High Quality Content by WIKIPEDIA articles! Protein C, also known as autoprothrombin IIA and blood coagulation factor XIV,:6822 is a zymogenic (inactive) protein, the activated form of which plays an important role in regulating blood clotting, inflammation, cell death and maintaining the permeability of blood vessel walls in humans and other animals. Activated protein C (APC) performs these operations primarily by proteolytically inactivating proteins Factor Va and Factor VIIIa. APC is classified as a serine protease, as it contains a residue of serine in its active site.:35 In humans, protein C is encoded by the PROC gene, which is found on chromosome 2.