Making MS-Based Glycan Analysis Easier

By Pegah R. Jalili, Ph.D., Principal Scientist, Analytical R&D, MilliporeSigma and Kevin Ray, Ph.D., Senior Manager Analytical R&D, MilliporeSigma

In a post-translational modification reaction called glycosylation, living organisms attach carbohydrate residues known as glycans to their proteins. The resulting glycoproteins fulfill numerous functions, including as structural components of cell membranes and mediating cell interactions. Some hormones (e.g., thyrotropin, hCG) and components of the immune system (immunoglobulins, interferons) are also glycoproteins.

Of course, glycosylation also occurs in expression systems that produce biological drugs, creating a complex spectrum of products that vary significantly with regards to in vivo stability, solubility, activity, safety, and efficacy. Extensive characterization is therefore essential to successfully develop biological drugs. Protein glycosylation is specifically mentioned in established technical guidelines e.g., ICH Q5E and Q6B and FDA’s published guidance for industry titled “Development of Therapeutic Protein Biosimilars”, so regulatory authorities tend to scrutinize glycosylation data thoroughly. However, the structural complexity of N-linked and O-linked glycans can make glycoprotein analysis challenging, so it is performed at several levels: intact protein, subunit, peptide, and glycan. Explore recent advances in mass spectrometry based methods for glycan analysis at the various levels.