Importance of 6-0-Sulfate Groups of Glucosamine Residues in Heparin for Activation of FGF-1 and FGF-2

Abstract

Treatment of the pyridinium salts of heparin with N-methyItrimethyIsilyl-trifluoro-acetamide (MTSTFA) in pyridine for 2 h at various temperatures caused specific 6-O-desul-fations from trisulfated disaccharide units to various degrees without detectable depolymerization or other chemical changes. In order to assess the importance of 6-O-sulfate groups in N-sulfated glucosamine (GleNS) residues to promote FGF-1 and FGF-2 activities, various 6-O-desulfated (6-O-DS-) heparins were quantitatively examined for activity as enhancers or inhibitors of specific FGF-1-and FGF-2-induced proliferation of BALB/c3T3 clone A31 (A31) cells and the chlorate-treated cells. The present results suggested that a high content of 6-O-sulfate groups in GleNS residues was required for activation of FGF-1, but not FGF-2. However, complete 6-O-desulfation of trisulfated disaccharide units in heparin resulted in loss of the ability to activate FGF-2, although the desulfated product bound strongly to FGF-2.