TABLE 1.
Steady-state ATPase parameters obtained in the present study for Drosophila nonmuscle myosin S1
| Parameter | Signal | Drosophila nonmuscle myosin-2 | Acanthamoeba nonmuscle myosin-2 (23) | Dictyostelium nonmuscle myosin-2 (24) | Human nonmuscle myosin-2A (25) |
|---|---|---|---|---|---|
| kbasal (s−1) | NADH assay | 0.016 | 0.05 | 0.08 ± 0.02 | 0.013 ± 0.004 |
| kcat (s−1)a | NADH assay | 0.54 ± 0.06 | 4.68 ± 0.73 | 2.6 ± 1 | 0.17 ± 0.005 |
| Kapp (µM)a | NADH assay | 152 ± 39 | 428 ± 97 | 102 ± 20 | 72 ± 4 |
| kcat /Kapp (µM−1 s−1) | NADH assay | 0.004 | 0.01b | 0.025c | 0.0025 |
For comparison, selected kinetic parameters from nonmuscle myosin-2s are listed. aMichaelis-Menten parameters obtained from a hyperbolic fit to the data set. bMaximum steady-state ATPase at 270 µM F-actin. cFrom the initial slope of the steady-state ATPase vs. [F-actin] plot.