Escherichia coli K-12 substr. MG1655 Reaction:

Superclasses: Reactions Classified By Conversion TypeSimple ReactionsChemical ReactionsComposite ReactionsElectron-Transfer-Reactions
Reactions Classified By Conversion TypeSimple ReactionsChemical Reactions
Reactions Classified By SubstrateSmall-Molecule Reactions

EC Number:

Enzymes and Genes:
regulator of KefC-mediated potassium transport and quinone oxidoreductaseInferred from experiment: kefF
NAD(P)H:quinone oxidoreductaseInferred from experiment: wrbA
chromate reductaseTraceable author statement to experimental support: yieF

Supersedes EC number:

Transport reaction diagram

Reaction Locations: inner membrane (sensu Gram-negative Bacteria)

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the direction in which it was curated.

Most BioCyc compounds have been protonated to a reference pH value of 7.3. Please see the PGDB Concepts Guide for more information.

Mass balance status: Balanced.

Instance reactions:
NADH + a ubiquinone[inner membrane] + H+ → NAD+ + an ubiquinol[inner membrane] (

NADH + a menaquinone[inner membrane] + H+ → NAD+ + a menaquinol[inner membrane] (no EC#)

Enzyme Commission Primary Name: NAD(P)H dehydrogenase (quinone)

Enzyme Commission Synonyms: menadione reductase, phylloquinone reductase, quinone reductase, dehydrogenase, reduced nicotinamide adenine dinucleotide (phosphate, quinone), DT-diaphorase, flavoprotein NAD(P)H-quinone reductase, menadione oxidoreductase, NAD(P)H dehydrogenase, NAD(P)H menadione reductase, NAD(P)H-quinone dehydrogenase, NAD(P)H-quinone oxidoreductase, NAD(P)H: (quinone-acceptor)oxidoreductase, NAD(P)H: menadione oxidoreductase, NADH-menadione reductase, naphthoquinone reductase, p-benzoquinone reductase, reduced NAD(P)H dehydrogenase, viologen accepting pyridine nucleotide oxidoreductase, vitamin K reductase, diaphorase, reduced nicotinamide-adenine dinucleotide (phosphate) dehydrogenase, vitamin-K reductase, NAD(P)H2 dehydrogenase (quinone), NQO1, QR1, NAD(P)H:(quinone-acceptor) oxidoreductase

The reaction is a two-electron reduction of quinones to quinols.

Enzyme Commission Summary:
A flavoprotein. The enzyme catalyses a two-electron reduction and has a preference for short-chain acceptor quinones, such as ubiquinone, 1,4-benzoquinone, juglone and duroquinone [Sparla96]. The animal, but not the plant, form of the enzyme is inhibited by dicoumarol.

Citations: [Braun98, Wosilait60, Maerki60, Giuditta61, Di67, Jaiswal00, Li95]

Gene-Reaction Schematic

Expand/Contract the Schematic connections:

Gene-Reaction Schematic

Relationship Links: BRENDA:EC:, ENZYME:EC:, IUBMB-ExplorEnz:EC:


Braun98: Braun M, Bungert S, Friedrich T (1998). "Characterization of the overproduced NADH dehydrogenase fragment of the NADH:ubiquinone oxidoreductase (complex I) from Escherichia coli." Biochemistry 37(7);1861-7. PMID: 9485311

Di67: Di Prisco G, Casola L, Giuditta A (1967). "Purification and properties of a soluble reduced nicotinamide-adenine dinucleotide (phosphate) dehydrogenase from the hepatopancreas of Octopus vulgaris." Biochem J 105(2);455-60. PMID: 4171422

Giuditta61: Giuditta A, Strecker HJ (1961). "Purification and some properties of a brain diaphorase." Biochim Biophys Acta 48;10-9. PMID: 13705804

Jaiswal00: Jaiswal AK (2000). "Characterization and partial purification of microsomal NAD(P)H:quinone oxidoreductases." Arch Biochem Biophys 375(1);62-8. PMID: 10683249

Li95: Li R, Bianchet MA, Talalay P, Amzel LM (1995). "The three-dimensional structure of NAD(P)H:quinone reductase, a flavoprotein involved in cancer chemoprotection and chemotherapy: mechanism of the two-electron reduction." Proc Natl Acad Sci U S A 92(19);8846-50. PMID: 7568029

Maerki60: Maerki F, Martius C (1960). "[Vitamin K reductase, preparation and properties]." Biochem Z 333;111-35. PMID: 13765127

Sparla96: Sparla F, Tedeschi G, Trost P (1996). "NAD(P)H:(Quinone-Acceptor) Oxidoreductase of Tobacco Leaves Is a Flavin Mononucleotide-Containing Flavoenzyme." Plant Physiol 112(1);249-258. PMID: 12226388

Wosilait60: Wosilait WD (1960). "The reduction of vitamin K1 by an enzyme from dog liver." J Biol Chem 235;1196-201. PMID: 13846011

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