DETERMINATION OF FUNCTIONAL LEVELS OF PROTEIN-C, AN ANTITHROMBOTIC PROTEIN, USING THROMBIN THROMBOMODULIN COMPLEX
- 1 January 1984
- journal article
- research article
- Vol. 63 (1) , 15-21
Abstract
Protein C is a vitamin K-dependent plasma protein. Activated protein C is a potent anticoagulant and enhances blood clot lysis. A functional assay was develop for protein C in human plasma. The measurement of protein C is accomplished by the addition of thrombomodulin, an endothelial-cell-associated cofactor for protein C activation, and thrombin in a 1:1 molar complex. The activated protein C formed in the plasma is immunoadsorbed with goat anti-human protein C IgG-agarose. The immunoadsorbed activated protein C retains the ability to hydrolyze chromogenic substrates, and after unbound plasma proteins are removed by washing the bound activated protein C is quantitated by incubation with the substrate H-D-phenylalanylpipecolylarginyl-p-nitroanilide (S-2238). Normal individuals have functional protein C levels of 3.9-5.9 .mu.g/ml, with a mean value of 4.8 .mu.g/ml. Individuals undergoing warfarin anticoagulation and patients with advanced liver diseases have decreased levels, as do certain patients with evidence of intravascular clotting. Functional protein C levels correlate well with immunologic levels of the protein in the patient groups studied. Heparin enhances the rate of activated protein C inhibition, as monitored by recovery of activated protein C by immunoadsorption. A patient with recurrent venous thrombosis and abnormal functional protein C activity, but normal levels of antigen, was identified.This publication has 16 references indexed in Scilit:
- Isolation of a membrane-bound cofactor for thrombin-catalyzed activation of protein C.Journal of Biological Chemistry, 1982
- Deficiency of protein C in congenital thrombotic disease.Journal of Clinical Investigation, 1981
- Generation of fibrinolytic activity by infusion of activated protein C into dogs.Journal of Clinical Investigation, 1981
- Identification of an endothelial cell cofactor for thrombin-catalyzed activation of protein C.Proceedings of the National Academy of Sciences, 1981
- Deficiency of protein C inhibitor in combined factor V/VIII deficiency disease.Journal of Clinical Investigation, 1980
- The inhibition of blood coagulation by activated protein C through the selective inactivation of activated factor VBiochimica et Biophysica Acta (BBA) - Enzymology, 1979
- Human Plasma Protein CJournal of Clinical Investigation, 1979
- The subunit structure of thrombin-activated factor V. Isolation of activated factor V, separation of subunits, and reconstitution of biological activity.Journal of Biological Chemistry, 1979
- Anticoagulant properties of bovine plasma protein C following activation by thrombinBiochemistry, 1977
- Quantitative estimation of proteins by electrophoresis in agarose gel containing antibodiesAnalytical Biochemistry, 1966