In enzymology, a copalyl diphosphate synthase (EC 5.5.1.12) is an enzyme that catalyzes the chemical reaction

geranylgeranyl diphosphate ${\displaystyle \rightleftharpoons }$ (+)-copalyl diphosphate

Hence, this enzyme has one substrate, geranylgeranyl diphosphate, and one product, (+)-copalyl diphosphate.

This enzyme belongs to the family of isomerases, specifically the class of intramolecular lyases. The systematic name of this enzyme class is (+)-copalyl-diphosphate lyase (decyclizing). This enzyme participates in diterpenoid biosynthesis.

References

• RB; Flory, JE; Jetter, R; Ravn, MM; Lee, HJ; Coates, RM; Croteau, RB (2000). "Abietadiene synthase from grand fir (Abies grandis): characterization and mechanism of action of the "pseudomature" recombinant enzyme". Biochemistry. 39 (50): 15592–602. doi:10.1021/bi001997l. PMID 11112547.
• Peters RJ, Ravn MM, Coates RM, Croteau RB (2001). "Bifunctional abietadiene synthase: free diffusive transfer of the (+)-copalyl diphosphate intermediate between two distinct active sites". J. Am. Chem. Soc. 123 (37): 8974–8. doi:10.1021/ja010670k. PMID 11552804.
• Peters RJ, Croteau RB (2002). "Abietadiene synthase catalysis: mutational analysis of a prenyl diphosphate ionization-initiated cyclization and rearrangement". Proc. Natl. Acad. Sci. U.S.A. 99 (2): 580–4. Bibcode:2002PNAS...99..580P. doi:10.1073/pnas.022627099. PMC 117348. PMID 11805316.
• Ravn MM, Peters RJ, Coates RM, Croteau R (2002). "Mechanism of abietadiene synthase catalysis: stereochemistry and stabilization of the cryptic pimarenyl carbocation intermediates". J. Am. Chem. Soc. 124 (24): 6998–7006. doi:10.1021/ja017734b. PMID 12059223.
• Peters RJ, Croteau RB (2002). "Abietadiene synthase catalysis: conserved residues involved in protonation-initiated cyclization of geranylgeranyl diphosphate to (+)-copalyl diphosphate". Biochemistry. 41 (6): 1836–42. doi:10.1021/bi011879d. PMID 11827528.