The synthesis of (S)-β-macrocarpene from (2E,6E)-farnesyl diphosphate proceeds in two steps. The first step is the cyclization to (S)-β-bisabolene (cf. EC 18.104.22.168, (S)-β-bisabolene synthase). The second step is the isomerization to (S)-β-macrocarpene.
Kollner, T.G., Schnee, C., Li, S., Svatos, A., Schneider, B., Gershenzon, J. and Degenhardt, J. Protonation of a neutral (S)-β-bisabolene intermediate is involved in (S)-β-macrocarpene formation by the maize sesquiterpene synthases TPS6 and TPS11. J. Biol. Chem.283 (2008) 20779–20788. [PMID: 18524777]