Gold nanoparticle-glutathione-functionalized porous graphene oxide-based hydrophilic beads for the selective enrichment of N-linked glycopeptides.

Abstract

A three-dimensional structured porous graphene oxide-polyethylenimine bead (pGP) is synthesized for immobilizing gold nanoparticles and modifying glutathione molecules (denoted as pGP/AuG). The pGP/AuG has open pore structure, honeycomb-like channels, and excellent hydrophilicity. By taking advantages of the porous structure, abundant binding sites, and multivalent interactions between glycopeptides and both glutathione molecules and free amino groups, the pGP/AuG is adopted to the selective enrichment of N-linked glycopeptides with low limit of detection (2fmol), high enrichment selectivity (1:500), binding capacity (333.3mg/g), recovery yield (91.3 ± 2.1%), and repeatability (< 6.0% RSD) using matrix-assisted laser desorption/ionization time of flight mass spectrometrydetection method. Furthermore, the practical applicability of pGP/AuG is evaluated, in which 209 N-glycosylated peptides corresponding to 128 N-glycosylated proteins are identified from 1μL human serum in three independent analysis procedures, suggesting the great potential for application in glycoproteome fields.Graphical abstract Schematic presentation of preparation for porous graphene oxide-based hydrophilic beads (pGP/AuG) with honeycomb-like microstructure. The pGP/AuG was successfully used for enriching and identifying glycopeptides from actual biological sample.