TABLE IV.

Rate constants and partial charges for scheme I at 20°C

Transition	K0a	qeffb
	s−1	eo
O1-C3	3,130 ± 722c	−0.116 ± 0.064
C3-O1d	4,670 ± 536	0.158 ± 0.043**
O2-C4d	4,531 ± 1,034	−0.190 ± 0.052*
C4-O2d	230 ± 38	0.396 ± 0.101**
C3-C4	2,902 ± 586	−0.064 ± 0.068
C4-C3	525 ± 235	0.184 ± 0.078
C4-C5	1,257 ± 983	0.093 ± 0.073
C5-C4d	489 ± 288	0.252 ± 0.078*
C5-C6	54.9 ± 9.5	0.055 ± 0.031
C6-C5d	29.6 ± 4.7	0.335 ± 0.053**
C6-C7d	1.01 ± 0.28	0.224 ± 0.082*
C7-C6	1.49 ± 0.52	0.027 ± 0.135

All values are means ± SEM obtained from simultaneous fitting of scheme I to eight different channels (20°C) at voltages ranging from 20 to 140 mV.

^aRate constants at 0 mV.

^bEffective partial charge for the indicated rate constant.

^cEstimates of the robustness of the estimated parameters were also made for simultaneous fitting of voltage data from single channels. For channel 2, represented in Figs. 1, 3, 5, 8, 9, 11, and 13, the estimated SEM for rate constants O1-C3 through C6-C5 ranged from ∼3 to ∼10% of the value of each rate constant and for C6-C7 and C7-C6 was ∼25%. The estimated SEM for the voltage sensitivities for rates O1-C3 through C6-C5 ranged from ∼2.4 to ∼14% (mean of ∼8%); for rates C3-O1 and C7-C6, it was ∼19%, and for C6-C7 it was 30%.

^dTransitions that have significant partial charges were estimated using a Wilcoxon signed ranks test (*, P < 0.05; **, P < 0.01).