Protein S

Protein S (S for Seattle) 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-binding protein (C4BP). The best characterized function of Protein S is its role in the anti coagulation pathway, where it  functions as a cofactor to Protein C in the inactivation of Factors Va and VIIIa. Only the free form has cofactor activity.

TECHNOCLOT^® Protein S is a reagent kit for the quantitative determination of protein S activity in human plasma to detect inherited or acquired protein S deficiencies.