Table 1.

Kinetic Parameters of the Phosphorylated and Unphosphorylated huM3MD ATPase Cycle

	signal/method	p-myosin IIIA	up-myosin IIIAa
steady state
Vo (s−1)		0.07±0.02	0.05
Vmax (s−1)		1.6±0.2	0.54
Kactin (μM)		10.3±3.2	0.13
ATP binding
K1k+2 (μM−1 s−1)	mant-ATP	0.20± 0.01	14
k−2 (s−1)		0.05±0.02	0.2
K′1k′+2 (μM−1 s−1)	mant-ATP	0.13±0.01	0.16
k′−2 (s−1)		0.65±0.2	7.4
ATP hydrolysis
k+3 + k−3 (s−1)	quenched-flow	3.7 ±0.4	0.15
phosphate release
k+4obs (s−1)	MDCC-PBP	0.36±0.01	0.14–0.16
k′+4obs (s−1)		70± 24	1.14–1.26
ADP binding
k+5 (s−1)	mant-ADP cold chase	8.6±0.6	6.5
k−5 (μM−1 s−1)	mant-ADP binding	0.87±0.03	0.4
k′+5 (s−1)	mant-ADP cold chase	8.1±0.06	6.2
k′−5 (μM−1 s−1)	mant-ADP binding	0.56±0.03	0.58
actin binding
k−6 (μM−1 s−1)	light scattering	0.54±0.03	29.8
k+6 (s−1)	light scattering	0.13±0.02	2.3
K6 (nM)		240	68.8
k−8 (μM−1 s−1)	light scattering		92.9
k+8 (s−1)	light scattering		8.6
K8 (μM)			0.09
k−10 (μM−1 s−1)	light scattering	0.14±0.02	23.8
k+10 (s−1)	light scattering	0.15±0.02	2
K10 (nM)		1071	71.4

^aFrom ref 1.