Absolute Quantification of Histone PTM Marks by MRM-Based LC-MS/MS

The N-terminal tails of core histonesharbor the sites of numerous post-translational modifications (PTMs) with important roles in the regulation of chromatin structure and function. Profiling histonePTM marks provides data that help understand the epigenetics events in cells and their connections with cancer and other diseases. Our previous study demonstrated that specific derivatization of histonepeptides by NHS propionate significantly improved their chromatographic performance on reversed phase columns for LC/MS analysis. As a step forward, we recently developed a multiple reaction monitoring (MRM) based LC-MS/MS method to analyze 42 targeted histonepeptides. By using stable isotopic labeledpeptides as internal standards that are spiked into the reconstituted solutions, this method allows to measure absolute concentration of the tryptic peptides of H3 histoneproteins extracted from cancer cell lines. The method was thoroughly validated for the accuracy and reproducibility through analyzing recomb...