sequential action of EC 2.6.1.86, 2-amino-4-deoxychorismate synthase and this enzyme leads to the formation of the benzoxazolinate moiety of the enediyne antitumour antibiotic C-1027 [1,2].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Van Lanen, S.G., Lin, S. and Shen, B. Biosynthesis of the enediyne antitumor antibiotic C-1027 involves a new branching point in chorismate metabolism. Proc. Natl. Acad. Sci. USA 105 (2008) 494–499. [DOI] [PMID: 18182490]
2.  Yu, L., Mah, S., Otani, T. and Dedon, P. The benzoxazolinate of C-1027 confers intercalative DNA binding. J. Am. Chem. Soc. 117 (1995) 8877–8878. [DOI]
[EC 1.3.8.16 created 2008 as 1.3.99.24, transferred 2020 to EC 1.3.8.16.]
 
 
EC 1.3.8.17     
Accepted name: dehydro coenzyme F420 reductase
Reaction: oxidized coenzyme F420-0 + FMN = dehydro coenzyme F420-0 + FMNH2
Glossary: dehydro coenzyme F420-0 = 2-{[5-deoxy-5-(8-hydroxy-2,4-dioxopyrimidino[4,5-b]quinolin-10(2H)-yl)-L-ribityloxy]hydroxyphosphoryloxy}prop-2-enoate
Other name(s): fbiB (gene name)
Systematic name: oxidized coenzyme F420-0:FMN oxidoreductase
Comments: This enzyme is involved in the biosynthesis of factor 420 (coenzyme F420), a redox-active compound found in all methanogenic archaea, as well as some eubacteria. In some eubacteria the enzyme is multifunctional, also catalysing the activities of EC 6.3.2.31, coenzyme F420-0:L-glutamate ligase, and EC 6.3.2.34, coenzyme F420-1:γ-L-glutamate ligase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Bashiri, G., Antoney, J., Jirgis, E.NM., Shah, M.V., Ney, B., Copp, J., Stuteley, S.M., Sreebhavan, S., Palmer, B., Middleditch, M., Tokuriki, N., Greening, C., Scott, C., Baker, E.N. and Jackson, C.J. A revised biosynthetic pathway for the cofactor F420 in prokaryotes. Nat. Commun. 10:1558 (2019). [DOI] [PMID: 30952857]
[EC 1.3.8.17 created 2021]
 
 
EC 1.3.98.1     
Accepted name: dihydroorotate dehydrogenase (fumarate)
Reaction: (S)-dihydroorotate + fumarate = orotate + succinate
Other name(s): DHOdehase (ambiguous); dihydroorotate dehydrogenase (ambiguous); dihydoorotic acid dehydrogenase (ambiguous); DHOD (ambiguous); DHODase (ambiguous); dihydroorotate oxidase; pyr4 (gene name)
Systematic name: (S)-dihydroorotate:fumarate oxidoreductase
Comments: Binds FMN. The reaction, which takes place in the cytosol, is the only redox reaction in the de novo biosynthesis of pyrimidine nucleotides. Molecular oxygen can replace fumarate in vitro. Other class 1 dihydroorotate dehydrogenases use either NAD+ (EC 1.3.1.14) or NADP+ (EC 1.3.1.15) as electron acceptor. The membrane bound class 2 dihydroorotate dehydrogenase (EC 1.3.5.2) uses quinone as electron acceptor.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9029-03-2
References:
1.  Björnberg, O., Rowland, P., Larsen, S. and Jensen, K.F. Active site of dihydroorotate dehydrogenase A from Lactococcus lactis investigated by chemical modification and mutagenesis. Biochemistry 36 (1997) 16197–16205. [DOI] [PMID: 9405053]
2.  Rowland, P., Björnberg, O., Nielsen, F.S., Jensen, K.F. and Larsen, S. The crystal structure of Lactococcus lactis dihydroorotate dehydrogenase A complexed with the enzyme reaction product throws light on its enzymatic function. Protein Sci. 7 (1998) 1269–1279. [DOI] [PMID: 9655329]
3.  Nørager, S., Arent, S., Björnberg, O., Ottosen, M., Lo Leggio, L., Jensen, K.F. and Larsen, S. Lactococcus lactis dihydroorotate dehydrogenase A mutants reveal important facets of the enzymatic function. J. Biol. Chem. 278 (2003) 28812–28822. [DOI] [PMID: 12732650]
4.  Zameitat, E., Pierik, A.J., Zocher, K. and Löffler, M. Dihydroorotate dehydrogenase from Saccharomyces cerevisiae: spectroscopic investigations with the recombinant enzyme throw light on catalytic properties and metabolism of fumarate analogues. FEMS Yeast Res. 7 (2007) 897–904. [DOI] [PMID: 17617217]
5.  Inaoka, D.K., Sakamoto, K., Shimizu, H., Shiba, T., Kurisu, G., Nara, T., Aoki, T., Kita, K. and Harada, S. Structures of Trypanosoma cruzi dihydroorotate dehydrogenase complexed with substrates and products: atomic resolution insights into mechanisms of dihydroorotate oxidation and fumarate reduction. Biochemistry 47 (2008) 10881–10891. [DOI] [PMID: 18808149]
6.  Cheleski, J., Wiggers, H.J., Citadini, A.P., da Costa Filho, A.J., Nonato, M.C. and Montanari, C.A. Kinetic mechanism and catalysis of Trypanosoma cruzi dihydroorotate dehydrogenase enzyme evaluated by isothermal titration calorimetry. Anal. Biochem. 399 (2010) 13–22. [DOI] [PMID: 19932077]
[EC 1.3.98.1 created 1961 as EC 1.3.3.1, transferred 2011 to EC 1.3.98.1]
 
 
EC 1.3.99.24      
Transferred entry: 2-amino-4-deoxychorismate dehydrogenase. Now EC 1.3.8.16, 2-amino-4-deoxychorismate dehydrogenase
[EC 1.3.99.24 created 2008, deleted 2020]
 
 
EC 1.3.99.33     
Accepted name: urocanate reductase
Reaction: dihydrourocanate + acceptor = urocanate + reduced acceptor
For diagram of histidine catabolism, click here
Glossary: urocanate = 3-(1H-imidazol-4-yl)prop-2-enoate
dihydrourocanate = 3-(1H-imidazol-4-yl)propanoate
Other name(s): urdA (gene name)
Systematic name: dihydrourocanate:acceptor oxidoreductase
Comments: The enzyme from the bacterium Shewanella oneidensis MR-1 contains a noncovalently-bound FAD and a covalently-bound FMN. It functions as part of an anaerobic electron transfer chain that utilizes urocanate as the terminal electron acceptor. The activity has been demonstrated with the artificial donor reduced methyl viologen.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Bogachev, A.V., Bertsova, Y.V., Bloch, D.A. and Verkhovsky, M.I. Urocanate reductase: identification of a novel anaerobic respiratory pathway in Shewanella oneidensis MR-1. Mol. Microbiol. 86 (2012) 1452–1463. [DOI] [PMID: 23078170]
[EC 1.3.99.33 created 2013]
 
