Analysis of the binding of different conformational forms of PAI-1 to paionin-4 by surface plasmon resonance
The steady-state binding of the indicated PAI-1 forms, in concentrations between 0.03 and 2 μM, to paionin-4-D1D2 was determined by the use of a BIACORE T100 instrument, with paionin-4-D1D2 immobilized on a CM5 chip. The KD values were determined by plotting the steady-state binding of the different PAI-1 forms to the chips versus the injected concentrations of the various PAI-1 forms and fitting the data to the equation [PAI-1 bound] = ([paionin-4-D1D2] × [PAI-1])/(KD + [PAI-1]. Means ± S.D. of three independent experiments are indicated.
| PAI-1 Form | KD |
|---|---|
| nM | |
| Active PAI-1 | 448 ± 54 |
| Latent PAI-1 | 339 ± 15a |
| uPA-PAI-1 complex | 195 ± 33a |
| PAI-1 14-1B | 1020 ± 50a |
↵ a Significantly different from the value for active PAI-1 wt (P < 0.01).