EC 1.14.13.134      
Transferred entry: β-amyrin 11-oxidase. Now EC 1.14.14.152, β-amyrin 11-oxidase
[EC 1.14.13.134 created 2011, deleted 2018]
 
 
EC 1.14.13.173      
Transferred entry: 11-oxo-β-amyrin 30-oxidase. Now EC 1.14.14.115, 11-oxo-β-amyrin 30-oxidase.
[EC 1.14.13.173 created 2013, deleted 2018]
 
 
EC 1.14.14.115     
Accepted name: 11-oxo-β-amyrin 30-oxidase
Reaction: 11-oxo-β-amyrin + 3 O2 + 3 [reduced NADPH—hemoprotein reductase] = glycyrrhetinate + 3 [oxidized NADPH—hemoprotein reductase] + 4 H2O (overall reaction)
(1a) 11-oxo-β-amyrin + O2 + [reduced NADPH—hemoprotein reductase] = 30-hydroxy-11-oxo-β-amyrin + [oxidized NADPH—hemoprotein reductase] + H2O
(1b) 30-hydroxy-11-oxo-β-amyrin + O2 + [reduced NADPH—hemoprotein reductase] = glycyrrhetaldehyde + [oxidized NADPH—hemoprotein reductase] + 2 H2O
(1c) glycyrrhetaldehyde + O2 + [reduced NADPH—hemoprotein reductase] = glycyrrhetinate + [oxidized NADPH—hemoprotein reductase] + H2O
Other name(s): CYP72A; CYP72A154; 11-oxo-β-amyrin 30-monooxygenase
Systematic name: 11-oxo-β-amyrin,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (30-hydroxylating)
Comments: A cytochrome P-450 (heme-thiolate) protein. The enzyme from the plant Glycyrrhiza uralensis (licorice) is involved in the biosynthesis of the triterpenoid saponin glycyrrhizin. The enzyme from the plant Medicago truncatula can also hydroxylate β-amyrin.
References:
1.  Seki, H., Sawai, S., Ohyama, K., Mizutani, M., Ohnishi, T., Sudo, H., Fukushima, E.O., Akashi, T., Aoki, T., Saito, K. and Muranaka, T. Triterpene functional genomics in licorice for identification of CYP72A154 involved in the biosynthesis of glycyrrhizin. Plant Cell 23 (2011) 4112–4123. [PMID: 22128119]
[EC 1.14.14.115 created 2013 as EC 1.14.13.173, transferred 2018 to EC 1.14.14.115]
 
 
EC 1.14.14.152     
Accepted name: β-amyrin 11-oxidase
Reaction: β-amyrin + 2 [reduced NADPH—hemoprotein reductase] + 2 O2 = 11-oxo-β-amyrin + 2 [oxidized NADPH—hemoprotein reductase] + 3 H2O (overall reaction)
(1a) β-amyrin + [reduced NADPH—hemoprotein reductase] + O2 = 11α-hydroxy-β-amyrin + [oxidized NADPH—hemoprotein reductase] + H2O
(1b) 11α-hydroxy-β-amyrin + [reduced NADPH—hemoprotein reductase] + O2 = 11-oxo-β-amyrin + [oxidized NADPH—hemoprotein reductase] + 2 H2O
Other name(s): CYP88D6
Systematic name: β-amyrin,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (hydroxylating)
Comments: A cytochrome P-450 (heme-thiolate) protein from the plant Glycyrrhiza uralensis (Chinese licorice) that participates in the glycyrrhizin biosynthesis pathway. The enzyme is also able to oxidize 30-hydroxy-β-amyrin to 11α,30-dihydroxy-β-amyrin but this is not thought to be part of glycyrrhizin biosynthesis.
References:
1.  Seki, H., Ohyama, K., Sawai, S., Mizutani, M., Ohnishi, T., Sudo, H., Akashi, T., Aoki, T., Saito, K. and Muranaka, T. Licorice β-amyrin 11-oxidase, a cytochrome P450 with a key role in the biosynthesis of the triterpene sweetener glycyrrhizin. Proc. Natl. Acad. Sci. USA 105 (2008) 14204–14209. [PMID: 18779566]
[EC 1.14.14.152 created 2011 as EC 1.14.13.134, transferred 2018 to EC 1.14.14.152]
 
