In some plants, such as Salvia miltiorrhiza, this enzyme is monofunctional. In other plants this activity is often a part of a bifunctional enzyme. For example, in Selaginella moellendorffii this activity is catalysed by a bifunctional enzyme that also catalyses EC 4.2.3.131, miltiradiene synthase, while in the tree Abies grandis (grand fir) it is catalysed by a bifunctional enzyme that also catalyses EC 4.2.3.18, abietadiene synthase.
Sugai Y, Ueno Y, Hayashi K, Oogami S, Toyomasu T, Matsumoto S, Natsume M, Nozaki H, Kawaide H
Title
Enzymatic (13)C labeling and multidimensional NMR analysis of miltiradiene synthesized by bifunctional diterpene cyclase in Selaginella moellendorffii.
Abietadiene synthase catalysis: conserved residues involved in protonation-initiated cyclization of geranylgeranyl diphosphate to (+)-copalyl diphosphate.