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].
Molecular Weight of Polypeptide: 24.0 kD (experimental) [Hayashi90]
Molecular Weight of Multimer: 50 kD (experimental) [Hayashi90]
Enzymatic reaction of: NADH dehydrogenase (quinone)
EC Number: 22.214.171.124menadione + 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] dicoumarol [Hayashi90, Comment 1]Kinetic Parameters:
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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