. 2000 Oct 3;97(21):11203–11208. doi: 10.1073/pnas.200362897

Table 1.

Basal and actin-activated ATPase activities of wild-type and two mutant HMMs

	Ca²⁺-ATPase^*, s⁻¹	EDTA(K⁺)-ATPase^†, s⁻¹	Actin-activated Mg²⁺-ATPase^‡
	Ca²⁺-ATPase^*, s⁻¹	EDTA(K⁺)-ATPase^†, s⁻¹	V_max, s⁻¹		K_d, mM
			P	UP	P	UP
Wild type	0.53	1.7	1.8	ND	0.1	ND
W441F	0.55	1.76	1.8	ND	0.09	ND
W512F	3.9	0.024	0.08	0.09	0.05	0.05

The ATPase activities are per HMM head.

Assay conditions were HMM (0.1 mg/ml for wild type and W441F, and 0.02 mg/ml for W512F), 0.1 mg/ml BSA, 10 mM CaCl₂, 0.45 M KCl, and 20 mM Tris⋅HCl (pH 7.5).

^†

Assay conditions were HMM (0.04 mg/ml for wild type and W441F, and 0.15 mg/ml for W512F), 0.1 mg/ml BSA, 10 mM EDTA, 0.45 M KCl, and 20 mM Tris⋅HCl (pH 8.0).

^‡

The maximum actin-activated Mg²⁺-ATPase activity of HMM, V_max, and the apparent dissociation constant for actin, K_d, were calculated from the data sets in Fig. 5 for wild-type and W441F HMMs and in Fig. 6 for W512F HMM. P, Phosphorylated HMM; UP, unphosphorylated HMM; ND, not determined.