Reaction: (2E,6E)-farnesyl diphosphate = (E)-α-bisabolene + diphosphate
For diagram of reaction click here and mechanism click here.
Other name(s): bisabolene synthase
Systematic name: (2E,6E)-farnesyl-diphosphate diphosphate-lyase [(E)-α-bisabolene-forming]
Comments: This cytosolic sesquiterpenoid synthase requires a divalent cation cofactor (Mg2+ or, to a lesser extent, Mn2+) to neutralize the negative charge of the diphosphate leaving group. While unlikely to encounter geranyl diphosphate (GDP) in vivo as it is localized to plastids, the enzyme can use GDP as a substrate in vitro to produce (+)-(4R)-limonene [cf. EC 126.96.36.199, (R)-limonene synthase]. The enzyme is induced as part of a defense mechanism in the grand fir Abies grandis as a response to stem wounding.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:
1. Bohlmann, J., Crock, J., Jetter, R. and Croteau, R. Terpenoid-based defenses in conifers: cDNA cloning, characterization, and functional expression of wound-inducible (E)-α-bisabolene synthase from grand fir (Abies grandis). Proc. Natl. Acad. Sci. USA 95 (1998) 6756-6761. [PMID: 9618485]