Accepted name: L-sorbose oxidase
Reaction: L-sorbose + O2 = 5-dehydro-D-fructose + H2O2
Systematic name: L-sorbose:oxygen 5-oxidoreductase
Comments: Also acts on D-glucose, D-galactose and D-xylose, but not on D-fructose. 2,6-Dichloroindophenol can act as acceptor.
1.  Yamada, Y., Iizuka, K., Aida, K. and Uemura, T. Enzymatic studies on the oxidation of sugar and sugar alcohol. 3. Purification and properties of L-sorbose oxidase from Trametes sanguinea. J. Biochem. (Tokyo) 62 (1967) 223–229. [PMID: 5586487]
[EC created 1972]
Accepted name: pyridoxine 4-oxidase
Reaction: pyridoxine + O2 = pyridoxal + H2O2
Other name(s): pyridoxin 4-oxidase; pyridoxol 4-oxidase
Systematic name: pyridoxine:oxygen 4-oxidoreductase
Comments: A flavoprotein. Can also use 2,6-dichloroindophenol as an acceptor.
1.  Sundaram, T.K. and Snell, E.E. The bacterial oxidation of vitamin B6. V. The enzymatic formation of pyridoxal and isopyridoxal from pyridoxine. J. Biol. Chem. 244 (1969) 2577–2584. [PMID: 5769992]
[EC created 1972, modified 1976]
Accepted name: ecdysone oxidase
Reaction: ecdysone + O2 = 3-dehydroecdysone + H2O2
Other name(s): β-ecdysone oxidase
Systematic name: ecdysone:oxygen 3-oxidoreductase
Comments: 2,6-Dichloroindophenol can act as an acceptor.
1.  Koolman, J. and Karlson, P. Ecdysone oxidase, an enzyme from the blowfly Calliphora erythrocephala (Meigen). Hoppe-Seyler's Z. Physiol. Chem. 35 (1975) 1131. [PMID: 297]
[EC created 1976]
Accepted name: glucose 1-dehydrogenase (FAD, quinone)
Reaction: D-glucose + a quinone = D-glucono-1,5-lactone + a quinol
Other name(s): glucose dehydrogenase (Aspergillus); FAD-dependent glucose dehydrogenase; D-glucose:(acceptor) 1-oxidoreductase; glucose dehydrogenase (acceptor); gdh (gene name)
Systematic name: D-glucose:quinone 1-oxidoreductase
Comments: A glycoprotein containing one mole of FAD per mole of enzyme. 2,6-Dichloroindophenol can act as acceptor. cf. EC, glucose 1-dehydrogenase (PQQ, quinone).
1.  Bak, T.-G. Studies on glucose dehydrogenase of Aspergillus oryzae. II. Purification and physical and chemical properties. Biochim. Biophys. Acta 139 (1967) 277–293. [PMID: 6034674]
2.  Cavener, D.R. and MacIntyre, R.J. Biphasic expression and function of glucose dehydrogenase in Drosophila melanogaster. Proc. Natl. Acad. Sci. USA 80 (1983) 6286–6288. [PMID: 6413974]
3.  Lovallo, N. and Cox-Foster, D.L. Alteration in FAD-glucose dehydrogenase activity and hemocyte behavior contribute to initial disruption of Manduca sexta immune response to Cotesia congregata parasitoids. J. Insect Physiol. 45 (1999) 1037–1048. [PMID: 12770264]
4.  Inose, K., Fujikawa, M., Yamazaki, T., Kojima, K. and Sode, K. Cloning and expression of the gene encoding catalytic subunit of thermostable glucose dehydrogenase from Burkholderia cepacia in Escherichia coli. Biochim. Biophys. Acta 1645 (2003) 133–138. [PMID: 12573242]
5.  Sygmund, C., Klausberger, M., Felice, A.K. and Ludwig, R. Reduction of quinones and phenoxy radicals by extracellular glucose dehydrogenase from Glomerella cingulata suggests a role in plant pathogenicity. Microbiology 157 (2011) 3203–3212. [PMID: 21903757]
6.  Sygmund, C., Staudigl, P., Klausberger, M., Pinotsis, N., Djinovic-Carugo, K., Gorton, L., Haltrich, D. and Ludwig, R. Heterologous overexpression of Glomerella cingulata FAD-dependent glucose dehydrogenase in Escherichia coli and Pichia pastoris. Microb. Cell Fact. 10:106 (2011). [PMID: 22151971]
[EC created 1972 as EC, modified 1976, transferred 2013 to EC]
Accepted name: D-2-hydroxyacid dehydrogenase (quinone)
Reaction: (R)-2-hydroxyacid + a quinone = 2-oxoacid + a quinol
Other name(s): (R)-2-hydroxy acid dehydrogenase; (R)-2-hydroxy-acid:(acceptor) 2-oxidoreductase; D-lactate dehydrogenase (ambiguous)
Systematic name: (R)-2-hydroxyacid:quinone oxidoreductase
Comments: The enzyme from mammalian kidney contains one mole of FAD per mole of enzyme.(R)-lactate, (R)-malate and meso-tartrate are good substrates. Ubiquinone-1 and the dye 2,6-dichloroindophenol can act as acceptors; NAD+ and NADP+ are not acceptors.
