Abstract The regulation of triterpenoid saponin biosynthesis in Gypsophila paniculata and Saponaria officinalis suspension cells has been investigated by studying the effects of adding gypsogenin 3,O-glucuronide, a ubiquitous saponin precursor in plants of the genus Gypsophila which contain gypsogenin saponins, to the cultures. Treatment of suspended G. paniculata cells with gypsogenin 3,O-glucuronide 24 hr before administration of [ 14 C]acetate resulted in a marked reduction in the incorporation of radioactivity into saponins and their precursors but not into sterols and steryl glucosides. 2,3-Oxidosqualene-cycloartenol and -amyrin cyclase activities were measured in microsomal fractions obtained from suspension cultures of the two species. Pretreatment of cultures with gypsogenin 3,O-glucuronide was shown to lead to inhibition (in G. paniculata cells) or stimulation (in S. officinalis cells) of the 2,3-oxidosqualene-amyrin cyclase activity and was without any marked effect on 2,3-oxidosqualene-cycloartenol cyclase activity. These results strongly suggest that in these species 2,3-oxidosqualene-cyclases are regulating steps in the isoprenoid pathway orienting the biosynthetic flux towards either tetracyclic or pentacyclic triterpenes.

中文翻译：

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满天星和皂草细胞悬浮培养物的 gypsogenin 3,O-glucuronide 预处理对微粒体 2,3-oxidosqualene cycloartenol 和 Amyrin 环化酶活性的影响

摘要 通过研究向培养物中添加满天星属植物中普遍存在的皂苷前体 gypsogenin 3,O-葡糖醛酸苷的影响，研究了满天星和皂草悬浮细胞中三萜皂苷生物合成的调节作用。在施用 [ 14 C] 乙酸盐前 24 小时，用 gypsogenin 3,O-葡糖苷酸处理悬浮的 G. paniculata 细胞，导致放射性掺入皂苷及其前体中的显着减少，但未掺入甾醇和甾醇糖苷中。2,3-Oxidosqualene-cycloartenol 和-amyrin 环化酶活性在从这两个物种的悬浮培养物中获得的微粒体级分中测量。用 gypsogenin 3,O-葡糖苷酸预处理培养物显示出抑制作用（在 G. 2,3-氧化角鲨烯-香树脂素环化酶活性的刺激（在 S. officinalis 细胞中），并且对 2,3-氧化角鲨烯-环木蒿醇环化酶活性没有任何显着影响。这些结果强烈表明，在这些物种中，2,3-氧化角鲨烯环化酶正在调节类异戊二烯途径中的步骤，将生物合成通量定向为四环或五环三萜。