"Linkage region" sequences of heparins and heparan sulfates: Detection andquantification by nuclear magnetic resonance spectroscopy

The C-13 NMR spectra of most heparin and heparan sulfate preparations displ ay minor signals not attributable to the glycosaminoglycan chains of these polysaccharides. These signals have been "concentrated" in oligosaccharides isolated from an acid hydrolyzate of heparin and shown to arise from the s equence GlcA-Gal-Gal-Xyl of the "linkage region" (LR) connecting the carboh ydrate chains to the peptide chains in the original proteoglycans. Mono- an d two-dimensional H-1 and C-13 NMR analysis of the major oligosaccharide (L R-OLIGO) indicated the prevalent structure GlcA-GlcNAc-GlcA-Gal-Gal-Xyl, wh ere GlcNAc is partially 6-O-sulfated. C-13 NMR signals at 84.6 and 85.0 ppm , arising from C-3 of the two Gal residues, lend themselves to easy detecti on and quantification of the linkage region in heparins and heparan sulfate s and can be used to assess the importance of the LR in the modulation of v arious biological activities of these glycosaminoglycans. (C) 1999 Academic Press.