Kinetics determination of porcine plasmin parameters and comparison with human plasmin

Abstract

responsible for dissolving blood clots. Studies with plasmins from different animals have demonstrated higher affinity than human plasmin for substrate analogs made exclusively for the latter. This has been confirmed by the activation and kinetics of the porcine plasminogen/plasmin system, which had so far not been determined or compared with the human system. The methods used in this study for purification of plasminogen were affinity and ion exchange chromatographies. Urokinase was used for the activation of plasminogen to plasmin and kinetic parameters were determined with the chromogenic substrate S-2251. The N-terminals were determined by the Edman degradation method. Porcine plasmin showed higher affinity (K_m) than human plasmin for the chromogenic substrate, 1.55 mM and 5.3 mM, respectively; contrariwise, human plasmin demonstrated higher velocity in the substrate to product conversion: 0.1 UA/seg) vs. 0.033 UA/seg. The N-terminals differed in the amino acids 1 and 3: DPPDDY (for porcine) and EPLDDY (for human).