Fibrinogenolytic substance (hementerin) of Brazilian blood-sucking leeches (Haementeria lutzi Pinto 1920).

The fibrinogenolytic activity of the salivary gland extract from the Brazilian blood-sucking leech Haementeria lutzi Pinto 1920 is characterized. The substance, named here hementerin, is stable and active at very low protein concentration, does not exhibit direct proteolytic activity on casein, fibrinogen, or fibrin, and is able to activate the human plasma fibrinolytic system in the presence of a serum cofactor and/or calcium. This indirect activation mechanism distinguishes hementerin from hirudin and shows a similarity with streptokinase. The effect on blood coagulation tests is reported.