Hydrophilic tripeptide combined with magnetic titania as a multipurpose platform for universal enrichment of phospho- and glycopeptides.

Both of phosphorylation and glycosylation are playing crucial roles in biological processes. For deep analysis of phosphorylation and glycosylation, a multifunctional nanocomposite (dubbed Mag TiO2-GSH) is constructed by coating hydrophilic tripeptide on the surface of magnetic titania. The introduction of titanium oxide and hydrophilic tripeptide endows the nanocomposite specific affinity preference towards phospho- and glycopeptides. Besides, the employment of magnetic nanoparticles dramatically simplifies the solid-liquid separation process. Combining all above mentioned performance of Mag TiO2-GSH nanocomposites with mass spectrometry technique, a multipurpose platform is built for the universal enrichment of phospho- and glycopeptides. In addition to the high sensitivity and selectivity, they also perform excellent in biological samples. Thus, a total of 975 phosphopeptides and 1243 glycopeptides are identified from merely 100 μg mouse brain extracts at the same time, which will make it possible to exceedingly advance the phospho- and glycoproteomics and simplify the screening of related biomarkers.