protein C

Protein C is a vitamin K-dependent glycoprotein that serves as a natural anticoagulant and anti-inflammatory agent. It circulates in the plasma as an inactive zymogen and is converted to its active form, activated protein C (APC), by the thrombin-thrombomodulin complex on endothelial surfaces. APC exerts its anticoagulant effect by inactivating coagulation factors Va and VIIIa, thereby inhibiting thrombin generation. Additionally, it exhibits cytoprotective, anti-inflammatory, and anti-apoptotic properties through its interaction with the endothelial protein C receptor (EPCR) and protease-activated receptor 1 (PAR-1). A recombinant activated form, drotrecogin alfa (Xigris), was previously approved for severe sepsis but was withdrawn from the market in 2011 after subsequent trials failed to demonstrate a survival benefit. However, plasma-derived protein C concentrates (e.g., Ceprotin) remain approved for the treatment of congenital protein C deficiency and purpura fulminans.

Brand names

XigrisCeprotin

Other names

drotrecogin alfaactivated protein CAPCrhAPChuman protein C concentratePC concentrate