Description
Introduction: Plasminogen (PLG) is a circulating zymogen that is converted to the active enzyme plasmin by cleavage of the peptide bond between Arg-560 and Val-561, which is mediated by urokinase and tissue plasminogen activator. The main function of plasmin is to dissolve fibrin blood clots. Plasmin is a serine protease that is released as plasminogen from the liver into the circulation and activated by tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), and factor XII (Hageman factor). Fibrin is a cofactor for plasminogen activation by tissue plasminogen activator. Urokinase plasminogen activator receptor (uPAR) is a cofactor for plasminogen activation by urokinase plasminogen activator. Plasmin is inactivated by alpha 2-antiplasmin, a serine protease inhibitor (serpin). Apart from fibrinolysis, plasminogen is shown to play important role in wound healing, liver repair as well as the maintenance of liver homeostasis.
Principle of the Assay: This assay employs the competitive inhibition enzyme immunoassay technique. An antibody specific to PLG has been pre-coated onto a microplate. Standards or samples are added to the appropriate microtiter plate wells with biotin-conjugated PLG and incubated. A competitive inhibition reaction is launched between PLG (Standards or samples) and Biotin-conjugated PLG with the pre-coated antibody specific for PLG. The more amount of PLG in samples, the less antibody bound by Biotin-conjugated PLG. Then Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. The substrate solutions are added to the wells, respectively. And the color develops in opposite to the amount of PLG in the sample. The color development is stopped and the intensity of the color is measured