Development of polycationic materials for specific enrichment and mass spectrometric detection of phosphopeptides in proteomic studies

Phosphorylation is the most common post-translational modification and is regulated by kinase signaling pathways. Defects in this pathway may be related to various diseases such as cancer, diabetes, chronic inflammatory diseases or neurodegenerative diseases. Therefore, different analytical approaches have been developed to identify phosphorylation for following kinase activity in cells. The identification of phosphorylation may be helpful to understand the reasons behind disease conditions and in developing new therapeutic approaches. Mass spectrometry is generally used for monitoring changes in protein phosphorylation. However, even with the advantages of mas sspectrometry, it is difficult to detect phosphorylated peptides in the presence of high abundance of non-phosphorylated peptides. Furthermore, the ionization efficiencies of phosphorylated peptides are lower than those of their non-phosphorylated counterparts due to the presence of phosphorylated sites on the structure. Thus, the development of highly specific enrichment methods for phosphopeptides for complex mixtures has been necessary prior to their mass spectrometric analysis for the successful evaluation of phosphoproteomics data. Therefore, polymeric gel based materials were synthesized following an easy and inexpensive process, and their highly specific and efficient phosphopeptide enrichment performance in MALDI-MS applications were investigated in this study.