| . | . | TR-F . | Cosedimentation . | ||
|---|---|---|---|---|---|
| Filament . | PKA . | Kd (μM) . | Bmax (maximal Δτ) . | Kd (μM) . | Bmax (fraction bound; C0–C2/actin) . |
| Actin | − | 2.5 ± 0.4 | 5.1 ± 0.3 | 4.3 ± 0.3 | 1.56 ± 0.04 |
| Actin | + | 19 ± 5a | 9 ± 1a | 6.5 ± 0.3a | 1.48 ± 0.03 |
| Actin–Tm | − | 1.4 ± 0.5b | 4.6 ± 0.4 | 3.3 ± 0.4 | 1.61 ± 0.06 |
| Actin–Tm | + | 3.6 ± 0.7a,c | 4.5 ± 0.3c | 6.6 ± 0.4a | 1.46 ± 0.04 |
| . | . | TR-F . | Cosedimentation . | ||
|---|---|---|---|---|---|
| Filament . | PKA . | Kd (μM) . | Bmax (maximal Δτ) . | Kd (μM) . | Bmax (fraction bound; C0–C2/actin) . |
| Actin | − | 2.5 ± 0.4 | 5.1 ± 0.3 | 4.3 ± 0.3 | 1.56 ± 0.04 |
| Actin | + | 19 ± 5a | 9 ± 1a | 6.5 ± 0.3a | 1.48 ± 0.03 |
| Actin–Tm | − | 1.4 ± 0.5b | 4.6 ± 0.4 | 3.3 ± 0.4 | 1.61 ± 0.06 |
| Actin–Tm | + | 3.6 ± 0.7a,c | 4.5 ± 0.3c | 6.6 ± 0.4a | 1.46 ± 0.04 |
Data are mean ± SE (n > 4) for a binding curve of eight concentrations of C0–C2 (0-20 µM) to 1 µM of actin (Fig. 1) fit to a quadratic equation. Significant difference due to PKA treatment (− versus + PKA rows).
P < 0.05. Significant difference due to presence of Tm (actin versus actin–Tm rows of same PKA condition).
P = 0.10. Units for Bmax are lifetime change (maximal Δτ) for TR-F and fraction of actin bound (C0–C2/actin) for cosedimentation.
P < 0.05. Trending difference in Kd due to presence of Tm. See Discussion for a detailed discussion of Kd and Bmax uses and limitations.