Quantification and Mass Isotopomer Profiling of α-Keto Acids in Central Carbon Metabolism
作者:Michael Zimmermann、Uwe Sauer、Nicola Zamboni
DOI:10.1021/ac500472c
日期:2014.3.18
Mass spectrometry has been established as a powerful and versatile technique for studying cellular metabolism. Applications range from profiling of metabolites to accurate quantification and tracing of stable isotopes through the biochemical reaction network. Despite broad coverage of central carbon metabolism, most methods fail to provide accurate assessments of the α-keto acids oxaloacetic acid, pyruvate, and glyoxylate because these compounds are highly reactive and degraded during sample processing and mass spectrometric measurement. We present a derivatization procedure to chemically stabilize these compounds readily during quenching of cellular metabolism. Stable derivatives were analyzed by ultrahigh pressure liquid chromatography coupled tandem mass spectrometry to accurately quantify the abundance of α-keto acids in biological matrices. Eventually, we demonstrated that the developed protocol is suited to measure mass isotopomers of these α-keto acids in tracer studies with stable isotopes. In conclusion, the here described method fills one of the last technical gaps for metabolomics investigations of central carbon metabolism.
质谱法是研究细胞新陈代谢的一种功能强大、用途广泛的技术。其应用范围从代谢物的剖面分析到稳定同位素在生化反应网络中的精确定量和追踪。尽管该技术广泛应用于中心碳代谢,但大多数方法都无法对α-酮酸草酰乙酸、丙酮酸和乙醛酸进行准确评估,因为这些化合物在样品处理和质谱测量过程中会发生高度反应和降解。我们提出了一种衍生化程序,可在细胞代谢淬灭过程中以化学方式稳定这些化合物。通过超高压液相色谱耦合串联质谱法分析稳定的衍生物,可以准确地量化生物基质中α-酮酸的丰度。最后,我们证明了所开发的方案适用于在稳定同位素示踪研究中测量这些 α-酮酸的质量同位素。总之,本文所描述的方法填补了代谢组学研究中枢碳代谢的最后一个技术空白。