 
EC 1.4.1.13     
Accepted name: glutamate synthase (NADPH)
Reaction: 2 L-glutamate + NADP+ = L-glutamine + 2-oxoglutarate + NADPH + H+ (overall reaction)
(1a) L-glutamate + NH3 = L-glutamine + H2O
(1b) L-glutamate + NADP+ + H2O = NH3 + 2-oxoglutarate + NADPH + H+
Other name(s): glutamate (reduced nicotinamide adenine dinucleotide phosphate) synthase; L-glutamate synthase; L-glutamate synthetase; glutamate synthetase (NADP); NADPH-dependent glutamate synthase; glutamine-ketoglutaric aminotransferase; NADPH-glutamate synthase; NADPH-linked glutamate synthase; glutamine amide-2-oxoglutarate aminotransferase (oxidoreductase, NADP); L-glutamine:2-oxoglutarate aminotransferase, NADPH oxidizing; GOGAT
Systematic name: L-glutamate:NADP+ oxidoreductase (transaminating)
Comments: Binds FMN, FAD, 2 [4Fe-4S] clusters and 1 [3Fe-4S] cluster. The reaction takes place in the direction of L-glutamate production. The protein is composed of two subunits, α and β. The α subunit is composed of two domains, one hydrolysing L-glutamine to NH3 and L-glutamate (cf. EC 3.5.1.2, glutaminase), the other combining the produced NH3 with 2-oxoglutarate to produce a second molecule of L-glutamate (cf. EC 1.4.1.4, glutamate dehydrogenase [NADP+]). The β subunit transfers electrons from the cosubstrate. The NH3 is channeled within the α subunit through a 31 Å channel. The chanelling is very efficient and in the intact α-β complex ammonia is produced only within the complex. In the absence of the β subunit, coupling between the two domains of the α subunit is compromised and some ammonium can leak.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 37213-53-9
References:
1.  Miller, R.E. and Stadtman, E.R. Glutamate synthase from Escherichia coli. An iron-sulfide flavoprotein. J. Biol. Chem. 247 (1972) 7407–7419. [PMID: 4565085]
2.  Tempest, D.W., Meers, J.L. and Brown, C.M. Synthesis of glutamate in Aerobacter aerogenes by a hitherto unknown route. Biochem. J. 117 (1970) 405–407. [PMID: 5420057]
3.  Vanoni, M.A. and Curti, B. Glutamate synthase: a complex iron-sulfur flavoprotein. Cell. Mol. Life Sci. 55 (1999) 617–638. [DOI] [PMID: 10357231]
4.  Ravasio, S., Curti, B. and Vanoni, M.A. Determination of the midpoint potential of the FAD and FMN flavin cofactors and of the 3Fe-4S cluster of glutamate synthase. Biochemistry 40 (2001) 5533–5541. [DOI] [PMID: 11331018]
[EC 1.4.1.13 created 1972 as EC 2.6.1.53, transferred 1976 to EC 1.4.1.13, modified 2001, modified 2012]
 
 
EC 1.4.1.14     
Accepted name: glutamate synthase (NADH)
Reaction: 2 L-glutamate + NAD+ = L-glutamine + 2-oxoglutarate + NADH + H+
(1a) L-glutamate + NH3 = L-glutamine + H2O
(1b) L-glutamate + NAD+ + H2O = NH3 + 2-oxoglutarate + NADH + H+
Other name(s): glutamate (reduced nicotinamide adenine dinucleotide) synthase; NADH: GOGAT; L-glutamate synthase (NADH); L-glutamate synthetase; NADH-glutamate synthase; NADH-dependent glutamate synthase
Systematic name: L-glutamate:NAD+ oxidoreductase (transaminating)
Comments: A flavoprotein (FMN). The reaction takes place in the direction of L-glutamate production. The protein is composed of two domains, one hydrolysing L-glutamine to NH3 and L-glutamate (cf. EC 3.5.1.2, glutaminase), the other combining the produced NH3 with 2-oxoglutarate to produce a second molecule of L-glutamate (cf. EC 1.4.1.2, glutamate dehydrogenase).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 65589-88-0
References:
1.  Roon, R.J., Even, H.L. and Larimore, F. Glutamate synthase: properties of the reduced nicotinamide adenine dinucleotide-dependent enzyme from Saccharomyces cerevisiae. J. Bacteriol. 118 (1974) 89–95. [PMID: 4362465]
2.  Boland, M.J. and Benny, A.G. Enzymes of nitrogen metabolism in legume nodules. Purification and properties of NADH-dependent glutamate synthase from lupin nodules. Eur. J. Biochem. 79 (1977) 355–362. [DOI] [PMID: 21790]
3.  Masters, D.S., Jr. and Meister, A. Inhibition of homocysteine sulfonamide of glutamate synthase purified from Saccharomyces cerevisiae. J. Biol. Chem. 257 (1982) 8711–8715. [PMID: 7047525]
4.  Anderson, M.P., Vance, C.P., Heichel, G.H. and Miller, S.S. Purification and characterization of NADH-glutamate synthase from alfalfa root nodules. Plant Physiol. 90 (1989) 351–358. [PMID: 16666762]
5.  Blanco, L., Reddy, P.M., Silvente, S., Bucciarelli, B., Khandual, S., Alvarado-Affantranger, X., Sanchez, F., Miller, S., Vance, C. and Lara-Flores, M. Molecular cloning, characterization and regulation of two different NADH-glutamate synthase cDNAs in bean nodules. Plant Cell Environ. 31 (2008) 454–472. [PMID: 18182018]
[EC 1.4.1.14 created 1978, modified 2019]
 
