Figure 2: Representative MS/MS spectrum obtained in analyses of IMAC-enriched digests of depleted BAL proteomes. The spectrum displays a prominent product ion at m/z 860.7 that corresponds to loss of H3PO4 from the molecular ion ([M+2H]2+ at m/z 909.9). Furthermore, y- and b-ions are present that define phosphopeptide sequence and site of phosphorylation. The peptide IEDVGpSDEEDDSGKDK belongs to HSP 90-beta.