title: Proenzyme to urokinase-type plasminogen activator in the mouse in vivo.
abstract: We have investigated whether urokinase-type plasminogen activator (u-PA) is present in the mouse in vivo as the proenzyme or as the active enzyme. u-PA in extracts of various murine tissues was of a one-polypeptide chain form with an electrophoretic mobility indistinguishable from purified proenzyme (pro-u-PA), as demonstrated by SDS-polyacrylamide gel electrophoresis under reducing conditions followed by immunoblotting. No 2-chain u-PA was detected in any of the extracts (detection limit 10% of that of one-chain u-PA). In bladder urine more than half of the u-PA was of the one-chain form. Together with previous immunocytochemical studies of the normal murine tissues and studies of the Lewis lung carcinoma, the present results indicate that in these tissues the one-chain proenzyme is the predominant form of u-PA in intracellular stores and for the first time demonstrates that at least in some cases the one-chain form constitutes a sizeable fraction of the u-AP in extracellular fluids in the intact organism.
mesh_terms: D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D004792:Enzyme Precursors / Q000032:analysis*; D005260:Female; D005753:Gastric Mucosa / Q000201:enzymology; D007124:Immunoenzyme Techniques; D007668:Kidney / Q000201:enzymology; D008168:Lung / Q000201:enzymology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010920:Placenta / Q000201:enzymology; D011247:Pregnancy; D014568:Urokinase-Type Plasminogen Activator / Q000032:analysis*; D014649:Vas Deferens / Q000201:enzymology
chemical_list: D004792:Enzyme Precursors; D014568:Urokinase-Type Plasminogen Activator