Elisabethatriene synthase (EC 4.2.3.41, elisabethatriene cyclase) is an enzyme with systematic name geranylgeranyl-diphosphate diphosphate-lyase (elisabethatriene-forming). This enzyme catalyses the following chemical reaction
This enzyme requires Mg<sup>2+</sup> or less efficiently Mn<sup>2+</sup>.