Functionally active thrombomodulin is present in human platelets.

We found functionally active thrombomodulin in human platelets (60 +/- 18 molecules per platelet). Protein C appeared not to be activated by thrombin with gel-filtered platelets. However, the activation of protein C by thrombin was accelerated by thrombin-stimulated and washed platelets. This cofactor activity of the platelets was neutralized by the anti… (More)