The Enzyme Database

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EC 2.5.1.70     Relevance: 100%
Accepted name: naringenin 8-dimethylallyltransferase
Reaction: prenyl diphosphate + (–)-(2S)-naringenin = diphosphate + sophoraflavanone B
For diagram of sophoraflavanone G biosynthesis, click here
Glossary: dimethylallyl = prenyl = 3-methylbut-2-en-1-yl
(–)-(2S)-naringenin = (–)-(2S)-5,7-dihydroxy-2-(4-hydroxyphenyl)-2,3-dihydrochromen-4-one
sophoraflavanone B = (–)-(2S)-8-prenylnaringenin = (–)-(2S)-5,7-dihydroxy-2-(4-hydroxyphenyl)-8-(3-methylbut-2-en-1-yl)-2,3-dihydrochromen-4-one
Other name(s): N8DT; dimethylallyl-diphosphate:naringenin 8-dimethylallyltransferase
Systematic name: prenyl-diphosphate:naringenin 8-prenyltransferase
Comments: Requires Mg2+. This membrane-bound protein is located in the plastids [2]. In addition to naringenin, the enzyme can prenylate several other flavanones at the C-8 position, but more slowly. Along with EC 1.14.14.142 (8-dimethylallylnaringenin 2′-hydroxylase) and EC 2.5.1.71 (leachianone-G 2′′-dimethylallyltransferase), this enzyme forms part of the sophoraflavanone-G-biosynthesis pathway.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Yamamoto, H., Senda, M. and Inoue, K. Flavanone 8-dimethylallyltransferase in Sophora flavescens cell suspension cultures. Phytochemistry 54 (2000) 649–655. [DOI] [PMID: 10975499]
2.  Zhao, P., Inoue, K., Kouno, I. and Yamamoto, H. Characterization of leachianone G 2′′-dimethylallyltransferase, a novel prenyl side-chain elongation enzyme for the formation of the lavandulyl group of sophoraflavanone G in Sophora flavescens Ait. cell suspension cultures. Plant Physiol. 133 (2003) 1306–1313. [DOI] [PMID: 14551337]
[EC 2.5.1.70 created 2007]
 
 
EC 2.1.1.232     Relevance: 99.4%
Accepted name: naringenin 7-O-methyltransferase
Reaction: S-adenosyl-L-methionine + (2S)-naringenin = S-adenosyl-L-homocysteine + (2S)-sakuranetin
For diagram of naringenin methyl ethers biosynthesis, click here
Glossary: (2S)-naringenin = (2S)-5,7,4′-trihydroxyflavan-4-one
(2S)-sakuranetin = (2S)-5,4′-dihydroxy-7-methoxyflavan-4-one
Other name(s): NOMT
Systematic name: S-adenosyl-L-methionine:(2S)-5,7,4′-trihydroxyflavanone 7-O-methyltransferase
Comments: The enzyme is involved in the biosynthesis of the sakuranetin, an inducible defense mechanism of the plant Oryza sativa (Asian rice) against pathogen attack.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Rakwal, R., Agrawal, G.K., Yonekura, M. and Kodama, O. Naringenin 7-O-methyltransferase involved in the biosynthesis of the flavanone phytoalexin sakuranetin from rice (Oryza sativa L.). Plant Sci. 155 (2000) 213–221. [DOI] [PMID: 10814825]
[EC 2.1.1.232 created 2011]
 
 
EC 2.1.1.231     Relevance: 87.6%
Accepted name: flavonoid 4′-O-methyltransferase
Reaction: S-adenosyl-L-methionine + a 4′-hydroxyflavanone = S-adenosyl-L-homocysteine + a 4′-methoxyflavanone
For diagram of naringenin methyl ethers biosynthesis, click here
Glossary: naringenin = 4′,5,7-trihydroxyflavan-4-one
Other name(s): SOMT-2; 4′-hydroxyisoflavone methyltransferase
Systematic name: S-adenosyl-L-methionine:flavonoid 4′-O-methyltransferase
Comments: The enzyme catalyses the 4′-methylation of naringenin. In vitro it catalyses the 4′-methylation of apigenin, quercetin, daidzein and genistein.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Kim, D.H., Kim, B.G., Lee, Y., Ryu, J.Y., Lim, Y., Hur, H.G. and Ahn, J.H. Regiospecific methylation of naringenin to ponciretin by soybean O-methyltransferase expressed in Escherichia coli. J. Biotechnol. 119 (2005) 155–162. [DOI] [PMID: 15961179]
[EC 2.1.1.231 created 2011]
 
 
EC 2.4.1.185     Relevance: 86.9%
Accepted name: flavanone 7-O-β-glucosyltransferase
Reaction: UDP-glucose + a flavanone = UDP + a flavanone 7-O-β-D-glucoside
For diagram of the biosynthesis of naringenin derivatives, click here
Other name(s): uridine diphosphoglucose-flavanone 7-O-glucosyltransferase; naringenin 7-O-glucosyltransferase; hesperetin 7-O-glucosyl-transferase
Systematic name: UDP-glucose:flavanone 7-O-β-D-glucosyltransferase
Comments: Naringenin and hesperetin can act as acceptors. No action on flavones or flavonols.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 125752-73-0
References:
1.  McIntosh, C.A., Latchinian, L. and Mansell, R.L. Flavanone-specific 7-O-glucosyltransferase activity in Citrus paradisi seedlings: purification and characterization. Arch. Biochem. Biophys. 282 (1990) 50–57. [DOI] [PMID: 2171434]
2.  McIntosh, C.A. and Mansell, R.L. Biosynthesis of naringin in Citrus paradisi - UDP-glucosyl-transferase activity in grapefruit seedlings. Phytochemistry 29 (1990) 1533–1538.
[EC 2.4.1.185 created 1992]
 
 
EC 1.14.11.9     Relevance: 80.5%
Accepted name: flavanone 3-dioxygenase
Reaction: a (2S)-flavan-4-one + 2-oxoglutarate + O2 = a (2R,3R)-dihydroflavonol + succinate + CO2
For diagram of flavonoid biosynthesis, click here and for diagram of naringenin derivatives biosynthesis, click here
Other name(s): naringenin 3-hydroxylase; flavanone 3-hydroxylase; flavanone 3β-hydroxylase; flavanone synthase I; (2S)-flavanone 3-hydroxylase; naringenin,2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating); F3H; flavanone,2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating)
Systematic name: (2S)-flavan-4-one,2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating)
Comments: Requires Fe2+ and ascorbate. This plant enzyme catalyses an early step in the flavonoid biosynthesis pathway, leading to the production of flavanols and anthocyanins. Substrates include (2S)-naringenin, (2S)-eriodictyol, (2S)-dihydrotricetin and (2S)-pinocembrin. Some enzymes are bifuctional and also catalyse EC 1.14.20.6, flavonol synthase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 75991-43-4
References:
1.  Forkmann, G., Heller, W. and Grisebach, H. Anthocyanin biosynthesis in flowers of Matthiola incana flavanone 3- and flavonoid 3′-hydroxylases. Z. Naturforsch. C: Biosci. 35 (1980) 691–695.
2.  Charrier, B., Coronado, C., Kondorosi, A. and Ratet, P. Molecular characterization and expression of alfalfa (Medicago sativa L.) flavanone-3-hydroxylase and dihydroflavonol-4-reductase encoding genes. Plant Mol. Biol. 29 (1995) 773–786. [PMID: 8541503]
3.  Pelletier, M.K. and Shirley, B.W. Analysis of flavanone 3-hydroxylase in Arabidopsis seedlings. Coordinate regulation with chalcone synthase and chalcone isomerase. Plant Physiol. 111 (1996) 339–345. [PMID: 8685272]
4.  Wellmann, F., Matern, U. and Lukačin, R. Significance of C-terminal sequence elements for Petunia flavanone 3β-hydroxylase activity. FEBS Lett. 561 (2004) 149–154. [DOI] [PMID: 15013767]
5.  Jin, Z., Grotewold, E., Qu, W., Fu, G. and Zhao, D. Cloning and characterization of a flavanone 3-hydroxylase gene from Saussurea medusa. DNA Seq 16 (2005) 121–129. [DOI] [PMID: 16147863]
6.  Shen, G., Pang, Y., Wu, W., Deng, Z., Zhao, L., Cao, Y., Sun, X. and Tang, K. Cloning and characterization of a flavanone 3-hydroxylase gene from Ginkgo biloba. Biosci Rep 26 (2006) 19–29. [DOI] [PMID: 16779664]
[EC 1.14.11.9 created 1983, modified 1989, modified 2004, modified 2016]
 
