Bacher Adelbert, Chen Fan, Eisenreich Wolfgang
Lehrstuhl für Biochemie, Technische Universität München, 85748 Garching, Germany.
Metabolites. 2016 Jul 14;6(3):21. doi: 10.3390/metabo6030021.
(13)CO₂ pulse-chase experiments monitored by high-resolution NMR spectroscopy and mass spectrometry can provide (13)C-isotopologue compositions in biosynthetic products. Experiments with a variety of plant species have documented that the isotopologue profiles generated with (13)CO₂ pulse-chase labeling are directly comparable to those that can be generated by the application of [U-(13)C₆]glucose to aseptically growing plants. However, the application of the (13)CO₂ labeling technology is not subject to the experimental limitations that one has to take into account for experiments with [U-(13)C₆]glucose and can be applied to plants growing under physiological conditions, even in the field. In practical terms, the results of biosynthetic studies with (13)CO₂ consist of the detection of pairs, triples and occasionally quadruples of (13)C atoms that have been jointly contributed to the target metabolite, at an abundance that is well above the stochastic occurrence of such multiples. Notably, the connectivities of jointly transferred (13)C multiples can have undergone modification by skeletal rearrangements that can be diagnosed from the isotopologue data. As shown by the examples presented in this review article, the approach turns out to be powerful in decoding the carbon topology of even complex biosynthetic pathways.
通过高分辨率核磁共振光谱和质谱监测的二氧化碳脉冲追踪实验能够提供生物合成产物中的碳-13同位素异构体组成。对多种植物物种进行的实验表明，用二氧化碳脉冲追踪标记产生的同位素异构体谱与将[U-碳-13]葡萄糖应用于无菌生长植物所产生的谱直接可比。然而，二氧化碳标记技术的应用不受使用[U-碳-13]葡萄糖进行实验时必须考虑的实验限制，并且可以应用于生理条件下生长的植物，甚至是田间生长的植物。实际上，二氧化碳生物合成研究的结果包括检测共同贡献给目标代谢物的成对、三个甚至偶尔四个碳-13原子，其丰度远高于此类多个原子的随机出现情况。值得注意的是，共同转移的多个碳-13原子的连接性可能因骨架重排而发生改变，这可以从同位素异构体数据中诊断出来。如本文综述文章中的例子所示，该方法在解码甚至复杂生物合成途径的碳拓扑结构方面证明是强大的。
