Hemextin B (monomer): does not show anticoagulant activity. Seems only to synergitically enhance hemextin A activity. Hemextin AB complex: specifically inhibits the activation of FX (F10) by the TF-FVIIa complex (extrinsic tenase complex (ETC)) (IC(50)= 100 nM, Ki=50 nM) by non-competitively inhibiting the enzymatic activity of FVIIa. Heterotetramer composed of 2 hemextin A and 2 hemextin B chains; non-covalently linked. Does not exists as a complex in the crude venom. Expressed by the venom gland. May contain several disulfide bonds. Belongs to the snake three-finger toxin family. Short-chain subfamily. Type IB cytotoxin sub-subfamily.