 
EC 1.1.1.234     Relevance: 78.8%
Accepted name: flavanone 4-reductase
Reaction: (2S)-flavan-4-ol + NADP+ = (2S)-flavanone + NADPH + H+
For diagram of the biosynthesis of naringenin derivatives, click here
Systematic name: (2S)-flavan-4-ol:NADP+ 4-oxidoreductase
Comments: Involved in the biosynthesis of 3-deoxyanthocyanidins from flavanones such as naringenin or eriodictyol.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 115232-53-6
References:
1.  Stich, K. and Forkmann, G. Biosynthesis of 3-deoxyanthocyanins with flower extracts from Sinningia cardinalis. Phytochemistry 27 (1988) 785–789.
[EC 1.1.1.234 created 1992]
 
 
EC 2.3.1.74     Relevance: 68.5%
Accepted name: chalcone synthase
Reaction: 3 malonyl-CoA + 4-coumaroyl-CoA = 4 CoA + naringenin chalcone + 3 CO2
For diagram of chalcone and stilbene biosynthesis, click here
Glossary: phloretin = 3-(4-hydroxyphenyl)-1-(2,4,6-trihydroxyphenyl)propan-1-one
Other name(s): naringenin-chalcone synthase; flavanone synthase; 6′-deoxychalcone synthase; chalcone synthetase; DOCS; CHS
Systematic name: malonyl-CoA:4-coumaroyl-CoA malonyltransferase (cyclizing)
Comments: The enzyme catalyses the first committed step in the biosynthesis of flavonoids. It can also act on dihydro-4-coumaroyl-CoA, forming phloretin.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 56803-04-4
References:
1.  Ayabe, S.-I., 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]
2.  Heller, W. and Hahlbrock, K. Highly purified "flavanone synthase" from parsley catalyzes the formation of naringenin chalcone. Arch. Biochem. Biophys. 200 (1980) 617–619. [DOI] [PMID: 7436427]
3.  Yahyaa, M., Ali, S., Davidovich-Rikanati, R., Ibdah, M., Shachtier, A., Eyal, Y., Lewinsohn, E. and Ibdah, M. Characterization of three chalcone synthase-like genes from apple (Malus x domestica Borkh.). Phytochemistry 140 (2017) 125–133. [DOI] [PMID: 28482241]
[EC 2.3.1.74 created 1984, modified 2018]
 
 
EC 1.14.13.21      
Transferred entry: flavonoid 3′-monooxygenase. Now EC 1.14.14.82, flavonoid 3′-monooxygenase.
[EC 1.14.13.21 created 1983, deleted 2018]
 
 
EC 1.14.11.23      
Transferred entry: flavonol synthase. Now EC 1.14.20.6, flavonol synthase
[EC 1.14.11.23 created 2004, deleted 2018]
 
 
EC 1.14.13.88      
Transferred entry: flavanoid 3,5-hydroxylase. Now EC 1.14.14.81, flavanoid 3,5-hydroxylase
[EC 1.14.13.88 created 2004, deleted 2018]
 
 
EC 1.14.20.6     Relevance: 65%
Accepted name: flavonol synthase
Reaction: a dihydroflavonol + 2-oxoglutarate + O2 = a flavonol + succinate + CO2 + H2O
For diagram of flavonoid biosynthesis, click here, for diagram of kaempferol biosynthesis, click here and for diagram of myricetin biosynthesis, click here
Other name(s): FLS (gene name)
Systematic name: dihydroflavonol,2-oxoglutarate:oxygen oxidoreductase
Comments: In addition to the desaturation of (2R,3R)-dihydroflavonols to flavonols, the enzyme from Citrus unshiu (satsuma mandarin) also has a non-specific activity that trans-hydroxylates the flavanones (2S)-naringenin and the unnatural (2R)-naringenin at C-3 to kaempferol and (2R,3R)-dihydrokaempferol, respectively [2]. Requires Fe2+.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 146359-76-4
References:
1.  Wellmann, F., Lukačin, R., Moriguchi, T., Britsch, L., Schiltz, E. and Matern, U. Functional expression and mutational analysis of flavonol synthase from Citrus unshiu. Eur. J. Biochem. 269 (2002) 4134–4142. [DOI] [PMID: 12180990]
2.  Lukačin, R., Wellmann, F., Britsch, L., Martens, S. and Matern, U. Flavonol synthase from Citrus unshiu is a bifunctional dioxygenase. Phytochemistry 62 (2003) 287–292. [DOI] [PMID: 12620339]
3.  Martens, S., Forkmann, G., Britsch, L., Wellmann, F., Matern, U. and Lukačin, R. Divergent evolution of flavonoid 2-oxoglutarate-dependent dioxygenases in parsley. FEBS Lett. 544 (2003) 93–98. [DOI] [PMID: 12782296]
4.  Turnbull, J.J., Nakajima, J., Welford, R.W., Yamazaki, M., Saito, K. and Schofield, C.J. Mechanistic studies on three 2-oxoglutarate-dependent oxygenases of flavonoid biosynthesis: anthocyanidin synthase, flavonol synthase, and flavanone 3β-hydroxylase. J. Biol. Chem. 279 (2004) 1206–1216. [DOI] [PMID: 14570878]
[EC 1.14.20.6 created 2004 as EC 1.14.11.23, transferred 2018 to EC 1.14.20.6]
 
 
EC 2.1.1.75     Relevance: 64.6%
Accepted name: apigenin 4′-O-methyltransferase
Reaction: S-adenosyl-L-methionine + apigenin = S-adenosyl-L-homocysteine + acacetin
For diagram of apigenin derivatives biosynthesis, click here
Glossary: apigenin = 4′,5,7-trihydroxyflavone
acacetin = 4′-methoxy-5,7-dihydroxyflavone
naringenin = 4′,5,7-trihydroxyflavan-4-one
Other name(s): flavonoid O-methyltransferase; flavonoid methyltransferase; S-adenosyl-L-methionine:5,7,4′-trihydroxyflavone 4′-O-methyltransferase
Systematic name: S-adenosyl-L-methionine:apigenin 4′-O-methyltransferase
Comments: Converts apigenin into acacetin. Naringenin can also act as an acceptor, but more slowly.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 118251-36-8
References:
1.  Kuroki, G. and Poulton, J.E. The para-O-methylation of apigenin to acacetin by cell-free extracts of Robinia pseudoacacia L. Z. Naturforsch. C: Biosci. 36 (1981) 916–920.
[EC 2.1.1.75 created 1984]
 