1.  Tubbs, P.K. and Greville, G.D. Dehydrogenation of D-lactate by a soluble enzyme from kidney mitochondria. Biochim. Biophys. Acta 34 (1959) 290–291. [PMID: 13839714]
2.  Tubbs, P.K. and Greville, G.D. The oxidation of D-α-hydroxy acids in animal tissues. Biochem. J. 81 (1961) 104–114. [PMID: 13922962]
3.  Cammack, R. Assay, purification and properties of mammalian D-2-hydroxy acid dehydrogenase. Biochem. J. 115 (1969) 55–64. [PMID: 5359443]
4.  Cammack, R. D-2-hydroxy acid dehydrogenase from animal tissue. Methods Enzymol. 41 (1975) 323–329. [PMID: 236454]
[EC created 2014]
Transferred entry: glucose dehydrogenase (acceptor). Now EC, glucose 1-dehydrogenase (FAD, quinone)
[EC created 1972, modified 1976, deleted 2013]
Transferred entry: fructose 5-dehydrogenase, now classified as EC, fructose 5-dehydrogenase.
[EC created 1972, deleted 2021.]
Accepted name: sorbose dehydrogenase
Reaction: L-sorbose + acceptor = 5-dehydro-D-fructose + reduced acceptor
Other name(s): L-sorbose:(acceptor) 5-oxidoreductase
Systematic name: L-sorbose:acceptor 5-oxidoreductase
Comments: 2,6-Dichloroindophenol can act as acceptor.
1.  Sato, K., Yamada, Y., Aida, K. and Uemara, T. Enzymatic studies on the oxidation of sugar and sugar alcohol. 8. Particle-bound L-sorbose dehydrogenase from Gluconobacter suboxydans. J. Biochem. (Tokyo) 66 (1969) 521–527. [PMID: 5354025]
[EC created 1972]
Accepted name: glycolate dehydrogenase
Reaction: glycolate + acceptor = glyoxylate + reduced acceptor
Other name(s): glycolate oxidoreductase; glycolic acid dehydrogenase; glycolate:(acceptor) 2-oxidoreductase
Systematic name: glycolate:acceptor 2-oxidoreductase
Comments: Also acts on (R)-lactate. 2,6-Dichloroindophenol and phenazine methosulfate can act as acceptors.
1.  Lord, J.M. Glycolate oxidoreductase in Escherichia coli. Biochim. Biophys. Acta 267 (1972) 227–237. [PMID: 4557653]
[EC created 1978]
Accepted name: cellobiose dehydrogenase (acceptor)
Reaction: cellobiose + acceptor = cellobiono-1,5-lactone + reduced acceptor
Other name(s): cellobiose dehydrogenase; cellobiose oxidoreductase; Phanerochaete chrysosporium cellobiose oxidoreductase; CBOR; cellobiose oxidase; cellobiose:oxygen 1-oxidoreductase; CDH; cellobiose:(acceptor) 1-oxidoreductase
Systematic name: cellobiose:acceptor 1-oxidoreductase
Comments: Also acts, more slowly, on cello-oligosaccharides, lactose and D-glucosyl-1,4-β-D-mannose. The enzyme from the white rot fungus Phanerochaete chrysosporium is unusual in having two redoxin domains, one containing a flavin and the other a protoheme group. It transfers reducing equivalents from cellobiose to two types of redox acceptor: two-electron oxidants, including redox dyes, benzoquinones, and molecular oxygen, and one-electron oxidants, including semiquinone species, iron(II) complexes, and the model acceptor cytochrome c [9]. 2,6-Dichloroindophenol can act as acceptor in vitro.
