Enhanced detection of sulfated glycosylation sites in glycoproteins.
We demonstrate a method that enhances the mass spectral signal of mono- and disulfated glycopeptides, present in glycoproteins that contain many other nonsulfated glycoforms. This method utilizes the tripeptide Lys-Lys-Lys as an ion-pairing reagent to complex selectively to sulfated species, and enhance their ion signal. The method is applied to the analysis of glycopeptides released from the enzymatic digestion of ovine luteinizing hormone. In this analysis, a disulfated glycopeptide is identified that was previously not detectable by MS assays, and a monosulfated glycoform, present at less than 1% abundance, is identified without any separation or enrichment of these species prior to analysis. In addition to enhancing the ion signal of sulfated glycopeptides, the ion-pairing technique is useful in obtaining structural information about the sulfated species.
Jiang
Hui
H
Department of Chemistry, University of Kansas, Lawrence, Kansas 66054, USA.
Irungu
Janet
J
Desaire
Heather
H
D001665:Binding Sites; D006020:Glycopeptides / Q000737:chemistry; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D006031:Glycosylation; D007202:Indicators and Reagents; D007986:Luteinizing Hormone; D013058:Mass Spectrometry / Q000379:methods; D009842:Oligopeptides; D021241:Spectrometry, Mass, Electrospray Ionization; D013431:Sulfates; D014357:Trypsin
D006020:Glycopeptides; D006023:Glycoproteins; D007202:Indicators and Reagents; D009842:Oligopeptides; D013431:Sulfates; D007986:Luteinizing Hormone; D014357:Trypsin
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