Thrombomodulin is a specific endothelial cell receptor that forms a 1:1 stoichiometric complex with thrombin. This complex is responsible for the conversion of protein C to the activated protein C (protein Ca). Human Thrombomodulin/THBD predicts a signal peptide and a mature chain that consists of following domains: C-type lectin, EGF-like, transmembrane and cytoplasmic. Predominantly synthesized by vascular endothelial cells, THBD inhibits coagulation and fibrinolysis. THBD gene polymorphisims are associated with human disease and THBD plays a role in thrombosis, stroke, arteriosclerosis, and cancer. For example, increased serum levels of THBD, due to protease cleavage, have been associated with smoking, cardiac surgery, atherosclerosis, liver cirrhosis, diabetes mellitus, cerebral and myocardial infarction, and multiple sclerosis.