title: Amiloride selectively inhibits the urokinase-type plasminogen activator.
abstract: The diuretic drug amiloride, an inhibitor of Na+ uptake, competitively inhibits the catalytic activity of the urokinase-type plasminogen activator (u-PA), with a Ki of 7 X 10(-6) M. Generation of plasmin, cleavage of peptide substrates, and interaction of u-PA with a specific macromolecular proteinase inhibitor are all prevented in the presence of the drug. In contrast, amiloride does not affect the activity of either tissue-type plasminogen activator, plasmin, plasma kallikrein or thrombin. The inhibition of u-PA by amiloride may be related to the previously reported inhibition of u-PA-type enzymes by Na+. Amiloride or related compounds could prove useful in selectively controlling u-PA-catalyzed extracellular proteolysis.
mesh_terms: D000584:Amiloride / Q000494:pharmacology*; D000818:Animals; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D010960:Plasminogen Activators / Q000037:antagonists & inhibitors*; D015849:Plasminogen Inactivators; D011480:Protease Inhibitors / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000037:antagonists & inhibitors; D014568:Urokinase-Type Plasminogen Activator / Q000037:antagonists & inhibitors*
chemical_list: D015849:Plasminogen Inactivators; D011480:Protease Inhibitors; D000584:Amiloride; D012964:Sodium; D010960:Plasminogen Activators; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator