title: [Inactivation and stabilization of urokinase fibrinolytic activity in vitro].
abstract: When incubated at 30 degrees C and pH 7.4, urokinase lost fibrinolytic activity (i.e., the plasminogen-activating activity measured by the time of fibrin clot lysis) but completely retained amidase activity. The enzyme inactivation rate depended on the urokinase concentration and, at concentrations of more than 1.5 microM, was described by a second order equation, which indicated that the enzyme underwent autolytic degradation (kaut = 3.8 x 10(-3) M-1 min-1). During incubation, urokinase (54 kDa) was converted into its low-molecular-mass form (33 kDa) and products of the A-chain degradation. The amidase activity did not correlate with the fibrinolytic activity in the cases when the enzyme molecule underwent local unfolding or partial degradation. The optimum mixture of agents for stabilizing the fibrinolytic activity of urokinase was found.
authors.affiliation: Lomonosov State University, Faculty of Chemistry, Moscow, Russia. arb@enzyme.chem.msu.su
authors.forename: R B
authors.initials: RB
authors.lastname: Aĭsina
authors.forename: L I
authors.initials: LI
authors.lastname: Mukhametova
authors.forename: I Iu
authors.initials: IIu
authors.lastname: Sazonova
authors.forename: S D
authors.initials: SD
authors.lastname: Varfolomeev
mesh_terms: D000418:Albumins / Q000737:chemistry; D000581:Amidohydrolases / Q000737:chemistry* / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D005343:Fibrinolytic Agents / Q000737:chemistry* / Q000494:pharmacology; D005990:Glycerol / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008239:Lysine / Q000737:chemistry; D008353:Mannitol / Q000737:chemistry; D008970:Molecular Weight; D010960:Plasminogen Activators / Q000737:chemistry* / Q000494:pharmacology; D017510:Protein Folding; D013696:Temperature; D014568:Urokinase-Type Plasminogen Activator / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D000418:Albumins; D005343:Fibrinolytic Agents; D008353:Mannitol; D010960:Plasminogen Activators; D014568:Urokinase-Type Plasminogen Activator; D000581:Amidohydrolases; C019665:amidase; D008239:Lysine; D005990:Glycerol