Profiling of N-linked oligosaccharides using phenylhydrazine derivatization and mass spectrometry.
N-linked oligosaccharide standards obtained from commercial sources were derivatized with phenylhydrazine (PHN) and analyzed by on-line reversed-phase high performance liquid chromatography (HPLC)/electrospray ionization mass spectrometry (ESI-MS). This procedure was then applied to mixtures of N-glycans enzymatically released from hen ovalbumin. Under ESI-MS conditions, phenylhydrazones of asialylated oligosaccharide standards and ovalbumin glycans produced mainly [M + 2H]2+ molecular ions at low cone voltage values, while minimal fragmentation was observed. Reversed-phase HPLC/ESI-MS total and selected ion chromatograms obtained for derivatized N-glycans from ovalbumin showed partial but useful separation. Overall glycan profiles obtained by ESI-MS were compared with results obtained by matrix-assisted laser desorption/ionization (MALDI)-MS. Qualitatively, profiles were similar from one technique to the other in terms of relative abundance of glycans versus composition. Post-source decay (PSD) analysis of the [M + Na]+ ions of PHN-glycans showed dominant B, C and internal B/Y, C/Y cleavages. These patterns were helpful in relating fragmentation to proposed structures. Cross-ring cleavage fragment ions (A-type) were also observed in most cases. The PHN derivatization method is fast and simple. It produces abundant parent ions in both MALDI-MS and ESI-MS, while avoiding the presence of salt contaminants during the labeling procedure.
Chemistry Department, University of Manitoba, 144 Dysart Road, Winnipeg, Man., Canada R3T 2N2.
Erika
E
Lattova
Hélène
H
Perreault
D002851:Chromatography, High Pressure Liquid / Q000379:methods; D009844:Oligosaccharides / Q000737:chemistry*; D010659:Phenylhydrazines / Q000737:chemistry*; D012015:Reference Standards; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet
D009844:Oligosaccharides; D010659:Phenylhydrazines; C030299:phenylhydrazine