Clevenstine E C, Broquist H P, Harris T M
Biochemistry. 1979 Aug 21;18(17):3658-63. doi: 10.1021/bi00584a003.
The phytopathogen Rhizoctonia leguminicola has previously been shown to incorporate pipecolic acid into the piperidine alkaloids 1-acetoxy-6-aminooctahydroindolizine (slaframine) and 3,4,5-trihydroxyoctahydro-1-pyrindine. In the experiments described here, resting cultures of R. leguminicola were incubated with [1-14C]- and [2-14C]malonic acid and with [1-14C]- and [2-2H]acetic acid. Both acids were incorporated into the ring systems of both alkaloids. Mass spectrometric analysis of 2H-enriched slaframine showed that the label resides in the five-membered ring and that the methyl carbon of acetate is joined to the carboxyl carbon of pipecolate. A pipecolate-dependent decarboxylation of [1-14C]malonate was demonstrated in cell-free extracts of R. leguminicola. The results account for previously unattributed carbons in the two alkaloids and suggest the formation of an eight-carbon intermediate common to both alkaloids by acylation of malonate with pipecolic acid.
植物病原菌豆类丝核菌先前已被证明能将哌啶酸掺入哌啶生物碱1-乙酰氧基-6-氨基八氢吲哚嗪（司拉菌素）和3,4,5-三羟基八氢-1-吡啶中。在本文所述的实验中，将豆类丝核菌的静止培养物与[1-¹⁴C]-和[2-¹⁴C]丙二酸以及[1-¹⁴C]-和[2-²H]乙酸一起孵育。两种酸都掺入了两种生物碱的环系统中。对富含²H的司拉菌素进行质谱分析表明，标记位于五元环中，并且乙酸的甲基碳与哌啶酸的羧基碳相连。在豆类丝核菌的无细胞提取物中证明了[1-¹⁴C]丙二酸的哌啶酸依赖性脱羧反应。这些结果解释了两种生物碱中以前未归因的碳，并表明通过丙二酸与哌啶酸的酰化反应形成了两种生物碱共有的八碳中间体。
