N-glycosylation characterization by liquid chromatography with mass spectrometry

Three methods are introduced here to fully characterize glycosylation at protein, peptides, and glycan levels by LC-MS (ESI TOF MS). At protein level, glycosylation could be detected by comparing protein masses with and without glycan. At peptide level, glycosylation sites could be detected by removing glycan and site specific glycosylation could be examined with glycopeptides. At glycan level, glycan profiling and identification could be achieved by analyzing released glycans labeled with procainamide. All these methods are MS based and able to provide a whole picture of glycosylation of a glycoprotein. These methods are also simple to implement in industrial or academic laboratory with proper training and instruments.