(-)-alpha-pinene synthase (EC 4.2.3.119, (-)-alpha-pinene/(-)-camphene synthase, (-)-alpha-pinene cyclase) is an enzyme with systematic name geranyl-diphosphate diphosphate-lyase (cyclizing, (-)-alpha-pinene-forming). This enzyme catalyses the following chemical reaction geranyl diphosphate (-)-alpha-pinene + diphosphate Cyclase II of Salvia officinalis (sage) gives about equal parts (-)-alpha-pinene, (-)-beta-pinene and (-)-camphene.