Isolation and characterization of a thrombin inhibitor from the tick ixodes ricinus

The secretion of the salivary glands of ticks, Ixodes ricinus, contains anticoagulant substances. Some years ago an antithromboplastin, ixodin, was described. The present paper refers the isolation and characterization of a second anticoagulant substance of the ticks named ixin. Ixin proved to be a relatively stable and specific thrombin inhibitor. The multi step procedure for isolation results in a 850-fold purification. The preparation obtained has a specific activity of 250 antithrombin units/mg. It is not homogeneous and still contaminated. The substance was assumed to be a miniprotein.