Rate and equilibrium constants of the Myo5 ATPase cycle
| . | Phosphorylated Myo5 . | Unphosphorylated Myo5 . |
|---|---|---|
| Steady-state actin-activated ATPase | ||
| Vmax (s−1) | 3.3 (±0.15) | ND |
| KATPase (µM) | 5.1 (±0.88) | ND |
| ATP binding | ||
| K1′ (µM−1) | ND | 0.006 (±0.0016) |
| k2′ (s−1) | ≥335 | 290 (±24) |
| K1′k2′ (µM−1 s−1)a | 0.39 (±0.017)b | 1.1 (±0.28)c |
| ADP release | ||
| k+5′ (s−1) | 74 ± 2.0 | 107 (±5.9) |
| . | Phosphorylated Myo5 . | Unphosphorylated Myo5 . |
|---|---|---|
| Steady-state actin-activated ATPase | ||
| Vmax (s−1) | 3.3 (±0.15) | ND |
| KATPase (µM) | 5.1 (±0.88) | ND |
| ATP binding | ||
| K1′ (µM−1) | ND | 0.006 (±0.0016) |
| k2′ (s−1) | ≥335 | 290 (±24) |
| K1′k2′ (µM−1 s−1)a | 0.39 (±0.017)b | 1.1 (±0.28)c |
| ADP release | ||
| k+5′ (s−1) | 74 ± 2.0 | 107 (±5.9) |
Summary of rate and equilibrium constants measured for Myo5 in this study. Errors are standard errors of the fits.
Determined from a linear fit of the unbinding rates.
Linear fit of all data for phosphorylated Myo5 in Fig. 2 E.
Linear fit of observed rates below 100 µM ATP for unphosphorylated Myo5 in Fig. 2 E. ND: Not determined.