Department of Technical Biochemistry, Technical University Dortmund, Emil-Figge-Str. 66, 44227 Dortmund, Germany.
Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Bunsen-Kirchhoff-Str. 11, 44139 Dortmund, Germany.
Plant Sci. 2019 Jul;284:108-116. doi: 10.1016/j.plantsci.2019.04.008. Epub 2019 Apr 12.
Cannabinoids are terpenophenolic compounds produced by Cannabis sativa L., which accumulate in storage cavities of glandular trichomes as a part of the exudates. We investigated if tetrahydrocannabinolic acid synthase and cannabidiolic acid synthase, which are involved in the last step of cannabinoid biosynthesis, are also secreted into Cannabis trichome exudates. The exudates were collected by microsuction from storage cavities of Cannabis glandular trichomes and were subjected for proteomic and metabolomic analyses. The catalytic activity of the exudates was documented by cannabigerolic acid biotransformation studies under hydrophobic conditions. Electrophoretic separations revealed protein bands at ˜65 kDa, which were further identified as tetrahydrocannabinolic acid synthase and cannabidiolic acid synthase. The accumulation of the enzymes in trichome exudates increased substantially during the flowering period in the drug-type Cannabis plants. The content of cannabinoids increased significantly after incubating hexane-diluted trichome exudates with cannabigerolic acid. In this study, we showed that Cannabis glandular trichomes secrete and accumulate cannabinoid synthases in storage cavities, and the enzymes able to convert cannabigerolic acid under hydrophobic trichome-mimicking conditions. Metabolite profiling of the exudates revealed compounds with hydrophilic, osmoprotective and amphiphilic properties, which may play a role in providing a necessary aqueous microenvironment, which enables enzyme solubility and biocatalysis under hydrophobic conditions of glandular trichomes.
大麻素是大麻（Cannabis sativa L.）产生的萜酚类化合物，作为分泌物的一部分积累在腺毛的储油腔中。我们研究了参与大麻素生物合成最后一步的四氢大麻酸合酶和大麻二酚酸合酶是否也分泌到大麻毛状体分泌物中。通过微吸从大麻腺毛的储油腔中收集分泌物，并对其进行蛋白质组学和代谢组学分析。通过在疏水条件下进行大麻酰基生物转化研究，记录了分泌物的催化活性。电泳分离显示出约 65 kDa 的蛋白质带，这些蛋白质带进一步被鉴定为四氢大麻酸合酶和大麻二酚酸合酶。在药用型大麻植物的花期，酶在毛状体分泌物中的积累显著增加。用己烷稀释的毛状体分泌物孵育后，大麻素的含量显著增加。在这项研究中，我们表明大麻腺毛在储油腔中分泌和积累大麻素合酶，并且这些酶能够在疏水的毛状体模拟条件下催化大麻酰基转化。分泌物的代谢物分析显示出具有亲水性、渗透保护和两亲性的化合物，它们可能在提供必要的水微环境方面发挥作用，从而使酶在腺毛的疏水条件下溶解和进行生物催化。
