ONE-DIMENSIONAL AND 2-DIMENSIONAL C-13-NMR CHARACTERIZATION OF 2 SERIES OF OLIGOSACCHARIDES DERIVED FROM PORCINE INTESTINAL MUCOSAL HEPARIN BY DEGRADATION WITH HEPARINASE

Two tetrasaccharides, two hexasaccharides, and a disaccharide have been purified from heparinase digests of porcine intestinal mucosal heparin in sufficient quantities to permit C-13-n.m.r. characterization of the species. The two tetrasaccharides are the sulfated iduronic acid-containing 4en-HexpA2SO3-(1 --> 4)-alpha-D-GlcpNSO3;6SO3-(1 --> 4)-alpha-L-IdopA2SO3-(1 --> 4)-D-GlcpNSO3;6SO3 and the non-sulfated glucuronic acid-containing 4en-HexpA2SO3-(1 --> 4)-alpha-D-GlcpNSO3;6SO3-(1 --> 4)-beta-D-GlcpA-(1 --> 4)-D-GlcpNSO3;6SO3. The two hexasaccharides are related to the two tetrasaccharides by the insertion of alpha-linked L-IdopA2SO3-(1 --> 4)-D-GlcpNSO3;6SO3 after the non-reducing end sulfated glucosamine residue. The disaccharide is 4en-HexpA2SO3-(1 --> 4)-alpha-D-GlcpNSO3;6SO3. The disaccharide, together with each of the iduronate-containing oligosaccharides, form one series of related di-, tetra-, and hexa-saccharides, while the disaccharide together with the glucuronate-containing oligosaccharides form a second series. Using inverse detection as a means of increasing sensitivity, two-dimensional n.m.r. C-13-H-1 heterocorrelation spectra have been obtained for all five oligosaccharides. The use-of two-dimensional heterocorrelation n.m.r. spectroscopy offers a much less ambiguous means of making C-13 resonance assignments than do traditional one-dimensional methods, while the use of inverse detection gives both greater sensitivity than direct detection, as well as values for the one-bond C-13-H-1 coupling constants. From a knowledge of the assignments of resonances in the H-1 spectra of these species, it has been possible to assign almost all of the C-13 resonances of these five oligosaccharides. Some corrections to previously published assignments for the tetrasaccharides have been made. In addition, one-bond C-13-H-1 coupling constant data have been obtained for all of the anomeric protons.