Protein C (PC) is a vitamin K-dependent glycoprotein produced in the liver. The concentration of PC in plasma is ~4ug/ml (~60 nM). A deficiency of Protein C (quantitative or qualitative) is a risk factor for vascular thrombosis. Protein C is expressed as a two-chain molecule with a molecular weight of 62 kD. The light chain (21kD of PC consists of two EGF-like domains and an amino-terminal domain containing one hydroxyaspartic acid and 11 γ-carboxyglutamic acid (gla) residues. These residues allow PC to bind to membranes that contain acidic phospholipids in a calcium dependent manner. The heavy chain of PC (41 kD) consists of the catalytic domain and an activation peptide. Activation of Protein C results from cleavage at residue Arg12 in the heavy chain by a complex of thrombin and a cell surface cofactor thrombomodulin.
The activation of PC is associated with the release of a small activation peptide (2-3 kD, called Protein C peptide, or PCP) from the N-terminal of the heavy chain. Activated Protein C (APC) is a serine protease with anticoagulant activity. APC, in complex with a phospholipid membrane, calcium and the Protein S cofactor, exhibits anticoagulant activity through the proteolytic inactivation of coagulation cofactors Va and VIIIa. The primary inhibitor of APC activity in plasma is Protein C Inhibitor (PCI, also called Plasminogen Activator Inhibitor-3, PAI-3) and to a lesser extent by α1antitrypsin and α2macroglobulin. The inhibitory activity of PCI is stimulated approximately 10 fold by heparin1-3.
Materials Supplied:Antibodies for 5x96 well plates
Kit Components:P9102-38A: PC Capture Antibody: 1x500ul Supplied as a liquid in 50% glycerol. Purified by immunoaffinity chromatography. PS IgG Pab ShxHu for coating ELISA plates.
P9108-07B: PC (HRP) Dection Antibody: 1x500ul Supplied as a liquid in 50% glycerol. Purified by immunoaffinity chromatography. PS (HRP) GtxHu for detection of captured PS.
Storage and Stability:For long-term storage, aliquot and store at -20°C. Aliquots are stable for at least 6 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
