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EC 1.10.5.1 Details

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EC number

1.10.5.1

Accepted name

ribosyldihydronicotinamide dehydrogenase (quinone)

Reaction

1-(β-D-ribofuranosyl)-1,4-dihydronicotinamide + a quinone = 1-(β-D-ribofuranosyl)nicotinamide + a quinol

Other name(s)

NRH:quinone oxidoreductase 2, NQO2, NAD(P)H:quinone oxidoreductase-2 (misleading), QR2, quinone reductase 2, N-ribosyldihydronicotinamide dehydrogenase (quinone), NAD(P)H:quinone oxidoreductase2 (misleading)

Systematic name

1-(β-D-ribofuranosyl)-1,4-dihydronicotinamide:quinone oxidoreductase

CAS registry number

667919-86-0

Comment

A flavoprotein. Unlike EC 1.6.5.2, NAD(P)H dehydrogenase (quinone), this quinone reductase cannot use NADH or NADPH; instead it uses N-ribosyl- and N-alkyldihydronicotinamides. Polycyclic aromatic hydrocarbons, such as benz[a]anthracene, and the estrogens 17β-estradiol and diethylstilbestrol are potent inhibitors, but dicoumarol is only a very weak inhibitor [2]. This enzyme can catalyse both 2-electron and 4-electron reductions, but one-electron acceptors, such as potassium ferricyanide, cannot be reduced [3].

History

created 2005 as EC 1.10.99.2, transferred 2015 to EC 1.10.5.1

EC Tree

1 Oxidoreductases

1.1 Acting on the CH-OH group of donors

1.2 Acting on the aldehyde or oxo group of donors

1.3 Acting on the CH-CH group of donors

1.4 Acting on the CH-NH₂ group of donors

1.4.1 With NAD⁺ or NADP⁺ as acceptor

1.4.2 With a cytochrome as acceptor

1.4.3 With oxygen as acceptor

1.4.4 With a disulfide as acceptor

1.4.5 With a quinone or other compound as acceptor

1.4.7 With an iron-sulfur protein as acceptor

1.4.9 With a copper protein as acceptor

1.4.98. undefined

1.4.99 With unknown physiological acceptors

1.5 Acting on the CH-NH group of donors

1.6 Acting on NADH or NADPH

1.7 Acting on other nitrogenous compounds as donors

1.8 Acting on a sulfur group of donors

1.9 Acting on a heme group of donors

1.10 Acting on diphenols and related substances as donors

1.10.1 With NAD⁺ or NADP⁺ as acceptor

1.10.2 With a cytochrome as acceptor

1.10.3 With oxygen as acceptor

1.10.5 With a quinone or related compound as acceptor

1.10.5.1 ribosyldihydronicotinamide dehydrogenase (quinone)

1.10.9 With a copper protein as acceptor

1.10.99 With unknown physiological acceptors

1.11 Acting on a peroxide as acceptor

1.12 Acting on hydrogen as donor

1.13 Acting on single donors with incorporation of molecular oxygen (oxygenases)

1.14 Acting on paired donors, with incorporation or reduction of molecular oxygen

1.15 Acting on superoxide as acceptor

1.16 Oxidizing metal ions

1.17 Acting on CH or CH₂ groups

1.18 Acting on iron-sulfur proteins as donors

1.19 Acting on reduced flavodoxin as donor

1.20 Acting on phosphorus or arsenic in donors

1.21 Catalysing the reaction X-H + Y-H = X-Y

1.22 Acting on halogen in donors

1.23 Reducing C-O-C group as acceptor

1.97 Other oxidoreductases

1.97.1 Sole sub-subclass for oxidoreductases that do not belong in the other subclasses

1.98 Enzymes using H₂ as reductant (deleted subclass)

1.99 Other enzymes using O₂ as oxidant (deleted subclass)

7.1 Catalysing the translocation of hydrons

7.2 Catalysing the translocation of inorganic cations

7.3 Catalysing the translocation of inorganic anions and their chelates

7.4 Catalysing the translocation of amino acids and peptides

7.5 Catalysing the translocation of carbohydrates and their derivatives

7.6 Catalysing the translocation of other compounds