Table 2.

Transient kinetic parameters

Values are shown ± S.E. ND, not determined.

Parameter	Value		Nucleotide	Method
	WTa	sh1
ATP binding
kT (μm−1 s−1)	2.5 ± 0.04	1.7 ± 0.07	dmantATP	Stopped-flow fluorescence
kAT (μm−1 s−1)	0.5 ± 0.04	1.2 ± 0.14	dmantATP	Stopped-flow fluorescence
kAT (μm−1 s−1)	1.2 ± 0.03	1.2 ± 0.01	ATP	Light scattering
k−TA (s−1)	350 ± 19	420 ± 17.4	ATP	Light scattering
Hydrolysis
kH + k−H (s−1)	12 ± 0.9	0.05 ± 0.01	ATP	Quenched flow
KH	1	ND	ATP	Quenched flow
ADP binding
kD (μm−1 s−1)	1.2 ± 0.06	0.4 ± 0.04	dmantADP	Stopped-flow fluorescence
k−D (s−1)	2.1 ± 0.06	1.6 ± 0.43	dmantADP	Stopped-flow fluorescence
KD (μm)	1.75	4	dmantADP	k−D/kD
kAD (μm−1 s−1)	1.5 ± 0.09	1.8 ± 0.08	dmantADP	Stopped-flow fluorescence
k−AD (s−1)	1.7 ± 0.2	1.8 ± 0.2	dmantADP	Light scattering
k−AD (s−1)	1.28 ± 0.09	1 ± 0.01	ADP	Light scattering
KAD (μm)	1	0.8	dmantADP	k−AD/kAD
Pi release
k−DP (s−1)	0.26 ± 0.07	0.05	ATP	MDCC-PBP
k−DAP (s−1)	12 ± 0.03	≥0.05; >0.2b	ATP	MDCC-PBP
Actin binding
kA (μm−1 s−1)	4.7 ± 0.25	2.2 ± 0.2		Light scattering
kDA (m−1 s−1)	2.6 ± 0.25	0.5 ± 0.05		Light scattering

^a The rate constants for the WT myosin VIIa are from Haithcock et al. (37).

^b A biexponential fit to the data resulted in rates >0.2 s⁻¹ for the fast component. The amplitude of the fast phase was 5–20% of the total amplitude.