NMR in Glycoscience and Glycotechnology
CHAPTER 10: Analysis of Glycosaminoglycans by 15N-NMR Spectroscopy
Published:15 May 2017
Glycosaminoglycans (GAGs) are sulfated polysaccharides of complex structure endowed with multiple biomedical functions. Liquid-state 1D and 2D nuclear magnetic resonance (NMR) spectroscopy has been the analytical technique mostly employed in structural characterization of GAGs. Analyses have been performed primarily on 1H and 13C nuclei of anomeric and ring atoms. Nowadays, however, another isotope type, 15N from the composing amino sugars (hexosamine units), was proven to be also quite useful for analyses. The recent developments for enhancing NMR sensitivity such as the advent and spread of high magnetic fields, cryoprobe technology, isotopic labeling techniques, and novel 2D pulse sequences have been the principal factors to allow the progress of the 15N-based NMR structural analyses of GAGs. Despite the low abundance and sensitivity of 15N together with the few resultant 15N-related cross-peaks seen in the 2D spectra of GAGs, a big set of structural information can still be retrieved from the 15N–NMR analyses. This chapter aims therefore at describing this new set of structural information.