Table 3.
Binding of ADAMTS13 to VWF fragments (SPR)
| VWF construct | Global fitting |
RUmax plot |
||
|---|---|---|---|---|
| ka, ×104 M−1s−1 | kd, ×10−3s−1 | KD, nM | KD, nM | |
| VWFD4CK | 5.29 ± 1.49 | 6.62 ± 1.26 | 125 ± 16 | 161 ± 30 |
| VWFA3CK | 5.25 ± 1.44 | 6.30 ± 0.79 | 120 ± 62 | 124 ± 23 |
| VWFD4 | 1.11 ± 0.15 | 6.45 ± 0.65 | 619 ± 146 | 671 ± 192 |
| VWFB1CK | 0.93 ± 0.10 | 6.01 ± 0.12 | 643 ± 85 | 600 ± 160 |
The binding interactions between VWF fragments and ADAMTS13 were investigated using SPR. Recombinant ADAMTS13 was covalently immobilized on the chip surface and sequential injections of VWF fragments were performed over it. Two distinct methods were used to obtain the kinetic constants. The curves were globally fitted to the 1:1 Langmuir model, giving values for individual association (ka), dissociation (kd), and equilibrium dissociation (KD) constants. Alternatively, the maximal response (RUmax) at each VWF fragment concentration was plotted and fitted to the one-site binding model, giving values for KD constants. Mean values ± SEM are based on 3 independent experiments.