Characterization of a soluble plasminogen activator from kidney cell cultures

¹ Connaught Medical Research Laboratories, University of Toronto, Toronto, Canada

Primary cultures of monkey kidney cells and cultures of an established line of dog kidney cells have been shown to accumulate a fibrinolytic agent during the growth of the cells in serum-free media. A differential fibrin plate assay has been used to demonstrate this and show that the agent is an activator of plasminogen and not a fibrinolysokinase. The active material has been concentrated and its properties as an activator confirmed by a caseinolytic assay method. The plasminogen activator from both cultures has been shown by high speed centrifugation to be in solution and its properties have been found to be similar to urokinase.