 
EC 1.4.3.5     
Accepted name: pyridoxal 5′-phosphate synthase
Reaction: (1) pyridoxamine 5′-phosphate + H2O + O2 = pyridoxal 5′-phosphate + NH3 + H2O2
(2) pyridoxine 5′-phosphate + O2 = pyridoxal 5′-phosphate + H2O2
For diagram of pyridoxal biosynthesis, click here
Glossary: pyridoxamine = 4-aminomethyl-3-hydroxy-5-hydroxymethyl-2-methylpyridine
Other name(s): pyridoxamine 5′-phosphate oxidase; pyridoxamine phosphate oxidase; pyridoxine (pyridoxamine)phosphate oxidase; pyridoxine (pyridoxamine) 5′-phosphate oxidase; pyridoxaminephosphate oxidase (EC 1.4.3.5: deaminating); PMP oxidase; pyridoxol-5′-phosphate:oxygen oxidoreductase (deaminating) (incorrect); pyridoxamine-phosphate oxidase; PdxH
Systematic name: pyridoxamine-5′-phosphate:oxygen oxidoreductase (deaminating)
Comments: A flavoprotein (FMN). In Escherichia coli, the cofactor pyridoxal 5′-phosphate is synthesized de novo by a pathway that involves EC 1.2.1.72 (erythrose-4-phosphate dehydrogenase), EC 1.1.1.290 (4-phosphoerythronate dehydrogenase), EC 2.6.1.52 (phosphoserine transaminase), EC 1.1.1.262 (4-hydroxythreonine-4-phosphate dehydrogenase), EC 2.6.99.2 (pyridoxine 5′-phosphate synthase) and EC 1.4.3.5 (with pyridoxine 5′-phosphate as substrate). N4′-Substituted pyridoxamine derivatives are also oxidized in reaction (1) to form pyridoxal 5-phosphate and the corresponding primary amine.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9029-21-4
References:
1.  Choi, J.-D., Bowers-Komro, D.M., Davis, M.D., Edmondson, D.E. and McCormick, D.B. Kinetic properties of pyridoxamine (pyridoxine)-5′-phosphate oxidase from rabbit liver. J. Biol. Chem. 258 (1983) 840–845. [PMID: 6822512]
2.  Wada, H. and Snell, E.E. The enzymatic oxidation of pyridoxine and pyridoxamine phosphates. J. Biol. Chem. 236 (1961) 2089–2095. [PMID: 13782387]
3.  Notheis, C., Drewke, C. and Leistner, E. Purification and characterization of the pyridoxol-5′-phosphate:oxygen oxidoreductase (deaminating) from Escherichia coli. Biochim. Biophys. Acta 1247 (1995) 265–271. [DOI] [PMID: 7696318]
4.  Laber, B., Maurer, W., Scharf, S., Stepusin, K. and Schmidt, F.S. Vitamin B6 biosynthesis: formation of pyridoxine 5′-phosphate from 4-(phosphohydroxy)-L-threonine and 1-deoxy-D-xylulose-5-phosphate by PdxA and PdxJ protein. FEBS Lett. 449 (1999) 45–48. [DOI] [PMID: 10225425]
5.  Musayev, F.N., Di Salvo, M.L., Ko, T.P., Schirch, V. and Safo, M.K. Structure and properties of recombinant human pyridoxine 5′-phosphate oxidase. Protein Sci. 12 (2003) 1455–1463. [DOI] [PMID: 12824491]
6.  Safo, M.K., Musayev, F.N. and Schirch, V. Structure of Escherichia coli pyridoxine 5′-phosphate oxidase in a tetragonal crystal form: insights into the mechanistic pathway of the enzyme. Acta Crystallogr. D Biol. Crystallogr. 61 (2005) 599–604. [DOI] [PMID: 15858270]
7.  Zhang, Z. and McCormick, D.B. Uptake and metabolism of N-(4′-pyridoxyl)amines by isolated rat liver cells. Arch. Biochem. Biophys. 294 (1992) 394–397. [DOI] [PMID: 1567194]
[EC 1.4.3.5 created 1961, modified 2006]
 
 
EC 1.4.3.26     
Accepted name: pre-mycofactocin synthase
Reaction: 3-amino-5-[(4-hydroxyphenyl)methyl]-4,4-dimethylpyrrolidin-2-one + O2 + H2O = 5-[(4-hydroxyphenyl)methyl]-4,4-dimethylpyrrolidine-2,3-dione + NH3 + H2O2 (overall reaction)
(1a) 3-amino-5-[(4-hydroxyphenyl)methyl]-4,4-dimethylpyrrolidin-2-one + O2 = 5-[(4-hydroxyphenyl)methyl]-3-imino-4,4-dimethylpyrrolidin-2-one + H2O2
(1b) 5-[(4-hydroxyphenyl)methyl]-3-imino-4,4-dimethylpyrrolidin-2-one + H2O = 5-[(4-hydroxyphenyl)methyl]-4,4-dimethylpyrrolidine-2,3-dione + NH3 (spontaneous)
Glossary: 5-[(4-hydroxyphenyl)methyl]-4,4-dimethylpyrrolidine-2,3-dione = pre-mycofactocinone = PMFT
Other name(s): mftD (gene name)
Systematic name: 3-amino-5-[(4-hydroxyphenyl)methyl]-4,4-dimethylpyrrolidin-2-one:oxygen oxidoreductase
Comments: A flavoprotein (FMN). The enzyme participates in the biosynthesis of the enzyme cofactor mycofactocin. The enzyme uses oxygen as an electron source to oxidize a C-N bond, followed by spontaneous exchange with water to form an α-keto moiety on the resulting molecule.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Ayikpoe, R.S. and Latham, J.A. MftD catalyzes the formation of a biologically active redox center in the biosynthesis of the ribosomally synthesized and post-translationally modified redox cofactor mycofactocin. J. Am. Chem. Soc. 141 (2019) 13582–13591. [DOI] [PMID: 31381312]
[EC 1.4.3.26 created 2020]
 
 
EC 1.4.7.1     
Accepted name: glutamate synthase (ferredoxin)
Reaction: 2 L-glutamate + 2 oxidized ferredoxin = L-glutamine + 2-oxoglutarate + 2 reduced ferredoxin + 2 H+ (overall reaction)
(1a) L-glutamate + NH3 = L-glutamine + H2O
(1b) L-glutamate + 2 oxidized ferredoxin + H2O = NH3 + 2-oxoglutarate + 2 reduced ferredoxin + 2 H+
Other name(s): ferredoxin-dependent glutamate synthase; ferredoxin-glutamate synthase; glutamate synthase (ferredoxin-dependent)
Systematic name: L-glutamate:ferredoxin oxidoreductase (transaminating)
Comments: Binds a [3Fe-4S] cluster as well as FAD and FMN. The protein is composed of two domains, one hydrolysing L-glutamine to NH3 and L-glutamate (cf. EC 3.5.1.2, glutaminase), the other combining the produced NH3 with 2-oxoglutarate to produce a second molecule of L-glutamate. The NH3 is channeled through a 24 Å channel in the active protein. No hydrolysis of glutamine takes place without ferredoxin and 2-oxoglutarate being bound to the protein [5,6].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 62213-56-3
References:
1.  Galván, F., Márquez, A.J. and Vega, J.M. Purification and molecular properties of ferredoxin-glutamate synthase from Chlamydomonas reinhardii. Planta 162 (1984) 180–187. [PMID: 24254054]
2.  Lea, P.J. and Miflin, B.J. Alternative route for nitrogen assimilation in higher plants. Nature (Lond.) 251 (1974) 614–616. [PMID: 4423889]
3.  Ravasio, S., Dossena, L., Martin-Figueroa, E., Florencio, F.J., Mattevi, A., Morandi, P., Curti, B. and Vanoni, M.A. Properties of the recombinant ferredoxin-dependent glutamate synthase of Synechocystis PCC6803. Comparison with the Azospirillum brasilense NADPH-dependent enzyme and its isolated α subunit. Biochemistry 41 (2002) 8120–8133. [DOI] [PMID: 12069605]
4.  Navarro, F., Martin-Figueroa, E., Candau, P. and Florencio, F.J. Ferredoxin-dependent iron-sulfur flavoprotein glutamate synthase (GlsF) from the cyanobacterium Synechocystis sp. PCC 6803: expression and assembly in Escherichia coli. Arch. Biochem. Biophys. 379 (2000) 267–276. [DOI] [PMID: 10898944]
5.  van den Heuvel, R.H., Ferrari, D., Bossi, R.T., Ravasio, S., Curti, B., Vanoni, M.A., Florencio, F.J. and Mattevi, A. Structural studies on the synchronization of catalytic centers in glutamate synthase. J. Biol. Chem. 277 (2002) 24579–24583. [DOI] [PMID: 11967268]
6.  van den Heuvel, R.H., Svergun, D.I., Petoukhov, M.V., Coda, A., Curti, B., Ravasio, S., Vanoni, M.A. and Mattevi, A. The active conformation of glutamate synthase and its binding to ferredoxin. J. Mol. Biol. 330 (2003) 113–128. [DOI] [PMID: 12818206]
[EC 1.4.7.1 created 1976, modified 2012]
 
