A COMPARATIVE-STUDY ON THE MECHANISM OF THE ANTICOAGULANT ACTION OF MOLLUSK AND MAMMALIAN HEPARINS

The anticlotting activities on some steps of the coagulation cascade o f mollusc and mammalian heparins were studied. AT III-high affinity he parin is a more potent inhibitor than unfractionated heparin and mollu sc heparin in the intrinsic and extrinsic pathways of thrombin and fac tor Xa generation. Mollusan heparin has about the same activity as the AT III high affinity-heparin on the inhibition of factor Xa and throm bin in the presence of antithrombin III and four times more inhibitory activity than unfractionated heparin on the heparin cofactor II media ted inhibition of thrombin.