Vitamin K-dependent protein S Rabbit Polyclonal Antibody

Protein S is a vitamin K-dependent plasma glycoprotein synthesized in the endothelium. In the circulation, Protein S exists in two forms: a free form and a complex form bound to complement protein C4b. In the plasma, circulating Protein S becomes inactive upon complexing with C4b-binding protein (C4BP); 60-70% of Protein S circulates in complex with C4BP. Its major function is as a cofactor to facilitate the action of activated protein C (APC) on its substrates, activated factor V (FVa), and activated factor VIII (FVIIIa).