Full length articleFacile preparation of molybdenum (VI) oxide - Modified graphene oxide nanocomposite for specific enrichment of phosphopeptides

•The nanocomposite was synthesized by a simple two-step strategy.•It is the first time that molybdenum has ever applied in proteomics.•The as-prepared nanocomposite was successfully applied by metal oxide affinity chromatography.•Enriching phosphopeptides with excellent specificity, high detection sensitivity (1 fmol/mL) and well recovery (91.13%).

To promote the development of phosphoproteome analysis in highly selective efficient tracing phosphorylated proteins or peptides, views of researches should not confined with intrinsic materials and their modification. New materials are supposed to be explored for phosphoproteome analysis. In this work, we first introduced Molybdenum (VI) oxide (MoO3) into phosphoproteome, loading on the graphene oxide (GO) nanosheets forming MoO3/GO nanocomposites by a simple two-step strategy. The GO nanosheets offered MoO3 a perfect stable platform for separation and concentration and MoO3 exhibited wonderful property in enriching phosphopeptides with highly selectivity and sensitivity on GO nanosheets. Specifically, the as-synthesized MoO3/GO nanocomposites exhibited excellent specificity (β-casein: BSA = 1:1000), high detection sensitivity (1 fmol/mL) and well recovery (91.13%) in enriching phosphopeptides by metal oxide affinity chromatography (MOAC). Moreover, the as-synthesized MoO3/GO nanocomposites provided effective enrichment of phosphopeptides from nonfat milk (a total of twelve phosphopeptides signals) and human serum (a total of four endogenous phosphopeptides signals), displaying great biological compatibility, which demonstrated that the MoO3/GO nanocomposites is a promising candidate in selectively identifying and determining low-abundance phosphorylated peptides in biological sample.