Figure 4. Mass spectrometry analyses of two peptides derived from the tryptic digest of protein contained within the PEG11 immuno-reactive region of the SDS-PAGE gel.

Seven unique peptides were identified by using two parallel mass spectrometry approaches. Example product ion ms/ms spectra for peptides identified by each technique are shown. (A) LC-MALDI-MS/MS, and; (B) LC-ES-MS/MS. For each peptide, the amino acid sequence is tabulated along with the theoretical m/z values corresponding to the y and b ions. The experimentally detected sequence ions are denoted by bold typeface and grey shading (insets). A selection of the sequence ions is labelled in the ms/ms spectra.