3C-O2-1535 PDF
Quantitative Glycopeptides Profiling using Stable Isotope Labeling and MALDI TOF MS
We have developed an effective, sensitive method for quantitative glycopeptides profiling using stable isotope labeling and MALDI-TOF mass spectrometry.In this work, 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. These reagents were quantitatively reacted with glycopeptides from human serum IgG (hIgG) at a wide range of concentrations, so that 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 glycopeptide from hIgG and IgG1 produced by myeloma plasma, and quantitatively analyzed their glycopeptides by mixing Bz-labeled IgG1 glycopeptides with d-Bz-labeled hIgG glycopeptides. And also we performed glycan structural identification for hIgG glycopeptides by combining the highly specific recognition of endo-β-N-acetyl glucosaminidases from Streptococcus pneumoniae (endo-D) with MALDI-TOF MS analysis. The obtained data revealed the glycan profile and the ratio of the glycan structural isomer having the galactosylated extension on IgG1, IgG2 and IgG3 glycopetides.