Conformational changes and anticoagulant activity of chondroitin sulfate following its O-sulfonation.
Chondroitin sulfate from bovine tracheal cartilage, with the basic structure (4-O-sulfo-D-GalpNAc beta-1-->4-D-GlcpA)n, was chemically modified by O-sulfonation. Depending on the reaction conditions, the products showed a different degree of O-sulfonation. A fully O-sulfonated chondroitin sulfate, having no free hydroxyl groups, and a sulfo ester group:disaccharide unit ratio of 4.0 was prepared. This chondroitin sulfate derivative was shown by 1H NMR spectroscopy to have a uronate residue with an altered conformation. Usually, the uronate residue in chondroitin sulfate resides in the 4C1 form. Fully O-sulfonated chondroitin sulfate had an uronate residue in the 1C4 form at 30 degrees C, similar to the preferred conformation of the 2-O-sulfo-iduronate residue most commonly found in heparin. The 2S0 form of the uronate residue was also found in fully O-sulfonated chondroitin sulfate at 60 degrees C. The anti-factor IIa activity of fully O-sulfonated chondroitin sulfate was 40 units/mg. This value is similar to the activities reported for various low-molecular-weight heparins, and substantially higher than those previously reported for partially O-sulfonated chondroitin sulfates having an average sulfate group/disaccharide unit of 2.5 to 3.3. The anti-factor Xa activity of the fully O-sulfonated chondroitin sulfate was 12 units/mg. This value is considerably lower than the activities reported for various low-molecular-weight heparins, consistent with the critical importance of an antithrombin III pentasaccharide binding site for anti-factor Xa activity. These findings suggest that the conformational change of glucuronic acid residue in chondroitin sulfate resulting from its full O-sulfonation can result in enhanced anticoagulant activity, particularly as measured by anti-factor IIa assay.
Faculty of Pharmaceutical Sciences, Chiba University, Japan.
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Maruyama
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Toida
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Imanari
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Yu
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Linhardt
D000818:Animals; D000925:Anticoagulants / Q000737:chemistry* / Q000494:pharmacology; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002417:Cattle; D002809:Chondroitin Sulfates / Q000737:chemistry* / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D065427:Factor Xa Inhibitors; D005965:Glucuronates / Q000737:chemistry; D020723:Glucuronic Acid; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009904:Optical Rotation; D011516:Prothrombin / Q000037:antagonists & inhibitors; D013055:Spectrophotometry, Infrared; D013431:Sulfates / Q000032:analysis; D013451:Sulfonic Acids / Q000737:chemistry / Q000494:pharmacology; D013696:Temperature
D000925:Anticoagulants; D065427:Factor Xa Inhibitors; D005965:Glucuronates; D013431:Sulfates; D013451:Sulfonic Acids; D020723:Glucuronic Acid; D011516:Prothrombin; C025337:Factor IIa; D002809:Chondroitin Sulfates