EC |
4.2.1.123 |
Accepted name: |
tetrahymanol synthase |
Reaction: |
tetrahymanol = squalene + H2O |
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For diagram of hopene and tetrahymanol biosynthesis, click here |
Glossary: |
tetrahymanol = gammaceran-3β-ol |
Systematic name: |
squalene hydro-lyase (tetrahymanol-forming) |
Comments: |
The reaction occurs in the reverse direction. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc |
References: |
1. |
Saar, J., Kader, J.C., Poralla, K. and Ourisson, G. Purification and some properties of the squalene-tetrahymanol cyclase from Tetrahymena thermophila. Biochim. Biophys. Acta 1075 (1991) 93–101. [DOI] [PMID: 1892870] |
2. |
Giner, J.L., Rocchetti, S., Neunlist, S., Rohmer, M. and Arigoni, D. Detection of 1,2-hydride shifts in the formation of euph-7-ene by the squalene-tetrahymanol cyclase of Tetrahymena pyriformis. Chem. Commun. (Camb.) (2005) 3089–3091. [DOI] [PMID: 15959594] |
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[EC 4.2.1.123 created 2011] |
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EC |
4.2.1.129 |
Accepted name: |
squalene—hopanol cyclase |
Reaction: |
hopan-22-ol = squalene + H2O |
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For diagram of hopene and tetrahymanol biosynthesis, click here |
Other name(s): |
squalene—hopene cyclase (ambiguous) |
Systematic name: |
hopan-22-ol hydro-lyase |
Comments: |
The enzyme produces the cyclization products hopene (cf. EC 5.4.99.17) and hopanol from squalene at a constant ratio of 5:1. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB |
References: |
1. |
Hoshino, T., Nakano, S., Kondo, T., Sato, T. and Miyoshi, A. Squalene-hopene cyclase: final deprotonation reaction, conformational analysis for the cyclization of (3R,S)-2,3-oxidosqualene and further evidence for the requirement of an isopropylidene moiety both for initiation of the polycyclization cascade and for the formation of the 5-membered E-ring. Org Biomol Chem 2 (2004) 1456–1470. [DOI] [PMID: 15136801] |
2. |
Sato, T., Kouda, M. and Hoshino, T. Site-directed mutagenesis experiments on the putative deprotonation site of squalene-hopene cyclase from Alicyclobacillus acidocaldarius. Biosci. Biotechnol. Biochem. 68 (2004) 728–738. [PMID: 15056909] |
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[EC 4.2.1.129 created 2011] |
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