 
EC 2.4.1.286     Relevance: 63%
Accepted name: chalcone 4′-O-glucosyltransferase
Reaction: (1) UDP-α-D-glucose + naringenin chalcone = UDP + 2′,4,4′,6′-tetrahydroxychalcone 4′-O-β-D-glucoside
(2) UDP-α-D-glucose + 2′,3,4,4′,6′-pentahydroxychalcone = UDP + 2′,3,4,4′,6′-pentahydroxychalcone 4′-O-β-D-glucoside
For diagram of aureusidin biosynthesis, click here
Glossary: naringenin chalcone = 2′,4,4′,6′-tetrahydroxychalcone = 3-(4-hydroxyphemyl)-1-(2,4,6-trihydroxyphenyl)prop-2-en-1-one
Other name(s): 4′CGT
Systematic name: UDP-α-D-glucose:2′,4,4′,6′-tetrahydroxychalcone 4′-O-β-D-glucosyltransferase
Comments: Isolated from the plant Antirrhinum majus (snapdragon). Involved in the biosynthesis of aurones, plant flavonoids that provide yellow color to the flowers.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Ono, E., Fukuchi-Mizutani, M., Nakamura, N., Fukui, Y., Yonekura-Sakakibara, K., Yamaguchi, M., Nakayama, T., Tanaka, T., Kusumi, T. and Tanaka, Y. Yellow flowers generated by expression of the aurone biosynthetic pathway. Proc. Natl. Acad. Sci. USA 103 (2006) 11075–11080. [DOI] [PMID: 16832053]
[EC 2.4.1.286 created 2012]
 
 
EC 1.14.14.81     Relevance: 60.1%
Accepted name: flavanoid 3′,5′-hydroxylase
Reaction: a flavanone + 2 [reduced NADPH—hemoprotein reductase] + 2 O2 = a 3′,5′-dihydroxyflavanone + 2 [oxidized NADPH—hemoprotein reductase] + 2 H2O (overall reaction)
(1a) a flavanone + [reduced NADPH—hemoprotein reductase] + O2 = a 3′-hydroxyflavanone + [oxidized NADPH—hemoprotein reductase] + H2O
(1b) a 3′-hydroxyflavanone + [reduced NADPH—hemoprotein reductase] + O2 = a 3′,5′-dihydroxyflavanone + [oxidized NADPH—hemoprotein reductase] + H2O
For diagram of myricetin biosynthesis, click here, for diagram of the biosynthesis of naringenin derivatives, click here and for diagram of flavonoid biosynthesis, click here
Other name(s): flavonoid 3′,5′-hydroxylase
Systematic name: flavanone,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (3′,5′-dihydroxylating)
Comments: A cytochrome P-450 (heme-thiolate) protein found in plants. The 3′,5′-dihydroxyflavanone is formed via the 3′-hydroxyflavanone. In Petunia hybrida the enzyme acts on naringenin, eriodictyol, dihydroquercetin (taxifolin) and dihydrokaempferol (aromadendrin). The enzyme catalyses the hydroxylation of 5,7,4′-trihydroxyflavanone (naringenin) at either the 3′ position to form eriodictyol or at both the 3′ and 5′ positions to form 5,7,3′,4′,5′-pentahydroxyflavanone (dihydrotricetin). The enzyme also catalyses the hydroxylation of 3,5,7,3′,4′-pentahydroxyflavanone (taxifolin) at the 5′ position, forming ampelopsin.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 94047-23-1
References:
1.  Menting, J., Scopes, R.K. and Stevenson, T.W. Characterization of flavonoid 3′,5′-hydroxylase in microsomal membrane fraction of Petunia hybrida flowers. Plant Physiol. 106 (1994) 633–642. [PMID: 12232356]
2.  Shimada, Y., Nakano-Shimada, R., Ohbayashi, M., Okinaka, Y., Kiyokawa, S. and Kikuchi, Y. Expression of chimeric P450 genes encoding flavonoid-3′, 5′-hydroxylase in transgenic tobacco and petunia plants1. FEBS Lett. 461 (1999) 241–245. [DOI] [PMID: 10567704]
3.  de Vetten, N., ter Horst, J., van Schaik, H.P., de Boer, A., Mol, J. and Koes, R. A cytochrome b5 is required for full activity of flavonoid 3′, 5′-hydroxylase, a cytochrome P450 involved in the formation of blue flower colors. Proc. Natl. Acad. Sci. USA 96 (1999) 778–783. [DOI] [PMID: 9892710]
[EC 1.14.14.81 created 2004 as EC 1.14.13.88, transferred 2018 to EC 1.14.14.81]
 
 
EC 1.14.14.82     Relevance: 59.8%
Accepted name: flavonoid 3′-monooxygenase
Reaction: a flavonoid + [reduced NADPH—hemoprotein reductase] + O2 = a 3′-hydroxyflavonoid + [oxidized NADPH—hemoprotein reductase] + H2O
For diagram of flavonoid biosynthesis, click here and for diagram of the biosynthesis of naringenin derivatives, click here
Other name(s): CYP75B1 (gene name); flavonoid 3′-hydroxylase; flavonoid 3-hydroxylase (incorrect); NADPH:flavonoid-3′-hydroxylase (incorrect); flavonoid 3-monooxygenase (incorrect)
Systematic name: flavonoid,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (3′-hydroxylating)
Comments: A cytochrome P-450 (heme-thiolate) protein found in plants. Acts on a number of flavonoids, including the flavanone naringenin and the flavone apigenin. Does not act on 4-coumarate or 4-coumaroyl-CoA.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 75991-44-5
References:
1.  Forkmann, G., Heller, W. and Grisebach, H. Anthocyanin biosynthesis in flowers of Matthiola incana flavanone 3- and flavonoid 3′-hydroxylases. Z. Naturforsch. C: Biosci. 35 (1980) 691–695.
2.  Brugliera, F., Barri-Rewell, G., Holton, T.A. and Mason, J.G. Isolation and characterization of a flavonoid 3′-hydroxylase cDNA clone corresponding to the Ht1 locus of Petunia hybrida. Plant J. 19 (1999) 441–451. [PMID: 10504566]
3.  Schoenbohm, C., Martens, S., Eder, C., Forkmann, G. and Weisshaar, B. Identification of the Arabidopsis thaliana flavonoid 3′-hydroxylase gene and functional expression of the encoded P450 enzyme. Biol. Chem. 381 (2000) 749–753. [PMID: 11030432]
[EC 1.14.14.82 created 1983 as EC 1.14.13.21, transferred 2018 to EC 1.14.14.82]
 
