EC - Tropinone reductase II

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IntEnz Enzyme Nomenclature


Accepted name:
tropinone reductase II
Other names:
pseudotropine forming tropinone reductase
tropinone (ψ-tropine-forming) reductase
tropinone reductase [ambiguous]
Systematic name:
pseudotropine:NADP+ 3-oxidoreductase



This enzyme along with EC, tropine dehydrogenase, represents a branch point in tropane alkaloid metabolism [3]. Tropine (the product of EC is incorporated into hyoscyamine and scopolamine whereas pseudotropine (the product of EC is the first specific metabolite on the pathway to the calystegines [3]. Both enzymes are always found together in any given tropane-alkaloid-producing species, have a common substrate, tropinone, and are strictly stereospecific [2].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC00060
Structural data: CSA , EC2PDB
Gene Ontology: GO:0050358
CAS Registry Number: 136111-61-0


  1. Dräger, B., Hashimoto, T. and Yamada, Y.
    Purification and characterization of pseudotropine forming tropinone reductase from Hyoscyamus niger root cultures.
    Agric. Biol. Chem. 52: 2663-2667 (1988).
  2. Couladis, M.M, Friesen, J.B., Landgrebe, M.E. and Leete, E.
    Enzymes catalysing the reduction of tropinone to tropine and ψ-tropine isolated from the roots of Datura innoxia.
    Pytochemistry 30: 801-805 (1991).
  3. Nakajima, K., Hashimoto, T. and Yamada, Y.
    Two tropinone reductases with different stereospecificities are short-chain dehydrogenases evolved from a common ancestor.
    Proc. Natl. Acad. Sci. USA 90: 9591-9595 (1993). [PMID: 8415746]
  4. Dräger, B.
    Tropinone reductases, enzymes at the branch point of tropane alkaloid metabolism.
    Phytochemistry 67: 327-337 (2006). [PMID: 16426652]

[EC created 1992, modified 2007]