An effective method for de novo peptide sequencing based on phosphorylation strategy and mass spectrometry

An effective method for peptide sequencing based on phosphorylation strategy and UPLC–MS/MS is proposed in this report. A phosphorylation reaction was carried out by mixing model peptide solution with phosphorylation solution. UPLC–MS/MS was used to analyze and characterize the phosphorylated peptides in the optimized ramp collision energy mode. The results illustrated that this phosphorylation approach significantly strengthened the signal intensity of both a1 and b series ions of the spectra of the modified peptides. It also can be used to effectively distinguish glutamine (Q) and lysine (K) residues in peptides. The feasibility of this approach was validated by analyzing the trypsin-digested BSA. Data suggested that this proposed method could be a useful tool for the de novo peptide sequencing in proteome research.