KEGG   ENZYME: 1.3.1.122
Entry
EC 1.3.1.122                Enzyme                                 

Name
(S)-8-oxocitronellyl enol synthase;
CrISY;
8-oxogeranial:NAD(P)+ oxidoreductase (cyclizing, cis-trans-nepetalactol forming);
iridoid synthase (incorrect)
Class
Oxidoreductases;
Acting on the CH-CH group of donors;
With NAD+ or NADP+ as acceptor
Sysname
(S)-8-oxocitronellyl enol:NAD(P)+ oxidoreductase
Reaction(IUBMB)
(S)-8-oxocitronellyl enol + NAD(P)+ = (6E)-8-oxogeranial + NAD(P)H + H+ [RN:R12517 R12518]
Reaction(KEGG)
R12517 R12518
Substrate
(S)-8-oxocitronellyl enol [CPD:C22225];
NAD+ [CPD:C00003];
NADP+ [CPD:C00006]
Product
(6E)-8-oxogeranial [CPD:C17622];
NADH [CPD:C00004];
NADPH [CPD:C00005];
H+ [CPD:C00080]
Comment
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.
History
EC 1.3.1.122 created 2013 as EC 1.3.1.99, part transferred 2019 to EC 1.3.1.122
Pathway
ec00902  Monoterpenoid biosynthesis
ec01100  Metabolic pathways
ec01110  Biosynthesis of secondary metabolites
Orthology
K20144  (S)-8-oxocitronellyl enol synthase
Genes
OEU: 111393291
Reference
1  [PMID:23172143]
  Authors
Geu-Flores F, Sherden NH, Courdavault V, Burlat V, Glenn WS, Wu C, Nims E, Cui Y, O'Connor SE
  Title
An alternative route to cyclic terpenes by reductive cyclization in iridoid biosynthesis.
  Journal
Nature 492:138-42 (2012)
DOI:10.1038/nature11692
  Sequence
Reference
2  [PMID:26768532]
  Authors
Hu Y, Liu W, Malwal SR, Zheng Y, Feng X, Ko TP, Chen CC, Xu Z, Liu M, Han X, Gao J, Oldfield E, Guo RT
  Title
Structures of Iridoid Synthase from Cantharanthus roseus with Bound NAD(+) , NADPH, or NAD(+) /10-Oxogeranial: Reaction Mechanisms.
  Journal
Angew Chem Int Ed Engl 54:15478-15482 (2015)
DOI:10.1002/anie.201508310
  Sequence
Reference
3  [PMID:26709230]
  Authors
Alagna F, Geu-Flores F, Kries H, Panara F, Baldoni L, O'Connor SE, Osbourn A
  Title
Identification and Characterization of the Iridoid Synthase Involved in Oleuropein Biosynthesis in Olive (Olea europaea) Fruits.
  Journal
J Biol Chem 291:5542-54 (2016)
DOI:10.1074/jbc.M115.701276
  Sequence
[oeu:111393291]
Reference
4  [PMID:26868105]
  Authors
Qin L, Zhu Y, Ding Z, Zhang X, Ye S, Zhang R
  Title
Structure of iridoid synthase in complex with NADP(+)/8-oxogeranial reveals the structural basis of its substrate specificity.
  Journal
J Struct Biol 194:224-30 (2016)
DOI:10.1016/j.jsb.2016.02.010
  Sequence
Reference
5  [PMID:29091815]
  Authors
Sherden NH, Lichman B, Caputi L, Zhao D, Kamileen MO, Buell CR, O'Connor SE
  Title
Identification of iridoid synthases from Nepeta species: Iridoid cyclization does not determine nepetalactone stereochemistry.
  Journal
Phytochemistry 145:48-56 (2018)
DOI:10.1016/j.phytochem.2017.10.004
Reference
6  [PMID:30531909]
  Authors
Lichman BR, Kamileen MO, Titchiner GR, Saalbach G, Stevenson CEM, Lawson DM, O'Connor SE
  Title
Uncoupled activation and cyclization in catmint reductive terpenoid biosynthesis.
  Journal
Nat Chem Biol 15:71-79 (2019)
DOI:10.1038/s41589-018-0185-2
Reference
7  [PMID:30664302]
  Authors
Lichman BR, O'Connor SE, Kries H
  Title
Biocatalytic Strategies towards [4+2] Cycloadditions.
  Journal
Chemistry 25:6864-6877 (2019)
DOI:10.1002/chem.201805412
Other DBs
ExplorEnz - The Enzyme Database: 1.3.1.122
IUBMB Enzyme Nomenclature: 1.3.1.122
ExPASy - ENZYME nomenclature database: 1.3.1.122
BRENDA, the Enzyme Database: 1.3.1.122

DBGET integrated database retrieval system