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ENZYME

ENZYME entry: EC 1.6.5.5

Accepted Name
NADPH:quinone reductase
Alternative Name(s)
quinone oxidoreductase
zeta-crystallin
Reaction catalysed
2 a quinone + H(+) + NADPH <=> 2 a 1,4-benzosemiquinone + NADP(+)
Comment(s)
  • Specific for NADPH.
  • Catalyzes the one-electron reduction of certain quinones, with the orthoquinones 1,2-naphthoquinone and 9,10-phenanthrenequinone being the best substrates.
  • Dicoumarol (cf. EC 1.6.5.2) and nitrofurantoin are competitive inhibitors with respect to the quinone substrate.
  • The semiquinone free-radical product may be non-enzymically reduced to the hydroquinone or oxidized back to quinone in the presence of O2.
  • Abundant in the lens of the eye of some mammalian species.
Cross-references
BRENDA1.6.5.5
EC2PDB1.6.5.5
ExplorEnz1.6.5.5
PRIAM enzyme-specific profiles1.6.5.5
KEGG Ligand Database for Enzyme Nomenclature1.6.5.5
IUBMB Enzyme Nomenclature1.6.5.5
IntEnz1.6.5.5
MEDLINEFind literature relating to 1.6.5.5
MetaCyc1.6.5.5
Rhea expert-curated reactions1.6.5.5
UniProtKB/Swiss-Prot
P28304, QOR1_ECOLIQ53FA7, QORX_HUMANP11415, QOR_CAVPO
Q08257, QOR_HUMANQ28452, QOR_LAMGUP42865, QOR_LEIAM
P47199, QOR_MOUSEQ0MVN8, QOR_PIGQ5R4S7, QOR_PONAB
P43903, QOR_PSEAEQ6AYT0, QOR_RATP40783, QOR_SALTY
O74489, QOR_SCHPOP38230, QOR_YEASTQ9AYU1, QR1_TRIVS

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All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 1.6.5.-
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