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Characterization of oligosaccharide moieties of glycopeptides by microwave-assisted partial acid hydrolysis and mass spectrometry

Authors

  • Bao-Shiang Lee,

    Corresponding author
    1. Protein Research Laboratory, Research Resources Center, 835 S. Wolcott Ave., University of Illinois, Chicago, IL 60612, USA
    • Protein Research Laboratory, Research Resources Center, 835 S. Wolcott Ave., University of Illinois, Chicago, IL 60612, USA.
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  • Sangeeth Krishnanchettiar,

    1. Protein Research Laboratory, Research Resources Center, 835 S. Wolcott Ave., University of Illinois, Chicago, IL 60612, USA
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  • Syed Salman Lateef,

    1. Protein Research Laboratory, Research Resources Center, 835 S. Wolcott Ave., University of Illinois, Chicago, IL 60612, USA
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  • Shalini Gupta

    1. Protein Research Laboratory, Research Resources Center, 835 S. Wolcott Ave., University of Illinois, Chicago, IL 60612, USA
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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. Copyright © 2005 John Wiley & Sons, Ltd.

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