STUDIES ON THE ACTIVATION OF PLASMINOGEN: III. INSOLUBLE DERIVATIVES OF THE PROACTIVATOR AND THE ACTIVATOR

Abstract

An insoluble derivative of plasminogen was prepared by coupling it to a diazotized copolymer of p-amino-DL-phenylalanine and L-leucine. The product was found to be active as a proactivator but not as a plasminogen, i.e. on the addition of streptokinase, activator was formed but not plasmin.The availability of insoluble proactivator and activator has made possible the study of the kinetics and pH dependence of the formation of the activator from proactivator and streptokinase, as well as the formation of plasmin from plasminogen. The first process was found to be independent of pH in the range 4–10; the second process was optimal at pH values 7.5–9.0. On the basis of these data, the possible role of some functional groups in the interaction of streptokinase with plasminogen and the activator activity is discussed.