BIOSYNTHESIS OF THE SESQUITERPENE PATCHOULOL FROM FARNESYL PYROPHOSPHATE IN LEAF EXTRACTS OF POGOSTEMON-CABLIN (PATCHOULI) - MECHANISTIC CONSIDERATIONS
BIOSYNTHESIS OF THE SESQUITERPENE PATCHOULOL FROM FARNESYL PYROPHOSPHATE IN LEAF EXTRACTS OF POGOSTEMON-CABLIN (PATCHOULI) - MECHANISTIC CONSIDERATIONS
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DOI：
10.1016/0003-9861(87)90425-5
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发表时间：
1987-07-01
影响因子：
3.9
通讯作者：
SATTERWHITE, DM
中科院分区：
文献类型：
--
作者：
CROTEAU, R;MUNCK, SL;SATTERWHITE, DM
已经提出了几种机械替代的酶催化的，亲电环化法呢基焦磷酸三环倍半萜醇patchoulol，这是广藿香（广藿香）的精油的特征成分。这些替代方案包括涉及去质子化-再质子化步骤和单环和双环烯烃germacrene和bulnesene的中间体的方案，以及涉及仅具有叔阳离子中间体且没有任何去质子化-再质子化步骤的1，3-氢化物移位的方案。分析研究，基于分析的P. cablin叶油在植物发育的不同阶段，并在体内的时间过程中的调查，使用14 CO2和[14 C]蔗糖，没有迹象表明，germacrene和bulnesene的中间体在广藿香醇生物合成。从P. cablin叶制备可溶性酶系统，其能够将焦磷酸法呢酯转化为广藿香醇，并且用标记和未标记的烯烃用该系统进行同位素稀释实验，以证实倍半萜烯烯烃不作为游离中间体参与无环前体向广藿香醇的转化。从[12，1 - 3 - 14 C;1- 3 H]法呢基焦磷酸生物合成衍生的Pactchoulol被化学降解以建立产物的总体结构模式。用[12，13 - 14 C;6- 3 H]法呢基焦磷酸盐作为前体的类似研究消除了去质子化步骤，以在广藿香醇的生物合成中形成结合的烯属中间体，同时为氢化物移位机制提供了支持性证据。
Several mechanistic alternatives have been proposed for the enzyme-catalyzed, electrophilic cyclization of farnesyl pyrophosphate to the tricyclic sesquiterpene alcohol patchoulol, which is the characteristic component of the essential oil of Pogostemon cablin (patchouli). These alternatives include schemes involving deprotonation-reprotonation steps and the intermediacy of the monocyclic and bicyclic olefins germacrene and bulnesene, respectively, and involving a 1,3-hydride shift with only tertiary cationic intermediates and without any deprotonation-reprotonation steps. Analytical studies, based on analyses of P. cablin leaf oil at different stages of plant development, and in vivo time-course investigations, using 14CO2 and [14C]sucrose, gave no indication that germacrene and bulnesene were intermediates in patchoulol biosynthesis. A soluble enzyme system from P. cablin leaves was prepared, which was capable of converting farnesyl pyrophosphate to patchoulol, and isotopic dilution experiments with both labeled and unlabeled olefins were carried out with this system to confirm that sesquiterpene olefins did not participate as free intermediates in the transformation of the acyclic precursor to patchoulol. Pactchoulol derived biosynthetically from [12,13-14C;1-3H]farnesyl pyrophosphate was chemically degraded to establish the overall construction pattern of the product. Similar studies with [12,13-14C;6-3H]farnesyl pyrophosphate as a precursor eliminated deprotonation steps to form bound olefinic intermediates in the biosynthesis of patchoulol, while providing supporting evidence for the hydride shift mechanism.