EC
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1.3.1.99
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Transferred entry: | iridoid synthase. Now known to be catalyzed by two different enzymes, EC 1.3.1.122, (S)-8-oxocitronellyl enol synthase, and EC 5.5.1.34, (+)-cis,trans-nepetalactol synthase
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[EC 1.3.1.99 created 2013, deleted 2019] |
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EC |
1.3.1.122 |
Accepted name: |
(S)-8-oxocitronellyl enol synthase |
Reaction: |
(S)-8-oxocitronellyl enol + NAD(P)+ = (6E)-8-oxogeranial + NAD(P)H + H+ |
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For diagram of secologanin biosynthesis, click here |
Glossary: |
(S)-8-oxocitronellyl enol = (2E,6S,7E)-8-hydroxy-2,6-dimethylocta-2,7-dienal |
Other name(s): |
CrISY; 8-oxogeranial:NAD(P)+ oxidoreductase (cyclizing, cis-trans-nepetalactol forming); iridoid synthase (incorrect) |
Systematic name: |
(S)-8-oxocitronellyl enol:NAD(P)+ oxidoreductase |
Comments: |
Isolated from the plants Catharanthus roseus, Olea europaea (common olive), and several Nepeta species. The enzyme reduces 8-oxogeranial, generating an unstable product that is subsequently cyclized into several possible products, either non-enzymically or by dedicated cyclases. The products, known as iridoids, are involved in the biosynthesis of many indole alkaloids. cf. EC 1.3.1.123, 7-epi-iridoid synthase. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB |
References: |
1. |
Geu-Flores, F., Sherden, N.H., Courdavault, V., Burlat, V., Glenn, W.S., Wu, C., Nims, E., Cui, Y. and O'Connor, S.E. An alternative route to cyclic terpenes by reductive cyclization in iridoid biosynthesis. Nature 492 (2012) 138–142. [DOI] [PMID: 23172143] |
2. |
Hu, Y., Liu, W., Malwal, S.R., Zheng, Y., Feng, X., Ko, T.P., Chen, C.C., Xu, Z., Liu, M., Han, X., Gao, J., Oldfield, E. and Guo, R.T. Structures of iridoid synthase from Catharanthus roseus with bound NAD+, NADPH, or NAD+/10-oxogeranial: Reaction mechanisms. Angew. Chem. Int. Ed. Engl. 54 (2015) 15478–15482. [PMID: 26768532] |
3. |
Alagna, F., Geu-Flores, F., Kries, H., Panara, F., Baldoni, L., O'Connor, S.E. and Osbourn, A. Identification and characterization of the iridoid synthase involved in oleuropein biosynthesis in olive (Olea europaea) fruits. J. Biol. Chem. 291 (2016) 5542–5554. [PMID: 26709230] |
4. |
Qin, L., Zhu, Y., Ding, Z., Zhang, X., Ye, S. and Zhang, R. Structure of iridoid synthase in complex with NADP+/8-oxogeranial reveals the structural basis of its substrate specificity. J. Struct. Biol. 194 (2016) 224–230. [PMID: 26868105] |
5. |
Sherden, N.H., Lichman, B., Caputi, L., Zhao, D., Kamileen, M.O., Buell, C.R. and O'Connor, S.E. Identification of iridoid synthases from Nepeta species: Iridoid cyclization does not determine nepetalactone stereochemistry. Phytochemistry 145 (2018) 48–56. [PMID: 29091815] |
6. |
Lichman, B.R., Kamileen, M.O., Titchiner, G.R., Saalbach, G., Stevenson, C.EM., Lawson, D.M. and O'Connor, S.E. Uncoupled activation and cyclization in catmint reductive terpenoid biosynthesis. Nat. Chem. Biol. 15 (2019) 71–79. [PMID: 30531909] |
7. |
Lichman, B.R., O'Connor, S.E. and Kries, H. Biocatalytic strategies towards [4+2] cycloadditions. Chemistry 25 (2019) 6864–6877. [PMID: 30664302] |
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[EC 1.3.1.122 created 2013 as EC 1.3.1.99, part transferred 2019 to EC 1.3.1.122] |
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EC |
1.3.1.123 |
Accepted name: |
8-oxogeranial reductase |
Reaction: |
(R)-8-oxocitronellyl enol + NADP+ = (6E)-8-oxogeranial + NADPH + H+ |
Glossary: |
(R)-8-oxocitronellyl enol = (2E,6R,7E)-8-hydroxy-2,6-dimethylocta-2,7-dienal |
Other name(s): |
AmISY |
Systematic name: |
(R)-8-oxocitronellyl enol:NADP+ oxidoreductase |
