Trapping Reactive Metabolites

Zheng, J., Ma, L., Xin, B., Olah, T., Humphreys, W., and Zhu, M. (2007). Screening and Identification of GSH-trapped reactive metabolites using hybrid triple quadruple linear ion trap mass spectrometry. Chem. Res. Toxicol. 20 757-766. 

Zhu, M., Ma, L., Zhang, H., and Humphreys, W. G. (2007). Detection and structural characterization of glutathione-trapped reactive metabolites using hquid chromatography-high-resolution mass spectrometry and mass defect filtering. Anal. Chem. 79 8333-8341. 

Baughman, T.M. Wells-Knecht, M. Wells-Knecht, K. Zhao, Z. Method Validation for a Glutathione-trapping Reactive Metabolite Assay Using Drugs with Structural Moieties Known to Produce Reactive Species, Drug Metab. Rev. 35(S2), 112 (2003). 

Mass Defect Shifts of GSH-Trapped Reactive Metabolites That Are Formed via Common P450-Mediated Bioactivation Reactions... 

Ma, L. et al., Rapid screening of glutathione-trapped reactive metabolites by linear ion trap mass spectrometry with isotope pattern-dependent scanning and postacquisition data mining, Chem. Res. Toxicol., 21 (7), 1477, 2008. 

FIGURE 10.10 Analysis of [ H]GSH trapped reactive metabolites by HPLC with TopCount (Zhu et al., 2005b). A nonlabeled drug (50 mM) was incubated with a mixture of GSH (1 mM) and trace [ H]GSH (1-2 p,Ci/mL) in human liver microsomes. After precipitating proteins, the samples were analyzed by HPLC (1 mL/min) with TopCount (4wlls/min, 10-min counting time) (a) Radioactivity profile of the incubation. Ml and M2 were GSH-trapped reactive metabolites and (b) Radioactivity profile of a control incubation sample (without NADPH). 

Zhang H, Yang Y. An algorithm for thorough background subtraction from high-resolution LC/MS data Application for detection of glutathione-trapped reactive metabolites. J Mass Spectrom 2008 43 1181—1190. 

As an alternative approach, pMRM—EPI was developed for detection and characterization of GSH-trapped reactive metabolites using a 4000 QTRAP (Zheng et al., 2007). In the analysis, pMRM transitions are constructed from the protonated molecules of potential GSH adducts to their product ions derived from neutral losses of 129 and 307 Da in the positive ion mode. Once a predicted GSH adduct is detected, acquisition of its MS/MS spectrum in the positive ion mode is triggered (Fig. 15.8Z)). The MRM survey scan can be set to monitor up to 100 transitions with the 4000 QTRAP without a signifieant loss of sensitivity. The effectiveness and reliability of this approach were evaluated using several model compounds known to undergo bioactivation in HLM. Results showed that the MRM-based approaeh... 

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