 
EC 2.3.1.156     Relevance: 59.7%
Accepted name: phloroisovalerophenone synthase
Reaction: (1) isovaleryl-CoA + 3 malonyl-CoA = 4 CoA + 3 CO2 + phlorisovalerophenone
(2) isobutyryl-CoA + 3 malonyl-CoA = 4 CoA + 3 CO2 + phlorisobutyrophenone
For diagram of polyketides biosynthesis, click here
Glossary: phlorisobutyrophenone = 2-methyl-1-(2,4,6-trihydroxyphenyl)propan-1-one
phlorisovalerophenone = 3-methyl-1-(2,4,6-trihydroxyphenyl)butan-1-one
Other name(s): valerophenone synthase; 3-methyl-1-(trihydroxyphenyl)butan-1-one synthase; acylphloroglucinol synthase; isovaleryl-CoA:malonyl-CoA acyltransferase
Systematic name: acyl-CoA:malonyl-CoA acyltransferase
Comments: Closely related to EC 2.3.1.74, naringenin-chalcone synthase. Also acts on isobutyryl-CoA as substrate to give phlorisobutyrophenone. The products are intermediates in the biosynthesis of the bitter acids in hops (Humulus lupulus) and glucosides in strawberry (Fragaria X ananassa). It is also able to generate naringenin chalcone from 4-coumaroyl-CoA.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Fung, S.Y., Zuurbier, K.W.M., Paniego, N.B., Scheffer, J.J.C. and Verpoorte, R. Enzymes from the biosynthesis of hop α and β acids. Proc. 26th Congr. Eur. Brew. Conv. (1997) 215–221.
2.  Zuurbier, K.W.M., Leser, J., Berger, T., Hofte, A.J.P., Schroder, G., Verpoorte, R. and Schroder, J. 4-Hydroxy-2-pyrone formation by chalcone and stilbene synthase with nonphysiological substrates. Phytochemistry 49 (1998) 1945–1951. [PMID: 9883590]
3.  Song, C., Ring, L., Hoffmann, T., Huang, F.C., Slovin, J. and Schwab, W. Acylphloroglucinol biosynthesis in strawberry fruit. Plant Physiol. 169 (2015) 1656–1670. [DOI] [PMID: 26169681]
[EC 2.3.1.156 created 2000]
 
 
EC 1.14.13.136      
Transferred entry: 2-hydroxyisoflavanone synthase. Now EC 1.14.14.87, 2-hydroxyisoflavanone synthase
[EC 1.14.13.136 created 2011, modified 2013, deleted 2018]
 
 
EC 1.14.14.87     Relevance: 55.9%
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]
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
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]
[EC 1.14.14.87 created 2011 as EC 1.14.13.136, modified 2013, transferred 2018 to EC 1.14.14.87]
 
 
EC 2.5.1.136     Relevance: 55.7%
Accepted name: 2-acylphloroglucinol 4-prenyltransferase
Reaction: prenyl diphosphate + a 2-acylphloroglucinol = diphosphate + a 2-acyl-4-prenylphloroglucinol
Glossary: naringenin chalcone = 2′,4,4′,6′-tetrahydroxychalcone = 3-(4-hydroxyphenyl)-1-(2,4,6-trihydroxyphenyl)prop-2-en-1-one
phlorisovalerophenone = 3-methyl-1-(2,4,6-trihydroxyphenyl)butan-1-one
Other name(s): PT-1 (gene name); PT1L (gene name); aromatic prenyltransferase (ambiguous); dimethylallyl-diphosphate:2-acylphloroglucinol 4-dimethylallyltransferase
Systematic name: prenyl-diphosphate:2-acylphloroglucinol 4-prenyltransferase
Comments: The enzyme, characterized from hop (Humulus lupulus), acts on phlorisovalerophenone, phlormethylbutanophenone, and phlorisobutanophenone during the synthesis of bitter acids. It also acts with much lower activity on naringenin chalcone. Forms a complex with EC 2.5.1.137, 2-acyl-4-prenylphloroglucinol 6-prenyltransferase, which catalyses additional prenylation reactions. Requires Mg2+.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Tsurumaru, Y., Sasaki, K., Miyawaki, T., Uto, Y., Momma, T., Umemoto, N., Momose, M. and Yazaki, K. HlPT-1, a membrane-bound prenyltransferase responsible for the biosynthesis of bitter acids in hops. Biochem. Biophys. Res. Commun. 417 (2012) 393–398. [DOI] [PMID: 22166201]
2.  Li, H., Ban, Z., Qin, H., Ma, L., King, A.J. and Wang, G. A heteromeric membrane-bound prenyltransferase complex from hop catalyzes three sequential aromatic prenylations in the bitter acid pathway. Plant Physiol. 167 (2015) 650–659. [DOI] [PMID: 25564559]
[EC 2.5.1.136 created 2017]
 
 
EC 1.14.14.142     Relevance: 55.7%
Accepted name: 8-dimethylallylnaringenin 2′-hydroxylase
Reaction: sophoraflavanone B + [reduced NADPH—hemoprotein reductase] + O2 = leachianone G + [oxidized NADPH—hemoprotein reductase] + H2O
For diagram of sophoraflavanone G biosynthesis, click here
Glossary: dimethylallyl = prenyl = 3-methylbut-2-en-1-yl
lavandulyl = 5-methyl-2-(prop-1-en-2-yl)hex-4-en-1-yl
leachianone G = (–)-(2S)-2′-hydroxy-8-prenylnaringenin = (–)-(2S)-2-(2,4-dihydroxyphenyl)-5,7-dihydroxy-8-(3-methylbut-2-en-1-yl)-2,3-dihydro-4H-chromen-4-one
naringenin = 5,7-dihydroxy-2-(4-hydroxyphenyl)-2,3-dihydrochromen-4-one
sophoraflavanone B = (–)-(2S)-8-prenylnaringenin = (–)-(2S)-5,7-dihydroxy-2-(4-hydroxyphenyl)-8-(3-methylbut-2-en-1-yl)-2,3-dihydro-4H-chromen-4-one
Other name(s): 8-DMAN 2′-hydroxylase
Systematic name: sophoraflavanone-B,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (2′-hydroxylating)
Comments: A membrane-bound cytochrome P-450 (heme-thiolate) protein that is associated with the endoplasmic reticulum [1,2]. This enzyme is specific for sophoraflavanone B as substrate. Along with EC 2.5.1.70 (naringenin 8-dimethylallyltransferase) and EC 2.5.1.71 (leachianone G 2′′-dimethylallyltransferase), this enzyme forms part of the sophoraflavanone G biosynthetic pathway.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Yamamoto, H., Yatou, A. and Inoue, K. 8-Dimethylallylnaringenin 2′-hydroxylase, the crucial cytochrome P450 mono-oxygenase for lavandulylated flavanone formation in Sophora flavescens cultured cells. Phytochemistry 58 (2001) 671–676. [DOI] [PMID: 11672730]
2.  Zhao, P., Inoue, K., Kouno, I. and Yamamoto, H. Characterization of leachianone G 2′′-dimethylallyltransferase, a novel prenyl side-chain elongation enzyme for the formation of the lavandulyl group of sophoraflavanone G in Sophora flavescens Ait. cell suspension cultures. Plant Physiol. 133 (2003) 1306–1313. [DOI] [PMID: 14551337]
[EC 1.14.14.142 created 2007 asEC 1.14.13.103, transferred 2018 to EC 1.14.14.142]
 
 
EC 2.4.1.236     Relevance: 53.1%
Accepted name: flavanone 7-O-glucoside 2′′-O-β-L-rhamnosyltransferase
Reaction: UDP-β-L-rhamnose + a flavanone 7-O-β-D-glucoside = UDP + a flavanone 7-O-[α-L-rhamnosyl-(1→2)-β-D-glucoside]
For diagram of apigenin derivatives biosynthesis, click here, for diagram of luteolin derivatives biosynthesis, click here and for diagram of naringenin derivatives biosynthesis, click here
Glossary: UDP-β-L-rhamnose = UDP-6-deoxy-β-L-mannose
Other name(s): UDP-rhamnose:flavanone-7-O-glucoside-2′′-O-rhamnosyltransferase; 1→2 UDP-rhamnosyltransferase; UDP-L-rhamnose:flavanone-7-O-glucoside 2′′-O-β-L-rhamnosyltransferase
Systematic name: UDP-β-L-rhamnose:flavanone-7-O-glucoside 2′′-O-α-L-rhamnosyltransferase
Comments: Acts on the 7-O-glucoside of naringenin and hesperetin, also the flavone 7-O-glucosides of luteolin and apigenin.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 125752-89-8
References:
1.  Bar-Peled, M., Lewinsohn, E., Fluhr, R. and Gressel, J. UDP-rhamnose:flavanone-7-O-glucoside-2′′-O-rhamnosyltransferase. Purification and characterization of an enzyme catalyzing the production of bitter compounds in citrus. J. Biol. Chem. 266 (1991) 20953–20959. [PMID: 1939145]
[EC 2.4.1.236 created 2004]
 
