Separation of neoglycoproteins with different degrees of glycosylation by boronate chromatography

The separation of glycoproteins as glycoforms with specific degrees of glycosylation has been a problem until now. A technique involving boronate affinity chromatography has been developed to separate a heterogeneous sample of neoglycoprotein, chymotrypsin modified with maltose via reductive amination, into individual fractions with different degrees of glycosylation. Low-molecular-mass polyhydroxyl compounds, such as tris(hydroxymethyl)aminomethane (Tris), pentaerythritol, and triethanolamine proved efficient eluents due to their ability to form strong tridentate complexes with the boronate ligand. Compounds leading to either: too strong interaction with the boronate ligand (e.g. D-sorbitol and polyvinly alcohol), or too weak or no interaction (e.g. dextran) were not suitable eluents. The study provided the opportunity to probe further into the effect of glycosylation on the function of glycoproteins.