

Alpha-thrombin is a serine protease and a key enzyme in the blood coagulation
wound healing processes. Thrombin is generated by proteolytic activation of the
zymogen prothrombin and is commonly recognized as the enzyme responsible fo
the conversion of fibrinogen to fibrin. In addition to cleaving fibrinogen, thrombin
is responsible for activating platelets and is indirectly responsible for regulation
its own production and inhibition through multiple proteolytic feedback pathway
which include the activation of factors V, VIII, XI and Protein C. The central
importance of thrombin to the overall coagulation process is established by the
fact that any perturbation within the blood coagulation system that results in
significantly amplified or impaired as well as accelerated or delayed thrombin
generation will result in clinically relevant hemorrhagic or thrombotic events.
Thrombin activity is down-regulated by inactivation of the cofactors, factor Va a
VIIIa or by direct inhibition of thrombin by its principal inhibitor, anti-thrombin-III
In addition to its pivitol role in the blood coagulation process, thrombin also
contributes to the wound healing process. It activates protease activated
receptor-1 (PAR-1) and in this manner can affect cellular function, growth and
proliferation. Intact thrombin, as well as fragments of thrombin, have also been
shown to have angiogenic, mitogenic and chemotactic activities.