Introduction Protein C is a vitamin K-dependent plasma antithrombotic and anti-inflammatory zymogenic glycoprotein that is synthesized in the liver. Protein C has a light chain of 155 amino acids (21 kDa) and a heavy chain of 262 amino acids (41 kDa) linked by a disulfide bond. On endothelial cell membrane, thrombin-thrombomodulin complex cleaves a 12-reside peptide from protein C amino terminus of the heavy chain and converts it to activated protein C (APC). APC inactivates coagulation Factor Va and Factor VIIIa and performs a major role in regulating blood clotting, inflammation, and apoptosis (1-3). Protein C deficiency causes neonatal purpura fulminans, thrombophilia, and recurrent venous thrombosis (4-6). Protein C pathway components have been studied in the treatment of complex disorders, including severe sepsis, thrombosis, and ischemic stroke (7).
Principal of the Assay The AssayMax Human Protein C ELISA (Enzyme-Linked Immunosorbent Assay) kit is designed for detection of human Protein C in urine, saliva, milk, and cell culture supernatant. This assay employs a quantitative sandwich enzyme immunoassay technique that measures human Protein C in less than 4 hours. A polyclonal antibody specific for human Protein C has been pre-coated onto a 96-well microplate with removable strips. Protein C in standards and samples is sandwiched by the immobilized antibody and the biotinylated polyclonal antibody specific for Protein C, which is recognized by a streptavidin-peroxidase conjugate. All unbound material is then washed away and a peroxidase enzyme substrate is added. The color development is stopped and the intensity of the color is measured.