Cyclase II of Salvia officinalis (sage) gives about equal parts (-)-alpha-pinene, (-)-beta-pinene and (-)-camphene, plus traces of other monoterpenoids. (3S)-Linalyl diphosphate can also be used by the enzyme in preference to (3R)-linalyl diphosphate. The 4-pro-S-hydrogen of geranyl diphosphate is lost. Requires Mg2+ (preferred to Mn2+) [1-6]. The enzyme from Abies grandis (grand fir) gives roughly equal parts (-)-alpha-pinene and (-)-beta-pinene. However the clone ag11 gave 35% (-)-limonene, 24% (-)-alpha-pinene and 20% (-)-beta-phellandrene. It requires Mn2+ and K+ (Mg2+ is ineffective) [7-10]. Synthase I from Pinus taeda (loblolly pine) produces (-)-alpha-pinene with traces of (-)-beta-pinene and requires Mn2+ (preferred to Mg2+) [11,12]. The enzyme from Picea sitchensis (Sika spruce) forms 70% (-)-alpha-pinene and 30% (-)-beta-pinene . The recombinant PmeTPS1 enzyme from Pseudotsuga menziesii (Douglas fir) gave roughly equal proportions of (-)-alpha-pinene and (-)-camphene plus traces of other monoterpenoids . See also EC 18.104.22.168, (-)-beta-pinene synthase; EC 22.214.171.124, (-)-camphene synthase; EC 126.96.36.199, (-)-limonene synthase; and EC 188.8.131.52, (-)-beta-phellandrene synthase.
Isotopically sensitive branching in the formation of cyclic monoterpenes: proof that (-)-alpha-pinene and (-)-beta-pinene are synthesized by the same monoterpene cyclase via deprotonation of a common intermediate.