Optimized mucin-selective enrichment strategy to probe the mucinome

Mucin-domain glycoproteins are densely O-glycosylated and play critical roles in a host of biological functions. Previously, we developed a mucin-selective enrichment strategy by employing a catalytically inactive mucinase (StcE) conjugated to solid support. While this method was effective, it suffered from low throughput and high sample requirements. Further, we recently introduced a new mucinase (SmE) and demonstrated it has complementary recognition patterns to StcE. Here, we optimized our previous enrichment method to increase throughput and lower sample input amounts while maintaining mucin selectivity and enhancing glycopeptide signal. We also compare the ability of different mucinases, lectins, and mucin binding domains to enrich mucins from various cell lines and human serum. Overall, we demonstrate that our improved method StcE effectively isolates more mucin-domain glycoproteins, resulting in a high number of O-glycopeptides, which will allow for enhanced analysis of the mucinome.