Fig. 1.

Clot lysis assay design. Potency of rt-PA was determined by simultaneous clot formation and clot lysis. In this reaction, rt-PA (sample or standard) was mixed with plasminogen, thrombin and fibrinogen together to allow the formation of fibrin clot by thrombin and fibrinogen and subsequent lysis by plasmin converted from plasminogen by rtPA. The change in turbidity was used to determine the kinetics of enzyme reaction.