Table 2. Summary of transient kinetic results for human M2β-S1 exchanged with K104E versus WT RLC.
| Rate/equilibrium constants (± SE) | WT | K104E |
|---|---|---|
| ATP binding (actomyosin)a, n = 3 | ||
| K’1Tk’+2T (µM–1·s–1) | 7.7 ± 0.1 | 7.6 ± 0.3 |
| K0.5 (µM) | 174 ± 60 | 62 ± 14 |
| k’+2T (s–1) | 1,527 ± 358 | 636 ± 76 |
| Actomyosin ADP release (pyrene)a, n = 4 | ||
| k’+D (s–1) | 242.5 ± 17.2 | 284.4 ± 9.9 |
| Actomyosin mantADP releaseb, n = 4 | ||
| k’+D (s–1) | 196.5 ± 15.6 | 157.1 ± 5.8 |
k’+2T, maximal rate of ATP-induced dissociation; K’1Tk’+2T, second-order rate constant for ATP binding. K0.5’, ATP concentration at which the observed rate constant is one-half maximal.
a
Pyrene actin fluorescence.
b
mantADP fluorescence.