EC 4.2.3.32     
Accepted name: levopimaradiene synthase
Reaction: (+)-copalyl diphosphate = abieta-8(14),12-diene + diphosphate
Glossary: levopimaradiene = abieta-8(14),12-diene
Other name(s): PtTPS-LAS; LPS; copalyl-diphosphate diphosphate-lyase [abieta-8(14),12-diene-forming]
Systematic name: (+)-copalyl-diphosphate diphosphate-lyase [abieta-8(14),12-diene-forming]
Comments: In Ginkgo, the enzyme catalyses the initial cyclization step in the biosynthesis of ginkgolides, a structurally unique family of diterpenoids that are highly specific platelet-activating-factor receptor antagonists [1]. Levopimaradiene is widely distributed in higher plants. In some species the enzyme also forms abietadiene, palustradiene, and neoabietadiene [2].
References:
1.  Schepmann, H.G., Pang, J. and Matsuda, S.P. Cloning and characterization of Ginkgo biloba levopimaradiene synthase which catalyzes the first committed step in ginkgolide biosynthesis. Arch. Biochem. Biophys. 392 (2001) 263–269. [PMID: 11488601]
2.  Ro, D.K. and Bohlmann, J. Diterpene resin acid biosynthesis in loblolly pine (Pinus taeda): functional characterization of abietadiene/levopimaradiene synthase (PtTPS-LAS) cDNA and subcellular targeting of PtTPS-LAS and abietadienol/abietadienal oxidase (PtAO, CYP720B1). Phytochemistry 67 (2006) 1572–1578. [PMID: 16497345]
[EC 4.2.3.32 created 2008, modified 2012]