Accurate Assessment of Amino Acid Mass Isotopomer Distributions for Metabolic Flux Analysis
作者:Maciek R. Antoniewicz、Joanne K. Kelleher、Gregory Stephanopoulos
DOI:10.1021/ac0708893
日期:2007.10.1
Metabolic flux analysis based on stable-isotope labeling experiments and analysis of mass isotopomer distributions (MID) of cellular metabolites is a tool of great significance for metabolic engineering and study of human disease. This method relies on accurate and precise measurements of mass isotopomers by gas chromatography/mass spectrometry. To improve flux estimates, we assessed potential errors in determining MID of tert-butyldimethylsilyl-derivatized amino acids, which were attributed to (i) the choice of integration algorithm, (ii) concentration effects, and (iii) overlapping fragments. We report 29 amino acid fragments that are useful for flux analysis and another 18 fragments that should be rejected, most importantly Val-302, Leu-200, Leu-302, Ile-302, Ser-302, and Asp-316. In addition, we provide a protocol to minimize errors for determining MID to less than 0.4 mol % for accepted fragments.
基于稳定同位素标记实验和细胞代谢物质量异构体分布(MID)的代谢流分析,对于代谢工程和人类疾病研究具有重要意义。该方法依赖于通过气相色谱/质谱法对质量异构体进行准确和精确的测量。为了提高流量估计的准确性,我们评估了在确定叔丁基二甲基硅烷衍生氨基酸MID中可能出现的误差,这些误差归因于(i)积分算法的选择,(ii)浓度效应,以及(iii)重叠片段。我们报告了29个对流量分析有用的氨基酸片段,以及18个应拒绝的片段,最重要的是Val-302、Leu-200、Leu-302、Ile-302、Ser-302和Asp-316。此外,我们提供了一个协议,以将确定MID的误差减少到接受片段的0.4 mol %以下。