EC - Morphine 6-dehydrogenase

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IntEnz Enzyme Nomenclature


Accepted name:
morphine 6-dehydrogenase
Other names:
naloxone reductase
reductase, naloxone
Systematic name:
morphine:NAD(P)+ 6-oxidoreductase



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

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC00061
Structural data: CSA , EC2PDB
Gene Ontology: GO:0050109
CAS Registry Numbers: 106640-77-1 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 : 5259-5264 (1985). [PMID: 2580834]
  2. Yamano, S., Nishida, F. and Toki, S.
    Guinea-pig liver morphine 6-dehydrogenase as a naloxone reductase.
    Biochem. Pharmacol. 35 : 4321-4326 (1986). [PMID: 3539118]

[EC created 1989, modified 1990]