 
EC 5.3.3.11     Relevance: 52.6%
Accepted name: isopiperitenone Δ-isomerase
Reaction: isopiperitenone = piperitenone
For diagram of (–)-carvone, perillyl aldehyde and pulegone biosynthesis, click here
Systematic name: isopiperitenone Δ84-isomerase
Comments: Involved in the biosynthesis of menthol and related monoterpenes in peppermint (Mentha piperita) leaves.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 96595-07-2
References:
1.  Kjonaas, R.B., Venkatachalam, K.V. and Croteau, R. Metabolism of monoterpenes: oxidation of isopiperitenol to isopiperitenone, and subsequent isomerization to piperitenone by soluble enzyme preparations from peppermint (Mentha piperita) leaves. Arch. Biochem. Biophys. 238 (1985) 49–60. [DOI] [PMID: 3885858]
[EC 5.3.3.11 created 1989]
 
 
EC 1.1.1.243     Relevance: 49.5%
Accepted name: carveol dehydrogenase
Reaction: (–)-trans-carveol + NADP+ = (–)-carvone + NADPH + H+
For diagram of (–)-carvone, perillyl aldehyde and pulegone biosynthesis, click here
Other name(s): (–)-trans-carveol dehydrogenase
Systematic name: (–)-trans-carveol:NADP+ oxidoreductase
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, UM-BBD, CAS registry number: 122653-66-1
References:
1.  Gershenzon, J., Maffei, M. and Croteau, R. Biochemical and histochemical-localization of monoterpene biosynthesis in the glandular trichomes of spearmint (Mentha spicata). Plant Physiol. 89 (1989) 1351–1357. [PMID: 16666709]
[EC 1.1.1.243 created 1992]
 
 
EC 4.2.3.186     Relevance: 47.4%
Accepted name: ent-13-epi-manoyl oxide synthase
Reaction: ent-8α-hydroxylabd-13-en-15-yl diphosphate = ent-13-epi-manoyl oxide + diphosphate
For diagram of (–)-kolavenyl diphosphate derived diterpenoids, click here
Glossary: Ent-13-epi-manoyl oxide = (13R)-ent-8,13-epoxylabd-14-ene
Other name(s): SmKSL2; ent-LDPP synthase
Systematic name: ent-8α-hydroxylabd-13-en-15-yl-diphosphate diphosphate-lyase (cyclizing, ent-13-epi-manoyl-oxide-forming)
Comments: Isolated from the plant Salvia miltiorrhiza (red sage).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Cui, G., Duan, L., Jin, B., Qian, J., Xue, Z., Shen, G., Snyder, J.H., Song, J., Chen, S., Huang, L., Peters, R.J. and Qi, X. Functional divergence of diterpene syntheses in the medicinal plant Salvia miltiorrhiza. Plant Physiol. 169 (2015) 1607–1618. [DOI] [PMID: 26077765]
[EC 4.2.3.186 created 2017]
 
 
EC 5.5.1.28     Relevance: 47.2%
Accepted name: (–)-kolavenyl diphosphate synthase
Reaction: geranylgeranyl diphosphate = (–)-kolavenyl diphosphate
For diagram of (–)-kolavenyl diphosphate derived diterpenoids, click here
Glossary: (–)-kolavenyl diphosphate = (2E)-5-[(1R,2S,4aS,8aS)-1,2,4a,5-tetramethyl-1,2,3,4,4a,7,8,8a-octahydronaphthalen-1-yl]-3-methylpent-2-en-1-yl diposphate
Other name(s): SdKPS; TwTPS14; TwTPS10/KPS; SdCPS2; clerodienyl diphosphate synthase; CLPP
Systematic name: (–)-kolavenyl diphosphate lyase (ring-opening)
Comments: Isolated from the hallucinogenic plant Salvia divinorum (seer’s sage) and the medicinal plant Tripterygium wilfordii (thunder god vine).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Hansen, N.L., Heskes, A.M., Hamberger, B., Olsen, C.E., Hallstrom, B.M., Andersen-Ranberg, J. and Hamberger, B. The terpene synthase gene family in Tripterygium wilfordii harbors a labdane-type diterpene synthase among the monoterpene synthase TPS-b subfamily. Plant J. 89 (2017) 429–441. [DOI] [PMID: 27801964]
2.  Chen, X., Berim, A., Dayan, F.E. and Gang, D.R. A (–)-kolavenyl diphosphate synthase catalyzes the first step of salvinorin A biosynthesis in Salvia divinorum. J. Exp. Bot. 68 (2017) 1109–1122. [DOI] [PMID: 28204567]
[EC 5.5.1.28 created 2017]
 
 
EC 4.2.3.95     Relevance: 47%
Accepted name: (-)-α-cuprenene synthase
Reaction: (2E,6E)-farnesyl diphosphate = (-)-α-cuprenene + diphosphate
For diagram of biosynthesis of bicyclic sesquiterpenoids derived from bisabolyl cation, click here and for diagram of trichodiene and (–)-α-cuprenene biosynthesis, click here
Other name(s): Cop6
Systematic name: (-)-α-cuprenene hydrolase [cyclizing, (-)-α-cuprenene-forming]
Comments: The enzyme from the fungus Coprinopsis cinerea produces (-)-α-cuprenene with high selectivity.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Lopez-Gallego, F., Agger, S.A., Abate-Pella, D., Distefano, M.D. and Schmidt-Dannert, C. Sesquiterpene synthases Cop4 and Cop6 from Coprinus cinereus: catalytic promiscuity and cyclization of farnesyl pyrophosphate geometric isomers. ChemBioChem 11 (2010) 1093–1106. [DOI] [PMID: 20419721]
[EC 4.2.3.95 created 2012]
 
 
EC 4.2.3.6     Relevance: 45.5%
Accepted name: trichodiene synthase
Reaction: (2E,6E)-farnesyl diphosphate = trichodiene + diphosphate
For diagram of biosynthesis of bicyclic sesquiterpenoids derived from bisabolyl cation, click here and for diagram of trichodiene and (–)-α-cuprenene biosynthesis, click here
Other name(s): trichodiene synthetase; sesquiterpene cyclase; trans,trans-farnesyl-diphosphate sesquiterpenoid-lyase
Systematic name: (2E,6E)-farnesyl-diphosphate diphosphate-lyase (cyclizing, trichodiene-forming)
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 101915-76-8
References:
1.  Hohn, T.M. and Vanmiddlesworth, F. Purification and characterization of the sesquiterpene cyclase trichodiene synthetase from Fusarium sporotrichioides. Arch. Biochem. Biophys. 251 (1986) 756–761. [DOI] [PMID: 3800398]
2.  Hohn, T.M. and Beremand, P.D. Isolation and nucleotide sequence of a sesquiterpene cyclase gene from the trichothecene-producing fungus Fusarium sporotrichioides. Gene 79 (1989) 131–138. [DOI] [PMID: 2777086]
3.  Rynkiewicz, M.J., Cane, D.E. and Christianson, D.W. Structure of trichodiene synthase from Fusarium sporotrichioides provides mechanistic inferences on the terpene cyclization cascade. Proc. Natl. Acad. Sci. USA 98 (2001) 13543–13548. [DOI] [PMID: 11698643]
[EC 4.2.3.6 created 1989 as EC 4.1.99.6, transferred 2000 to EC 4.2.3.6]
 
