文摘
Glycosylation is an important PTM and is critical for the manufacture and efficacy of therapeutic glycoproteins. Glycan significantly influences the biological properties of human follicle-stimulating hormone (hFSH). Using a glycoproteomic strategy, this study compared the glycosylation of a putative highly purified FSH (uhFSH) obtained from human urine with that of a recombinant human FSH (rhFSH) obtained from Chinese hamster ovary (CHO) cells. Intact and subunit masses, N-glycans, N-glycosylation sites, and intact N- and O-glycopeptides were analyzed and compared by mass spectrometry. Classic and complementary analytical methods, including SDS-PAGE, isoelectric focusing, and the Steelman–Pohley bioassay were also employed to compare their intact molecular weights, charge variants, and specific activities. Results showed that highly sialylated, branched, and macro-heterogeneity glycans are predominant in the uhFSH compared with those in rhFSH. The O-glycopeptides of both hFSHs, which have not been described previously, were characterized herein. A high degree of heterogeneity was observed in the N-glycopeptides of both hFSHs. The differences in glycosylation provide useful information in elucidating and in further investigation the critical glycan structures of hFSH.