Chemical change involved in the oxidative-reductive depolymerization of heparin

• Published in: Carbohydrate research 1992-12, Vol.236, p.165-180
• Main Authors: Nagasawa, Kinzo, Uchiyama, Hideki, Sato, Noriko, Hatano, Akiko
• Format: Article
• Language: English
• Subjects: Applied sciences; Carbohydrates - analysis; Chromatography, High Pressure Liquid - methods; Exact sciences and technology; Heparin - chemistry; Heparin Lyase; Heparin, Low-Molecular-Weight - isolation & purification; Iduronic Acid - analogs & derivatives; Iduronic Acid - analysis; Natural polymers; Nitrous Acid; Oligosaccharides - analysis; Oxidation-Reduction; Physicochemistry of polymers; Polymers - chemistry; Polysaccharide-Lyases; Starch and polysaccharides; Uronic Acids - analysis
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/0008-6215(92)85014-Q

A solution of hog intestinal heparin (average M r 12000, anti-clotting activity 168 USP units/mg) in 0.2 M phosphate buffer (pH 7.2), was incubated in the presence of Fe 2+ for 20 h at 50° under an O 2 atmosphere to yield oxidative-reductively depolymerized heparin (ORD heparin, average M r 3000, anti-clotting activity 34 USP units/mg). Chemical analysis of the ORD heparin showed a 22, 26, and 14% loss of hexosamine, uronic acid, and N-acetyl group, respectively, but no remarkable loss of both total and N-sulfate groups. 1H and 13C NMR spectroscopic analysis indicated no decrease in the amount of l-iduronic acid 2-sulfate, but a marked loss of nonsulfated uronic acid (73 and 39% loss of d-glucuronic acid and l-iduronic acids, respectively, the sum of which corresponds to the chemically determined loss of total uronic acid). The results indicated that the ORD reaction of heparin proceeds essentially by destruction of monosaccharide units, except l-iduronic acid 2-sulfate residues, due to oxygen-derived free radicals, followed by secondary hydrolytic cleavage of the resulting unstable residues.