Glycopeptide analysis by mass spectrometry.

Glycosylation is one of the most important post-translational modifications found in nature. Identifying and characterizing glycans is an important step in correlating glycosylation structure to the glycan's function, both in normal glycoproteins and those that are modified in a disease state. Glycans on a protein can be characterized by a variety of methods. This review focuses on the mass spectral analysis of glycopeptides, after subjecting the glycoprotein to proteolysis. This analytical approach is useful in characterizing glycan heterogeneity and correlating glycan compositions to their attachment sites on the protein. The information obtained from this approach can serve as the foundation for understanding how glycan compositions affect protein function, in both normal and aberrant glycoproteins.