Global metabolite profiling

Saghatelian A, Trauger SA, Want EJ, Hawkins EG, Siuzdak G, Cravatt BF, Assignment of Endogenous Substrates to Enzymes by Global Metabolite Profiling, Biochemistry 43 14332—14339, 2004. 

Resin-bound FABP-GST was incubated with the complex lipid mixture. After incubation for 1 h, the mixture was removed, the beads washed, and the protein eluted through addition of glutathione. Analysis of the eluate by global metabolite profiling and XCMS revealed the specific enrichment of fatty acids by FABP from the lipid extracts (Table 2). More specifically, oleic acid, linoleic acid, and arachidonic acid were all enriched and this is consistent with observed lipid specificity of FABP2. This example demonstrates the ability of PMI metabolomics to identify natural binding partners from complex mixtures of natural lipids. 

Saghatelian, A., Trauger, S.A., Want, EJ. et al. (2004) Assignment of endogenous substrates to enzymes by global metabolite profiling. Biochemistry, 43, 14332-9. 

Theodoridis, G., Gika, H.G., and Wilson, I.D., LC-MS based methodology for global metabolite profiling in metabonomics/metabolomics, Trends Anal. Chem., 27(3), 251, 2008. 

In its relationship to functional proteomics, the global metabolite profiling offers a potentially powerful strategy to the functional assignment of enzyme networks because ... 

The in vivo substrates and effectors of enzymes may differ from those of the in vitro. The novel natural substrates/effectors/products can only be detected/analyzed by the global metabolite profiling. 

Metabolite extraction from suspension-cultured mammalian cells for global metabolite profiling. Nat. Protoc., 6, 1241-1249. 

Theodoridis, G. A., Gika, H. G., Want, E. J., and Wilson, I. D. 2012. Liquid chromatog-raphy-mass spectrometry based global metabolite profiling A review. Anal. Chim. Acta 711 7-16. 

Maharjan, R. P. Ferenci,T. Global metabolite analysis the influence of extraction methodology on metabolome profiles of Escherichia coli. Anal. Biochem. 2003,313, 154-154. 

Fig. 5 Discovery metabolite profiling of brain tissue, where mass ion intensity ratios (FAAH / / FAAH+/+) of metabolites are presented on three-dimensional surface plots. Global view of the relative levels of metabolites in FAAH / and FAAH+/+ brains, plotted over a mass range of 200-1,200 m/z and liquid chromatography retention times of 0-105 min (plot shown for negative ionization mode). FAAH / brains possessed highly elevated levels of A-acyl ethanolamines (NAEs) (lipid group 4) and an unknown class of lipids (group 5), identified as A-acyl taurines (NATs). Other lipids, e.g., free fatty acids (group 1), phospholipids (group 2), and ceramides (group 3) were unaltered in these samples...

Based on these results, UHPLC coupled to high-resolution MS seems to be the best choice for metabolomics, and the workflow diagram of a typical MS-based metabolite profiling study is presented in Figure 4.8. However, it is also important to check whether the retention time stability and mass accuracy are sufficient because they can critically influence the number of detected features and the data treatment method. This topic was widely discussed in several recent papers (99, 110). One example reported that the shift in the retention time and the mass shift were only 0.03 min and less than 4 ppm, respectively, after 600 injections of a pooled quality control sample over a 5 day period (102). Similar results were also obtained in another study (101), in which the retention times and mass shifts were estimated to be 0.03 min and less than 5 ppm, respectively. Finally, it was discovered that the first few injections on the UHPLC system were not representative and should be discarded (99). Therefore, based on the assessment of the QC samples, UHPLC-MS provides a powerful and repeatable method for the global metabolomic analysis of biological samples (99, 110). 

This paper will review the known metabolic pathways of CW agents, excretion profiles where these have been measured, and methods for the analysis of metabolites in urine or blood. Examples are provided of detection in cases of human exposure. The review focuses mainly on sulfur mustard and nerve agents that represent the greatest global CW threat, and for which most analytical methods have been developed. 

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