KEGG   ENZYME: 4.2.1.139
Entry
EC 4.2.1.139                Enzyme                                 

Name
pterocarpan synthase;
medicarpin synthase;
medicarpan synthase;
7,2'-dihydroxy-4'-methoxyisoflavanol dehydratase;
2',7-dihydroxy-4'-methoxyisoflavanol dehydratase;
DMI dehydratase;
DMID;
2'-hydroxyisoflavanol 4,2'-dehydratase;
PTS (gene name);
4'-methoxyisoflavan-2',4,7-triol hydro-lyase [(-)-medicarpin-forming]
Class
Lyases;
Carbon-oxygen lyases;
Hydro-lyases
Sysname
(4R)-4,2'-dihydroxyisoflavan hydro-lyase (pterocarpan-forming)
Reaction(IUBMB)
a (4R)-4,2'-dihydroxyisoflavan = a pterocarpan + H2O [RN:R12307]
Reaction(KEGG)
R12307 > R07738
Substrate
(4R)-4,2'-dihydroxyisoflavan [CPD:C21738]
Product
pterocarpan [CPD:C22071];
H2O [CPD:C00001]
Comment
The enzyme catalyses the formation of the additional ring in pterocarpan, the basic structure of phytoalexins produced by leguminous plants, including (-)-medicarpin, (+)-medicarpin, (-)-maackiain and (+)-maackiain. The enzyme requires that the hydroxyl group at C-4 of the substrate is in the (4R) configuration. The configuration of the hydrogen atom at C-3 determines whether the pterocarpan is the (+)- or (-)-enantiomer. The enzyme contains amino acid motifs characteristic of dirigent proteins.
History
EC 4.2.1.139 created 2013, modified 2019
Pathway
ec00943  Isoflavonoid biosynthesis
ec01110  Biosynthesis of secondary metabolites
Reference
1  [PMID:7805842]
  Authors
Guo L, Dixon RA, Paiva NL
  Title
The 'pterocarpan synthase' of alfalfa: association and co-induction of vestitone  reductase and 7,2'-dihydroxy-4'-methoxy-isoflavanol (DMI) dehydratase, the two final enzymes in medicarpin biosynthesis.
  Journal
FEBS Lett 356:221-5 (1994)
DOI:10.1016/0014-5793(94)01267-9
Reference
2  [PMID:8071365]
  Authors
Guo L, Dixon RA, Paiva NL.
  Title
Conversion of vestitone to medicarpin in alfalfa (Medicago sativa L.) is catalyzed by two independent enzymes. Identification, purification, and characterization of vestitone reductase and 7,2'-dihydroxy-4'-methoxyisoflavanol  dehydratase.
  Journal
J Biol Chem 269:22372-8 (1994)
Reference
3  [PMID:28394400]
  Authors
Uchida K, Akashi T, Aoki T
  Title
The Missing Link in Leguminous Pterocarpan Biosynthesis is a Dirigent Domain-Containing Protein with Isoflavanol Dehydratase Activity.
  Journal
Plant Cell Physiol 58:398-408 (2017)
DOI:10.1093/pcp/pcw213
Other DBs
ExplorEnz - The Enzyme Database: 4.2.1.139
IUBMB Enzyme Nomenclature: 4.2.1.139
ExPASy - ENZYME nomenclature database: 4.2.1.139
BRENDA, the Enzyme Database: 4.2.1.139

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