Table 2. Dissociation constants for the binding of TβR-I 7– 91 variants to TGF-β3 in the presence of a near-saturating concentration of TβR-II (2 μM).
Analyte | Saturating receptor | Kd (μM) | Rmax (RU) |
---|---|---|---|
TβR-II ED | None | 0.52 ±0.04 | 445 ± 19 |
TβR-I 7–91 | None | ND | ND |
TβR-I 7–91 | 2 μM TβR-II ED | 0.31 ±0.02 | 536 ± 28 |
P55G TβR-I 7–91 | 2 μM TβR-II ED | ND | ND |
R58A TβR-I 7–91 | 2 μM TβR-II ED | 20.2±2.2 | 750 ±38 |
P59G TβR-I 7–91 | 2 μM TβR-II ED | ND | ND |
P64A TβR-I 7–91 | 2 μM TβR-II ED | 0.30 ±0.03 | 362 ± 23 |
All Kd values, except that for R58A TβR-I, were determined by fitting the observed concentration-dependent maximal response to derive both Kd and Rmax; for R58A TβR-I, Kd was fitted, but Rmax was fixed at the same value obtained for TβR-II binding over the same surface.
ND, not determined due to the minimal response observed.