TABLE 3.

Basal and MT-stimulated ATPase assay IC₅₀ values for kinesin-5 motor domains treated with either monastrol or STC

These median inhibitory concentration values were obtained from the data curve fits to the Hill equation as shown in Figs. 2 and 3. We find no significant differences in the response of the chimeras to either monastrol or STC (Wilcoxon signed rank test (α = 0.05)). S.E. are reported. ND, not detectable.

Motor domain	Monastrol IC50		STC IC50
	Basal	MT-stimulated	Basal	MT-stimulated
	μm		μm
HsEg5	4.9 ± 0.6	4.1 ± 0.4	0.9 ± 0.05	0.3 ± 0.02a
Klp61F-WT	ND	ND	ND	ND
Klp61F-L5	ND	4.4 ± 0.9	0.7 ± 0.2	0.5 ± 0.03
Klp61F-L5-α3	ND	6.7 ± 1.9	1.3 ± 0.7	0.5 ± 0.06

^a The Morrison equation was used to obtain IC₅₀ values for HsEg5 treated with STC in the presence of saturating MT.