ID   1.6.5.5
DE   NADPH:quinone reductase.
AN   quinone oxidoreductase.
AN   zeta-crystallin.
CA   2 a quinone + H(+) + NADPH = 2 a 1,4-benzosemiquinone + NADP(+).
CC   -!- Specific for NADPH.
CC   -!- Catalyzes the one-electron reduction of certain quinones, with the
CC       orthoquinones 1,2-naphthoquinone and 9,10-phenanthrenequinone being
CC       the best substrates.
CC   -!- Dicoumarol (cf. EC 1.6.5.2) and nitrofurantoin are competitive
CC       inhibitors with respect to the quinone substrate.
CC   -!- The semiquinone free-radical product may be non-enzymically reduced
CC       to the hydroquinone or oxidized back to quinone in the presence of
CC       O2.
CC   -!- Abundant in the lens of the eye of some mammalian species.
DR   P28304, QOR1_ECOLI ;  Q53FA7, QORX_HUMAN ;  P11415, QOR_CAVPO  ;
DR   Q08257, QOR_HUMAN  ;  Q28452, QOR_LAMGU  ;  P42865, QOR_LEIAM  ;
DR   P47199, QOR_MOUSE  ;  Q0MVN8, QOR_PIG    ;  Q5R4S7, QOR_PONAB  ;
DR   P43903, QOR_PSEAE  ;  Q6AYT0, QOR_RAT    ;  P40783, QOR_SALTY  ;
DR   O74489, QOR_SCHPO  ;  P38230, QOR_YEAST  ;  Q9AYU1, QR1_TRIVS  ;
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