Thrombomodulin (TM) is an integral membrane glycoprotein expressed on the surface of endothelial cells. Its discovery by Esmon and Owen has focused attention on the importance of the protein C anticoagulant pathway (1,2). TM serves as a cofactor for protein C activation by forming a 1:1 stoichiometric complex with thrombin (Kd=10e-10M), which accelerates the rate of protein C activation by 1000-fold relative to the rate with thrombin alone. In addition to facilitating protein C activation, the binding of thrombin to TM drastically alters the procoagulant activity of thrombin. When bound to TM, thrombin no longer clots fibrinogen, activates factor V, inactivates protein S or triggers platelet aggregation.
TM is a single chain protein composed of 5 distinct domains. The domain structure of TM is similar to the low density lipoprotein (LDL) receptor. A short cytoplasmic domain containing a free cysteine is located at the COOH-terminal end and is joined by a membrane spanning region to an O-glycosylation rich domain. The latter is followed by an epidermal growth factor (EGF) homology region and the NH2-terminal hydrophobic domain. The EGF homology region contains 6 EGF-like domains and contains the binding sites for both thrombin and protein C.
Localization:Endothelial cell membrane, traces of degraded, yet functional, TM detected in human urine and plasma (7,8)
Mode of Action:Cofactor; enhances the proteolytic activation of protein C by thrombin
Specific activity:~500 U/mg
Extinction Coefficient: E1%1cm, 280nm=8.8 (5)
Isoelectric Point: 2.5 (2)
Structure:Single chain, NH2-terminal hydrophobic domain, six EGF domains, one O-glycosylation rich domain, one transmembrane domain, COOH-terminal cytoplasmic domain
Post-translational Modifications: b-hydroxyasparagine (0.5 mol/mol of protein) (6)
Storage and Stability:Aliquot to avoid repeated freezing and thawing and freeze at -70°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Aliquots are stable for at least 6 months.
仕様
Size：50ug
Source Antigen：Rabbit lung
Grade：Highly Purified
Purity：≥95% by SDS-PAGE. Thrombomodulin is isolated from rabbit lung by a modification (3) of the procedure described by Galvin et al. (4). Purity is determined by SDS-PAGE analysis and activity is determined using a chromogenic assay for protein C activation.
Form：Supplied as a liquid in 0.02M Tris, 0.15M sodium chloride, pH 7.4, 0.05% polidocanol (PDOC).
