Abstract
Acceleration effects of various sulfated polysaccharides toward the anticoagulant activities of antithrombin III (AT III) and heparin cofactor II (HC II) were investigated in the purified system. And the neutralizing effects of histidinerich glycoprotein (HRG) toward these acceleration were also investigated. Heparin, chondroition polysulf ates-1, -5 and dextran sulfate (DS)-I (M. W.; 500, 000, S-contents; 18%) accelerated the antithrombin activities of both AT III and HC II, while dermatan sulfate, DS-II (M. W.; 4, 000, S-contents; 18%) and DS-III (M. W.; 4, 000, S-contents; 4.5%) accelerated only that of HC II. By the addition of HRG, the accelerating effects of heparin and chondroitin polysulfates toward the anticoagulant activities of AT III and HC II were neutralized in a dose-dependent manner resulting in the restoration of the thrombin activity. Therefore, it seems likely that HRG is a regulating factor of the anticoagulant activity of heparin in plasma. On the contrary, HRG showed a little neutralization activity for dermatan sulfate and DS-III, and it did not show any neutralizing effect toward DS-I and DS-II. These results indicate that the activities of AT III, HC II and HRG depend not only on the species but on the molecular weights and S-contents of the sulfated polysaccharides.
