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.
