Thrombin, what is correct
Thrombin in circulation is a procoagulant, but binding with thrombomodulin i.e. thrombin-thrombomodulin acts as an anticoagulant. This complex activates Protein C and Protein S(anticoagulant) see below how the fibrinolytic system is activated.
Thrombin does not activate factor X
Thrombin converts fibrinogen to fibrin
Thrombomodulin is a thrombin binding protein secreted by endothelial cells of vessels except cerebral vessels. This binds with thrombin, forming a complex, which has anticoagulant properties.
Thrombomodulin-thrombin complex activates Protein C. Activated protein C inactivates factor V and VIII with protein S.
Activated Protein C inactivates inhibitor of tissue plasminogen activator (t-PA) so more plasminogen is converted to plasmin, leading fibrinolysis (clot breaking).
Ref Ganong chapter 31 edition 26.