M. Triquigneaux, B. Tuccio, R. Lauricella et L. Charles Laboratoire Chimie Provence, UMR 6264,...
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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, Campus de St Jérôme, 13397 Marseille cedex 20. EPR/MS combination: Mechanism elucidation applied to thiol compounds
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Transcript of M. Triquigneaux, B. Tuccio, R. Lauricella et L. Charles Laboratoire Chimie Provence, UMR 6264,...
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, 13397 Marseille cedex 20.
EPR/MS combination:
Mechanism elucidation applied
to thiol compounds
Electronic Paramagnetic Resonance
Specificity paramagnetic species only
Sensitivity concentration 10-7-10-8 mol/L
Structure g factor, hyperfine coupling constants…
R1 N
O
R2
Nitroxide
EPR/MS Combination
1
How to access the global structure of nitroxide ?
EPR/MS Combination
aN ~ 15.5 G
aH ~ 1.8 GN
O
CH
NH2
NH
O
O
HN
HN
NH
NH2
O
OH
N
O
CH
OHaN aH
2
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), 47-53.
El Hassan I., Charles L., Lauricella R., Tuccio B., New J. Chem., 32 (2008), 680-688.
H+
R1 N
O
R2 R1 N+
O
R2 R1 N
OH
R2+2
H+
3
Glutathione
Aim of the study: reactivity of glutathione toward MNP
O
HO
NH2
O
NH
O
HN
O
OH
SH
R.
antioxidant
physiological substrate
toxic by-products
S-transferase MNPxenobiotics
N
O
?
MNP
4
1) Glutathione MNP
2) Oxidant
S-adduct
O
HO
NH2
O
NH
O
HN
O
OH
S
NO
aN = 18.2 G
EPR Study
Experimental conditions
5
1) Glutathione MNP Oxidant
2) Photo-irradiation
EPR Study
O-adduct
NO O
O
HO
NH2
O
NH
O
HN
O
OH
S
NOO
aN = 27.1 G
Experimental conditions
6
No Detection of S- and O-adducts as nitroxides
Detection of derived redox species
MS Study
S-adduct
O-adduct
m/z 393.1 m/z 407.1
m/z 409.1
ESI-MS in negative mode
GS
NOCH3
- H
-- H
-
GNSHO
- H
-
GSN
OHO
7
MS/MS Study
S-adductESI-MS/MS in negative mode
128.1143.1
179.1210.1
254.1
272.1
393.1
25 eV393.1
m/z
Glutathione product ions
Dieckhaus C., Fernandez-Metzler C., King R., Krolikowski P., Baillie T., Chem. Res. Toxicol., 18 (2005), 630-638.
O
HO
NH2
O
NH
O
HN
O
OH
S
NOH
- H
-
O
HO
NH2
O
NH
O
HN
O
OH
S
NOH
- H
-
8
MS/MS Study
O-adduct
ESI-MS/MS in negative mode
128.1143.1
179.1210.1
254.1
272.1
409.1 20 eV409.1Glutathione product ions
321.1304.1
m/z
- H-
O
HO
NH2
O
NH
O
HN
O
OH
S
NOHO
- H-
O
HO
NH2
O
NH
O
HN
O
OH
S
NOHO
9
MS/MS Study
m/z 409.1
m/z 409.1
m/z 321.1
m/z 304.1
N
OH
-
N
OH
-
OH
O
HO
NH2
O
NH
O
HN
O
OH
S
NOHO
- H
-
-
O
HO
NH2
O
NH
O
HN
O
OH
S
O- H
-- H
O
HO
NH2
O
NH
O
HN
O
OH
S
O
-- H
O
HO
NH2
O
NH
O
HN
O
OH
S
NOHO
H
-- H
O
HO
NH2
O
NH
O
HN
O
OH
S
10
MS/MS Study
Methylated product of S-adduct
ESI-MS/MS in negative mode
128
143254
Glutathione product ions
m/z 407.1 m/z 272.1
-- H
O
HO
NH2
O
NH
O
HN
O
OH
S
NOCH3
-- H
O
HO
NH2
O
NH
O
HN
O
OH
S
NOCH3 -
- HO
HO
NH2
O
NH
O
HN
O
OH
11
Inverted spin trapping
Forrester-Hepburn
-NO + NuH -N(OH)-Nu -N(O .) -Nuoxidation
-NO -.+NO -N(O.)-Nu oxidation
hν
NuH
Detection of reaction intermediates
Distinct experimental conditions
Mechanism elucidation
12
Mechanism elucidation
Forrester-Hepburn
Inverted spin trapping
MS RPE
N
O
N
OH
SG N
O
SGGSH oxidation
N+
O
N
O
OSGoxidation
h
GSH
GSOH
oxidation
S-adduct
O-adduct13
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
SACS teamProvence University,Laboratory LCP,Marseille
Spectropole FEDER OBJ2142-3341
Organization committee SMAP 2009
Acknowledgments
