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M. Triquigneaux, B. Tuccio, R. Lauricella et L. Charles Laboratoire Chimie Provence, UMR 6264, Equipe Spectrométries Appliquées à la Chimie Structurale,

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Presentation on theme: "M. Triquigneaux, B. Tuccio, R. Lauricella et L. Charles Laboratoire Chimie Provence, UMR 6264, Equipe Spectrométries Appliquées à la Chimie Structurale,"— Presentation transcript:

1 M. Triquigneaux, B. Tuccio, R. Lauricella et L. Charles Laboratoire Chimie Provence, UMR 6264, Equipe Spectrométries Appliquées à la Chimie Structurale, Campus de St Jérôme, Marseille cedex 20. EPR/MS combination: Mechanism elucidation applied to thiol compounds

2 Electronic Paramagnetic Resonance Specificity paramagnetic species only Sensitivity concentration mol/L Structure g factor, hyperfine coupling constants… Nitroxide EPR/MS Combination 1

3 How to access the global structure of nitroxide ? EPR/MS Combination a N ~ 15.5 G a H ~ 1.8 G aNaN aHaH 2

4 EPR/MS Combination Mass spectrometry Detection of nitroxide radical species Detection of derived redox species Nitroxide Oxoammonium Hydroxylamine m/z m/z – 1 m/z + 1 Tuccio B., Lauricella R., Charles L., Int. J. Mass Spec., 252 (2006), El Hassan I., Charles L., Lauricella R., Tuccio B., New J. Chem., 32 (2008), H+H+ H+H+ 3

5 Glutathione Aim of the study: reactivity of glutathione toward MNP R.R. antioxidant physiological substrate toxic by-products S-transferase MNP xenobiotics ? MNP 4

6 1) Glutathione MNP 2) Oxidant S-adduct a N = 18.2 G EPR Study Experimental conditions 5

7 1) Glutathione MNP Oxidant 2) Photo-irradiation EPR Study O-adduct a N = 27.1 G Experimental conditions 6

8 No Detection of S- and O-adducts as nitroxides Detection of derived redox species MS Study S-adduct O-adduct m/z 393.1m/z m/z ESI-MS in negative mode 7

9 MS/MS Study S-adduct ESI-MS/MS in negative mode eV m/z Glutathione product ions Dieckhaus C., Fernandez-Metzler C., King R., Krolikowski P., Baillie T., Chem. Res. Toxicol., 18 (2005),

10 MS/MS Study O-adduct ESI-MS/MS in negative mode eV Glutathione product ions m/z 9

11 MS/MS Study m/z m/z m/z

12 MS/MS Study Methylated product of S-adduct ESI-MS/MS in negative mode Glutathione product ions m/z 407.1m/z

13 Inverted spin trapping Forrester-Hepburn -NO + NuH -N(OH)-Nu -N(O. ) -Nu oxidation -NO -.+ NO -N(O. )-Nu oxidation hν NuH Detection of reaction intermediates Distinct experimental conditions Mechanism elucidation 12

14 Mechanism elucidation Forrester-Hepburn Inverted spin trapping MS RPE S-adduct O-adduct 13

15 MNP/GSH/oxidant Stable S-adduct New O-adduct Derivatization methylated product Detailed reactivity of glutathione toward MNP EPR/MS Structural characterization Mechanism elucidation Efficient method for radical study Conclusion 14

16 SACS team Provence University, Laboratory LCP, Marseille SpectropoleFEDER OBJ Organization committeeSMAP 2009 Acknowledgments


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