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 (uPA/PLAU) and Tissue Plasminogen Activator (tPA/PLAT). The main function of Plasmin is to dissolve Fibrin blood clots. Plasmin, like Trypsin, belongs to the family of serine proteases Fibrin is a cofactor for Plasminogen activation by tPA. Urokinase Plasminogen Activator Receptor (uPAR) is a cofactor for Plasminogen activation by uPA. Plasmin is inactivated by Alpha-2-Antiplasmin, a serine protease inhibitor (serpin).
Native Bovine Plasmin is prepared from plasminogen by activation with immobilized human uPA. 100% functionally active plasmin is purified from the activation reaction by immobilized soybean trypsin inhibitor (SBTI). Plasmin will undergo rapid auto proteolysis in the absence of benzamidine and should be used quickly once thawed. Partial cleavage of bovine plasmin between kringles 3 & 4 occurs upon activation, producing a low molecular weight band. This midiplasmin is 100% active.