In enzymology, an ent-copalyl diphosphate synthase (EC 5.5.1.13) is an enzyme that catalyzes the chemical reaction:
[11] The independent ent-kaurene syntheses in higher plants, of which there may be several per species, are much more heterogenous in size, ranging 161–816 residues, 19–94 kDa.
[12] ent-Copalyl diphosphate synthase has been isolated from a number of tissues in higher plants: cotyledon, hypocotyl and roots of sunflowers (Helianthus annuus) and Cucamonga manroot (Marah macrocarpus);[13] endosperm of squash (Cucurbita maxima)[14] and manroot (M. macrocarpus);[8] and leaves of rice (Oryza sativa).
[14] The reaction catalyzed by ent-copalyl diphosphate synthase can be seen as the first committed step in gibberellin biosynthesis.
A wide range of secondary metabolites, both terpenes and alkaloids, are also derived either from ent-copalyl pyrophosphate itself or from ent-kaurene or ent-kaurenoic acid, the next two intermediates on the metabolic pathway to gibberellins.