 
EC 1.14.13.104      
Transferred entry: (+)-menthofuran synthase. Now EC 1.14.14.143, (+)-menthofuran synthase
[EC 1.14.13.104 created 2008, deleted 2018]
 
 
EC 1.3.99.25     Relevance: 44.8%
Accepted name: carvone reductase
Reaction: (1) (+)-dihydrocarvone + acceptor = (–)-carvone + reduced acceptor
(2) (–)-isodihydrocarvone + acceptor = (+)-carvone + reduced acceptor
For diagram of (–)-carvone catabolism, click here
Glossary: (+)-dihydrocarvone = (1S,4R)-menth-8-en-2-one
(+)-isodihydrocarvone = (1S,4R)-menth-8-en-2-one
(–)-carvone = (4R)-mentha-1(6),8-dien-6-one = (5R)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one
Systematic name: (+)-dihydrocarvone:acceptor 1,6-oxidoreductase
Comments: This enzyme participates in the carveol and dihydrocarveol degradation pathway of the Gram-positive bacterium Rhodococcus erythropolis DCL14. The enzyme has not been purified, and requires an unknown cofactor, which is different from NAD+, NADP+ or a flavin.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  van der Werf, M.J. and Boot, A.M. Metabolism of carveol and dihydrocarveol in Rhodococcus erythropolis DCL14. Microbiology 146 (2000) 1129–1141. [DOI] [PMID: 10832640]
[EC 1.3.99.25 created 2008]
 
 
EC 1.1.1.296     Relevance: 44.5%
Accepted name: dihydrocarveol dehydrogenase
Reaction: menth-8-en-2-ol + NAD+ = menth-8-en-2-one + NADH + H+
For diagram of (–)-carvone catabolism, click here
Glossary: (+)-dihydrocarveol = (1S,2S,4S)-menth-8-en-2-ol
(+)-isodihydrocarveol = (1S,2S,4R)-menth-8-en-2-ol
(+)-neoisodihydrocarveol = (1S,2R,4R)-menth-8-en-2-ol
(–)-dihydrocarvone = (1S,4S)-menth-8-en-2-one
(+)-isodihydrocarvone = (1S,4R)-menth-8-en-2-one
Other name(s): carveol dehydrogenase (ambiguous)
Systematic name: menth-8-en-2-ol:NAD+ oxidoreductase
Comments: This enzyme from the Gram-positive bacterium Rhodococcus erythropolis DCL14 forms part of the carveol and dihydrocarveol degradation pathway. The enzyme accepts all eight stereoisomers of menth-8-en-2-ol as substrate, although some isomers are converted faster than others. The preferred substrates are (+)-neoisodihydrocarveol, (+)-isodihydrocarveol, (+)-dihydrocarveol and (–)-isodihydrocarveol.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  van der Werf, M.J. and Boot, A.M. Metabolism of carveol and dihydrocarveol in Rhodococcus erythropolis DCL14. Microbiology 146 (2000) 1129–1141. [DOI] [PMID: 10832640]
[EC 1.1.1.296 created 2008]
 
 
EC 1.14.11.22      
Transferred entry: flavone synthase. Now EC 1.14.20.5, flavone synthase
[EC 1.14.11.22 created 2004, deleted 2018]
 
 
EC 1.23.1.3     Relevance: 43%
Accepted name: (–)-pinoresinol reductase
Reaction: (–)-lariciresinol + NADP+ = (–)-pinoresinol + NADPH + H+
For diagram of (–)-lariciresinol biosynthesis, click here
Glossary: (–)-lariciresinol = 4-[(2R,3S,4S)-4-[(4-hydroxy-3-methoxyphenyl)methyl]-3-(hydroxymethyl)oxolan-2-yl]-2-methoxyphenol
(–)-pinoresinol = (1R,3aS,4R,6aS)-4,4′-(tetrahydro-1H,3H-furo[3,4-c]furan-1,4-diyl)bis(2-methoxyphenol)
Other name(s): pinoresinol/lariciresinol reductase; pinoresinol-lariciresinol reductases; (–)-pinoresinol-(–)-lariciresinol reductase; PLR
Systematic name: (–)-lariciresinol:NADP+ oxidoreductase
Comments: The reaction is catalysed in vivo in the opposite direction to that shown. A multifunctional enzyme that usually further reduces the product to (+)-secoisolariciresinol [EC 1.23.1.4, (–)-lariciresinol reductase]. Isolated from the plants Thuja plicata (western red cedar) [1], Linum perenne (perennial flax) [2] and Arabidopsis thaliana (thale cress) [3].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Fujita, M., Gang, D.R., Davin, L.B. and Lewis, N.G. Recombinant pinoresinol-lariciresinol reductases from western red cedar (Thuja plicata) catalyze opposite enantiospecific conversions. J. Biol. Chem. 274 (1999) 618–627. [DOI] [PMID: 9872995]
2.  Hemmati, S., Schmidt, T.J. and Fuss, E. (+)-Pinoresinol/(-)-lariciresinol reductase from Linum perenne Himmelszelt involved in the biosynthesis of justicidin B. FEBS Lett. 581 (2007) 603–610. [DOI] [PMID: 17257599]
3.  Nakatsubo, T., Mizutani, M., Suzuki, S., Hattori, T. and Umezawa, T. Characterization of Arabidopsis thaliana pinoresinol reductase, a new type of enzyme involved in lignan biosynthesis. J. Biol. Chem. 283 (2008) 15550–15557. [DOI] [PMID: 18347017]
[EC 1.23.1.3 created 2013]
 
 
EC 1.14.13.47      
Transferred entry: (S)-limonene 3-monooxygenase. Now EC 1.14.14.99, (S)-limonene 3-monooxygenase
[EC 1.14.13.47 created 1992, modified 2003, deleted 2018]
 
 
EC 3.1.1.83     Relevance: 42%
Accepted name: monoterpene ε-lactone hydrolase
Reaction: (1) isoprop(en)ylmethyloxepan-2-one + H2O = 6-hydroxyisoprop(en)ylmethylhexanoate (general reaction)
(2) 4-isopropenyl-7-methyloxepan-2-one + H2O = 6-hydroxy-3-isopropenylheptanoate
(3) 7-isopropyl-4-methyloxepan-2-one + H2O = 6-hydroxy-3,7-dimethyloctanoate
For diagram of (–)-carvone catabolism, click here and for diagram of menthol biosynthesis, click here
Other name(s): MLH
Systematic name: isoprop(en)ylmethyloxepan-2-one lactonohydrolase
Comments: The enzyme catalyses the ring opening of ε-lactones which are formed during degradation of dihydrocarveol by the Gram-positive bacterium Rhodococcus erythropolis DCL14. The enzyme also acts on ethyl caproate, indicating that it is an esterase with a preference for lactones (internal cyclic esters). The enzyme is not stereoselective.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  van der Vlugt-Bergmans , C.J. and van der Werf , M.J. Genetic and biochemical characterization of a novel monoterpene ε-lactone hydrolase from Rhodococcus erythropolis DCL14. Appl. Environ. Microbiol. 67 (2001) 733–741. [DOI] [PMID: 11157238]
[EC 3.1.1.83 created 2008]
 
 
EC 1.14.13.48      
Transferred entry: (S)-limonene 6-monooxygenase. Now classified as EC 1.14.14.51, (S)-limonene 6-monooxygenase
[EC 1.14.13.48 created 1992, modified 2003, deleted 2017]
 