 
EC 1.5.1.29      
Deleted entry: FMN reductase [NAD(P)H]. Now covered by EC 1.5.1.38 [FMN reductase (NADPH)], EC 1.5.1.39 [FMN reductase [NAD(P)H])] and EC 1.5.1.41 (riboflavin reductase [NAD(P)H])
[EC 1.5.1.29 created 1981 as EC 1.6.8.1, transferred 2002 to EC 1.5.1.29, modified 2002, deleted 2011]
 
 
EC 1.5.1.30     
Accepted name: flavin reductase (NADPH)
Reaction: reduced riboflavin + NADP+ = riboflavin + NADPH + H+
For diagram of riboflavin biosynthesis (late stages), click here
Other name(s): NADPH:flavin oxidoreductase; riboflavin mononucleotide (reduced nicotinamide adenine dinucleotide phosphate) reductase; flavin mononucleotide reductase; flavine mononucleotide reductase; FMN reductase (NADPH); NADPH-dependent FMN reductase; NADPH-flavin reductase; NADPH-FMN reductase; NADPH-specific FMN reductase; riboflavin mononucleotide reductase; riboflavine mononucleotide reductase; NADPH2 dehydrogenase (flavin); NADPH2:riboflavin oxidoreductase
Systematic name: reduced-riboflavin:NADP+ oxidoreductase
Comments: The enzyme reduces riboflavin, and, less efficiently, FMN and FAD. NADH is oxidized less efficiently than NADPH.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 56626-29-0
References:
1.  Yubisui, T., Tamura, M. and Takeshita, M. Characterization of a second form of NADPH-flavin reductase purified from human erythrocytes. Biochem. Int. 15 (1987) 1–8. [PMID: 3453680]
2.  Cunningham, O., Gore, M.G. and Mantle, T.J. Initial-rate kinetics of the flavin reductase reaction catalysed by human biliverdin-IXβ reductase (BVR-B). Biochem. J. 345 (2000) 393–399. [PMID: 10620517]
[EC 1.5.1.30 created 1982 as EC 1.6.8.2, transferred 2002 to EC 1.5.1.30, modified 2011]
 
 
EC 1.5.1.36     
Accepted name: flavin reductase (NADH)
Reaction: reduced flavin + NAD+ = flavin + NADH + H+
Other name(s): NADH-dependent flavin reductase; flavin:NADH oxidoreductase
Systematic name: flavin:NAD+ oxidoreductase
Comments: The enzyme from Escherichia coli W catalyses the reduction of free flavins by NADH. The enzyme has similar affinity to FAD, FMN and riboflavin. Activity with NADPH is more than 2 orders of magnitude lower than activity with NADH.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Galan, B., Diaz, E., Prieto, M.A. and Garcia, J.L. Functional analysis of the small component of the 4-hydroxyphenylacetate 3-monooxygenase of Escherichia coli W: a prototype of a new Flavin:NAD(P)H reductase subfamily. J. Bacteriol. 182 (2000) 627–636. [DOI] [PMID: 10633095]
[EC 1.5.1.36 created 2011]
 
 
EC 1.5.1.37     
Accepted name: FAD reductase (NADH)
Reaction: FADH2 + NAD+ = FAD + NADH + H+
For diagram of FAD biosynthesis, click here
Other name(s): NADH-FAD reductase; NADH-dependent FAD reductase; NADH:FAD oxidoreductase; NADH:flavin adenine dinucleotide oxidoreductase
Systematic name: FADH2:NAD+ oxidoreductase
Comments: The enzyme from Burkholderia phenoliruptrix can reduce either FAD or flavin mononucleotide (FMN) but prefers FAD. Unlike EC 1.5.1.36, flavin reductase (NADH), the enzyme can not reduce riboflavin. The enzyme does not use NADPH as acceptor.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Gisi, M.R. and Xun, L. Characterization of chlorophenol 4-monooxygenase (TftD) and NADH:flavin adenine dinucleotide oxidoreductase (TftC) of Burkholderia cepacia AC1100. J. Bacteriol. 185 (2003) 2786–2792. [DOI] [PMID: 12700257]
[EC 1.5.1.37 created 2011]
 
 
EC 1.5.1.38     
Accepted name: FMN reductase (NADPH)
Reaction: FMNH2 + NADP+ = FMN + NADPH + H+
For diagram of FAD biosynthesis, click here
Other name(s): FRP; flavin reductase P; SsuE
Systematic name: FMNH2:NADP+ oxidoreductase
Comments: The enzymes from bioluminescent bacteria contain FMN [4], while the enzyme from Escherichia coli does not [8]. The enzyme often forms a two-component system with monooxygenases such as luciferase. Unlike EC 1.5.1.39, this enzyme does not use NADH as acceptor [1,2]. While FMN is the preferred substrate, the enzyme can also use FAD and riboflavin with lower activity [3,6,8].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Gerlo, E. and Charlier, J. Identification of NADH-specific and NADPH-specific FMN reductases in Beneckea harveyi. Eur. J. Biochem. 57 (1975) 461–467. [DOI] [PMID: 1175652]
2.  Jablonski, E. and DeLuca, M. Purification and properties of the NADH and NADPH specific FMN oxidoreductases from Beneckea harveyi. Biochemistry 16 (1977) 2932–2936. [PMID: 880288]
3.  Jablonski, E. and DeLuca, M. Studies of the control of luminescence in Beneckea harveyi: properties of the NADH and NADPH:FMN oxidoreductases. Biochemistry 17 (1978) 672–678. [PMID: 23827]
4.  Lei, B., Liu, M., Huang, S. and Tu, S.C. Vibrio harveyi NADPH-flavin oxidoreductase: cloning, sequencing and overexpression of the gene and purification and characterization of the cloned enzyme. J. Bacteriol. 176 (1994) 3552–3558. [DOI] [PMID: 8206832]
5.  Tanner, J.J., Lei, B., Tu, S.C. and Krause, K.L. Flavin reductase P: structure of a dimeric enzyme that reduces flavin. Biochemistry 35 (1996) 13531–13539. [DOI] [PMID: 8885832]
6.  Liu, M., Lei, B., Ding, Q., Lee, J.C. and Tu, S.C. Vibrio harveyi NADPH:FMN oxidoreductase: preparation and characterization of the apoenzyme and monomer-dimer equilibrium. Arch. Biochem. Biophys. 337 (1997) 89–95. [DOI] [PMID: 8990272]
7.  Lei, B. and Tu, S.C. Mechanism of reduced flavin transfer from Vibrio harveyi NADPH-FMN oxidoreductase to luciferase. Biochemistry 37 (1998) 14623–14629. [DOI] [PMID: 9772191]
8.  Eichhorn, E., van der Ploeg, J.R. and Leisinger, T. Characterization of a two-component alkanesulfonate monooxygenase from Escherichia coli. J. Biol. Chem. 274 (1999) 26639–26646. [DOI] [PMID: 10480865]
[EC 1.5.1.38 created 2011]
 
