Magnetic resin composites for the enrichment of proteins, peptides and phosphopeptides.

There is growing interest in the development of materials for enriching proteins and phosphoproteins from complex sample matrices for mass spectrometric analysis. Herein, we designed and synthesized two types of magnetic resin composites, i.e. , MTS9200@Fe 3 O 4 and FPA90CL@Fe 3 O 4 , and assessed their applications as adsorbents for enriching proteins, peptides and phosphopeptides. With the combination of Fe 3+ -IMAC interaction (MTS9200) or electrostatic attraction (FPA90CL) of resins and the adsorption of Fe 3 O 4 , the prepared composites exhibited higher capacities for adsorbing a protein (bovine serum albumin, at 195.71 and 135.03 mg g -1 for MTS9200@Fe 3 O 4 and FPA90CL@Fe 3 O 4 , respectively) than MTS9200, FPA90CL and Fe 3 O 4 . In addition, due to the contributions of the hydrophobic skeleton of resins and Fe 3 O 4 , the magnetic resin composites allowed for efficient enrichment of peptides. Moreover, through Fe 3+ -IMAC interaction or electrostatic attraction of resins and Fe-O MOAC interaction of Fe 3 O 4 with phosphate groups, phosphopeptides could also be captured. Furthermore, we employed the prepared composites for enriching proteins and phosphopeptides from human serum, where 466 and 506 proteins, and 434 and 356 phosphorylation sites, were detected from human serum after being processed with FPA90CL@Fe 3 O 4 and MTS9200@Fe 3 O 4 , respectively. Together, our work revealed the great potential of magnetic resin composites as enrichment materials for proteomics and phosphoproteomics analysis.