Heparin as an hyperbolic modulator of plasminogen activation by t-PA

The effect of heparin on plasminogen activation, by t-PA, was re-exmamined using the Botts-Morales scheme for hyperbolic modulation. The modulation was found to be either positive, negative or non-existent depending on the presence of fibrin and the concentration of salt. Thermodynamic and kinetic parameters defining the modulation were derived computationally. Heparin appears to have a positive effect on plasminogen activation in solution, but no effect on plasminogen activation at the fibrin surface in physiological salt concentrations. © 1994 Longman Group Ltd.