Figure 2.

FAIMS improves identification of PTM crosstalk sites. The number of peptide groups in which multi-PTM peptides were observed as a function of FAIMS compensation voltage (CV) for the PTM combinations: multiphosphorylation (phospho–phospho) (A), phosphorylation–acetylation (phospho–acetyl) (B), phosphorylation–methylation (phospho–methyl) (C), multiacetylation (acetyl–acetyl) (D), acetylation–methylation (acetyl–methyl) (E), and multi-methylation (methyl–methyl) (F). The number of peptide groups detected with the FAIMS source removed from the instrument (LC-MS/MS) is included in each case.