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

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

Summary:
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: ?

Instance reaction of [a quinone + NAD(P)H + H+ → a quinol + NAD(P)+] (1.6.5.2):
i1: menadione + NADH + H+ = menadiol + NAD+ (1.6.99.5)

GO Terms:

Cellular Component: GO:0005829 - cytosol [Hayashi90]

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


Enzymatic reaction of: NADH dehydrogenase (quinone)

Synonyms: D-diaphorase

EC Number: 1.6.99.5

menadione + NADH + H+ <=> menadiol + NAD+

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, 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]


References

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


Report Errors or Provide Feedback
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 18.5 on Thu Dec 18, 2014, BIOCYC14B.