Glycoprotein is a kind of proteins widely distributed in the bodies of animals and plants. The identification of its characteristic is very difficult due to the complexity of its structure. In this paper, a serious of methods for glycoprotein analysis was established by mass spectrum. The molecular weight, quantity of N-glycans and sialic acids were determined by matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOFMS) directly. The glycosylation sites of glycoprotein were confirmed by its PMF,which produced by the combination digestion of PNGase F and Endoproteinase. The sequence of glycopeptide was detected by liquid chromatography-mass spectrometry (LCMS). The recombined biotechnologic productions including rhEPO,proUK and Spike protein of SARS coronavirus were well characterized by using these methods.
Erythropoietin (EPO) is a glycoprotein with three N-glycosylation sites and one O-glycosylation sites. According to the reference, all of the N-glyco-chains were acid complex type. The amount of sialic acid in rhEPO was determined and two N-glycosylation sites on it were confirmed by matrix-assisted laser desorption time of flight-time of flight mass spectrometry (MALDI-TOF-TOFMS) in this paper. The total amount of sialic acid in rhEPO accounts for 12.97%. Two N-glycosylation sites (Asn38,Asn83) were identified successfully.
