EC - Tropinone reductase I

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IntEnz Enzyme Nomenclature


Accepted name:
tropinone reductase I
Other names:
tropine dehydrogenase
tropinone reductase [ambiguous]
Systematic name:
tropine:NADP+ 3α-oxidoreductase



Also oxidizes other tropan-3α-ols, but not the corresponding β-derivatives [1]. This enzyme along with EC, tropinone reductase II, represents a branch point in tropane alkaloid metabolism [4]. 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 [4]. Both enzymes are always found together in any given tropane-alkaloid-producing species, have a common substrate, tropinone, and are strictly stereospecific [3].

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:0050356
CAS Registry Number: 118390-87-7


  1. Koelen, K.J. and Gross, G.G.
    Partial purification and properties of tropine dehydrogenase from root cultures of Datura stramonium.
    Planta Med. 44 : 227-230 (1982).
  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.
    Phytochemistry 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 1984, modified 2007]