A triarylphosphine–trimethylpiperidine reagent for the one-step derivatization and enrichment of protein post-translational modifications and identification by mass spectrometry.

We report a new reagent that is capable of both chemical derivatization and selective enrichment of azide-labeled PTM peptides for sensitive identification by mass spectrometry (MS). Facile sample recovery, enhanced ionization and fragmentation in MS of the enriched PTM peptides are achieved, which leads to the identification of 3293 O-GlcNAc peptides and the location of 1706 sites in HeLa cells and efficiently expands the current mapping scale. [ABSTRACT FROM AUTHOR]