TABLE 3.

Actin-activated myosin MgATPase and in vitro motility assays with endogenous wild-type and expressed actins

Dictyostelium myosin S1 was used in the ATPase assays, and full-length Dictyostelium myosin II was used in the in vitro motility assays (see “Experimental Procedures”). ATPase assays were performed with and without added phalloidin, as indicated. The data were calculated from the experiments shown in Fig. 7. n, number of filaments quantified.

Actin	Actin-activated ATPase		Motility
	Vmax	Km	n	V
	s−1	μm		μm/s
WT with/without phalloidina	9.4 ± 0.1	42 ± 0.5	62	3.66 ± 0.62
Y/Y without phalloidin	10	48	99	3.53 ± 0.58
Y/F without phalloidin	12	62	93	3.77 ± 0.76
Y/A with phalloidin	9.6	50	85	3.86 ± 0.66
Y/E with phalloidin	9.6	32	88	3.66 ± 0.78

^a Applies only to ATPase assay; all in vitro motility assays have phalloidin-stabilized actin filaments.