 
EC 1.5.1.39     
Accepted name: FMN reductase [NAD(P)H]
Reaction: FMNH2 + NAD(P)+ = FMN + NAD(P)H + H+
For diagram of FAD biosynthesis, click here
Other name(s): FRG
Systematic name: FMNH2:NAD(P)+ oxidoreductase
Comments: Contains FMN. The enzyme can utilize NADH and NADPH with similar reaction rates. Different from EC 1.5.1.42, FMN reductase (NADH) and EC 1.5.1.38, FMN reductase (NADPH). The luminescent bacterium Vibrio harveyi possesses all three enzymes [1]. Also reduces riboflavin and FAD, but more slowly.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Watanabe, H. and Hastings, J.W. Specificities and properties of three reduced pyridine nucleotide-flavin mononucleotide reductases coupling to bacterial luciferase. Mol. Cell. Biochem. 44 (1982) 181–187. [PMID: 6981058]
[EC 1.5.1.39 created 2011]
 
 
EC 1.5.1.41     
Accepted name: riboflavin reductase [NAD(P)H]
Reaction: reduced riboflavin + NAD(P)+ = riboflavin + NAD(P)H + H+
For diagram of riboflavin biosynthesis (late stages), click here
Other name(s): NAD(P)H-FMN reductase (ambiguous); NAD(P)H-dependent FMN reductase (ambiguous); NAD(P)H:FMN oxidoreductase (ambiguous); NAD(P)H:flavin oxidoreductase (ambiguous); NAD(P)H2 dehydrogenase (FMN) (ambiguous); NAD(P)H2:FMN oxidoreductase (ambiguous); riboflavin mononucleotide reductase (ambiguous); flavine mononucleotide reductase (ambiguous); riboflavin mononucleotide (reduced nicotinamide adenine dinucleotide (phosphate)) reductase; flavin mononucleotide reductase (ambiguous); riboflavine mononucleotide reductase (ambiguous); Fre
Systematic name: riboflavin:NAD(P)+ oxidoreductase
Comments: Catalyses the reduction of soluble flavins by reduced pyridine nucleotides. Highest activity with riboflavin. When NADH is used as acceptor, the enzyme can also utilize FMN and FAD as substrates, with lower activity than riboflavin. When NADPH is used as acceptor, the enzyme has a very low activity with FMN and no activity with FAD [1].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Fontecave, M., Eliasson, R. and Reichard, P. NAD(P)H:flavin oxidoreductase of Escherichia coli. A ferric iron reductase participating in the generation of the free radical of ribonucleotide reductase. J. Biol. Chem. 262 (1987) 12325–12331. [PMID: 3305505]
2.  Spyrou, G., Haggård-Ljungquist, E., Krook, M., Jörnvall, H., Nilsson, E. and Reichard, P. Characterization of the flavin reductase gene (fre) of Escherichia coli and construction of a plasmid for overproduction of the enzyme. J. Bacteriol. 173 (1991) 3673–3679. [DOI] [PMID: 2050627]
3.  Ingelman, M., Ramaswamy, S., Nivière, V., Fontecave, M. and Eklund, H. Crystal structure of NAD(P)H:flavin oxidoreductase from Escherichia coli. Biochemistry 38 (1999) 7040–7049. [DOI] [PMID: 10353815]
[EC 1.5.1.41 created 2011]
 
 
EC 1.5.1.42     
Accepted name: FMN reductase (NADH)
Reaction: FMNH2 + NAD+ = FMN + NADH + H+
For diagram of FAD biosynthesis, click here
Other name(s): NADH-FMN reductase; NADH-dependent FMN reductase; NADH:FMN oxidoreductase; NADH:flavin oxidoreductase
Systematic name: FMNH2:NAD+ oxidoreductase
Comments: The enzyme often forms a two-component system with monooxygenases. Unlike EC 1.5.1.38, FMN reductase (NADPH), and EC 1.5.1.39, FMN reductase [NAD(P)H], this enzyme has a strong preference for NADH over NADPH, although some activity with the latter is observed [1,2]. While FMN is the preferred substrate, FAD can also be used with much lower activity [1,3].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Duane, W. and Hastings, J.W. Flavin mononucleotide reductase of luminous bacteria. Mol. Cell. Biochem. 6 (1975) 53–64. [PMID: 47604]
2.  Gerlo, E. and Charlier, J. Identification of NADH-specific and NADPH-specific FMN reductases in Beneckea harveyi. Eur. J. Biochem. 57 (1975) 461–467. [DOI] [PMID: 1175652]
3.  Uetz, T., Schneider, R., Snozzi, M. and Egli, T. Purification and characterization of a two-component monooxygenase that hydroxylates nitrilotriacetate from "Chelatobacter" strain ATCC 29600. J. Bacteriol. 174 (1992) 1179–1188. [DOI] [PMID: 1735711]
4.  Izumoto, Y., Mori, T. and Yamamoto, K. Cloning and nucleotide sequence of the gene for NADH:FMN oxidoreductase from Vibrio harveyi. Biochim. Biophys. Acta 1185 (1994) 243–246. [DOI] [PMID: 8167139]
[EC 1.5.1.42 created 2011]
 
 
EC 1.5.1.45     
Accepted name: FAD reductase [NAD(P)H]
Reaction: FADH2 + NAD(P)+ = FAD + NAD(P)H + H+
For diagram of FAD biosynthesis, click here
Other name(s): GTNG_3158 (gene name)
Systematic name: FADH2:NAD(P)+ oxidoreductase
Comments: This enzyme, isolated from the bacterium Geobacillus thermodenitrificans, participates in the pathway of tryptophan degradation. The enzyme is part of a system that also includes a bifunctional riboflavin kinase/FMN adenylyltransferase and EC 1.14.14.8, anthranilate 3-monooxygenase (FAD). It can reduce either FAD or flavin mononucleotide (FMN) but prefers FAD. The enzyme has a slight preference for NADPH as acceptor. cf. EC 1.5.1.37, FAD reductase (NADH).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Liu, X., Dong, Y., Li, X., Ren, Y., Li, Y., Wang, W., Wang, L. and Feng, L. Characterization of the anthranilate degradation pathway in Geobacillus thermodenitrificans NG80-2. Microbiology 156 (2010) 589–595. [DOI] [PMID: 19942660]
[EC 1.5.1.45 created 2012]
 
 
EC 1.5.3.22     
Accepted name: coenzyme F420H2 oxidase
Reaction: 2 reduced coenzyme F420 + O2 = 2 oxidized coenzyme F420 + 2 H2O
For diagram of coenzyme F420 biosynthesis, click here
Glossary: oxidized coenzyme F420 = N-(N-{O-[5-(8-hydroxy-2,4-dioxo-2,3,4,10-tetrahydropyrimido[4,5-b]quinolin-10-yl)-5-deoxy-L-ribityl-1-phospho]-(S)-lactyl}-γ-L-glutamyl)-L-glutamate
Other name(s): FprA
Systematic name: reduced coenzyme F420:oxygen oxidoreductase
Comments: The enzyme contains FMN and a binuclear iron center. The enzyme from the archaeon Methanothermobacter marburgensis is Si-face specific with respect to C-5 of coenzyme F420 [2].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Seedorf, H., Dreisbach, A., Hedderich, R., Shima, S. and Thauer, R.K. F420H2 oxidase (FprA) from Methanobrevibacter arboriphilus, a coenzyme F420-dependent enzyme involved in O2 detoxification. Arch. Microbiol. 182 (2004) 126–137. [DOI] [PMID: 15340796]
2.  Seedorf, H., Kahnt, J., Pierik, A.J. and Thauer, R.K. Si-face stereospecificity at C5 of coenzyme F420 for F420H2 oxidase from methanogenic Archaea as determined by mass spectrometry. FEBS J. 272 (2005) 5337–5342. [DOI] [PMID: 16218963]
3.  Seedorf, H., Hagemeier, C.H., Shima, S., Thauer, R.K., Warkentin, E. and Ermler, U. Structure of coenzyme F420H2 oxidase (FprA), a di-iron flavoprotein from methanogenic Archaea catalyzing the reduction of O2 to H2O. FEBS J. 274 (2007) 1588–1599. [DOI] [PMID: 17480207]
[EC 1.5.3.22 created 2013]
 
