| EC |
1.1.1.236 |
| Accepted name: |
tropinone reductase II |
| Reaction: |
pseudotropine + NADP+ = tropinone + NADPH + H+ |
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For diagram of reaction, click here |
| Glossary: |
pseudotropine = ψ-tropine = 3β-hydroxytropane = tropan-3-exo-ol |
| Other name(s): |
tropinone (ψ-tropine-forming) reductase; pseudotropine forming tropinone reductase; tropinone reductase (ambiguous); TR-II |
| Systematic name: |
pseudotropine:NADP+ 3-oxidoreductase |
| Comments: |
This enzyme along with EC 1.1.1.206, tropine dehydrogenase, represents a branch point in tropane alkaloid metabolism [3]. Tropine (the product of EC 1.1.1.206) is incorporated into hyoscyamine and scopolamine whereas pseudotropine (the product of EC 1.1.1.236) 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: |
BRENDA, EXPASY, Gene, KEGG, MetaCyc, PDB, CAS registry number: 136111-61-0 |
| References: |
| 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 (1988) 2663–2667. |
| 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 (1991) 801–805. |
| 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 (1993) 9591–9595. [DOI] [PMID: 8415746] |
| 4. |
Dräger, B. Tropinone reductases, enzymes at the branch point of tropane alkaloid metabolism. Phytochemistry 67 (2006) 327–337. [DOI] [PMID: 16426652] |
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| [EC 1.1.1.236 created 1992, modified 2007] |
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