HEPARIN-LIKE COMPOUNDS PREPARED BY CHEMICAL MODIFICATION OF CAPSULAR POLYSACCHARIDE FROM ESCHERICHIA-COLI K5

O-Sulfation of sulfaminoheparosan SAH, a glycosaminoglucuronan with th e structure ->4)-beta-D-GlcA(1-->4)-beta-D-GlcNSO(3)(-)-(1-->, obtaine d by N-deacetylation and N-sulfation of the capsular polysaccharide fr om E. coli K5, was investigated in order to characterize the sulfation pattern eliciting heparin-like activities. SAH was reacted (as the tr ibutylammonium salt in N,N-dimethylformamide) with pyridine-sulfur tri oxide under systematically different experimental conditions. The stru cture of O-sulfated products (SAHS), as determined by mono- and two-di mensional H-1 and C-13 NMR, varied with variation of reaction paramete rs. Sulfation of SAH preferentially occurred at O-6 of the GlcNSO(3)(- ) residues. Further sulfation occurred either at O-3 or at O-2 of the GlcA residues, depending on the experimental conditions. Products with significantly high affinity for antithrombin and antifactor Xa activi ty were obtained under well-defined conditions. These products contain ed the trisulfated aminosugar GlcNSO(3)(-)3,6SO(3)(-), which is a mark er component of the pentasaccharide sequence through which heparin bin ds to antithrombin.