Table 2. Fitting parameter of Q-V relationships.

	V1/2 (mV)	Z	A (nC)	n
Dr-VSPmChe WT	103 ± 5a,b,c	1.4 ± 0.1d,e,f	1.1 ± 0.6g,i	6
Dr-VSPmChe L223F	96 ± 4a	1.7 ± 0.1d	1.1 ± 0.3h,i	4
CiDr-VSPmChe WT	98 ± 4b	1.4 ± 0.2e	1.6 ± 0.4g,i	4
CiDr-VSPmChe L223F	96 ± 5c	1.4 ± 0.1f	1.6 ± 0.6h,i	6

Q-V curves shown in Fig. 4 D were fitted by single Boltzman distribution, Q(V) = A{1 + exp[(V − V_1/2)/slope]}, where “A” is the maximum charge amplitude, “V” is the membrane potential for test pulse, “V_1/2” is the half-maximum membrane potential, and “slope” is the steepness of the curve in mV per e-fold change. The effective valence, “Z” is calculated by slope = k_BT/Ze, where the parameter “e” is elementary electric charge, “k_B” is Boltzmann constant, and “T” is the absolute temperature. All data are shown as mean ± SD. n is the sample number. The statistical significance of differences was evaluated by a two-tailed Student’s t test. Sample numbers are different from those of Fig. 4, because fitting parameters in the table were obtained only from a set of cells that were able to be recorded over 150 mV.

^aP = 0.08.

^bP = 0.25.

^cP = 0.06.

^dP = 0.02.

^eP = 0.93.

^fP = 0.54.

^gP = 0.13.

^hP = 0.13.

ⁱP = 0.03 (Dr-VSP^mChe vs. CiDr-VSP^mChe).