Highly porous terpolymer-ZIF8@BA MOF composite for identification of mono- and multi-glycosylated peptides/proteins using MS-based bottom-up approach

A hydrophilic terpolymer MOF composite is designed with high surface area and porosity to enrich mono- and multi-glycosylated peptides facilitating a bottom-up approach. Terpolymer@ZIF-8 is synthesized using free radical polymerization followed by layer by layer ZIF-8 fabrication. Subsequent surface modification was made by aminophenylboronic acid (AMBA). The enrichment ability of terpolymer@ZIF-8@BA is evaluated by using tryptic digest of IgG and HRP to exemplify mono- and multi-glycosylated protein samples. Improved selectivity of 1:200 for spiked HRP in BSA digest and sensitivity down to 1 fmol μL −1 is achieved. Batch to batch reproducibility is better 1% RSD which favors the adoption of the developed method for routine N-linked glycopeptide/protein determination. Cost-effective nature of given approach is given by regeneration of the material up to four cycles. Total 318 N-linked glycopeptides have been identified from 1 μL human serum digest after subjecting the enriched and PNGase-treated deglycosylated peptides to LC-MS. Thus, terpolymer@ZIF-8@BA holds the potential both for mono- and multi-glycosylated peptides from complex biological sample. Graphical abstract