Component of iboga and aspidosperma monoterpenoid indole alkaloids (MIAs, e.g. tabersonine and catharanthine) biosynthesis pathway from 19E-geissoschizine. Catalyzes the conversion of O-acetylstemmadenine (OAS) to catharanthine. dihydroprecondylocarpine acetate = acetate + catharanthine + H(+) Alkaloid biosynthesis. Interacts with dehydroprecondylocarpine acetate synthase (DPAS). Expressed in leaf epidermis. Reduced accumulation of catharanthine, increased biosynthesis of vindoline, but normal levels of ajmalicine. Belongs to the 'GDXG' lipolytic enzyme family.