Multi-histidine functionalized material for the specific enrichment of sialylated glycopeptides

Sialylation, an important form of glycosylation, is involved in many biological processes and plays an important role in the development of diseases. However, due to the low abundance among various glycosylation and lack of efficient enrichment method with high specificity, the study of sialylation remains a challenge. Herein, multi-histidine modified microspheres (MHM) were synthesized to enrich sialylated glycopeptides. It was found that MHM could selectively enrich sialylated glycopeptides from over 100 times of non-sialylated glycopeptides, which indicated MHM possessed good enrichment specificity towards sialylated glycopeptides. Furthermore, MHM were utilized to the large-scale analysis of protein sialylation, and 510 intact glycopeptides were identified with over 94.5% sialylated glycopeptide specificity from 4 μL human serum. The good specificity could be attributed to the synergistic effect by the electrostatic interaction and hydrophilic interaction. Hence, MHM could provide an alternative approach for the analysis of site-specific sialylation at proteome level from complex biological samples.