 
EC 1.5.3.24     
Accepted name: sarcosine oxidase (5,10-methylenetetrahydrofolate-forming)
Reaction: sarcosine + 5,6,7,8-tetrahydrofolate + O2 = glycine + 5,10-methylenetetrahydrofolate + H2O2
Other name(s): TSOX; sarcosine oxidase (ambigious); heterotetrameric sarcosine oxidase
Systematic name: sarcosine, 5,6,7,8-tetrahydrofolate:O2 oxidoreductase (demethylating,5,10-methylenetetrahydrofolate-forming)
Comments: The enzyme, found in some bacterial species, is composed of four different subunits and two active sites connected by a large "reaction chamber". An imine intermediate is transferred between the sites, eliminating the production of toxic formaldehyde. The enzyme contains three cofactors: noncovalently bound FAD and NAD+, and FMN that is covalently bound to a histidine residue. In the absence of folate the enzyme catalyses the reaction of EC 1.5.3.1, sarcosine oxidase (formaldehyde-forming).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9029-22-5
References:
1.  Hayashi, S., Nakamura, S. and Suzuki, M. Corynebacterium sarcosine oxidase: a unique enzyme having covalently-bound and noncovalently-bound flavins. Biochem. Biophys. Res. Commun. 96 (1980) 924–930. [DOI] [PMID: 6158947]
2.  Suzuki, M. Purification and some properties of sarcosine oxidase from Corynebacterium sp. U-96. J. Biochem. (Tokyo) 89 (1981) 599–607. [DOI] [PMID: 7240129]
3.  Chlumsky, L.J., Zhang, L., Ramsey, A.J. and Jorns, M.S. Preparation and properties of recombinant corynebacterial sarcosine oxidase: evidence for posttranslational modification during turnover with sarcosine. Biochemistry 32 (1993) 11132–11142. [DOI] [PMID: 7692961]
4.  Chlumsky, L.J., Sturgess, A.W., Nieves, E. and Jorns, M.S. Identification of the covalent flavin attachment site in sarcosine oxidase. Biochemistry 37 (1998) 2089–2095. [DOI] [PMID: 9485355]
5.  Eschenbrenner, M., Chlumsky, L.J., Khanna, P., Strasser, F. and Jorns, M.S. Organization of the multiple coenzymes and subunits and role of the covalent flavin link in the complex heterotetrameric sarcosine oxidase. Biochemistry 40 (2001) 5352–5367. [DOI] [PMID: 11330998]
[EC 1.5.3.24 created 2022]
 
 
EC 1.5.8.3     
Accepted name: sarcosine dehydrogenase
Reaction: sarcosine + 5,6,7,8-tetrahydrofolate + oxidized [electron-transfer flavoprotein] = glycine + 5,10-methylenetetrahydrofolate + reduced [electron-transfer flavoprotein]
Other name(s): sarcosine N-demethylase; monomethylglycine dehydrogenase; sarcosine:(acceptor) oxidoreductase (demethylating); sarcosine:electron-transfer flavoprotein oxidoreductase (demethylating)
Systematic name: sarcosine, 5,6,7,8-tetrahydrofolate:electron-transferflavoprotein oxidoreductase (demethylating,5,10-methylenetetrahydrofolate-forming)
Comments: A flavoprotein (FMN) found in eukaryotes. In the absence of tetrahydrofolate the enzyme produces formaldehyde. cf. EC 1.5.3.1, sarcosine oxidase (formaldehyde-forming), and EC 1.5.3.24, sarcosine oxidase (5,10-methylenetetrahydrofolate-forming).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 37228-65-2, 93389-49-2
References:
1.  Hoskins, D.D. and MacKenzie, C.G. Solubilization and electron transfer flavoprotein requirement of mitochondrial sarcosine dehydrogenase and dimethylglycine dehydrogenase. J. Biol. Chem. 236 (1961) 177–183. [DOI] [PMID: 13716069]
2.  Frisell, W.R. and MacKenzie, C.G. Separation and purification of sarcosine dehydrogenase and dimethylglycine dehydrogenase. J. Biol. Chem. 237 (1962) 94–98. [DOI] [PMID: 13895406]
3.  Wittwer, A.J. and Wagner, C. Identification of the folate-binding proteins of rat liver mitochondria as dimethylglycine dehydrogenase and sarcosine dehydrogenase. Flavoprotein nature and enzymatic properties of the purified proteins. J. Biol. Chem. 256 (1981) 4109–4115. [DOI] [PMID: 6163778]
4.  Steenkamp, D.J. and Husain, M. The effect of tetrahydrofolate on the reduction of electron transfer flavoprotein by sarcosine and dimethylglycine dehydrogenases. Biochem. J. 203 (1982) 707–715. [DOI] [PMID: 6180732]
[EC 1.5.8.3 created 1972 as EC 1.5.99.1, transferred 2012 to EC 1.5.8.3, modified 2022]
 
 
EC 1.5.99.1      
Transferred entry: sarcosine dehydrogenase. Now EC 1.5.8.3, sarcosine dehydrogenase
[EC 1.5.99.1 created 1972, deleted 2012]
 
 
EC 1.5.99.4     
Accepted name: nicotine 6-hydroxylase
Reaction: (S)-nicotine + acceptor + H2O = (S)-6-hydroxynicotine + reduced acceptor
For diagram of nicotine catabolism by arthrobacter, click here
Other name(s): nicotine oxidase; D-nicotine oxidase; nicotine:(acceptor) 6-oxidoreductase (hydroxylating); L-nicotine oxidase; nicotine dehydrogenase (incorrect)
Systematic name: nicotine:acceptor 6-oxidoreductase (hydroxylating)
Comments: A metalloprotein (FMN). The enzyme can act on both the naturally found (S)-enantiomer and the synthetic (R)-enantiomer of nicotine, with retention of configuration in both cases [4].
Links to other databases: BRENDA, EAWAG-BBD, EXPASY, KEGG, MetaCyc, CAS registry number: 37256-31-8
References:
1.  Behrman, E.J. and Stanier, R.Y. The bacterial oxidation of nicotinic acid. J. Biol. Chem. 228 (1957) 923–945. [PMID: 13475371]
2.  Decker, K. and Bleeg, H. Induction and purification of stereospecific nicotine oxidizing enzymes from Arthrobacter oxidans. Biochim. Biophys. Acta 105 (1965) 313–324. [PMID: 5849820]
3.  Hochstein, L.I. and Dalton, B.P. The purification and properties of nicotine oxidase. Biochim. Biophys. Acta 139 (1967) 56–68. [DOI] [PMID: 4962139]
4.  Hochstein, L.I. and Rittenberg, S.C. The bacterial oxidation of nicotine. II. The isolation of the first oxidative product and its identification as (1)-6-hydroxynicotine. J. Biol. Chem. 234 (1959) 156–160. [PMID: 13610912]
[EC 1.5.99.4 created 1972, modified 2023]
 