Comments: |
The enzyme, characterized from the plant Antirrhinum majus (snapdragon), is involved in biosynthesis of 7-epi-iridoids such as antirrhinoside. The enzyme catalyses the stereospecific reduction of 8-oxogeranial, forming an unstable product that in the absence of additional cylases undergoes spontaneous cyclization to (–)-cis,trans-nepetalactol. cf. EC 1.3.1.122, (S)-8-oxocitronellyl enol synthase. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc |
References: |
1. |
Kries, H., Kellner, F., Kamileen, M.O. and O'Connor, S.E. Inverted stereocontrol of iridoid synthase in snapdragon. J. Biol. Chem. 292 (2017) 14659–14667. [PMID: 28701463] |
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Lichman, B.R., O'Connor, S.E. and Kries, H. Biocatalytic strategies towards [4+2] cycloadditions. Chemistry 25 (2019) 6864–6877. [PMID: 30664302] |
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[EC 1.3.1.123 created 2019] |
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EC |
5.5.1.34 |
Accepted name: |
(+)-cis,trans-nepetalactol synthase |
Reaction: |
(S)-8-oxocitronellyl enol = (+)-cis,trans-nepetalactol |
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For diagram of secologanin biosynthesis, click here |
Glossary: |
(S)-8-oxocitronellyl enol = (2E,6S,7E)-8-hydroxy-2,6-dimethylocta-2,7-dienal
(+)-cis,trans-nepetalactol = (+)-iridodial lactol = (4aS,7S,7aR)-4,7-dimethyl-1,4a,5,6,7,7a-hexahydrocyclopenta[c]pyran-1-ol |
Other name(s): |
NEPS1 (gene name); NEPS2 (gene name) |
Systematic name: |
(S)-8-oxocitronellyl enol cyclase [(+)-cis,trans-nepetalactol-forming] |
Comments: |
The enzyme, characterized from the plant Nepeta mussinii, binds an NAD+ cofactor. The product is a precursor of (+)-cis,trans-nepetalactone, the primary ingredient responsible for the psychoactive effects catnip has on cats. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc |
References: |
1. |
Lichman, B.R., Kamileen, M.O., Titchiner, G.R., Saalbach, G., Stevenson, C.EM., Lawson, D.M. and O'Connor, S.E. Uncoupled activation and cyclization in catmint reductive terpenoid biosynthesis. Nat. Chem. Biol. 15 (2019) 71–79. [PMID: 30531909] |
2. |
Lichman, B.R., O'Connor, S.E. and Kries, H. Biocatalytic strategies towards [4+2] cycloadditions. Chemistry 25 (2019) 6864–6877. [PMID: 30664302] |
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[EC 5.5.1.34 created 2019] |
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EC |
5.5.1.35 |
Accepted name: |
(+)-cis,cis-nepetalactol synthase |
Reaction: |
(S)-8-oxocitronellyl enol = (+)-cis,cis-nepetalactol |
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For diagram of secologanin biosynthesis, click here |
Glossary: |
(S)-8-oxocitronellyl enol = (2E,6S,7E)-8-hydroxy-2,6-dimethylocta-2,7-dienal
(+)-cis,cis-nepetalactol =(4aR,7S,7aS)-4,7-dimethyl-1,4a,5,6,7,7a-hexahydrocyclopenta[c]pyran-1-ol |
Other name(s): |
NEPS3 (gene name) |
Systematic name: |
(S)-8-oxocitronellyl enol cyclase [(+)-cis,cis-nepetalactol-forming] |
Comments: |
The enzyme, characterized from the plant Nepeta mussinii, binds an NAD+ cofactor. The product is a precursor of (+)-cis,cis-nepetalactone, one of the stereoisomers responsible for the psychoactive effects catnip has on cats. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB |
References: |
1. |
Lichman, B.R., Kamileen, M.O., Titchiner, G.R., Saalbach, G., Stevenson, C.EM., Lawson, D.M. and O'Connor, S.E. Uncoupled activation and cyclization in catmint reductive terpenoid biosynthesis. Nat. Chem. Biol. 15 (2019) 71–79. [PMID: 30531909] |
2. |
Lichman, B.R., O'Connor, S.E. and Kries, H. Biocatalytic strategies towards [4+2] cycloadditions. Chemistry 25 (2019) 6864–6877. [PMID: 30664302] |
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[EC 5.5.1.35 created 2019] |
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