Summary
Kabi human plasminogen and plasmin and two Behringwerke preparations of human plasminogen were examined for antigen content, purity and specific activity with the 1st International W.H.O. human plasmin reference preparation and with the plasminogen content of an 8 donor normal plasma pool. In relation to the plasminogen content of the preparation with the highest specific activity, the 8 donor plasma pool contained 0.186 mg/ ml of plasminogen. This plasminogen on complete conversion to plasmin by streptokinase or urokinase corresponded to 4.35 International units/ml of plasmin as defined by the International reference preparation.
Protein adsorption from highly purified plasminogens of low protein content induced variable underestimates of antigen and of biological activity. To prevent this it is recommended to issue these purified preparations in an inert carrier medium or alternatively to release these preparations with data pertaining to salt content and optical measurement prior to lyophilisation. When standards of high purity and low protein content are being examined for antigen and enzyme, it is recommended likewise that an inert protein carrier should be present in the diluent. Measurement of proactivator was considered to be unsuitable in reference to proactivator content of highly purified plasmin and plasminogen.
