title: A novel method for relative quantitation of N-glycans by isotopic labeling using ¹⁸O-water.
abstract: Quantitation is an essential aspect of comprehensive glycomics study. Here, a novel isotopic-labeling method is described for N-glycan quantitation using (18)O-water. The incorporation of the (18)O-labeling into the reducing end of N-glycans is simply and efficiently achieved during peptide-N4-(N-acetyl-β-glucosaminyl) asparagine amidase F release. This process provides a 2-Da mass difference compared with the N-glycans released in (16)O-water. A mathematical calculation method was also developed to determine the (18)O/(16)O ratios from isotopic peaks. Application of this method to several standard glycoprotein mixtures and human serum demonstrated that this method can facilitate the relative quantitation of N-glycans over a linear dynamic range of two orders, with high accuracy and reproducibility.
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, USA.
authors.forename: Shujuan
authors.initials: S
authors.lastname: Tao
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, USA.
authors.forename: Ron
authors.initials: R
authors.lastname: Orlando
mesh_terms: D054794:Glycomics / Q000379:methods; D006023:Glycoproteins / Q000737:chemistry*; D006801:Humans; D007553:Isotope Labeling / Q000379:methods*; D013058:Mass Spectrometry; D010103:Oxygen Isotopes; D011134:Polysaccharides / Q000032:analysis* / Q000097:blood / Q000737:chemistry; D015203:Reproducibility of Results
chemical_list: D006023:Glycoproteins; D010103:Oxygen Isotopes; D011134:Polysaccharides
keywords: glycomics; glycoprotein analysis; mass spectrometry; tandem mass spectrometry