Hirudin

Hirudin is a naturally occurring peptidein the salivary glandsof medicinal leeches(Hirudo medicinalis) that has a blood anticoagulantproperty. This is fundamental for the leeches? alimentary habit of hematophagy, since it keeps the blood flowing after the initial phlebotomyperformed by the worm on the host?s skin. Hirudin was discovered by J.B. Haycraftin 1884.

The effect of hirudin on the blood coagulationbiochemical cascade is the inhibition of thrombin. Thrombin is a serine protease, produced from prothrombin, by the action of an enzyme, prothrombinase., in the final states of coagulation. It converts fibrinogenin the blood to fibrin, forming the clot or thrombus.

Hirudin is the most powerful natural inhibitor of thrombin, due to its binding specificity. Therefore, hirudin prevents or dissolves the formation of clots and thrombi(thrombolytic activity), and has therapeutic value in blood coagulation disorders, in the treatment of skinhematomasand of superficial varicose veins, either as an injectable or a topical application cream. In some aspects, hirudin has advantages over more commonly used anticoagulants and thrombolytics, such as heparin, because it doesn?t interfere with other serum proteinsand can act also on bound thrombin.

It is difficult to extract large amounts of hirudin from natural sources, so a method for synthesizing it by recombinantbiotechnologyhas been developed.

See also

• Hirudotherapy

pt:Hirudina

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It uses material from the http://en.wikipedia.org/wiki/Hirudin Wikipedia article Hirudin.