title: Characterization of oligosaccharide moieties of glycopeptides by microwave-assisted partial acid hydrolysis and mass spectrometry.
abstract: Microwave-assisted partial acid hydrolysis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry were used to study oligosaccharide structures of glycopeptides. Tryptic N-glycosylated peptides of horseradish peroxidase, with MH+ ions at m/z 2533, 2612, 3355, 3673, and 5647, were used as test cases. Within a microwave exposure with trifluoroacetic acid of 2 min, partial cleavages of the oligosaccharides of these tryptic N-glycosylated peptides were observed. The data showed that the most labile group within the oligosaccharides is the fucose (Fuc) residue, and that a majority of the end cleavage products are peptides with one N-acetylglucosamine (GlcNAc) residue linked to asparagine (Asn). In addition, the glycopeptides with m/z 3355 and 3673 carry an oligosaccharide (Xyl)Man3(Fuc)GlcNAc2, the glycopeptide at m/z 5647 carries two oligosaccharides (Xyl)Man3(Fuc)GlcNAc2, and the glycopeptides at m/z 2612 and 2533 carry (Xyl)Man3GlcNAc2 and (Fuc)GlcNAc, respectively. However, the glycosylation site of the m/z 2612 peptide at Asn286 is partially occupied. This simple and rapid method is particularly useful in identifying glycopeptides and obtaining monosaccharide compositions of glycopeptides.
authors.affiliation: Protein Research Laboratory, Research Resources Center, 835 S. Wolcott Ave., University of Illinois, Chicago, IL 60612, USA. boblee@uic.edu
authors.forename: Bao-Shiang
authors.initials: BS
authors.lastname: Lee
authors.forename: Sangeeth
authors.initials: S
authors.lastname: Krishnanchettiar
authors.forename: Syed Salman
authors.initials: SS
authors.lastname: Lateef
authors.forename: Shalini
authors.initials: S
authors.lastname: Gupta
mesh_terms: D000143:Acids / Q000737:chemistry*; D000595:Amino Acid Sequence; D002236:Carbohydrate Conformation; D006020:Glycopeptides / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry; D006868:Hydrolysis; D008872:Microwaves; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000032:analysis* / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000143:Acids; D006020:Glycopeptides; D009844:Oligosaccharides; D006735:Horseradish Peroxidase