Table 1.
Rates and equilibrium constants for the myo1c3IQ and R156W-myo1c3IQ ATPasea
| Myo1c3IQ | R156W-myo1c3IQ | |
|---|---|---|
| Steady-State ATPase Activity | ||
| [Actin] dependence of ATPase Rate | 0.041 (± 0.0015) µM−1s−1 | 0.010 (± 0.0004) µM−1s−1 |
| Vmax | > 7 s−1 | > 2 s−1 |
| ATP Binding | ||
| 1 / K1’ | 220 (± 60) µM | 250 (± 40) µM |
| k2’ | 150 (± 15) s−1 | 230 (± 14) s−1 |
| Kα | 1.2 (± 0.31) | 4.2 (± 1.6) |
| k+α | 37 (± 5.4) s−1 | 26 (± 3.1) s−1 |
| k−α | 31 (± 9.1) s−1 | 6.2 (± 2.5) s−1 |
| ATP Hydrolysis | ||
| k3app | 140 (± 9.0) s−1 | 160 (± 14) s−1 |
| ADP release | ||
| K5’ | 1.8 (± 0.54) µM | 1.6 (± 0.27) µM |
| k+5’ | 24 (± 0.50) s−1 | 19 (± 0.087) s−1 |
| k−5’ | 13 (± 4.0) µM−1s−1 | 12 (± 2.0) µM−1s−1 |
a
Experiments performed in KMg25 (10 mM MOPS (pH 7.0), 25 mM KCl, 1 mM EGTA, 1 mM DTT, 1 mM MgCl2) at 37 °C.