Protein S (S-Protein) is a vitamin K-dependent plasma glycoprotein synthesized in the endothelium. Protein S exists in two forms: a free form and a complex form bound to complement protein C4b-binding protein (C4BP).
Free Protein S plays a role in the anti-coagulation pathway, where it functions as a cofactor to Protein C in the inactivation of Factors Va and VIIIa. Read more…