EC
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1.14.13.87
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Transferred entry: | licodione synthase. Now EC 1.14.14.140, licodione synthase
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[EC 1.14.13.87 created 2004, deleted 2018] |
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EC
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1.14.13.136
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Transferred entry: | 2-hydroxyisoflavanone synthase. Now EC 1.14.14.87, 2-hydroxyisoflavanone synthase
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[EC 1.14.13.136 created 2011, modified 2013, deleted 2018] |
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EC |
1.14.14.87 |
Accepted name: |
2-hydroxyisoflavanone synthase |
Reaction: |
(1) liquiritigenin + O2 + [reduced NADPH—hemoprotein reductase] = 2,4′,7-trihydroxyisoflavanone + H2O + [oxidized NADPH—hemoprotein reductase] (2) (2S)-naringenin + O2 + [reduced NADPH—hemoprotein reductase] = 2,4′,5,7-tetrahydroxyisoflavanone + H2O + [oxidized NADPH—hemoprotein reductase] |
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For diagram of daidzein biosynthesis, 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, [reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (hydroxylating, aryl migration) |
Comments: |
A cytochrome P-450 (heme thiolate) protein found in plants. 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, PDB |
References: |
1. |
Kochs, G. and Grisebach, H. Enzymic synthesis of isoflavones. Eur. J. Biochem. 155 (1986) 311–318. [DOI] [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. [DOI] [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. [DOI] [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. [DOI] [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. [DOI] [PMID: 15809082] |
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[EC 1.14.14.87 created 2011 as EC 1.14.13.136, modified 2013, transferred 2018 to EC 1.14.14.87] |
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EC
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1.14.14.140
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Transferred entry: | licodione synthase. Now included with EC 1.14.14.162, flavanone 2-hydroxylase
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[EC 1.14.14.140 created 2004 as EC 1.14.13.87, transferred 2018 to EC 1.14.14.140, transferred 2018 to EC 1.14.14.162, deleted 2018] |
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EC |
1.14.14.162 |
Accepted name: |
flavanone 2-hydroxylase |
Reaction: |
a flavanone + [reduced NADPH—hemoprotein reductase] + O2 = a 2-hydroxyflavanone + [oxidized NADPH—hemoprotein reductase] + H2O |
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For diagram of licodione biosynthesis, click here |
Other name(s): |
CYP93G2 (gene name); CYP93B1 (gene name); (2S)-flavanone 2-hydroxylase; licodione synthase |
Systematic name: |
flavanone,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (2-hydroxylating) |
Comments: |
A cytochrome P-450 (heme thiolate) plant enzyme that catalyses the 2-hydroxylation of multiple flavanones such as (2S)-naringenin, (2S)-eriodictyol, (2S)-pinocembrin, and (2S)-liquiritigenin. The products are meta-stable and exist in an equilibrium with open forms such as 1-(4-hydroxyphenyl)-3-(2,4,6-trihydroxyphenyl)propane-1,3-dione. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc |
References: |
1. |
Otani, K., Takahashi, T., Furuya, T. and Ayabe, S. Licodione synthase, a cytochrome P450 monooxygenase catalyzing 2-hydroxylation of 5-deoxyflavanone, in cultured Glycyrrhiza echinata L. cells. Plant Physiol. 105 (1994) 1427–1432. [PMID: 12232298] |
2. |
Akashi, T., Aoki, T. and Ayabe, S. Identification of a cytochrome P450 cDNA encoding (2S)-flavanone 2-hydroxylase of licorice (Glycyrrhiza echinata L.; Fabaceae) which represents licodione synthase and flavone synthase II. FEBS Lett. 431 (1998) 287–290. [DOI] [PMID: 9708921] |
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Du, Y., Chu, H., Chu, I.K. and Lo, C. CYP93G2 is a flavanone 2-hydroxylase required for C-glycosylflavone biosynthesis in rice. Plant Physiol. 154 (2010) 324–333. [PMID: 20647377] |
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[EC 1.14.14.162 created 2018. EC 1.14.14.140 created 2004 as EC 1.14.13.87, transferred 2018 to EC 1.14.14.140, transferred 2018 to EC 1.14.14.162] |
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EC |
2.1.1.65 |
Accepted name: |
licodione 2′-O-methyltransferase |
Reaction: |
S-adenosyl-L-methionine + licodione = S-adenosyl-L-homocysteine + 2′-O-methyllicodione |
