Escherichia coli K-12 substr. MG1655 Reaction:

Superclasses: Reactions Classified By Conversion Type Simple Reactions Chemical Reactions
Reactions Classified By Conversion Type Simple Reactions Chemical Reactions Composite Reactions Electron-Transfer-Reactions
Reactions Classified By Substrate Small-Molecule Reactions

EC Number:

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

Supersedes EC number:

Transport reaction diagram

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

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, 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, and some reactions have been computationally balanced for hydrogen by adding free protons. 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: ?

Gene-Reaction Schematic

Instance reactions of [an electron-transfer quinone[inner membrane] + NAD(P)H + H+ → an electron-transfer quinol[inner membrane] + NAD(P)+] (
i1: NADH + a ubiquinone[inner membrane] + H+ → NAD+ + an ubiquinol[inner membrane] (

i2: NADH + a menaquinone[inner membrane] + H+ → NAD+ + a menaquinol[inner membrane] (no EC#)

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
Page generated by SRI International Pathway Tools version 19.0 on Fri Oct 9, 2015, BIOCYC14B.