 
EC 1.14.20.5     Relevance: 41.6%
Accepted name: flavone synthase I
Reaction: a flavanone + 2-oxoglutarate + O2 = a flavone + succinate + CO2 + H2O
For diagram of flavonoid biosynthesis, click here and for diagram of the biosynthesis of naringenin derivatives, click here
Other name(s): FNSI (gene name)
Systematic name: flavanone,2-oxoglutarate:oxygen oxidoreductase (dehydrating)
Comments: The enzyme, which has been found in rice and in members of the Apiaceae (a plant family), is a member of the 2-oxoglutarate-dependent dioxygenases, and requires ascorbate and Fe2+ for full activity.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 138263-98-6
References:
1.  Martens, S., Forkmann, G., Matern, U. and Lukačin, R. Cloning of parsley flavone synthase I. Phytochemistry 58 (2001) 43–46. [DOI] [PMID: 11524111]
2.  Lukačin, R., Matern, U., Junghanns, K.T., Heskamp, M.L., Britsch, L., Forkmann, G. and Martens, S. Purification and antigenicity of flavone synthase I from irradiated parsley cells. Arch. Biochem. Biophys. 393 (2001) 177–183. [DOI] [PMID: 11516175]
3.  Martens, S., Forkmann, G., Britsch, L., Wellmann, F., Matern, U. and Lukačin, R. Divergent evolution of flavonoid 2-oxoglutarate-dependent dioxygenases in parsley. FEBS Lett. 544 (2003) 93–98. [DOI] [PMID: 12782296]
[EC 1.14.20.5 created 2004 as EC 1.14.11.22, transferred 2018 to EC 1.14.20.5]
 
 
EC 2.3.1.146     Relevance: 41.3%
Accepted name: pinosylvin synthase
Reaction: 3 malonyl-CoA + cinnamoyl-CoA = 4 CoA + pinosylvin + 4 CO2
For diagram of chalcone and stilbene biosynthesis, click here
Other name(s): stilbene synthase (ambiguous); pine stilbene synthase (ambiguous)
Systematic name: malonyl-CoA:cinnamoyl-CoA malonyltransferase (cyclizing)
Comments: Not identical with EC 2.3.1.74 (naringenin-chalcone synthase) or EC 2.3.1.95 (trihydroxystilbene synthase).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 72994-49-1
References:
1.  Gehlert, R., Schöppner, A. and Kindl, H. Stilbene synthase from seedlings of Pinus sylvestris - purification and induction in response to fungal infection. Mol. Plant-Microbe Interaction 3 (1990) 444–449.
[EC 2.3.1.146 created 1992]
 
 
EC 1.14.13.49      
Transferred entry: (S)-limonene 7-monooxygenase. Now classified as EC 1.14.14.52, (S)-limonene 7-monooxygenase
[EC 1.14.13.49 created 1992, modified 2003, deleted 2017]
 
 
EC 1.14.13.152      
Transferred entry: geraniol 8-hydroxylase. Now EC 1.14.14.83, geraniol 8-hydroxylase
[EC 1.14.13.152 created 2012, deleted 2018]
 
 
EC 2.3.1.95     Relevance: 40.3%
Accepted name: trihydroxystilbene synthase
Reaction: 3 malonyl-CoA + 4-coumaroyl-CoA = 4 CoA + trans-resveratrol + 4 CO2
For diagram of chalcone and stilbene biosynthesis, click here
Glossary: trans-resveratrol = 3,4′,5-trihydroxy-trans-stilbene
Other name(s): resveratrol synthase; stilbene synthase (ambiguous)
Systematic name: malonyl-CoA:4-coumaroyl-CoA malonyltransferase (cyclizing)
Comments: Not identical with EC 2.3.1.74 naringenin-chalcone synthase or EC 2.3.1.146 pinosylvin synthase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 128449-70-7
References:
1.  Schöppner, A. and Kindl, H. Purification and properties of a stilbene synthase from induced cell suspension cultures of peanut. J. Biol. Chem. 259 (1984) 6806–6811. [PMID: 6427224]
[EC 2.3.1.95 created 1989]
 
 
EC 2.1.1.46     Relevance: 38.4%
Accepted name: isoflavone 4′-O-methyltransferase
Reaction: S-adenosyl-L-methionine + a 4′-hydroxyisoflavone = S-adenosyl-L-homocysteine + a 4′-methoxyisoflavone
For diagram of the biosynthesis of biochanin A, click here and for diagram of the biosynthesis of formononetin and derivatives, click here
Other name(s): 4′-hydroxyisoflavone methyltransferase; isoflavone methyltransferase; isoflavone O-methyltransferase
Systematic name: S-adenosyl-L-methionine:4′-hydroxyisoflavone 4′-O-methyltransferase
Comments: Requires Mg2+ for activity. The enzyme catalyses the methylation of daidzein and genistein. It does not methylate naringenin, apigenin, luteolin or kaempferol.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 55071-80-2
References:
1.  Wengenmayer, H., Ebel, J. and Grisebach, H. Purification and properties of a S-adenosylmethionine: isoflavone 4′-O-methyltransferase from cell suspension cultures of Cicer arietinum L. Eur. J. Biochem. 50 (1974) 135–143. [DOI] [PMID: 4452353]
[EC 2.1.1.46 created 1976, modified 2011]
 
 
EC 1.14.99.34     Relevance: 38.3%
Accepted name: monoprenyl isoflavone epoxidase
Reaction: 7-O-methylluteone + NADPH + H+ + O2 = dihydrofurano derivatives + NADP+ + H2O
Glossary: luteone = 3-(2,4-dihydroxyphenyl)-5,7-dihydroxy-6-(3-methyl-2-butenyl)-4H-1-benzopyran-4-one
naringenin = 4′,5,7-trihydroxyflavan-4-one
Other name(s): monoprenyl isoflavone monooxygenase; 7-O-methylluteone:O2 oxidoreductase; 7-O-methylluteone,NADPH:O2 oxidoreductase
Systematic name: 7-O-methylluteone,NADPH:oxygen oxidoreductase
Comments: A flavoprotein (FAD) with high specificity for monoprenyl isoflavone. The product of the prenyl epoxidation reaction contains an oxygen atom derived from O2, but not from H2O. It is slowly and non-enzymically converted into the corresponding dihydrofurano derivative. The enzyme in the fungus Botrytis cinerea is induced by the substrate analogue, 6-prenylnaringenin.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 198496-86-5
References:
1.  Tanaka, M. and Tahara, S. FAD-dependent epoxidase as a key enzyme in fungal metabolism of prenylated flavonoids. Phytochemistry 46 (1997) 433–439.
[EC 1.14.99.34 created 2000]
 
 
EC 1.14.14.162     Relevance: 37.4%
Accepted name: flavanone 2-hydroxylase
Reaction: a flavanone + [reduced NADPH—hemoprotein reductase] + O2 = a 2-hydroxyflavanone + [oxidized NADPH—hemoprotein reductase] + H2O
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]
3.  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]
[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]
 
