|Superclasses:||Reactions Classified By Conversion Type → Simple Reactions → Chemical Reactions|
|Reactions Classified By Substrate → Small-Molecule Reactions|
EC Number: 188.8.131.52
In Pathway: formononetin biosynthesis
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.
Most BioCyc compounds have been protonated to a reference pH value of 7.3, and some reactions have been computationally balanced for hydrogen by adding free protons. Please see the PGDB Concepts Guide for more information.
Mass balance status: Balanced.
Enzyme Commission Primary Name: 2,7,4′-trihydroxyisoflavanone 4′-O-methyltransferase
Enzyme Commission Synonyms: SAM:2,7,4'-trihydroxyisoflavanone 4'-O-methyltransferase, HI4'OMT, HMM1, MtIOMT5, S-adenosyl-L-methionine:2,7,4'-trihydroxyisoflavanone 4'-O-methyltransferase
Standard Gibbs Free Energy (ΔrG'° in kcal/mol): -4.360016 [Latendresse13]
Enzyme Commission Summary:
Specifically methylates 2,4',7-trihydroxyisoflavanone on the 4'-position. No activity with isoflavones [Deavours06]. The enzyme is involved in formononetin biosynthesis in legumes [Akashi03]. The protein from pea (Pisum sativum) also methylates (+)-6a-hydroxymaackiain at the 3-position (cf. EC 184.108.40.2060, (+)-6a-hydroxymaackiain 3-O-methyltransferase) [Akashi06].
Akashi03: Akashi T, Sawada Y, Shimada N, Sakurai N, Aoki T, Ayabe S (2003). "cDNA cloning and biochemical characterization of S-adenosyl-L-methionine: 2,7,4'-trihydroxyisoflavanone 4'-O-methyltransferase, a critical enzyme of the legume isoflavonoid phytoalexin pathway." Plant Cell Physiol 44(2);103-12. PMID: 12610212
Akashi06: Akashi T, VanEtten HD, Sawada Y, Wasmann CC, Uchiyama H, Ayabe S (2006). "Catalytic specificity of pea O-methyltransferases suggests gene duplication for (+)-pisatin biosynthesis." Phytochemistry 67(23);2525-30. PMID: 17067644
Deavours06: Deavours BE, Liu CJ, Naoumkina MA, Tang Y, Farag MA, Sumner LW, Noel JP, Dixon RA (2006). "Functional analysis of members of the isoflavone and isoflavanone O-methyltransferase enzyme families from the model legume Medicago truncatula." Plant Mol Biol 62(4-5);715-33. PMID: 17001495
Liu06b: Liu CJ, Deavours BE, Richard SB, Ferrer JL, Blount JW, Huhman D, Dixon RA, Noel JP (2006). "Structural basis for dual functionality of isoflavonoid O-methyltransferases in the evolution of plant defense responses." Plant Cell 18(12);3656-69. PMID: 17172354
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