1.  Coudray, M.-R., Canebascini, G. and Meier, H. Characterization of a cellobiose dehydrogenase in the cellulolytic fungus porotrichum (Chrysosporium) thermophile. Biochem. J. 203 (1982) 277–284. [PMID: 7103940]
2.  Dekker, R.F.H. Induction and characterization of a cellobiose dehydrogenase produced by a species of Monilia. J. Gen. Microbiol. 120 (1980) 309–316.
3.  Dekker, R.F.H. Cellobiose dehydrogenase produced by Monilia sp. Methods Enzymol. 160 (1988) 454–463.
4.  Habu, N., Samejima, M., Dean, J.F. and Eriksson, K.E. Release of the FAD domain from cellobiose oxidase by proteases from cellulolytic cultures of Phanerochaete chrysosporium. FEBS Lett. 327 (1993) 161–164. [PMID: 8392950]
5.  Baminger, U., Subramaniam, S.S., Renganathan, V. and Haltrich, D. Purification and characterization of cellobiose dehydrogenase from the plant pathogen Sclerotium (Athelia) rolfsii. Appl. Environ. Microbiol. 67 (2001) 1766–1774. [PMID: 11282631]
6.  Hallberg, B.M., Henriksson, G., Pettersson, G. and Divne, C. Crystal structure of the flavoprotein domain of the extracellular flavocytochrome cellobiose dehydrogenase. J. Mol. Biol. 315 (2002) 421–434. [PMID: 11786022]
7.  Ayers, A.R., Ayers, S.B. and Eriksson, K.-E. Cellobiose oxidase, purification and partial characterization of a hemoprotein from Sporotrichum pulverulentum. Eur. J. Biochem. 90 (1978) 171–181. [PMID: 710416]
8.  Ayers, A.R. and Eriksson, K.-E. Cellobiose oxidase from Sporotrichum pulverulentum. Methods Enzymol. 89 (1982) 129–135. [PMID: 7144569]
9.  Mason, M.G., Nicholls, P., Divne, C., Hallberg, B.M., Henriksson, G. and Wilson, M.T. The heme domain of cellobiose oxidoreductase: a one-electron reducing system. Biochim. Biophys. Acta 1604 (2003) 47–54. [PMID: 12686420]
[EC created 1983, modified 2002 (EC created 1983, incorporated 2002, EC created 1986, incorporated 2005)]
Accepted name: alkan-1-ol dehydrogenase (acceptor)
Reaction: primary alcohol + acceptor = aldehyde + reduced acceptor
Other name(s): polyethylene glycol dehydrogenase; alkan-1-ol:(acceptor) oxidoreductase
Systematic name: alkan-1-ol:acceptor oxidoreductase
Comments: A quinoprotein. Acts on C3-C16 linear-chain saturated primary alcohols, C4-C7 aldehydes and on non-ionic surfactants containing polyethylene glycol residues, such as Tween 40 and 60, but not on methanol and only very slowly on ethanol. 2,6-Dichloroindophenol can act as acceptor. cf. EC alcohol dehydrogenase (acceptor).
1.  Kawai, F., Kimura, T., Tani, Y., Yamada, H., Ueno, T. and Fukami, H. Identification of reaction-products of polyethylene-glycol dehydrogenase. Agric. Biol. Chem. 47 (1983) 1669–1671.
2.  Kawai, F., Yamanaka, H., Ameyama, M., Shinagawa, E., Matsushita, K. and Adachi, O. Identification of the prosthetic group and further characterization of a novel enzyme, polyethylene-glycol dehydrogenase. Agric. Biol. Chem. 49 (1985) 1071–1076.
[EC created 1989]
Transferred entry: polyvinyl-alcohol dehydrogenase (acceptor). Now EC, polyvinyl alcohol dehydrogenase (cytochrome)
[EC created 1989, deleted 2010]
Accepted name: 3-hydroxycyclohexanone dehydrogenase
Reaction: 3-hydroxycyclohexanone + acceptor = cyclohexane-1,3-dione + reduced acceptor
Systematic name: 3-hydroxycyclohexanone:acceptor 1-oxidoreductase
Comments: 2,6-Dichloroindophenol and methylene blue can act as acceptors.
