Table 2.
Equilibrium binding studies of RPTPμ constructs using surface plasmon resonance
| Analyte | Dissociation constanta (μM) | Goodness-of-fit for nonlinear regression (χ2) |
||
|---|---|---|---|---|
| One-site model | Two-sites model | |||
| Immobilized ligand: Exμ | ||||
| Kd1 | Kd2 | |||
| MIF1 | 7.9±0.9 (9.3±0.8) | NA | 0.4 | 0.2 |
| MIF2 | 8.1±0.5 (4.1±0.4) | 0.33±0.04 (0.61±0.06) | 1.1 | 0.02 |
| MIF3 | 9.5±1.0 (4.9±0.5) | 0.27±0.06 (0.52±0.03) | 2.8 | 0.1 |
| Exμ | 5.5±0.4 (3.4±0.2) | 0.18±0.05 (0.60±0.06) | 4.8 | 0.3 |
| MIg, F34t | No binding up to 50 μM | |||
| IF14t, F14t | NDb | |||
| Immobilized ligand: MIF1 | ||||
| Kd1 | Kd1′ | |||
| MIF1 | 1.1±0.08 (3.0±0.3) | 33±2 (17±1) | 7.3 | 0.05 |
| aExcept for MIF1 binding to immobilized Exμ, which was fitted with a 1:1 binding model, nonlinear fitting for the Req binding curves was performed with the simultaneous two-sites binding model: Req=Conc*Rmax1/(Kd1+Conc)+Conc*Rmax2/(Kd2+Conc). Values in parentheses were obtained when nonlinear fitting of the Req binding curves was performed separately for the two binding sites, as guided by the two linear segments in the Scatchard plots. | ||||
| bNot determined as the proteins exhibited polydisperse behaviour and nonspecific binding to sensor chip. | ||||
| NA, not available. | ||||