 
EC 1.14.14.83     Relevance: 36.5%
Accepted name: geraniol 8-hydroxylase
Reaction: geraniol + [reduced NADPH—hemoprotein reductase] + O2 = (6E)-8-hydroxygeraniol + [oxidized NADPH—hemoprotein reductase] + H2O
For diagram of acyclic monoterpenoid biosynthesis, click here
Other name(s): CYP76B6 (gene name); G10H (gene name)
Systematic name: geraniol,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (8-hydroxylating)
Comments: A cytochrome P-450 (heme thiolate) protein found in plants. Also hydroxylates nerol and citronellol, cf. EC 1.14.14.84, linalool 8-monooxygenase. The recommended numbering of geraniol gives 8-hydroxygeraniol as the product rather than 10-hydroxygeraniol as used by references 1-3. See prenol nomenclature Pr-1. The cloned enzyme also catalysed, but less efficiently, the 3′-hydroxylation of naringenin (cf. EC 1.14.14.82, flavonoid 3′-monooxygenase) [3].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Collu, G., Unver, N., Peltenburg-Looman, A.M., van der Heijden, R., Verpoorte, R. and Memelink, J. Geraniol 10-hydroxylase, a cytochrome P450 enzyme involved in terpenoid indole alkaloid biosynthesis. FEBS Lett. 508 (2001) 215–220. [DOI] [PMID: 11718718]
2.  Wang, J., Liu, Y., Cai, Y., Zhang, F., Xia, G. and Xiang, F. Cloning and functional analysis of geraniol 10-hydroxylase, a cytochrome P450 from Swertia mussotii Franch. Biosci. Biotechnol. Biochem. 74 (2010) 1583–1590. [PMID: 20699579]
3.  Sung, P.H., Huang, F.C., Do, Y.Y. and Huang, P.L. Functional expression of geraniol 10-hydroxylase reveals its dual function in the biosynthesis of terpenoid and phenylpropanoid. J. Agric. Food Chem. 59 (2011) 4637–4643. [DOI] [PMID: 21504162]
[EC 1.14.14.83 created 2012 as EC 1.14.13.152, transferred 2018 to EC 1.14.14.83]
 
 
EC 1.14.13.105     Relevance: 35.6%
Accepted name: monocyclic monoterpene ketone monooxygenase
Reaction: (1) (–)-menthone + NADPH + H+ + O2 = (4R,7S)-7-isopropyl-4-methyloxepan-2-one + NADP+ + H2O
(2) dihydrocarvone + NADPH + H+ + O2 = 4-isopropenyl-7-methyloxepan-2-one + NADP+ + H2O
(3) (iso)-dihydrocarvone + NADPH + H+ + O2 = 6-isopropenyl-3-methyloxepan-2-one + NADP+ + H2O
(4a) 1-hydroxymenth-8-en-2-one + NADPH + H+ + O2 = 7-hydroxy-4-isopropenyl-7-methyloxepan-2-one + NADP+ + H2O
(4b) 7-hydroxy-4-isopropenyl-7-methyloxepan-2-one = 3-isopropenyl-6-oxoheptanoate (spontaneous)
For diagram of (–)-carvone catabolism, click here, for diagram of limonene catabolism, click here and for diagram of menthol biosynthesis, click here
Other name(s): 1-hydroxy-2-oxolimonene 1,2-monooxygenase; dihydrocarvone 1,2-monooxygenase; MMKMO
Systematic name: (–)-menthone,NADPH:oxygen oxidoreductase
Comments: A flavoprotein (FAD). This Baeyer-Villiger monooxygenase enzyme from the Gram-positive bacterium Rhodococcus erythropolis DCL14 has wide substrate specificity, catalysing the lactonization of a large number of monocyclic monoterpene ketones and substituted cyclohexanones [2]. Both (1R,4S)- and (1S,4R)-1-hydroxymenth-8-en-2-one are metabolized, with the lactone product spontaneously rearranging to form 3-isopropenyl-6-oxoheptanoate [1].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  van der Werf, M.J., Swarts, H.J. and de Bont, J.A. Rhodococcus erythropolis DCL14 contains a novel degradation pathway for limonene. Appl. Environ. Microbiol. 65 (1999) 2092–2102. [PMID: 10224006]
2.  Van Der Werf, M.J. Purification and characterization of a Baeyer-Villiger mono-oxygenase from Rhodococcus erythropolis DCL14 involved in three different monocyclic monoterpene degradation pathways. Biochem. J. 347 (2000) 693–701. [PMID: 10769172]
3.  van der Werf, M.J. and Boot, A.M. Metabolism of carveol and dihydrocarveol in Rhodococcus erythropolis DCL14. Microbiology 146 (2000) 1129–1141. [DOI] [PMID: 10832640]
[EC 1.14.13.105 created 2008]
 
 
EC 1.14.13.103      
Transferred entry: 8-dimethylallylnaringenin 2-hydroxylase. Now EC 1.14.14.142, 8-dimethylallylnaringenin 2-hydroxylase
[EC 1.14.13.103 created 2007, deleted 2018]
 
 
EC 2.1.1.339     Relevance: 35.3%
Accepted name: xanthohumol 4-O-methyltransferase
Reaction: S-adenosyl-L-methionine + xanthohumol = S-adenosyl-L-homocysteine + 4-O-methylxanthohumol
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]
[EC 2.1.1.339 created 2017, modified 2018]
 
 
EC 2.5.1.71     Relevance: 29.6%
Accepted name: leachianone-G 2′′-dimethylallyltransferase
Reaction: prenyl diphosphate + leachianone G = diphosphate + sophoraflavanone G
For diagram of sophoraflavanone G biosynthesis, click here
Glossary: dimethylallyl = prenyl = 3-methylbut-2-en-1-yl
isopentenyl = 3-methylbut-3-en-1-yl
lavandulyl = 5-methyl-2-(prop-1-en-2-yl)hex-4-en-1-yl
leachianone G = (–)-(2S)-2′-hydroxy-8-prenylnaringenin = (–)-(2S)-2-(2,4-dihydroxyphenyl)-5,7-dihydroxy-8-(3-methylbut-2-en-1-yl)-2,3-dihydro-4H-chromen-4-one
sophoraflavanone G = (2S)-2-(2,4-dihydroxyphenyl)-5,7-dihydroxy-8-[(2R)-5-methyl-2-(prop-1-en-2-yl)hex-4-en-1-yl]-2,3-dihydro-4H-chromen-4-one
Other name(s): LG 2′′-dimethylallyltransferase; leachianone G 2′′-dimethylallyltransferase; LGDT; dimethylallyl-diphosphate:leachianone-G 2′′-dimethylallyltransferase
Systematic name: prenyl-diphosphate:leachianone-G 2′′-prenyltransferase
Comments: This membrane-bound enzyme is located in the plastids and requires Mg2+ for activity. The reaction forms the lavandulyl sidechain of sophoraflavanone G by transferring a prenyl group to the 2′′ position of another prenyl group attached at position 8 of leachianone G. The enzyme is specific for prenyl diphosphate as the prenyl donor, as it cannot be replaced by isopentenyl diphosphate or geranyl diphosphate. Euchrenone a7 (a 5-deoxy derivative of leachianone G) and kenusanone I (a 7-methoxy derivative of leachianone G) can also act as substrates, but more slowly. Along with EC 1.14.14.142 (8-dimethylallylnaringenin 2′-hydroxylase) and EC 2.5.1.70 (naringenin 8-dimethylallyltransferase), this enzyme forms part of the sophoraflavanone-G-biosynthesis pathway.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Zhao, P., Inoue, K., Kouno, I. and Yamamoto, H. Characterization of leachianone G 2′′-dimethylallyltransferase, a novel prenyl side-chain elongation enzyme for the formation of the lavandulyl group of sophoraflavanone G in Sophora flavescens Ait. cell suspension cultures. Plant Physiol. 133 (2003) 1306–1313. [DOI] [PMID: 14551337]
[EC 2.5.1.71 created 2007]
 
 


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