Kinetic characteristics of fibrinogen and fibrin hydrolysis by plasmin 1 and 2 and miniplasmin.

Fibrinogen and fibrin hydrolysis by native plasmin 1 and 2 and by miniplasmin was studied. The degree of hydrolysis was estimated by the number of amino groups determined with trinitrobenzene sulphonic acid. The process was shown to obey Michaelis-Menten kinetics. Kinetic parameters of fibrinogen and fibrin hydrolysis by plasmin forms 1 and 2 were identical (KM = 6.5 X 10(-6) M, kcat = 7.1 sec-1) while for hydrolysis by miniplasmin KM = 20.0 X 10(-6) M, kcat = 3.58 sec-1. Thus, it was demonstrated that enzymatic properties of plasmin are to some extent dependent on the presence of lysine-binding sites. However, this appears not to have a decisive effect on fibrinolytic process.