Summary
Fibrin polymers formed from fibrinogen with thrombin in the presence of EDTA were
suspended in a medium containing glucose, arabic gum and imidazole-HCl buffer and
were sonicated at 20 kHz for 20 min to make a suspension containing fibrin particles
of small size. The fibrin suspension was used as a substrate of plasmin for determining
the enzymic activity of plasmin and plasminogen activated with urokinase. The kinetic
study on the reaction of the fibrin particles with plasmin in the presence and the
absence of fibrinogen revealed that Km value of fibrin for plasmin is 4.2 × 10-7 M and the Ki value of fibrinogen is 1.2 × 10-5 M.
