Guanidyl-functionalized graphene as a bifunctional adsorbent for selective enrichment of phosphopeptides

Guanidyl-functionalized graphene (GFG) was designed and synthesized. By simple modulation of the loading buffer this novel bifunctional adsorbent provides two enriching functions, one for global phosphopeptides, and the other for multiphosphopeptides with consecutive phosphorylated residues. GFG provides a promising perspective for consecutive phosphorylated peptide enrichment in phosphor-proteomic research and related biological process studies.