Abstract: Meizothrombin- and thrombin-inhibiting inhibitors which do not bind bivalent cations and which are used for the anticoagulant pretreatment of blood samples to be used in the determination of the functions and/or changes of state of blood cells and blood corpuscles, and for treating devices and receptacles used for taking and/or receiving blood samples.

Abstract: A method and composition for assaying protein C is described. The method comprises reacting a protein C-containing medium with a protein C-activating activator preparation obtained from venom of the snake Agkistrodon contortrix, or venom of another snake species which undergoes an immunological cross-reaction with the venom of Agkistrodon contortrix, to cause maximum activation of protein C and subsequently determining the quantity of activated protein C, said quantity being proportional to the amount of protein C in said medium. Also disclosed is a method and composition for treating thrombotic disorders with the activator preparation and a method of obtaining the activator preparation by culturing of a cloned microorganism.

Abstract: A process for the preparation of thrombin-like proteolytic enzymes from snake venoms or fractions thereof comprising contacting the snake venom or fraction thereof with heparin insolubilized by reaction with a water-insoluble carrier in order to bind the thrombin-like enzyme to the insolubilized heparin, removing the undesirable accompanying substances of the snake venom and splitting the thrombin-like enzyme from the insolubilized heparin.