Enhanced MALDI-TOF MS Analysis of Phosphopeptides Using an Optimized DHAP/DAHC Matrix
Figure 7
The MALDI MS analysis of phosphopeptides from CDK1-treated human histone H1. MS spectra of the tryptic peptides from CDK1-treated histone H1 with the untreated (Figure 7()) and alkaline phosphatase-treated histone H1 (Figure 7()). The two panels on the right show the magnified spectra to indicate the two phosphopeptides labeled with asterisks (). The MALDI-TOF/TOF-MS analysis of phosphorylation sites on the two monophosphopeptides VApTPKKASKPK, m/z 1234.7 (c), APTKKPKApTPVKK, m/z 1473.9 (d) from the CDK1-treated human histone H1. The neutral-loss peak of phosphopeptide was noted as [MH-P]. The fragment patterns of peptides were shown in the magnified MS/MS spectra. “B” in the amino sequence indicates a dehydroamino-2-butyric acid residue converted from a phosphothreonine residue by beta-elimination of . All the spectra were detected using DHAP/DAHC matrix in the positive mode.
