Serial Lectin Affinity Chromatography for Comparative Serum Glycoproteomics on Colon Cancer Biomarker Discovery

摘要

This study describes a simple and efficient approach for comparative analysis of sialylated glycoforms of proteins containing differentially branched complex-type glycans. Fractionation of complex tri- and tetraantennary N-linked glycoforms from biantennary N-linked glycoforms bearing terminal sialic acid residues was achieved using a serial lectin columns with immobilized SNA and Con A. These two fractions from the affinity selection were differentially labeled, mixed, and then deglycosylated with the enzyme PNGase F. The deglycosylated sample was further fractionated by RPC and analyzed by ESI mass spectrometry. The degree of sialylation in cancer plasma was higher than that of in healthy plasma. Most sialylated glycopeptides seemed to carry more tri- and tetra-antennary glycans than biantennary glycans.