NOVEL TAGS FOR THE STABLE ISOTOPIC LABELING OF CARBOHYDRATES
Effort has been made over the past year to assess the utility of tetraplex glycomics tags for comparison of glycoform abundances for glycans as a function of biological perturbation. As the importance of the post-translational modification of glycosylation continues to become an area of increased focus in biological systems, new tools become necessary for the analysis of carbohydrate mixtures. Due to the nature of the biosynthetic pathways of glycosylation it is necessary to utilize techniques that can measure small amounts of biologically relevant glycans with high precision. This current study endeavors to illustrate the utility of tetraplex stable isotope coded tags in the analysis of complex carbohydrate mixtures by mass spectrometry. Utilizing chondroitin sulfate proteoglycans, pharmaceutical preparations of heparin, and complex N-linked glycoproteins as model systems, we are able to quantify compositions and isomeric variations present using an isotope coding strategy. Tags allow for the direct comparison of quantities of glycan compositions within samples via nanospray ionization or, alternatively, with normal-phase capillary chromatography thereby allowing for the possibility of separation of isomeric compounds. In addition, the ability to discern isomeric compositions of heparin is shown based on the tandem mass spectra of each composition using nanospray ionization.
