Reaction: (2E,6E)-farnesyl diphosphate = 7-epi-α-selinene + diphosphate
For diagram of reaction click here.
Glossary: 7-epi-α-selinene = (2S,4aR,8aR)-4a,8-dimethyl-2-(prop-1-en-2-yl)-1,2,3,4,4a,5,6,8a-octahydronaphthalene
Systematic name: (2E,6E)-farnesyl-diphosphate diphosphate-lyase (7-epi-α-selinene-forming)
Comments: The recombinant enzyme from Vitis vinifera forms 49.5% (+)-valencene (cf. EC 4.2.3.73, valencene synthase) and 35.5% (–)-7-epi-α-selinene. Initial cyclization gives (+)-germacrene A in an enzyme bound form which is not released to the medium.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
References:
1. Lucker, J., Bowen, P. and Bohlmann, J. Vitis vinifera terpenoid cyclases: functional identification of two sesquiterpene synthase cDNAs encoding (+)-valencene synthase and (–)-germacrene D synthase and expression of mono- and sesquiterpene synthases in grapevine flowers and berries. Phytochemistry 65 (2004) 2649-2659. [PMID: 15464152]
2. Martin, D.M., Toub, O., Chiang, A., Lo, B.C., Ohse, S., Lund, S.T. and Bohlmann, J. The bouquet of grapevine (Vitis vinifera L. cv. Cabernet Sauvignon) flowers arises from the biosynthesis of sesquiterpene volatiles in pollen grains. Proc. Natl. Acad. Sci. USA 106 (2009) 7245-7250. [PMID: 19359488]