Multidimensional system enabling deglycosylation of proteins using a capillary reactor with peptide-N-glycosidase F immobilized on a porous polymer monolith and hydrophilic interaction liquid chromatography-mass spectrometry of glycans.

A reactor with immobilized peptide-N-glycosidase F on a monolithic polymer support in a capillary has been developed that allows fast and efficient release of N-linked glycans from immunoglobulin G molecules. Two different monolithic scaffolds based on poly(glycidyl methacrylate-co-ethylene dimethacrylate) and poly(butyl methacrylate-co-ethylene dimethacrylate) were prepared. A multistep photografting process was used to reduce non-specific adsorption of proteins and to obtain support containing reactive azlactone functionalities enabling the preparation of highly active immobilized peptide-N-glycosidase F. Performance of these reactors was determined through glycan release from several glycoproteins including ribonuclease B, chicken albumin, and human immunoglobulin G and their detection by matrix-assisted laser desorption-ionization/time-of-flight mass spectrometry. The optimized reactor was integrated into a multidimensional system comprising on-line glycan release and their separation via hydrophilic interaction liquid chromatography followed by electrospray ionization/time-of-flight mass spectrometry detection. Using the optimized monolithic reactor with immobilized peptide-N-glycosidase F, human immunoglobulin G was deglycosylated at room temperature in 5.5 min to an extent similar to that achieved with soluble enzyme after 24h at 37 degrees C.