The recombinant enzyme from Vitis vinifera gave 49.5% (+)-valencene and 35.5% (-)-7-epi-α-selinene. Initial cyclization gives (+)-germacrene A in an enzyme bound form which is not released to the medium.
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. Phytochemistry65 (2004) 2649–2659. [PMID: 15464152]