1.  Dangel, W., Tschech, A. and Fuchs, G. Enzyme-reactions involved in anaerobic cyclohexanol metabolism by a denitrifying Pseudomonas species. Arch. Microbiol. 152 (1989) 273–279. [PMID: 2505723]
[EC created 1992]
Transferred entry: dihydroorotate dehydrogenase. As the acceptor is now known, the enzyme has been transferred to EC, dihydroorotate dehydrogenase
[EC created 1983, deleted 2009]
Accepted name: cyclohexanone dehydrogenase
Reaction: cyclohexanone + acceptor = cyclohex-2-enone + reduced acceptor
Other name(s): cyclohexanone:(acceptor) 2-oxidoreductase
Systematic name: cyclohexanone:acceptor 2-oxidoreductase
Comments: 2,6-Dichloroindophenol can act as acceptor. The corresponding ketones of cyclopentane and cycloheptane cannot act as donors.
1.  Dangel, W., Tschech, A. and Fuchs, G. Enzyme-reactions involved in anaerobic cyclohexanol metabolism by a denitrifying Pseudomonas species. Arch. Microbiol. 152 (1989) 273–279. [PMID: 2505723]
[EC created 1992]
Accepted name: trimethylamine dehydrogenase
Reaction: trimethylamine + H2O + electron-transfer flavoprotein = dimethylamine + formaldehyde + reduced electron-transfer flavoprotein
Systematic name: trimethylamine:electron-transfer flavoprotein oxidoreductase (demethylating)
Comments: A number of alkyl-substituted derivatives of trimethylamine can also act as electron donors; phenazine methosulfate and 2,6-dichloroindophenol can act as electron acceptors. Contains FAD and a [4Fe-4S] cluster.
1.  Colby, J. and Zatman, L.J. The purification and properties of a bacterial trimethylamine dehydrogenase. Biochem. J. 121 (1971) 9P–10P. [PMID: 5116569]
2.  Steenkamp, D.J. and Singer, T.P. Participation of the iron-sulphur cluster and of the covalently bound coenzyme of trimethylamine dehydrogenase in catalysis. Biochem. J. 169 (1978) 361–369. [PMID: 204297]
3.  Huang, L.X., Rohlfs, R.J. and Hille, R. The reaction of trimethylamine dehydrogenase with electron transferring flavoprotein. J. Biol. Chem. 270 (1995) 23958–23965. [PMID: 7592591]
4.  Jones, M., Talfournier, F., Bobrov, A., Grossmann, J.G., Vekshin, N., Sutcliffe, M.J. and Scrutton, N.S. Electron transfer and conformational change in complexes of trimethylamine dehydrogenase and electron transferring flavoprotein. J. Biol. Chem. 277 (2002) 8457–8465. [PMID: 11756429]
5.  Scrutton, N.S. and Sutcliffe, M.J. Trimethylamine dehydrogenase and electron transferring flavoprotein. Subcell. Biochem. 35 (2000) 145–181. [PMID: 11192721]
[EC created 1976 as EC, transferred 2002 to EC]
Accepted name: methylglutamate dehydrogenase
Reaction: N-methyl-L-glutamate + acceptor + H2O = L-glutamate + formaldehyde + reduced acceptor
Other name(s): N-methylglutamate dehydrogenase; N-methyl-L-glutamate:(acceptor) oxidoreductase (demethylating)
Systematic name: N-methyl-L-glutamate:acceptor oxidoreductase (demethylating)
Comments: A number of N-methyl-substituted amino acids can act as donor; 2,6-dichloroindophenol is the best acceptor.
1.  Hersh, L.B., Stark, M.J., Worthen, S. and Fiero, M.K. N-Methylglutamate dehydrogenase: kinetic studies on the solubilized enzyme. Arch. Biochem. Biophys. 150 (1972) 219–226. [PMID: 5028076]
[EC created 1976]
Accepted name: spermidine dehydrogenase
Reaction: spermidine + acceptor + H2O = propane-1,3-diamine + 4-aminobutanal + reduced acceptor
Glossary: spermidine = N-(3-aminopropyl)butane-1,4-diamine
Other name(s): spermidine:(acceptor) oxidoreductase
Systematic name: spermidine:acceptor oxidoreductase
Comments: A flavohemoprotein (FAD). Ferricyanide, 2,6-dichloroindophenol and cytochrome c can act as acceptor. 4-Aminobutanal condenses non-enzymically to 1-pyrroline.
