Identification of glycoproteins containing specific glycans using a lectin-chemical method.

Glycosylation is one of the most common protein modifications. Each glycoprotein can be glycosylated at multiple glycosites, and each glycosites can be modified by different glycans. Due to this heterogeneity of glycosylation, it has proven difficult to study the structure-function relationship of specific glycans and their affected glycoproteins. Here, we report a novel method for rapid and quantitative identification of glycoproteins containing specific glycans. Lectin affinity isolations are followed by chemical immobilization of the captured glycopeptides, allowing the identification of glycoproteins containing specific glycans by subsequent mass spectrometry. The application of the method should be useful to facilitate our understanding of how changes in glycan associate with diseases, and to discover novel glycoproteins with certain glycans that could serve as biomarkers or therapeutic targets.