Ricerc@Sapienza

The project goal is that of preparing optimized materials for enrichment of peptides with phosphorylation, glycosylation, and/or sulfation modifications. These peptides have important biological activities but the direct analysis of protein post translational modifications (PTMs) without enrichment is impaired by suppression of non-modified peptides. The materials to be developed are magnetic nanoparticle functionalized with polymers based on 2-acrylamido-2-methylpropane sulfonic acid (AMPS) monomer with cross linker ethylene glycol dimethylacrylate (EGDMA) in presence of dimethyl sulfoxide as solvent and acetonitrile and/or 1,4-butanediol as porogens. Polymer preparation will be optimizated by Box-Behnken design (BBD) for the monomer-to-crosslinker ratio and the porogen composition. By this approach, the hydrophilicity of the surface and pore structure is expected to be modulated, to determine the most suited ones for enrichment of peptides with the target PTMs. The materials, prepared according to this experimental design, will be used for enrichment evaluation. Standard glycoprotein fetuin, phosphoprotein casein and sulfopeptides will initially be used for enrichment, then the most promising materials will be applied to serum protein digests. A combined simultaneous enrichment will also be tested if good results can be obtained from enrichment experiments on single PTM.