1.  Tabor, C.W. and Kellogg, P.D. Identification of flavin adenine dinucleotide and heme in a homogeneous spermidine dehydrogenase from Serratia marcescens. J. Biol. Chem. 245 (1970) 5424–5433. [PMID: 4918845]
2.  Tabor, H. and Tabor, C.W. Biosynthesis and metabolism of 1,4-diaminobutane, spermidine, spermine, and related amines. IIE2a Speridine dehydrogenase. Adv. Enzymol. Relat. Areas Mol. Biol. 36 (1972) 225–226.
[EC created 1976]
Accepted name: cytokinin dehydrogenase
Reaction: N6-prenyladenine + acceptor + H2O = adenine + 3-methylbut-2-enal + reduced acceptor
Glossary: zeatin = (E)-2-methyl-4-(9H-purin-6-ylamino)but-2-en-1-ol = (E)-N6-(4-hydroxy-3-methylbut-2-enyl)adenine
N6-prenyladenine = N6-(3-methylbut-2-en-1-yl)purin-6-amine
Other name(s): N6-dimethylallyladenine:(acceptor) oxidoreductase; 6-N-dimethylallyladenine:acceptor oxidoreductase; OsCKX2; CKX; cytokinin oxidase/dehydrogenase; N6-dimethylallyladenine:acceptor oxidoreductase
Systematic name: N6-prenyladenine:acceptor oxidoreductase
Comments: A flavoprotein (FAD). Catalyses the oxidation of cytokinins, a family of N6-substituted adenine derivatives that are plant hormones, where the substituent is a prenyl group. Although this activity was previously thought to be catalysed by a hydrogen-peroxide-forming oxidase, this enzyme does not require oxygen for activity and does not form hydrogen peroxide. 2,6-Dichloroindophenol, methylene blue, nitroblue tetrazolium, phenazine methosulfate and copper(II) in the presence of imidazole can act as acceptors. This enzyme plays a part in regulating rice-grain production, with lower levels of the enzyme resulting in enhanced grain production [2].
1.  Galuszka, P., Frebort, I., Sebela, M., Jacobsen, S. and Pec, P. Cytokinin oxidase or dehydrogenase? Mechanism of cytokinin degradation in plants. Eur. J. Biochem. 268 (2001) 450–461. [PMID: 11168382]
2.  Ashikari, M., Sakakibara, H., Lin, S., Yamamoto, T., Takashi, T., Nishimura, A., Angeles, E.R., Qian, Q., Kitano, H. and Matsuoka, M. Cytokinin oxidase regulates rice grain production. Science 309 (2005) 741–745. [PMID: 15976269]
[EC created 2001]
Accepted name: rubredoxin—NAD(P)+ reductase
Reaction: 2 reduced rubredoxin + NAD(P)+ + H+ = 2 oxidized rubredoxin + NAD(P)H
Glossary: benzyl viologen = 1,1′-dibenzyl-4,4′-bipyridinium
2,6-dichloroindophenol = 4-(2,6-dichloro-4-hydroxyphenylimino)cyclohexa-2,5-dien-1-one
menadione = 2-methyl-1,4-naphthoquinone
rubredoxin = iron-containing protein found in sulfur-metabolizing bacteria and archaea, participating in electron transfer
Other name(s): rubredoxin-nicotinamide adenine dinucleotide (phosphate) reductase; rubredoxin-nicotinamide adenine; dinucleotide phosphate reductase; NAD(P)+-rubredoxin oxidoreductase; NAD(P)H-rubredoxin oxidoreductase
Systematic name: rubredoxin:NAD(P)+ oxidoreductase
Comments: The enzyme from Pyrococcus furiosus requires FAD. It reduces a number of electron carriers, including benzyl viologen, menadione and 2,6-dichloroindophenol, but rubredoxin is the most efficient. Ferredoxin is not utilized.
1.  Petitdemange, H., Blusson, H. and Gay, R. Detection of NAD(P)H-rubredoxin oxidoreductases in Clostridia. Anal. Biochem. 116 (1981) 564–570. [PMID: 6274224]
2.  Ma, K. and Adams, M.W.W. A hyperactive NAD(P)H:rubredoxin oxidoreductase from the hyperthermophilic archaeon Pyrococcus furiosus. J. Bacteriol. 181 (1999) 5530–5533. [PMID: 10464233]
[EC created 1984, modified 2001, modified 2011]