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Among the numerous post-translational modifications that a protein can undergo, glycosylation is by far the most common, having the most profound influence on the structural and functional properties of the protein. Therefore, profiling glycosylation patterns in glycosylated proteins and defining the structures and locations of these glycans is important in understanding the structure-function relationship of glycans in glycosylated proteins. The work presented herein focuses on applying different mass-spectrometric methods to profile glycosylation patterns in glycoprotein hormones and HIV envelope proteins. To determine the structures and locations of the glycans on these proteins, a glycopeptide-based mass mapping approach was employed. Glycoprotein hormones mainly contain acidic glycans that are highly sulfated and/or sialylated. Th...

peer reviewed

Structural analysis of sulfated glycans is essential in understanding their biological significance. Here, we present a new approach to characterize sulfated glycans present on glycoproteins. The analysis is performed on glycopeptides, so information about the sulfated species is obtained in a glycosylation site-specific manner. This method employs an ion-pairing reagent to stabilize the SO3 group of the glycopeptide, allowing useful information to be obtained during MS/MS experiments. The amount of structural information obtained from (+)ESI-MS/MS of the ion-pair complexes for sulfated glycopeptides of equine thyroid stimulating hormone is compared with information obtained by (−)ESI-MS/MS of the underivatized, sulfated glycopeptides. The results indicate that this new method provides detailed insights into the sequence, branching, an...

Follicle stimulating hormone (FSH) is one of the important hormones that regulate gonadal functions. This hormone is glycosylated, and the glycans greatly influence the biological properties. In the present study the negatively charged glycopeptides of equine and human pituitary follicle stimulating hormone (eFSH and hFSH) have been characterized in a glycosylation site-specific manner using FT-ICR-MS and Edman sequencing. The characteristic pattern of glycan distribution at each glycosylation site has been deduced and compared between horse and human FSH preparations. The data suggest that site-specific differences exist between glycoforms of human and equine FSH. For instance, except for one site in the β subunit (Asn7) of hFSH all other sites in both species have sulfated glycoforms. Also, glycoforms at Asn52 of hFSH are all complex...

Supported by a CAVD Grant from the Bill and Melinda Gates Foundation.