Sclareol cyclase  Sclareol cyclase (, "geranylgeranyl pyrophosphate:sclareol cyclase", "geranylgeranyl pyrophosphate-sclareol cyclase", "GGPP:sclareol cyclase") is an enzyme with systematic name "geranylgeranyl-diphosphate diphosphohydrolase (sclareol-forming)". This enzyme catalyses the following chemical reaction  This enzyme requires Mg2+ or Mn2+ for activity.