BaSCX method for enriching methylated peptieds

Protein methylation as one of the most important post-translational modifications of proteins has been under the spotlight due to its essential role in many important biological processes. To data, antibody-based enrichment strategy is the most used approach to enrich methylated peptides. Unfortunately, its high cost prevents it from being widespread usage in most labs. In this paper, a cheap, friendly, and powerful method combined with basic strong cation exchange chromatography and multiple enzymes digestion was developed to achieve protein methylation identification. After enrichment, about 445 methylation forms on 376 methylation sites was identified from194 proteins in one single LC-MS/MS run using only 100 μg digests. And this method shows better performance for arginine methylation identification. Specially, the specificity of methylated peptides was up to 28.5%, this is the highest specificity towards methylated peptides as far as we known. In summary, this wonderful method has great potential in studying protein methylation, especially arginine methylation, regulated biological processes.