Tick salivary thrombin inhibitor that plays an important part in the anti-hemostatic strategy of ticks (Probable). Is a potent and highly selective thrombin inhibitor (Ki=10 pM) (PubMed:8947023). Expressed in salivary glands. Has two domains of the BPTI family. The N-terminal domain bind to the active site of thrombin, the C-terminal domain binds at the fibrinogen recognition exosite.