Reactivity toward chemical sulfation of hydroxyl groups of heparin

• Published in: Carbohydrate research 1989-10, Vol.193, p.165-172
• Main Authors: Ogamo, Akira, Metori, Atsuko, Uchiyama, Hideki, Nagasawa, Kinzo
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Biological and medical sciences; Carbohydrates; Fundamental and applied biological sciences. Psychology; Other biological molecules
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/0008-6215(89)85116-X

The pyridinium salt of hog-mucosal heparin was desulfated by heating in 3:6:1 (v/v) 1,4-dioxane-dimethyl sulfoxide-methanol at 90° for 72 h, with the intermittent addition of pyridinium chloride (5 mol/mol of disaccharide). After N-resulfation, the desulfated polysaccharide (tributylammonium salt) was treated with 5–20 mol of pyridine-sulfur trioxide in N,N-dimethylformamide per mol equiv. of hydroxyl group at −10, 0, or 20° for 1 h to undergo O-sulfation. The sulfated products were quantitatively analyzed for 6-sulfate and 2-sulfate esters in 2-amino-2-deoxy- d-glucose and l-idosuronic acid units, respectively, by 13C- and 1H-n.m.r. spectroscopy and for total sulfate content by a chemical method. The new procedure gave 97% of desulfation of heparin, i.e., 100% N- and 6-desulfation of 2-amino-2-deoxy- d-glucose and 91.5% 2-desulfation of l-idosiduronic acid units. The O-resulfation proceeded according to the order of reactivity of the hydroxyl groups: HO-6 in GlcN ⪢ HO-2 in IdoA > other available hydroxyl groups (HO-3 in GlcN, HO-3 in IdoA, and HO-2 or HO-3 in GlcA).