Simultaneous Quantification of Metabolites Involved in Central Carbon and Energy Metabolism Using Reversed-Phase Liquid Chromatography−Mass Spectrometry and in Vitro <sup>13</sup>C Labeling
作者:Wen-Chu Yang、Miroslav Sedlak、Fred E. Regnier、Nathan Mosier、Nancy Ho、Jiri Adamec
DOI:10.1021/ac801693c
日期:2008.12.15
Comprehensive analysis of intracellular metabolites is a critical component of elucidating cellular processes. Although the resolution and flexibility of reversed-phase liquid chromatography−mass spectrometry (RPLC−MS) makes it one of the most powerful analytical tools for metabolite analysis, the structural diversity of even the simplest metabolome provides a formidable analytical challenge. Here we describe a robust RPLC−MS method for identification and quantification of a diverse group of metabolites ranging from sugars, phosphosugars, and carboxylic acids to phosphocarboxylics acids, nucleotides, and coenzymes. This method is based on in vitro derivatization with a 13C-labeled tag that allows internal standard based quantification and enables separation of structural isomer pairs like glucose 6-phosphate and fructose 6-phosphate in a single chromatographic run. Calibration curves for individual metabolites showed linearity ranging over more than 2 orders of magnitude with correlation coefficients of R2 > 0.9975. The detection limits at a signal-to-noise ratio of 3 were below 1.0 μM (20 pmol) for most compounds. Thirty common metabolites involved in glycolysis, the pentose phosphate pathway, and tricarboxylic acid cycle were identified and quantified from yeast lysate with a relative standard deviation of less than 10%.
详细分析细胞内代谢物是阐明细胞过程的关键组成部分。尽管反相液相色谱-质谱联用(RPLC-MS)的分辨率和灵活性使其成为代谢物分析中最强大的分析工具之一,但即使是简单的代谢组,其结构的多样性也带来了巨大的分析挑战。本文描述了一种稳健的RPLC-MS方法,用于鉴定和定量一系列广泛的代谢物,包括糖类、磷酸糖、羧酸、磷酸羧酸、核苷酸和辅酶。该方法基于使用13C标记标签的体外衍生化,允许基于内标的定量,并能在单次色谱运行中分离结构异构体对,如葡萄糖6-磷酸和果糖6-磷酸。单个代谢物的校准曲线显示线性范围超过两个数量级,相关系数R² > 0.9975。大多数化合物的信噪比为3的检测限低于1.0 μM(20 pmol)。从酵母裂解液中鉴定和定量了涉及糖酵解、戊糖磷酸途径和三羧酸循环的30种常见代谢物,相对标准偏差小于10%。