Thrombomodulin is an integral membrane protein that spans a length of 559 residues and contains five structural domains. The hydrophobic amino terminal domain is made up of 223 amino acid residues. The adjacent domain contains six EGF type B repeats spanning a length of 236 residues. This is followed by a 34 amino acid-long Ser/Thr-rich domain, which may be involved in 0-linked glycosylation. The next domain is a putative membrane-spanning domain of 23 residues, followed by a carboxyl-terminal cytosolic tail of 38 residues. The gene encoding this protein lacks introns. Recombinant soluble thrombomodulin is a 491 amino acid glycoprotein containing the extracellular domain of thrombomodulin.
Thrombomodulin (TM) is an endothelial cell expressed transmembrane glycoprotein that can form a complex with the coagulation factor, thrombin. The thrombomodulin/thrombin complex converts protein C to its activated form, protein Ca, which in turn proteolytically cleaves and deactivates factor Va and factor VIIIa, two essential components of the coagulation mechanism. This inactivation reduces the generation of additional thrombin and thereby effectively prevents continued coagulation. Reduced levels of thrombomodulin can correlate with the pathogenesis of certain cardiovascular diseases, such as atherosclerosis and thrombosis. However, the serum levels of the truncated circulating form of thrombomodulin are typically elevated during inflammation and in the presence of various inflammatory related diseases.
