Comparative glycomic profiling of isotopically permethylated N-glycans by liquid chromatography/electrospray ionization mass spectrometry

Yunli Hu, Janie L. Desantos-Garcia, Yehia Mechref

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

Rationale: Mass spectrometry based comparative glycomics is essential for disease biomarker discovery. However, developing a reliable quantification method is still a challenging task. Methods: We here report an isotopic labeling strategy employing stable isotopic iodomethane for comparative glycomic profiling by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS). N-Glycans released from model glycoproteins and blood serum samples were permethylated with iodomethane ('light') and iodomethane-d1 or -d3 ('heavy') reagents. Permethylated samples were then mixed at equal volumes prior to LC/ESI-MS analysis. RESULTS Peak intensity ratios of N-glycans isotopically permethylated (Heavy/Light, H/L) were almost equal to the theoretical values. Observed differences were mainly related to the purity of 'heavy' iodomethane reagents (iodomethane-d1 or -d3). The data suggested the efficacy of this strategy to simultaneously quantify N-glycans derived from biological samples representing different cohorts. Accordingly, this strategy is effective in comparing multiple samples in a single LC/ESI-MS analysis. The potential of this strategy for defining glycomic differences in blood serum samples representing different esophageal diseases was explored. Conclusions: LC/ESI-MS comparative glycomic profiling of isotopically permethylated N-glycans derived from biological samples and glycoproteins reliably defined glycan changes associated with biological conditions or glycoproteins expression. As a biological application, this strategy permitted the reliable quantification of glycomic changes associated with different esophageal diseases, including high grade dysplasia, Barrett's disease, and esophageal adenocarcinoma.

Original languageEnglish
Pages (from-to)865-877
Number of pages13
JournalRapid Communications in Mass Spectrometry
Volume27
Issue number8
DOIs
StatePublished - Apr 30 2013

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