Protein S is a vitamin K-dependent,Porcineotent neutral anticoagulant plasma glycoprotein. Protein S has a molecular weight of appro, Xenopus/Amphibian,imately 70 kDa and consists of a single polypeptide chain. The concentration of protein S in human plasma is 25 ug/ml, with a half-life of appro, Xenopus/Amphibian,imately two days. About 40% of protein S in plasma is in a free form, wheraes 60% is comple, Xenopus/Amphibian,ed with C4b-binding Protein (C4BP). Only the free protein S functions as a cofactor to antigen presenting cells (APC) in the APC-dependent degradation of Factor Va and Factor VIIIa. This antibody is specific for human protein S.