IUBMB Enzyme Nomenclature


Accepted name: morphine 6-dehydrogenase

Reaction: morphine + NAD(P)+ = morphinone + NAD(P)H + H+

For diagram click here.

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-sulfanylethan-1-ol (2-mercaptoethanol).

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 97002-71-6


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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