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1.6.5.5: NADPH:quinone reductase

This is an abbreviated version!
For detailed information about NADPH:quinone reductase, go to the full flat file.

Word Map on EC 1.6.5.5

Reaction

NADPH
+
H+
+ 2 quinone =
NADP+
+ 2 semiquinone

Synonyms

ArsH, Dehydrogenase, reduced nicotinamide adenine dinucleotide (phosphate) (quinone), DT-diaphorase, EC 1.6.99.2, Flavoprotein NAD(P)H:quinone reductase, Menadione oxidoreductase, Menadione reductase, NAD(P)H dehydrogenase, NAD(P)H dehydrogenase (quinone), NAD(P)H menadione reductase, NAD(P)H quinone reductase, NAD(P)H-quinone dehydrogenase, NAD(P)H-quinone oxidoreductase, NAD(P)H-quinone reductase, NAD(P)H:(quinone-acceptor) oxidoreductase, NAD(P)H:menadione oxidoreductase, NAD(P)H:paraquat diaphorase, NAD(P)H:quinone reductase, NADH-menadione reductase, NADH-menaquinone reductase, NADH:quinone reductase, NADPH DT-diaphorase, NADPH quinone acceptor oxidoreductase, NADPH-dependent quinone reductase, NADPH:azodicarbonyl/quinone reductase, NADPH:quinone oxidoreductase, NADPH:quinone reductase, Naphthoquinone reductase, NfsA, nitroreductase A, old yellow enzyme, ORF 17150, p-Benzoquinone reductase, P1-ZCr, P1-zeta-crystallin, P36, PA0660, Phylloquinone reductase, PtoQOR, QAO, Qor, QorA, Quinone reductase, Reduced NAD(P)H dehydrogenase, TcOYE, TmQR1, VAT-1, vesicle amine transport protein-1, Viologen accepting pyridine nucleotide oxidoreductase, Vitamin K reductase, ZCr, zeta-Crystallin, zeta-crystallin homolog protein, zeta-crystallin/NADPH:quinone oxidoreductase, zeta-Crystallin/quinone reductase, Zta1, Zta1p

ECTree

     1 Oxidoreductases
         1.6 Acting on NADH or NADPH
             1.6.5 With a quinone or similar compound as acceptor
                1.6.5.5 NADPH:quinone reductase

Inhibitors

Inhibitors on EC 1.6.5.5 - NADPH:quinone reductase

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INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
2,3-Dimercaptopropanol
-
-
2,5-Dichloro-3,6-dihydroxy-1,4-benzoquinone
-
i.e. chloranilic acid, noncompetitive with respect to both NADPH and 9,10-phenanthrenequinone
4-chloromercuribenzoate
-
both NADPH and NADP1 suppress the inhibition, but NADH does not
4-Hydroxycoumarin
-
reversible time-independent inhibition. Only dicoumarol, 4-hydroxycoumarin and warfarin inhibit in micromolar ranges. 7-Hydroxy-4-methylcoumarin is ineffective. Competitive inhibition with respect to 2,6-dichlorophenolindophenol, uncompetitive with respect to NADPH. Phenolic hydroxyl group at the C-4 position in the coumarin skeleton is important for the maximal inhibition. Sequence of potency for the inhibitors in descending order: dicoumarol, 4-hydroxycoumarin, warfarin, coumarin
5,5'-dithiobis(2-nitrobenzoate)
ADP
-
10% inhibition at 0.2 mM
Cibacron blue 3GA
Colchicine
-
noncompetitive with respect to 9,10-phenanthrenequinone and 1,2-naphthoquinone, uncompetitive with respect to NADPH. Binding of colchicine occurs at or close to the NADPH binding site
coumarin
-
reversible time-independent inhibition. Only dicoumarol, 4-hydroxycoumarin and warfarin inhibit in micromolar ranges. 7-Hydroxy-4-methylcoumarin is ineffective. Competitive inhibition with respect to 2,6-dichlorophenolindophenol, uncompetitive with respect to NADPH. Phenolic hydroxyl group at the C-4 position in the coumarin skeleton is important for the maximal inhibition. Sequence of potency for the inhibitors in descending order: dicoumarol, 4-hydroxycoumarin, warfarin, coumarin
Cu2+
-
25% inhibition at 1 mM
dicoumarol
dithiothreitol
emodin
-
i.e. an anthraquinone, inhibits the enzymatic activity of NADPH-quinone reductase by binding to the active site. Emodin acts as a competitive inhibitor with respect to 2, 6-dichlorophenolindophenol, and emodin shows cytotoxicity against rat hepatocytes
FAD
-
60% inhibition at 0.2 mM
FMN
-
40% inhibition at 0.2 mM
menadione
-
-
N-ethylmaleimide
-
both NADPH and NADP1 suppress the inhibition, but NADH does not
NAD+
-
5% inhibition at 0.2 mM
NADP+
NADPH
substrate inhibition is observed at NADPH concentrations of more than 0.05 mM
Nitrofurantoin
o-phthalaldehyde
-
-
p-chloromercuriphenylsulfonate
-
-
pyridoxal-5'-phosphate
-
inactivation follows pseudo-first-order kinetics. NADPH protects against inactivation, 9,10-phenanthrenequinone does not protect. Inhibition is uncompetitive with NADPH and non-competitive with respect to 9,10-phenanthrenequinone
warfarin
Zn2+
-
25% inhibition at 1 mM
additional information
-