Binding of urokinase to plasma proteinase inhibitors.
125I-labelled urokinase was incubated with plasma and plasminogen free plasma, and the incubation mixtures were analyzed by agarose gel electrophoresis. Autoradiography demonstrated that non-reacted urokinase remained around the slit and that complex-formation with inhibitors altered the migration and resulted in two bands, a major one and a minor one. Crossed immunoelectrophoresis combined with autoradiography showed that the major band contained a complex between alpha 2-antiplasmin and urokinase. The minor band contained a complex between alpha 2-macroglobulin and urokinase. Also di-isopropylfluorophosphate-inactivated urokinase was bound to alpha 2-macroglobulin but not to alpha 2-antiplasmin. Thus, an intact active site of urokinase is not necessary for complex formation with alpha 2-macroglobulin.
D010450:Endopeptidases / Q000097:blood*; D006801:Humans; D011485:Protein Binding; D014568:Urokinase-Type Plasminogen Activator / Q000097:blood*; D000979:alpha-2-Antiplasmin / Q000378:metabolism*; D000511:alpha-Macroglobulins / Q000378:metabolism*
D000979:alpha-2-Antiplasmin; D000511:alpha-Macroglobulins; D010450:Endopeptidases; D014568:Urokinase-Type Plasminogen Activator