The esterase activity of the fibrinolytic system

Abstract

The esterase activity of the fibrinolytic system was measured with benzoyl-L-arginine ethyl ester or L-lysine ethyl ester as substrate. The acid formed was estimated by measuring the CO2 liberated from bicarbonate solutions. The relation of the 1st and 2d ionization constants of carbonic acid to the ionic strength was determined so as to make possible calculations on the carbon dioxide-bicarbonate buffer in the assay method. A method of determining human plasminogen in the presence of plasmin inhibitors is described. The relationship between the concentration of lysine esterase and of strepto-kinase is established, and the results are discussed in connection with those obtained by other investigators.