Strong cation exchange chromatography for analysis of sialylated glycopeptides.

Glycosylations represent major and essential co- and post-translational modification forms of proteins and facilitate a multitude of functions such as cell-cell interactions as well as protein folding and stability. The analysis of protein glycosylation is still an enormous task due to the vast heterogeneity and multitude of different possible carbohydrate structures. The elucidation of glycosylation sites - the attachment points of carbohydrate structures to the polypeptide backbone - is often among the first necessary steps of analysis. Therefore, we here present a simple protocol for charge-based enrichment of sialylated glycopeptides by strong cation exchange chromatography and subsequent analysis of glycosylation sites by mass spectrometry.