The role of glycosylation
Glycosylation is an enzymatic process which conjugates sugars to proteins and lipids. GlycoForm is working mainly, but not exclusively, on the linkage of sugars to proteins as it is known that the carbohydrate components of glycoproteins affect the functionality of the molecule by influencing protein folding, assembly and secretion processes. Many carbohydrate-based ligand-receptor mechanisms have been implicated in processes such as inflammation [1], cell surface communication [2] and immune response [3]. Without the proper shape, which is influenced by glycosylation, the ability of the protein to interact correctly with its receptor is compromised, possibly affecting function. Glycosylation also affects solubility and can prevent aggregation.
The challenge of producing homogeneous glycoproteins
The study of glycoproteins and their biological role is made difficult by the fact that glycoproteins occur as natural mixtures with the same peptide backbone, but with varying patterns of glycosylation. The fact that protein glycosylation is not under direct genetic control accounts for the production of such mixtures of so-called glycoforms. For this reason, the production of therapeutic glycoproteins in mammalian expression systems leads to mixtures of glycoforms with potentially different biological properties. The ability to produce homogeneous glycoproteins (a single glycoform) is of particular importance from a regulatory point of view, as the current therapeutic glycoproteins are marketed as multi-glycoform mixtures, e.g. erythropoietin and monoclonal antibodies.