Fig. 2.

Representative extracted ion chromatogram (XIC) and fragmentation of the double charged Aconitase peptide VGILSCTNNSSYEDMGR (containing Cys385) from a single analysis. The peptide containing the Cys residue labeled with d(0) NEM corresponds to the reduced form of the peptide and the d(5) NEM labeled peptide corresponds to reversibly oxidized Cys residue. The ratio of the intensity of the redox state of the Cys residue can be estimated from the intensity of the precursor ions and can be combined with complimentary data on the protein׳s abundance.