Protein C, also known as autoprothrombin IIA and blood coagulation factor XIX, is a zymogen, the activated form of which plays an important role in regulating anticoagulation, inflammation, and 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 since it contains a residue of serine in its active site. In humans, protein C is encoded by the "PROC" gene, which is found on chromosome 2.