. Author manuscript; available in PMC: 2014 Mar 1.

Published in final edited form as: Biochim Biophys Acta. 2012 Dec 19;1828(3):1159–1168. doi: 10.1016/j.bbamem.2012.12.005

Table 2.

Drug-stimulated ATPase activity of Wt and Trp Mutant proteins

	Verapamil ^a	Ks (µM) ^b	Valinomycin ^a	Ks (µM) ^b	FK506 ^a	Ks (µM)b	Cyclosporin A Ki (µM) ^c
Wt	5.1	9.7 ± 0.5	5.5	16 ± 0.9	4.0	4.7 ± 1.3	12 ± 1.5
W228F/W311Y	5.2	16 ± 1.2	5.5	12 ± 0.7	4.2	4.0 ± 0.7	11 ± 1.0
W694L/W1104Y	2.7	9.0 ± 0.7	3.7	15 ± 2.7	2.1	1.6 ± 0.4	15 ± 2.0
Quad	4.0	16 ± 3.1	4.4	12 ± 1.5	3.3	2.8 ± 0.3	10 ± 2.0

^a)

Fold maximum stimulation of ATPase activity at 150 µM verapamil, 70 µM valinomycin and 20 µM FK506.

^b)

Concentration required for half-maximal ATPase activity derived from plots of V vs. [drug] in Figure 6A, B, and C, fitted for a single exponential (mean± SEM).

^c)

Cyclosporin A concentration required for half maximal inhibition of verapamil-stimulated ATPase (Figure 6D) (mean± SEM).