title: Substrate specificity of tissue plasminogen activator and urokinase as determined with synthetic chromogenic substrates.
abstract: Three different synthetic chromogenic substrates )H-glutamylglycyl-L-arginine-p-nitroanilide (S-2227), pyro-glutamyl-glycyl-L-arginine-p-nitroanilide (S-2444), and H-D-isoleucyl-L-prolyl-L-arginine-p-nitroanilide (S-2288] were investigated for use in the measurement of plasminogen activator activity with high molecular weight urokinase (H-UK), low molecular weight urokinase (L-UK), and tissue plasminogen activator (TPA). The three substrates were hydrolyzed by both TPA-type and UK-type plasminogen activator. As regards the amidolytic activity of S-2227, TPA exhibited a weaker amidolytic activity, and L-UK a stronger activity. In the case of the amidolytic activity of S-2444, no great difference between the three activators was observed in terms of Vmax. As regards the amidolytic activity of S-2288, L-UK exhibited a stronger activity, and TPA a weaker activity. It is suggested that the molecular size of the synthetic chromogenic substrate was too small when compared to natural substrate (fibrin), and therefore that fibrin-binding sites around the catalytic site in TPA are not recognized.
mesh_terms: D002863:Chromogenic Compounds / Q000378:metabolism*; D007700:Kinetics; D009842:Oligopeptides; D010960:Plasminogen Activators / Q000378:metabolism*; D013379:Substrate Specificity; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism*
chemical_list: D002863:Chromogenic Compounds; D009842:Oligopeptides; C041320:glutamyl-glycyl-arginine-4-nitroanilide; C028190:5-oxo-prolyl-glycyl-arginine-4-nitroanilide; C041319:isoleucyl-prolyl-arginine-4-nitroanilide; D010960:Plasminogen Activators; D014568:Urokinase-Type Plasminogen Activator