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 |
2.3.1.185 |
Accepted name: |
tropine acyltransferase |
Reaction: |
an acyl-CoA + tropine = CoA + an O-acyltropine |
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For diagram of tropane alkaloid biosynthesis, click here |
Glossary: |
tropine = tropan-3α-ol = 3α-hydroxytropane |
Other name(s): |
tropine:acyl-CoA transferase; acetyl-CoA:tropan-3-ol acyltransferase; tropine acetyltransferase; tropine tigloyltransferase; TAT |
Systematic name: |
acyl-CoA:tropine O-acyltransferase |
Comments: |
This enzyme exhibits absolute specificity for the endo/3α configuration found in tropine as pseudotropine (tropan-3β-ol; see EC 2.3.1.186, pseudotropine acyltransferase) is not a substrate [3]. Acts on a wide range of aliphatic acyl-CoA derivatives, with tigloyl-CoA and acetyl-CoA being the best substrates. It is probably involved in the formation of the tropane alkaloid littorine, which is a precursor of hyoscyamine [4]. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 138440-79-6, 162535-29-7 |
References: |
1. |
Robins, R.J., Bachmann, P., Robinson, T., Rhodes, M.J. and Yamada, Y. The formation of 3α- and 3β-acetoxytropanes by Datura stramonium transformed root cultures involves two acetyl-CoA-dependent acyltransferases. FEBS Lett. 292 (1991) 293–297. [DOI] [PMID: 1959620] |
2. |
Robins, R.J., Bachmann,P., Peerless, A.C.J. and Rabot, S. Esterification reactions in the biosynthesis of tropane alkaloids in transformed root cultures. Plant Cell, Tissue Organ Cult. 38 (1994) 241–247. |
3. |
Boswell, H.D., Dräger, B., McLauchlan, W.R., Portsteffen, A., Robins, D.J., Robins, R.J. and Walton, N.J. Specificities of the enzymes of N-alkyltropane biosynthesis in Brugmansia and Datura. Phytochemistry 52 (1999) 871–878. [DOI] [PMID: 10626376] |
4. |
Li, R., Reed, D.W., Liu, E., Nowak, J., Pelcher, L.E., Page, J.E. and Covello, P.S. Functional genomic analysis of alkaloid biosynthesis in Hyoscyamus niger reveals a cytochrome P450 involved in littorine rearrangement. Chem. Biol. 13 (2006) 513–520. [DOI] [PMID: 16720272] |
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[EC 2.3.1.185 created 2008] |
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EC |
2.3.1.186 |
Accepted name: |
pseudotropine acyltransferase |
Reaction: |
an acyl-CoA + pseudotropine = CoA + an O-acylpseudotropine |
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For diagram of tropane alkaloid biosynthesis, click here |
Glossary: |
tropine = tropan-3β-ol = 3β-hydroxytropane |
Other name(s): |
pseudotropine:acyl-CoA transferase; tigloyl-CoA:pseudotropine acyltransferase; acetyl-CoA:pseudotropine acyltransferase; pseudotropine acetyltransferase; pseudotropine tigloyltransferase; PAT (ambiguous) |
Systematic name: |
acyl-CoA:pseudotropine O-acyltransferase |
Comments: |
This enzyme exhibits absolute specificity for the exo/3β configuration found in pseudotropine as tropine (tropan-3α-ol; see EC 2.3.1.185, tropine acyltransferase) and nortropine are not substrates [1]. Acts on a wide range of aliphatic acyl-CoA derivatives, including acetyl-CoA, β-methylcrotonyl-CoA and tigloyl-CoA [1]. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 138440-78-5, 162535-26-4 |
References: |
1. |
Rabot, S., Peerless, A.C.J. and Robins, R.J. Tigloyl-CoA:pseudotropine acyltransferase — an enzyme of tropane alkaloid biosynthesis. Phytochemistry 39 (1995) 315–322. |
2. |
Robins, R.J., Bachmann, P., Robinson, T., Rhodes, M.J. and Yamada, Y. The formation of 3α- and 3β-acetoxytropanes by Datura stramonium transformed root cultures involves two acetyl-CoA-dependent acyltransferases. FEBS Lett. 292 (1991) 293–297. [DOI] [PMID: 1959620] |
3. |
Robins, R.J., Bachmann,P., Peerless, A.C.J. and Rabot, S. Esterification reactions in the biosynthesis of tropane alkaloids in transformed root cultures. Plant Cell, Tissue Organ Cult. 38 (1994) 241–247. |
4. |
Boswell, H.D., Dräger, B., McLauchlan, W.R., Portsteffen, A., Robins, D.J., Robins, R.J. and Walton, N.J. Specificities of the enzymes of N-alkyltropane biosynthesis in Brugmansia and Datura. Phytochemistry 52 (1999) 871–878. [DOI] [PMID: 10626376] |
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[EC 2.3.1.186 created 2008] |
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