LC-MS/MS chromatograms from in vitro assays with purified IDS from either X. translucens pv. translucens (XttIDS) or E. tracheiphila (EtIDS) with IDP and DMADP as substrates, with comparison to a GGPP standard; or with purified CPS from either A. thaliana (AtCPS), X. translucens pv. translucens (XttCPS), or E. tracheiphila (EtCPS), with GGPP as substrate. (Right panel) Condensation of DMAPP with three molecules of IPP to form GGPP catalyzed by IDSs, and cyclization of GGPP to ent-CPP catalyzed by CPSs.