Escherichia coli K-12 substr. MG1655 Enzyme: NADH dehydrogenase (quinone)

Subunit composition of NADH dehydrogenase (quinone) = [subunit of NADH dehydrogenase (quinone)]2

This NADH dehydrogenase enzyme is thought to compete with the one-electron reduction pathway of quinones, which is potentially toxic as it generates superoxide radicals and hydrogen peroxide [Hayashi90].

The intracellular level of this enzyme is increased 23-fold by growth in the presence of 0.3 mM menadione, but not paraquat [Hayashi90]. The critical inductive signal is a 2-alkyl-1.4-quinone structure with an unsubstitued or Br-substituted C-3 [Unemoto92].

No gene has been identified for this enzyme yet. Based on its properties, it is possible that this enzyme is identical to either NAD(P)H:quinone oxidoreductase or chromate reductase.

Locations: cytosol

Molecular Weight of Polypeptide: 24.0 kD (experimental) [Hayashi90]

Molecular Weight of Multimer: 50 kD (experimental) [Hayashi90]

Gene-Reaction Schematic

Gene-Reaction Schematic

GO Terms:
Cellular Component:
GO:0005829 - cytosol [Hayashi90]

Last-Curated 22-Apr-2010 by Keseler I, SRI International

Enzymatic reaction of: NADH dehydrogenase (quinone)

Inferred from experiment

Synonyms: D-diaphorase

EC Number:

menadione + NADH + H+ ⇄ menadiol + NAD+

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.

Reversibility of this reaction is unspecified.

Alternative Substrates for menadione: 1,4-naphthoquinone [Hayashi90], 1,4-benzoquinone [Hayashi90], ubiquinone-1 [Hayashi90], 2,3-dimethyl-1,4-naphthoquinone [Hayashi90]

Cofactors or Prosthetic Groups: FMN [Hayashi90]

Inhibitors (Competitive): dicoumarol [Hayashi90, Comment 1]Kinetic Parameters:
Substrate Km (μM) Citations
NADH 132.0 [Hayashi90]
menadione 1.96 [Hayashi90]

pH(opt): 7-8 [Hayashi90]


Hayashi90: Hayashi M, Hasegawa K, Oguni Y, Unemoto T (1990). "Characterization of FMN-dependent NADH-quinone reductase induced by menadione in Escherichia coli." Biochim Biophys Acta 1990;1035(2);230-6. PMID: 2118386

Unemoto92: Unemoto T, Shimada H, Hayashi M (1992). "Chemical structures critical for the induction of FMN-dependent NADH-quinone reductase in Escherichia coli." Biochim Biophys Acta 1099(2);170-4. PMID: 1543701

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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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