 
EC 1.6.2.4     
Accepted name: NADPH—hemoprotein reductase
Reaction: NADPH + H+ + n oxidized hemoprotein = NADP+ + n reduced hemoprotein
Other name(s): CPR; FAD-cytochrome c reductase; NADP-cytochrome c reductase; NADP-cytochrome reductase; NADPH-dependent cytochrome c reductase; NADPH:P-450 reductase; NADPH:ferrihemoprotein oxidoreductase; NADPH—cytochrome P-450 oxidoreductase; NADPH-cytochrome c oxidoreductase; NADPH-cytochrome c reductase; NADPH—cytochrome p-450 reductase; NADPH-ferricytochrome c oxidoreductase; NADPH-ferrihemoprotein reductase; TPNH2 cytochrome c reductase; TPNH-cytochrome c reductase; aldehyde reductase (NADPH-dependent); cytochrome P-450 reductase; cytochrome c reductase (reduced nicotinamide adenine dinucleotide phosphate, NADPH, NADPH-dependent); dihydroxynicotinamide adenine dinucleotide phosphate-cytochrome c reductase; ferrihemoprotein P-450 reductase; reduced nicotinamide adenine dinucleotide phosphate-cytochrome c reductase; reductase, cytochrome c (reduced nicotinamide adenine dinucleotide phosphate)
Systematic name: NADPH:hemoprotein oxidoreductase
Comments: A flavoprotein containing both FMN and FAD. This enzyme catalyses the transfer of electrons from NADPH, an obligatory two-electron donor, to microsomal P-450 monooxygenases (e.g. EC 1.14.14.1, unspecific monooxygenase) by stabilizing the one-electron reduced form of the flavin cofactors FAD and FMN. It also reduces cytochrome b5 and cytochrome c. The number n in the equation is 1 if the hemoprotein undergoes a 2-electron reduction, and is 2 if it undergoes a 1-electron reduction.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9023-03-4
References:
1.  Haas, E., Horecker, B.L. and Hogness, T.R. The enzymatic reduction of cytochrome c, cytochrome c reductase. J. Biol. Chem. 136 (1940) 747–774.
2.  Horecker, B.L. Triphosphopyridine nucleotide-cytochrome c reductase in liver. J. Biol. Chem. 183 (1950) 593–605.
3.  Lu, A.Y.H., Junk, K.W. and Coon, M.J. Resolution of the cytochrome P-450-containing ω-hydroxylation system of liver microsomes into three components. J. Biol. Chem. 244 (1969) 3714–3721. [PMID: 4389465]
4.  Masters, B.S.S., Kamin, H., Gibson, Q.H. and Williams, C.H., Jr. Studies on the mechanism of microsomal triphosphopyridine nucleotide-cytochrome c reductase. J. Biol. Chem. 240 (1965) 921–931. [PMID: 14275154]
5.  Williams, C.H., Jr. and Kamin, H. Microsomal triphosphopyridine nucleotide-cytochrome c reductase in liver. J. Biol. Chem. 237 (1962) 587–595. [PMID: 14007123]
6.  Masters, B.S.S., Bilimoria, M.H, Kamen, H. and Gibson, Q.H. The mechanism of 1- and 2-electron transfers catalyzed by reduced triphosphopyridine nucleotide-cytochrome c reductase. J. Biol. Chem. 240 (1965) 4081–4088. [PMID: 4378860]
7.  Sevrioukova, I.F. and Peterson, J.A. NADPH-P-450 reductase: Structural and functional comparisons of the eukaryotic and prokaryotic isoforms. Biochimie 77 (1995) 562–572. [DOI] [PMID: 8589067]
8.  Wang, M., Roberts, D.L., Paschke, R., Shea, T.M., Masters, B.S. and Kim, J.J. Three-dimensional structure of NADPH-cytochrome P450 reductase: prototype for FMN- and FAD-containing enzymes. Proc. Natl. Acad. Sci. USA 94 (1997) 8411–8416. [DOI] [PMID: 9237990]
9.  Munro, A.W., Noble, M.A., Robledo, L., Daff, S.N. and Chapman, S.K. Determination of the redox properties of human NADPH-cytochrome P450 reductase. Biochemistry 40 (2001) 1956–1963. [DOI] [PMID: 11329262]
10.  Gutierrez, A., Grunau, A., Paine, M., Munro, A.W., Wolf, C.R., Roberts, G.C. and Scrutton, N.S. Electron transfer in human cytochrome P450 reductase. Biochem. Soc. Trans. 31 (2003) 497–501. [DOI] [PMID: 12773143]
[EC 1.6.2.4 created 1972, modified 2003]
 
 
EC 1.6.5.3      
Transferred entry: NADH:ubiquinone reductase (H+-translocating). Now EC 7.1.1.2, NADH:ubiquinone reductase (H+-translocating)
[EC 1.6.5.3 created 1961, deleted 1965, reinstated 1983, modified 2011, modified 2013, deleted 2018]
 
 
EC 1.6.5.7     
Accepted name: 2-hydroxy-1,4-benzoquinone reductase
Reaction: 2-hydroxy-1,4-benzoquinone + NADH + H+ = hydroxyquinol + NAD+
For diagram of 4-nitrophenol metabolism, click here
Glossary: hydroxyquinol = 1,2,4-trihydroxybenzene
Other name(s): hydroxybenzoquinone reductase; 1,2,4-trihydroxybenzene:NAD oxidoreductase
Systematic name: NADH:2-hydroxy-1,4-benzoquinone oxidoreductase
Comments: A flavoprotein (FMN) that differs in substrate specificity from other quinone reductases. The enzyme in Burkholderia cepacia is inducible by 2,4,5-trichlorophenoxyacetate.
Links to other databases: BRENDA, EAWAG-BBD, EXPASY, KEGG, MetaCyc, CAS registry number: 214466-94-1
References:
1.  Zaborina, O., Daubaras, D.L., Zago, A., Xun, L., Saido, K. , Klem,T., Nikolic, D. and Chakrabarty, A.M. Novel pathway for conversion of chlorohydroxyquinol to maleylacetate in Burkholderia cepacia AC1100. J. Bacteriol. 180 (1998) 4667–4675. [PMID: 9721310]
[EC 1.6.5.7 created 2000, modified 2004]
 
 
EC 1.6.5.8      
Transferred entry: NADH:ubiquinone reductase (Na+-transporting). Now EC 7.2.1.1, NADH:ubiquinone reductase (Na+-transporting)
[EC 1.6.5.8 created 2011, deleted 2018]
 
