We recently discovered several nonlysine-analog conforma-tional modulators for plasminogen. These include SMTP-6, thioplabin B and complestatin that are low molecular mass compounds of microbial origin. Unlike lysine-analog mod-ulators,which increaseplasminogenactivationbut inhibit its binding to fibrin, the nonlysine-analog modulators enhance both activation and fibrin binding of plasminogen. Here we show that some nonlysine-analog modulators promote autoproteolyticgenerationof plasmin(ogen) derivativeswith its catalytic domain undergoing extensive fragmentation (PMDs), which have angiostatin-like anti-endothelial activ-ity
