EC |
1.1.1.206 |
Accepted name: |
tropinone reductase I |
Reaction: |
tropine + NADP+ = tropinone + NADPH + H+ |
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For diagram of reaction, click here |
Glossary: |
tropine = 3α-hydroxytropane = tropan-3-endo-ol |
Other name(s): |
tropine dehydrogenase; tropinone reductase (ambiguous); TR-I |
Systematic name: |
tropine:NADP+ 3α-oxidoreductase |
Comments: |
Also oxidizes other tropan-3α-ols, but not the corresponding β-derivatives [1]. This enzyme along with EC 1.1.1.236, tropinone reductase II, represents a branch point in tropane alkaloid metabolism [4]. 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 [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: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 118390-87-7 |
References: |
1. |
Koelen, K.J. and Gross, G.G. Partial purification and properties of tropine dehydrogenase from root cultures of Datura stramonium. Planta Med. 44 (1982) 227–230. [PMID: 17402126] |
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 1.1.1.206 created 1984, modified 2007] |
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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, 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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EC
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1.1.1.293
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Deleted entry: | tropinone reductase I. This enzyme was already in the Enzyme List as EC 1.1.1.206, tropine dehydrogenase so EC 1.1.1.293 has been withdrawn at the public-review stage |
[EC 1.1.1.293 created 2007, withdrawn while undergoing public review] |
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EC
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1.14.11.14
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Transferred entry: | 6β-hydroxyhyoscyamine epoxidase. Now EC 1.14.20.13, 6β-hydroxyhyoscyamine epoxidase
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[EC 1.14.11.14 created 1992, deleted 2018] |
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EC |
1.14.20.13 |
Accepted name: |
6β-hydroxyhyoscyamine epoxidase |
Reaction: |
(6S)-6β-hydroxyhyoscyamine + 2-oxoglutarate + O2 = scopolamine + succinate + CO2 + H2O |
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For diagram of tropane alkaloid biosynthesis, click here |
Glossary: |
scopolamine = hyoscine = (1R,2R,4S,5S,7s)-9-methyl-3-oxa-9-azatricyclo[3.3.1.02,4]nonan-7-yl (2S)-3-hydroxy-2-phenylpropanoate |
Other name(s): |
hydroxyhyoscyamine dioxygenase; (6S)-6-hydroxyhyoscyamine,2-oxoglutarate oxidoreductase (epoxide-forming) |
Systematic name: |
(6S)-6β-hydroxyhyoscyamine,2-oxoglutarate:oxygen oxidoreductase (epoxide-forming) |
Comments: |
Requires Fe2+ and ascorbate. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 121479-53-6 |
References: |
1. |
Hashimoto, T., Kohno, J. and Yamada, Y. 6β-Hydroxyhyoscyamine epoxidase from cultured roots of Hyoscyamus niger. Phytochemistry 28 (1989) 1077–1082. |
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[EC 1.14.20.13 created 1992 as EC 1.14.11.14, transferred 2018 to EC 1.14.20.13] |
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