 
EC 1.6.5.9     
Accepted name: NADH:quinone reductase (non-electrogenic)
Reaction: NADH + H+ + a quinone = NAD+ + a quinol
Other name(s): type II NAD(P)H:quinone oxidoreductase; NDE2 (gene name); ndh (gene name); NDH-II; NDH-2; NADH dehydrogenase (quinone) (ambiguous); ubiquinone reductase (ambiguous); coenzyme Q reductase (ambiguous); dihydronicotinamide adenine dinucleotide-coenzyme Q reductase (ambiguous); DPNH-coenzyme Q reductase (ambiguous); DPNH-ubiquinone reductase (ambiguous); NADH-coenzyme Q oxidoreductase (ambiguous); NADH-coenzyme Q reductase (ambiguous); NADH-CoQ oxidoreductase (ambiguous); NADH-CoQ reductase (ambiguous); NADH-ubiquinone reductase (ambiguous); NADH-ubiquinone oxidoreductase (ambiguous); reduced nicotinamide adenine dinucleotide-coenzyme Q reductase (ambiguous); NADH-Q6 oxidoreductase (ambiguous); NADH2 dehydrogenase (ubiquinone) (ambiguous); NADH:ubiquinone oxidoreductase; NADH:ubiquinone reductase (non-electrogenic)
Systematic name: NADH:quinone oxidoreductase
Comments: A flavoprotein (FAD or FMN). Occurs in mitochondria of yeast and plants, and in aerobic bacteria. Has low activity with NADPH. Unlike EC 7.1.1.2, NADH:ubiquinone reductase (H+-translocating), this enzyme does not pump proteons of sodium ions across the membrane. It is also not sensitive to rotenone.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9028-04-0
References:
1.  Bergsma, J., Strijker, R., Alkema, J.Y., Seijen, H.G. and Konings, W.N. NADH dehydrogenase and NADH oxidation in membrane vesicle from Bacillus subtilis. Eur. J. Biochem. 120 (1981) 599–606. [PMID: 6800784]
2.  Møller, I.M, and Palmer, J.M. Direct evidence for the presence of a rotenone-resistant NADH dehydrogenase on the inner surface of plant mitochondria. Physiol. Plant. 54 (1982) 267–274. [DOI]
3.  de Vries, S. and Grivell, L.A. Purification and characterization of a rotenone-insensitive NADH:Q6 oxidoreductase from mitochondria of Saccharomyces cerevisiae. Eur. J. Biochem. 176 (1988) 377–384. [DOI] [PMID: 3138118]
4.  Kerscher, S.J., Okun, J.G. and Brandt, U. A single external enzyme confers alternative NADH:ubiquinone oxidoreductase activity in Yarrowia lipolytica. J. Cell Sci. 112 ( Pt 14) (1999) 2347–2354. [PMID: 10381390]
5.  Rasmusson, A.G., Soole, K.L. and Elthon, T.E. Alternative NAD(P)H dehydrogenases of plant mitochondria. Annu. Rev. Plant Biol. 55 (2004) 23–39. [DOI] [PMID: 15725055]
6.  Melo, A.M., Bandeiras, T.M. and Teixeira, M. New insights into type II NAD(P)H:quinone oxidoreductases. Microbiol. Mol. Biol. Rev. 68 (2004) 603–616. [PMID: 15590775]
[EC 1.6.5.9 created 2011 (EC 1.6.5.11 created 1972 as EC 1.6.99.5, transferred 2015 to EC 1.6.5.11, incorporated 2019), modified 2019]
 
 
EC 1.6.5.10     
Accepted name: NADPH dehydrogenase (quinone)
Reaction: NADPH + H+ + a quinone = NADP+ + a quinol
Other name(s): reduced nicotinamide adenine dinucleotide phosphate (quinone) dehydrogenase; NADPH oxidase; NADPH2 dehydrogenase (quinone)
Systematic name: NADPH:(quinone-acceptor) oxidoreductase
Comments: A flavoprotein [1, 2]. The enzyme from Escherichia coli is specific for NADPH and is most active with quinone derivatives and ferricyanide as electron acceptors [3]. Menaquinone can act as acceptor. The enzyme from hog liver is inhibited by dicoumarol and folic acid derivatives but not by 2,4-dinitrophenol [1].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 37256-37-4
References:
1.  Koli, A.K., Yearby, C., Scott, W. and Donaldson, K.O. Purification and properties of three separate menadione reductases from hog liver. J. Biol. Chem. 244 (1969) 621–629. [PMID: 4388793]
2.  Hayashi, M., Hasegawa, K., Oguni, Y. and Unemoto, T. Characterization of FMN-dependent NADH-quinone reductase induced by menadione in Escherichia coli. Biochim. Biophys. Acta 1035 (1990) 230–236. [DOI] [PMID: 2118386]
3.  Hayashi, M., Ohzeki, H., Shimada, H. and Unemoto, T. NADPH-specific quinone reductase is induced by 2-methylene-4-butyrolactone in Escherichia coli. Biochim. Biophys. Acta 1273 (1996) 165–170. [DOI] [PMID: 8611590]
[EC 1.6.5.10 created 1972 as EC 1.6.99.6, transferred 2011 to EC 1.6.5.10]
 
 
EC 1.6.8.1      
Transferred entry: NAD(P)H dehydrogenase (FMN). Now EC 1.5.1.29, FMN reductase
[EC 1.6.8.1 created 1981, deleted 2002]
 
 
EC 1.6.99.1     
Accepted name: NADPH dehydrogenase
Reaction: NADPH + H+ + acceptor = NADP+ + reduced acceptor
Other name(s): NADPH2 diaphorase; NADPH diaphorase; OYE; diaphorase; dihydronicotinamide adenine dinucleotide phosphate dehydrogenase; NADPH-dehydrogenase; NADPH-diaphorase; NADPH2-dehydrogenase; old yellow enzyme; reduced nicotinamide adenine dinucleotide phosphate dehydrogenase; TPNH dehydrogenase; TPNH-diaphorase; triphosphopyridine diaphorase; triphosphopyridine nucleotide diaphorase; NADPH2 dehydrogenase; NADPH:(acceptor) oxidoreductase
Systematic name: NADPH:acceptor oxidoreductase
Comments: A flavoprotein (FMN in yeast, FAD in plants).
Links to other databases: BRENDA, EAWAG-BBD, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9001-68-7
References:
1.  Åkesson, Å., Ehrenberg, A. and Theorell, H. Old yellow enzyme. In: Boyer, P.D., Lardy, H. and Myrbäck, K. (Ed.), The Enzymes, 2nd edn, vol. 7, Academic Press, New York, 1963, pp. 477–494.
2.  Avron, M. and Jagendorf, A.T. Some further investigations on chloroplast TPNH diaphorase. Arch. Biochem. Biophys. 72 (1957) 17–24. [DOI] [PMID: 13471057]
3.  Jagendorf, A.T. Chloroplast TPNH diaphorase. Methods Enzymol. 6 (1963) 430–434.
4.  Theorell, H. Das gelbe Oxydationsferment. Biochem. Z. 278 (1935) 263–290.
5.  Theorell, H. and Åkesson, Å. Molecular weight and FMN content of crystalline "old yellow enzyme". Arch. Biochem. Biophys. 65 (1956) 439–448. [DOI] [PMID: 13373435]
[EC 1.6.99.1 created 1961, modified 1976]
 
 


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