ACTIVE-SITES OF DERMATAN SULFATE FOR HEPARIN-COFACTOR-II - ISOLATION OF A NONASACCHARIDE FRAGMENT CONTAINING 4 DISACCHARIDE SEQUENCES [ALPHA-L-IDURONIC ACID 2-O-SULFATE (1,3)-BETA-D-N-ACETYLGALACTOSAMINE 4-SULFATE]

The active site of dermatan sulfate (DS) for heparin cofactor II (HCII) was isolated in a fragment obtained by periodate oxidation, borohydride reduction, mild acid hydrolysis, and SE- and SAX-chromatography of beef mucosal and pig skin DS preparations. Characterization by mass spectrometry, one- and two-dimensional NMR spectroscopy, and HPLC analysis of disaccharides, obtained by exhaustive digestion with chondroitinase-ABC, indicates that the fragment has the prevalent structure 1, GalNAc-4SO(3)-[IdoA-2SO(3)-GalNAc-4SO(3)](4)-R, where R is CH(CH2OH)CH(COO-)-OH. 1 is the largest DS fragment thus far isolated containing IdoA2SO(3) as the only uronic acid. Its lower activity (30%) with respect to the parent polymeric DS is explainable by Tollefsen model, requiring longer polyanionic chains for formation of ternary complex with thrombin.