 
EC 3.2.1.128     
Accepted name: glycyrrhizin hydrolase
Reaction: glycyrrhizin + H2O = β-D-glucuronosyl-(1→2)-D-glucuronate + glycyrrhetinate
Glossary: glycyrrhizin = glycyrrhizinate
glycyrrhetinate = 3-β-glycyrrhetinate = 3β-hydroxy-11-oxoolean-12-en-30-oate
Other name(s): glycyrrhizinate β-glucuronidase; glycyrrhizin β-hydrolase; glycyrrhizinic acid hydrolase
Systematic name: glycyrrhizinate glucuronosylhydrolase
Comments: The enzyme from Aspergillus niger is specific for the hydrolysis of the triterpenoid glycoside glycyrrhizin from roots of Glycyrrhiza sp.
References:
1.  Muro, T., Kuramoto, T., Imoto, K. and Okada, S. Purification and some properties of glycyrrhizinic acid hydrolase from Aspergillus niger GRM3. Agric. Biol. Chem. 50 (1986) 687–692.
[EC 3.2.1.128 created 1989]
 
 
EC 5.4.99.39     
Accepted name: β-amyrin synthase
Reaction: (3S)-2,3-epoxy-2,3-dihydrosqualene = β-amyrin
Other name(s): 2,3-oxidosqualene β-amyrin cyclase; AsbAS1; BPY; EtAS; GgbAS1; LjAMY1; MtAMY1; PNY; BgbAS
Systematic name: (3S)-2,3-epoxy-2,3-dihydrosqualene mutase (cyclizing, β-amyrin-forming)
Comments: Some organism possess a monofunctional β-amyrin synthase [3,4,6-11], other have a multifunctional enzyme that also catalyses the synthesis of α-amyrin (EC 5.4.99.40) [5] or lupeol (EC 5.4.99.41) [6].
References:
1.  Abe, I, Ebizuka, Y., Seo, S. and Sankawa, U. Purification of squalene-2,3-epoxide cyclases from cell suspension cultures of Rabdosia japonica Hara. FEBS Lett. 249 (1989) 100–104.
2.  Abe, I., Sankawa, U. and Ebizuka, Y. Purification of 2,3-oxdosqualene:β-amyrin cyclase from pea seedlings. Chem. Pharm. Bull. 37 (1989) 536.
3.  Kushiro, T., Shibuya, M. and Ebizuka, Y. β-Amyrin synthase-cloning of oxidosqualene cyclase that catalyzes the formation of the most popular triterpene among higher plants. Eur. J. Biochem. 256 (1998) 238–244. [PMID: 9746369]
4.  Hayashi, H., Huang, P., Kirakosyan, A., Inoue, K., Hiraoka, N., Ikeshiro, Y., Kushiro, T., Shibuya, M. and Ebizuka, Y. Cloning and characterization of a cDNA encoding β-amyrin synthase involved in glycyrrhizin and soyasaponin biosyntheses in licorice. Biol. Pharm. Bull. 24 (2001) 912–916. [PMID: 11510484]
5.  Husselstein-Muller, T., Schaller, H. and Benveniste, P. Molecular cloning and expression in yeast of 2,3-oxidosqualene-triterpenoid cyclases from Arabidopsis thaliana. Plant Mol. Biol. 45 (2001) 75–92. [PMID: 11247608]
6.  Iturbe-Ormaetxe, I., Haralampidis, K., Papadopoulou, K. and Osbourn, A.E. Molecular cloning and characterization of triterpene synthases from Medicago truncatula and Lotus japonicus. Plant Mol. Biol. 51 (2003) 731–743. [PMID: 12683345]
7.  Zhang, H., Shibuya, M., Yokota, S. and Ebizuka, Y. Oxidosqualene cyclases from cell suspension cultures of Betula platyphylla var. japonica: molecular evolution of oxidosqualene cyclases in higher plants. Biol. Pharm. Bull. 26 (2003) 642–650. [PMID: 12736505]
8.  Hayashi, H., Huang, P., Takada, S., Obinata, M., Inoue, K., Shibuya, M. and Ebizuka, Y. Differential expression of three oxidosqualene cyclase mRNAs in Glycyrrhiza glabra. Biol. Pharm. Bull. 27 (2004) 1086–1092. [PMID: 15256745]
9.  Kajikawa, M., Yamato, K.T., Fukuzawa, H., Sakai, Y., Uchida, H. and Ohyama, K. Cloning and characterization of a cDNA encoding β-amyrin synthase from petroleum plant Euphorbia tirucalli L. Phytochemistry 66 (2005) 1759–1766. [PMID: 16005035]
10.  Basyuni, M., Oku, H., Tsujimoto, E., Kinjo, K., Baba, S. and Takara, K. Triterpene synthases from the Okinawan mangrove tribe, Rhizophoraceae. FEBS J. 274 (2007) 5028–5042. [PMID: 17803686]
11.  Liu, Y., Cai, Y., Zhao, Z., Wang, J., Li, J., Xin, W., Xia, G. and Xiang, F. Cloning and functional analysis of a β-amyrin synthase gene associated with oleanolic acid biosynthesis in Gentiana straminea MAXIM. Biol. Pharm. Bull. 32 (2009) 818–824. [PMID: 19420748]
[EC 5.4.99.39 created 2011]
 
 


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