Accepted name: morphine 6-dehydrogenase
Reaction: morphine + NAD(P)+ = morphinone + NAD(P)H + H+
Other name(s): naloxone reductase; reductase, naloxone
Systematic name: morphine:NAD(P)+ 6-oxidoreductase
Comments: Also acts on some other alkaloids, including codeine, normorphine and ethylmorphine, but only very slowly on 7,8-saturated derivatives such as dihydromorphine and dihydrocodeine. In the reverse direction, also reduces naloxone to the 6α-hydroxy analogue. Activated by 2-mercaptoethanol.
1.  Yamano, S., Kaguera, E., Ishida, T. and Toki, S. Purification and characterization of guinea pig liver morphine 6-dehydrogenase. J. Biol. Chem. 260 (1985) 5259–5264. [PMID: 2580834]
2.  Yamano, S., Nishida, F. and Toki, S. Guinea-pig liver morphine 6-dehydrogenase as a naloxone reductase. Biochem. Pharmacol. 35 (1986) 4321–4326. [PMID: 3539118]
[EC created 1989, modified 1990]

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