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For diagram of licodione biosynthesis, click here |
Systematic name: |
S-adenosyl-L-methionine:licodione 2′-O-methyltransferase |
Comments: |
As well as licodione [1-(2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)-1,3-propanedione], the 2′′-hydroxy-derivative and isoliquiritigenin can act as acceptors, but more slowly. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 77000-07-8 |
References: |
1. |
Ayabe, S.-I., Yoshikawa, T., Kobayashi, M. and Furuya, T. Biosynthesis of retrochalcone, echinatin: involvement of O-methyltransferase to licodione. Phytochemistry 19 (1980) 2331–2336. |
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[EC 2.1.1.65 created 1983] |
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EC |
2.1.1.154 |
Accepted name: |
isoliquiritigenin 2′-O-methyltransferase |
Reaction: |
S-adenosyl-L-methionine + isoliquiritigenin = S-adenosyl-L-homocysteine + 2′-O-methylisoliquiritigenin |
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For diagram of daidzein biosynthesis, click here |
Glossary: |
isoliquiritigenin = 4,2′,4′-trihydroxychalcone |
Other name(s): |
chalcone OMT; CHMT |
Systematic name: |
S-adenosyl-L-methionine:isoliquiritigenin 2′-O-methyltransferase |
Comments: |
Not identical to EC 2.1.1.65, licodione 2′-O-methyltransferase [2]. While EC 2.1.1.154, isoliquiritigenin 2′-O-methyltransferase can use licodione as a substrate, EC 2.1.1.65 cannot use isoliquiritigenin as a substrate. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 139317-14-9 |
References: |
1. |
Maxwell, C.A., Edwards, R. and Dixon, R.A. Identification, purification, and characterization of S-adenosyl-L-methionine: isoliquiritigenin 2′-O-methyltransferase from alfalfa (Medicago sativa L.). Arch. Biochem. Biophys. 293 (1992) 158–166. [DOI] [PMID: 1731632] |
2. |
Ichimura, M., Furuno, T., Takahashi, T., Dixon, R.A. and Ayabe, S. Enzymic O-methylation of isoliquiritigenin and licodione in alfalfa and licorice cultures. Phytochemistry 44 (1997) 991–995. [DOI] [PMID: 9055445] |
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[EC 2.1.1.154 created 2004] |
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EC |
2.1.1.339 |
Accepted name: |
xanthohumol 4-O-methyltransferase |
Reaction: |
S-adenosyl-L-methionine + xanthohumol = S-adenosyl-L-homocysteine + 4-O-methylxanthohumol |
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For diagram of xanthohumol biosynthesis, click here |
Glossary: |
xanthohumol = 2′,4,4′-trihydroxy-6′-methoxy-3-prenylchalcone = (2E)-1-[2,4-dihydroxy-6-methoxy-3-(3-methylbut-2-en-1-yl)phenyl]-3-(4-hydroxyphenyl)prop-2-en-1-one
4-O-methylxanthohumol =2′,4′-dihydroxy-4,6′-dimethoxy-3-prenylchalcone = (2E)-1-[2,4-dihydroxy-6-methoxy-3-(3-methylbut-2-en-1-yl)phenyl]-3-(4-methoxyphenyl)prop-2-en-1-one |
Other name(s): |
OMT2 (ambiguous); S-adenosyl-L-methionine:xanthohumol 4′-O-methyltransferase (incorrect); xanthohumol 4′-O-methyltransferase (incorrect) |
Systematic name: |
S-adenosyl-L-methionine:xanthohumol 4-O-methyltransferase |
Comments: |
The enzyme from hops (Humulus lupulus) has a broad substrate specificity. The best substrates in vitro are resveratrol, desmethylxanthohumol, naringenin chalcone and isoliquiritigenin. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc |
References: |
1. |
Nagel, J., Culley, L.K., Lu, Y., Liu, E., Matthews, P.D., Stevens, J.F. and Page, J.E. EST analysis of hop glandular trichomes identifies an O-methyltransferase that catalyzes the biosynthesis of xanthohumol. Plant Cell 20 (2008) 186–200. [DOI] [PMID: 18223037] |
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[EC 2.1.1.339 created 2017, modified 2018] |
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EC |
2.3.1.170 |
Accepted name: |
6′-deoxychalcone synthase |
Reaction: |
3 malonyl-CoA + 4-coumaroyl-CoA + NADPH + H+ = 4 CoA + isoliquiritigenin + 3 CO2 + NADP+ + H2O |
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For diagram of daidzein biosynthesis, click here |
Glossary: |
isoliquiritigenin = 4,2′,4′-trihydroxychalcone
liquiritigenin = 7,4′-dihydroxyflavanone |
Systematic name: |
malonyl-CoA:4-coumaroyl-CoA malonyltransferase (cyclizing, reducing) |
Comments: |
Isoliquiritigenin is the precursor of liquiritigenin, a 5-deoxyflavanone. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 114308-23-5 |
References: |
1. |
Ayabe, S., Udagawa, A. and Furuya, T. NAD(P)H-dependent 6′-deoxychalcone synthase activity in Glycyrrhiza echinata cells induced by yeast extract. Arch. Biochem. Biophys. 261 (1988) 458–462. [DOI] [PMID: 3355160] |
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[EC 2.3.1.170 created 2004] |
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