Table 1.

Comparison of the steady-state parameters of the ATPase activity of human myosin-7a with rodent and Drosophila class 7 myosins

Michalelis-Menten parameters	Signal or calculation	Hs Myosin-7ad	Hs Myosin-7a [37]	Mm Myosin-7ae [47]	Dm Myosin-7a [48]	Dm Myosin-7a [42]	Rn Myosin-7a [49]	Dm Myosin-7b [50]	Mm Myosin-7b [46]
k basal (s−1)	NADH assay	0.05 ± 0.01	0.05 ± 0.01	0.18 ± 0.02	0.05 ± 0.001	0.057 ± 0.041	0.04	0.020	0.02–0.03
k cat (s−1)	NADH assay	0.35 ± 0.03a	0.45 ± 0.05	0.7 ± 0.02	1.0 ± 0.1	1.72 ± 0.12	0.53	8.5 ± 0.6	1.17 ± 0.03
K app,actin (μM)	NADH assay	8.3 ± 2.6a	12.8 ± 2.9	10.5 ± 1.7	1.1 ± 0.1	3.2 ± 1.1	32.7	39 ± 5	0.66 ± 0.01
k cat/K app,actin (μM−1s−1)	k cat/K bapp,actin	0.04 ± 0.02	0.04 ± 0.01	0.07 ± 0.01	0.91 ± 0.17	0.54 ± 0.22	0.02	0.22 ± 0.04	1.77 ± 0.06
k cat/K app,actin (μM−1s−1)	k cat/K capp,actin	0.02 ± 0.01	n.d.	n.d.	n.d.	n.d.	n.d.	n.d.	n.d.
K ATP (μM)	NADH assay	11.69 ± 1.77	n.d.	n.d.	n.d.	n.d.	154	n.d.	n.d.
K ATP (μM)	NADH assay	62.65 ± 7.09	n.d.	n.d.	n.d.	n.d.	231	n.d.	n.d.
k cat,ATP (s−1)	NADH assay	0.35 ± 0.01	n.d.	n.d.	n.d.	n.d.	0.46	n.d.	n.d.

^aValues for k _cat and K _app,_actin were calculated by fitting the data to a hyperbolic equation

^bThe apparent second order rate constant for F-actin binding (K _app,_actin) was obtained from the calculated ratio of both values

^cThe apparent second order rate constant for F-actin binding (K _app,_actin) was obtained from the initial slope

^dExperimental conditions: 25 mM HEPES (pH 7.4), 5 mM MgCl₂, 0.5 mM DTT, 2 mM ATP in the presence of an ATP regeneration system

^eValues in the presence of calmodulin