Investigation of kinetic parameters in vitro of serine proteinases included in the blood coagulation cascade.

During the last years the cases and death due to hemostatic violations exceed that of tumors. Enormous efforts have devoted to the prevention and treatment of some diseases such as arterial thrombosis. Antistasin, a 15 kDa anticoagulant protein isolated from salivary glands of the Mexican leech Haementeria officinalis, has been shown to be a potent inhibitor of Factor Xa in the blood coagulation cascade. Some short analogues which are hybrid structure between isoform 2 and 3 of antistasin and tripeptides inhibitors of serine proteinases were synthesized and reported in our previous work. Inhibitor constants, mechanism, and type of inhibition of some short analogues of antistasin are investigated. These analogs which show high anticoagulant activity in vitro in pure platelet human plasma.