Characterization of the glycosylation status of proteins

Proteins are posttranslationally modified by a number of mechanisms, by far the most significant of which in terms of the molecular mass and functional diversity is glycosylation. The oligosaccharide chains added shortly after biosynthesis at the ribosome, and further modified while the protein is translocated through the intracellular membranes, have multiple affects on transport, localization, stability, plasma membrane expression activity, and antigenicity. Characterization of the glycosylation patterns at each site around the protein is essential for detailed understanding of structure/function relationships and the design of potential therapeutic agents. This can be achieved by a series of chromatographic and physicochemical procedures including HPLC, GC, MS, NMR, and computer graphics molecular modeling, which culminate in information on monosaccharide sequence and linkage, glycoprotein conformation, and oligosaccharide-to-protein interactions.