Reaction: geranyl diphosphate = (+)-car-3-ene + diphosphate
For diagram of reaction click here and mechanism click here.
Glossary: (+)-car-3-ene = (1S,6R)-3,7,7-trimethylbicyclo[4.1.0]hept-3-ene
Other name(s): 3-carene cyclase; 3-carene synthase; 3CAR; (+)-3-carene synthase
Systematic name: geranyl-diphosphate diphosphate-lyase [cyclizing, (+)-car-3-ene-forming]
Comments: The enzyme reacts with (3S)-linalyl diphosphate twice as rapidly as geranyl diphosphate, but 25 times as rapidly as (3R)-linalyl diphosphate. It is assumed that (3S)-linalyl diphosphate is normally formed as an enzyme bound intermediate in the reaction. In the reaction the 5-pro-R hydrogen of geranyl diphosphate is eliminated during cyclopropane ring formation [1,2]. In Picea abies (Norway spruce) and Picea sitchensis (Sitka spruce) terpinolene is also formed [4,6]. See EC 4.2.3.113 terpinolene synthase. (+)-Car-3-ene is associated with resistance of Picea sitchensis (Sitka spruce) to white pine weevil [6].
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
References:
1. Savage, T.J. and Croteau, R. Biosynthesis of monoterpenes: regio- and stereochemistry of (+)-3-carene biosynthesis. Arch. Biochem. Biophys. 305 (1993) 581-587. [PMID: 8373196]
2. Savage, T.J., Ichii, H., Hume, S.D., Little, D.B. and Croteau, R. Monoterpene synthases from gymnosperms and angiosperms: stereospecificity and inactivation by cysteinyl- and arginyl-directed modifying reagents. Arch. Biochem. Biophys. 320 (1995) 257-265. [PMID: 7625832]
3. Savage, T.J., Hatch, M.W. and Croteau, R. Monoterpene synthases of Pinus contorta and related conifers. A new class of terpenoid cyclase. J. Biol. Chem. 269 (1994) 4012-4020. [PMID: 8307957]
4. Faldt, J., Martin, D., Miller, B., Rawat, S. and Bohlmann, J. Traumatic resin defense in Norway spruce (Picea abies): methyl jasmonate-induced terpene synthase gene expression, and cDNA cloning and functional characterization of (+)-3-carene synthase. Plant Mol. Biol. 51 (2003) 119-133. [PMID: 12602896]
5. Hamberger, B., Hall, D., Yuen, M., Oddy, C., Hamberger, B., Keeling, C.I., Ritland, C., Ritland, K. and Bohlmann, J. Targeted isolation, sequence assembly and characterization of two white spruce (Picea glauca) BAC clones for terpenoid synthase and cytochrome P450 genes involved in conifer defence reveal insights into a conifer genome. BMC Plant Biol. 9 (2009) 106. [PMID: 19656416]
6. Hall, D.E., Robert, J.A., Keeling, C.I., Domanski, D., Quesada, A.L., Jancsik, S., Kuzyk, M.A., Hamberger, B., Borchers, C.H. and Bohlmann, J. An integrated genomic, proteomic and biochemical analysis of (+)-3-carene biosynthesis in Sitka spruce (Picea sitchensis) genotypes that are resistant or susceptible to white pine weevil. Plant J. 65 (2011) 936-948. [PMID: 21323772]