Variation in Glycosylation Heterogeneity of Human Plasminogen Determined by Matrix‐assisted Laser Desorption/Ionization Mass Spectrometry

Post-translational glycosylation of native human plasminogen has been characterized using a combination of proteolytic digestion, reversed-phase HPLC and matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS). Accurate prediction of the mass of glycans attached to the N-linked site of plasminogen has been achieved using MALDI-MS with exoglycosidase treatment revealing monosaccharide and linkage information. Plasminogen has been shown to have a heterogeneous population of oligosaccharides attached to Asn-289 which differ only in the level of sialylation present on terminal galactose units.