The Effect of Lachesis Muta Venom (Clotase) on Blood Coagulation Factors

Clotase is a thrombin-like enzyme purified from the venom of Lachesis muta. It is a glucoprotein with a molecular weight of 3.6 x 10⁴ daltons and an iso-electric point of 5.1 (by electrophoretic mobility)(1). This enzyme was administered intravenously in 20 mongrel dogs in a dose of 2 µg/kg body weight over a period of 20 to 30 minutes. It was observed that 1 hour after administration of this enzyme, the fibrinogen level was decreased (335 ± 24 S.E.M. mg% before and 12.6 ± 7.1 S.E.M. mg% after). Three hours after administration, when the fibrinogen was completely depleted, no statistical difference was observed in the levels of factor II, V, VII, VIII and X. Six hours after administration of the drug a decrease in the levels of factor II and VII was observed when they were measured together. At this time, the platelet count had decreased (208 ± 33 S.E.M. x 10³/mm³ before and 143 ± 37 S.E.M. x 10³/mm³ after). The ethanol gelation test was positive 3 and 6 hours after administration of the enzyme. None of the dogs died during this experiment and no bleeding was observed from the mucosa, urinary tract or skin. (1) Magalhães, A. et al. Purification and characterization of a thrombin-like enzyme from the venom of Lachesis muta. X International Congress of Biochemistry, Hamburg, July, 1976.