Fig. 3.

MS/MS Spectra of unmodified (A) and PhHg-modified (B) rabbitt GAPDH peptide VPTPNVSVVDLTCR. ‘C#’ denotes a PhHg adduct of cysteine. Inset plots show the isotope distributions of the precursor ions as observed in MS¹. Peaks that match expected y and b fragmentation ions are labeled with m/z values reported as observed from the spectra. In (B), the top of the tallest peak matches a peak consistent with the neutral loss of 78 Daltons, equal to a phenyl group, from the precursor ion. The full height of this peak is not shown here in order to increase the visibility of y and b ions. Red labels under the x axis in (B) indicate peaks that correspond to a loss of 78 Daltons from a y ion.