Table 1.
Comparison of the rate and equilibrium constants for the interaction of S1 myosins with nucleotides at 20 °C and 100 mM KCl (pH 7.0)
| Parameter | S1(bovine)a masseter | S1 (rabbit)b fast skeletal | S1 (bovine)c,d cardiac | S1 (rabbit)e soleus | S1 (pig)a soleus |
|---|---|---|---|---|---|
| K1k+2 (106 M−1s−1) | 0.97 | 1.9 | 0.81d | 1.57 | – |
| k+2 (s−1) | 117 | >1000j | 138i | 191 | – |
| k+3+k-3 (s−1) | 18 | 131 | 12/138i | 21.6 | 24h.5h |
| k+6 (k-D) (s−1) | 0.9f–1.4g | 1.4 | 0.5 | 0.61 | 0.84 |
| k-6/K7 (k+D) (106 M−1s−1) | 1.24g | 1.5 | 1.4 | 1.5 | – |
| KD (μM) | 1.2g–2.8f | 2 | 0.33 | 0.41 | 0.5–1.4 |
a
This study.
b
From Ritchie et al.45
c
From Flamig & Cusanovich.11
d
From Smith & Cusanovich.12
e
From Iorga et al.9
f
From ADP-displacement data (Figure 4).
g
From ADP + S1 association experiment (Figure 2(c)).
h
Pig cardiac S1.24
i
The observed rate of 138 s−1, originally assigned to k+3 +k-3, actually represents k+2 (see Discussion).
j
From Miller & Greeves.20