5 epiaristolochene synthase

5-epiaristolochene synthase (EC 4.2.3.61, 5-epi-aristolochene synthase, tobacco epiaristolochene synthase, farnesyl pyrophosphate cyclase, EAS, TEAS) is an enzyme with systematic name (2E,6E)-farnesyl-diphosphate diphosphate-lyase ((+)-5-epiaristolochene-forming). This enzyme catalyses the following chemical reaction

(2E,6E)-farnesyl diphosphate ⇌ (+)-5-epiaristolochene + diphosphate

Initial cyclization gives (+)-germacrene A in an enzyme bound form.