APC-AAT complexes, neoepitope (human) monoclonal antibody (PC 7)

Protein C is a vitamin K-dependent serine protease produced in the liver and made up of 2 polypeptide chains. The 62kDa proenzyme is activated by thrombin, and the active enzyme cleaves factor Va and VIIIa, thus inhibiting blood coagulation. The molecular weight of the active enzyme is 55kDa. The normal concentration in human plasma is approximately 1-3 ng/mL due to the very fast turnover and the proenzyme concentration of approximately 3 ug/mL. The activated protein C (APC) is inhibited by members of the serine protease inhibitor (serpin) family, of which alpha1-antitrypsin (AAT) and protein C inhibitor (PCI) are the most important.