Molecules 2014, 19(7), 9944-9961; doi:10.3390/molecules19079944
Article

Relative Quantitation of Glycopeptides Based on Stable Isotope Labeling Using MALDI-TOF MS

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Received: 31 March 2014; in revised form: 1 July 2014 / Accepted: 7 July 2014 / Published: 9 July 2014
(This article belongs to the Special Issue Oligosaccharides and Glyco-Conjugates)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: We have developed an effective, sensitive method for quantitative glycopeptide profiling using stable isotope labeling and MALDI-TOF mass spectrometry (MS). In this study, we synthesized benzoic acid-d0 N-succinimidyl ester (BzOSu) and benzoic acid-d5 N-succinimidyl ester (d-BzOSu) as light and heavy isotope reagents for stable isotope quantification for the comparative analysis of glycopeptides. Using this approach provided enhanced ionization efficiency in both positive and negative modes by MALDI-TOF MS. These reagents were quantitatively reacted with glycopeptides from human serum IgG (hIgG) at a wide range of concentrations; the labeling efficiency of the glycopeptides showed high reproducibility and a good calibration curve was obtained. To demonstrate the practical utility of this approach, we characterized the structures of glycopeptides from hIgG and from IgG1 produced by myeloma plasma. The glycopeptides were quantitatively analyzed by mixing Bz-labeled IgG1 glycopeptides with d-Bz-labeled hIgG glycopeptides. Glycan structural identification of the hIgG glycopeptides was demonstrated by combining the highly specific recognition of endo-β-N-acetyl glucosaminidases from Streptococcus pyogenes (endoS) or from Streptococcus pneumoniae (endo-D) with MALDI-TOF MS analysis. The obtained data revealed the glycan profile and the ratio of glycan structural isomers containing a galactosylated extension on IgG1, IgG2 and IgG3 glycopetides.
Keywords: glycopeptides; stable isotope labeling; MALDI TOF-MS; quantitative glycopeptide profiling
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MDPI and ACS Style

Kurogochi, M.; Amano, J. Relative Quantitation of Glycopeptides Based on Stable Isotope Labeling Using MALDI-TOF MS. Molecules 2014, 19, 9944-9961.

AMA Style

Kurogochi M, Amano J. Relative Quantitation of Glycopeptides Based on Stable Isotope Labeling Using MALDI-TOF MS. Molecules. 2014; 19(7):9944-9961.

Chicago/Turabian Style

Kurogochi, Masaki; Amano, Junko. 2014. "Relative Quantitation of Glycopeptides Based on Stable Isotope Labeling Using MALDI-TOF MS." Molecules 19, no. 7: 9944-9961.


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