Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340.
Plant Physiol. 1989 Apr;89(4):1351-7. doi: 10.1104/pp.89.4.1351.
The primary monoterpene accumulated in the glandular trichomes of spearmint (Mentha spicata) is the ketone (-)-carvone which is formed by cyclization of the C(10) isoprenoid intermediate geranyl pyrophosphate to the olefin (-)-limonene, hydroxylation to (-)-trans-carveol and subsequent dehydrogenation. Selective extraction of the contents of the glandular trichomes indicated that essentially all of the cyclase and hydroxylase activities resided in these structures, whereas only about 30% of the carveol dehydrogenase was located here with the remainder located in the rest of the leaf. This distribution of carveol dehydrogenase activity was confirmed by histochemical methods. Electrophoretic analysis of the partially purified carveol dehydrogenase from extracts of both the glands and the leaves following gland removal indicated the presence of a unique carveol dehydrogenase species in the glandular trichomes, suggesting that the other dehydrogenase found throughout the leaf probably utilizes carveol only as an adventitious substrate. These results demonstrate that carvone biosynthesis takes place exclusively in the glandular trichomes in which this natural product accumulates.
留兰香油腺毛中积累的主要单萜是（-）-香芹酮，它是由 C（10）异戊烯基焦磷酸通过环化形成的烯烃（-）-柠檬烯，然后羟化形成（-）-反式香芹醇，随后脱氢。对腺毛内容物的选择性提取表明，几乎所有的环化酶和羟化酶活性都存在于这些结构中，而只有约 30%的香芹醇脱氢酶位于此处，其余的位于叶片的其余部分。通过组织化学方法证实了这种香芹醇脱氢酶活性的分布。从去除腺毛后的腺体和叶片提取物中部分纯化的香芹醇脱氢酶的电泳分析表明，腺毛中存在一种独特的香芹醇脱氢酶，这表明在叶片中发现的其他脱氢酶可能仅将香芹醇用作偶然的底物。这些结果表明，香芹酮的生物合成仅发生在积累这种天然产物的油腺毛中。
