IUBMB Enzyme Nomenclature

EC 1.14.13.136

Accepted name: 2-hydroxyisoflavanone synthase

Reaction: (1) liquiritigenin + O2 + NADPH + H+ = 2,4',7-trihydroxyisoflavanone + H2O + NADP+
(2) (2S)-naringenin + O2 + NADPH + H+ = 2,4',5,7-tetrahydroxyisoflavanone + H2O + NADP+

For diagram of reaction click here.

Glossary: liquiritigenin = 4',7-dihydroxyflavanone
(2S)-naringenin = 4',5,7-dihydroxyflavanone
2,4',5,7-tetrahydroxyisoflavanone = 2-hydroxy-2,3-dihydrogenistein

Other name(s): CYP93C; IFS; isoflavonoid synthase

Systematic name: liquiritigenin,NADPH:oxygen oxidoreductase (hydroxylating, aryl migration)

Comments: Requires cytochrome P450. The reaction involves the migration of the 2-phenyl group of the flavanone to the 3-position of the isoflavanone. The 2-hydroxyl group is derived from the oxygen molecule. EC 4.2.1.105, 2-hydroxyisoflavanone dehydratase, acts on the products with loss of water and formation of genistein and daidzein, respectively.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:

References:

1. Kochs, G. and Grisebach, H. Enzymic synthesis of isoflavones. Eur. J. Biochem. 155 (1986) 311-318. [PMID: 3956488]

2. Hashim, M.F., Hakamatsuka, T., Ebizuka, Y. and Sankawa, U. Reaction mechanism of oxidative rearrangement of flavanone in isoflavone biosynthesis. FEBS Lett 271 (1990) 219-222. [PMID: 2226805]

3. Steele, C. L., Gijzen, M., Qutob, D. and Dixon, R.A. Molecular characterization of the enzyme catalyzing the aryl migration reaction of isoflavonoid biosynthesis in soybean. Arch. Biochem. Biophys. 367 (1999) 146-150. [PMID: 10375412]

4. Sawada, Y., Kinoshita, K., Akashi, T., Aoki, T. and Ayabe, S. Key amino acid residues required for aryl migration catalysed by the cytochrome P450 2-hydroxyisoflavanone synthase. Plant J. 31 (2002) 555-564. [PMID: 12207646]

5. Sawada, Y. and Ayabe, S. Multiple mutagenesis of P450 isoflavonoid synthase reveals a key active-site residue. Biochem. Biophys. Res. Commun. 330 (2005) 907-913. [PMID: 15809082]

[EC 1.14.13.136 created 2011, modified 2013]


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