Diethylenetriamine Assisted Functionalization of Boronic Acid on poly GMA-MAA-DVB for Selective Enrichment of Glycoproteins and Glycopeptides

Abstract Cis-diol compounds are class of biomolecules including nucleosides, glycoproteins, saccharides, and nucleotides, which play vital roles in various biological processes. Due to low abundances of these species in the complex biological samples, their identification and analysis is difficult. Boronate affinity materials are commonly used for the isolation and enrichment of cis-diol compounds, due to their unique, facile and selective enrichment mechanism. In this study we report a selective approach to extract nucleosides, glycopeptides and glycoproteins using boronic acid functionalized GMA-MAA-DVB polymer. This novel polymer, reported for the first time in proteomics, have high BET surface area (132.8447 m2.g-1) which contribute to efficient enrichment and average pore size (20.3449 nm) to facilitates the nano confinement effect for strong interactions. Hydrophilic character of methacrylic acid and diethylenetriamine, along with inherent affinity of boronic acid for glycosylated biomolecules result in selectivity up to 1:500 for peptides and 1:1000 for glycoprotein. Binding constant for cis-diol compounds are in the range of 10-4 to 10-6 M and theoretical binding capacity upto 85 mg.g-1 for HRP and 180 mg.g-1 for IgG, respectively. Furthermore, boronic acid functionalized polymer (BFP) enrich glycoproteins and glycopeptides in range of 1pg.mL-1 and 0.04 ng.mL-1 with S/N≥3. Finally, material is applied to enrich the glycoproteins from healthy human saliva sample and six glycoproteins are identified.