title: Hydrophobic interactions in the urokinase active centre. Inhibitory action of alkyl ammonium and amidinium ions: comparison with trypsin.
abstract: In order to obtain information concerning the binding site of urokinase (EC 3.4.99.26) the inhibitory action of aliphatic ammonium and amidinium ions has been studied. The comparison between the corresponding K1 values for urokinase and trypsin shows that although the two enzymes possess a hydrophobic binding pocket of presumably equal length, they differ mainly in their behaviour towards n-alkylammonium ions with an alkyl chain longer than four methylene groups and towards benzylammonium and amidinium ions. This is an indication of a less rigid binding site in urokinase than in trypsin.
mesh_terms: D000578:Amidines / Q000494:pharmacology*; D001665:Binding Sites; D006801:Humans; D007477:Ions; D008297:Male; D011480:Protease Inhibitors; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D013053:Spectrophotometry; D014361:Trypsin Inhibitors; D014568:Urokinase-Type Plasminogen Activator / Q000037:antagonists & inhibitors*
chemical_list: D000578:Amidines; D007477:Ions; D011480:Protease Inhibitors; D000644:Quaternary Ammonium Compounds; D014361:Trypsin Inhibitors; D014568:Urokinase-Type Plasminogen Activator