血管内皮細胞のトロンビン結合における細胞表面ヘパラン硫酸の関与

抄録

It has been postulated that thrombin binds to endothelial cells through, at least in part, cell surface glycos-aminoglycans such as heparan sulfate, which could be antithrombin cofactor on the endothelium. In the present study we have directly evaluated ¹²⁵I-labeled bovine thrombin binding to cultured porcine aortic endothelial cells. Scatchard plot revealed high affinity binding sites (3×10^-8M) for thrombin on endothelial cells. Specific binding of ¹²⁵I-thrombin to endothelial cell surface was approximately by 50% inhibited in the presence of protamine sulfate and after the removal of cell surface heparan sulfate by the treatment of cells with heparitinase. Whereas, removal of chondroitin sulfates by chondroitinase ABC did not affect the binding.
Our results suggest that cell surface heparan sulfate is involved in approximately a half of high affinity binding sites for thrombin on endothelial cells.