Protein C is a Vitamin K-dependent glycoprotein that is produced in the liver. Protein C is similar to the prothrombin group of blood coagulation factors in its primary structure. Normal protein C concentration in human plasma is approximately 1-3 ng/ml and the proenzyme concentration is approximately 3?g/ml. Protein C regulates blood coagulation by inactivating factors Va and VIIIa in the presence of calcium ions and phospholipids. Protein C deficiency is associated with inherited thrombophilia, ecchymotic skin lesions.

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