Seems to play an essential role in plague transmission by mediating flea blockage in a temperature-dependent fashion. Fibrinolytic activity prevails at 37 degrees Celsius whereas coagulase expression predominates at lower temperatures (<30 degrees Celsius). Activates plasminogen by cleaving it. Converts human Glu-plasminogen to plasmin by cleaving the 560-Arg-|-Val-561 peptide bond that is also hydrolyzed by the mammalian u-plasminogen activator and t-plasminogen activator. Also cleaves arginyl bonds in other proteins. Belongs to the peptidase A26 family.