Recombinant proteins are increasingly used as therapeutics, and they form a large subset of the best-selling drugs. Their characterisation, from development to post-marketing quality control, is challenging due to their size and inherent heterogeneity caused notably by post-translational modifications.

Glycosylation is probably the most prominent PTM in terms of occurrence and alteration of protein function. Adequate glycosylation is critical for therapeutic proteins regarding binding, solubility and stability, safety, and for pharmacokinetics and dynamics properties.

Consequently, the glycosylation profile of therapeutic proteins is considered a critical quality attribute and it must undergo thorough analysis. Its early characterisation by sensitive assays also helps in the taking of informed decisions in later development stages.