Rational development of functional hydrophilic polymer to characterize site-specific glycan differences between bovine milk and colostrum.

As vastly modified on secreted proteins, N-glycosylation is found on milk proteins and undergo dynamic changes during lactation, characterizing milk protein glycosylation would benefit the elucidation of glycosylation pattern differences between samples. However, their low abundance required specific enrichment. Herein, through rational design and controllable synthesis, we developed a novel multi-functional polymer for the isolation of protein glycosylation. It efficiently separated glycopeptides from complex background inferences with mutual efforts of hydrophilic interaction chromatography (HILIC), metal ion affinity and ion exchange. By fine-tuning Ca2+ as regulators of aldehyde hyaluronic acid (HA) conformation, the grafting density of HA was remarkably improved. Moreover, grafting Ti4+ further enhanced the enrichment performance. Application of this material to characterize bovine milk and colostrum proteins yields 479 and 611 intact glycopeptides, respectively. Comparative analysis unraveled the distinct glycosylation pattern as well the different distribution of glycoprotein abundances between the two samples, offering insights for functional food development. • A novel functional polymer aHA-Ti for glycopeptide enrichment was prepared based on hyaluronic acid. • Ca2+ ions regulate aldehyde-hyaluronic acid conformation, enhancing aHA grafting density. • aHA-Ti enriches intact glycopeptides via hydrophilic interaction, metal ion affinity and ion exchange. • Determine distinct glycosylation patterns in bovine milk and colostrum at site-specific glycan level using the prepared material [ABSTRACT FROM AUTHOR]