Table 1. Kinetic parameters for TTX and... | Rockefeller University Press

Table 1.

Kinetic parameters for TTX and STX

Channel	K_d^L	K_d^H1	K_d^H2	k_off^H	k_on^H1	k_on^H2
	nM	nM	nM	s⁻¹	10⁶/M/s	10⁶/M/s
TTX parameters
DEKA	32 ± 4	9.6 ± 0.4	8.6 ± 3.6	0.031 ± 0.009	3.3 ± 0.9	3.7 ± 1.9
DERA	825 ± 36	99 ± 18	220 ± 52	0.26 ± 0.07	2.6 ± 0.9	1.2 ± 0.4
DEAA	6,600 ± 440	2,700 ± 130	2,780 ± 280	4.2 ± 0.2	1.5 ± 0.1	1.5 ± 0.2
DEHA	8,660 ± 320	1,920 ± 370	3,240 ± 260	6.5 ± 2.7	3.5 ± 1.6	2.1 ± 0.8
STX parameters
DEKA	5.70 ± 0.39	1.19 ± 0.04	0.91 ± 0.59	0.022 ± 0.003	19 ± 3	24 ± 16
DERA	399 ± 17	17.5 ± 4.3	131 ± 40	0.73 ± 0.11	42 ± 12	5.6 ± 1.9

Channel	K_d^L	K_d^H1	K_d^H2	k_off^H	k_on^H1	k_on^H2
	nM	nM	nM	s⁻¹	10⁶/M/s	10⁶/M/s
TTX parameters
DEKA	32 ± 4	9.6 ± 0.4	8.6 ± 3.6	0.031 ± 0.009	3.3 ± 0.9	3.7 ± 1.9
DERA	825 ± 36	99 ± 18	220 ± 52	0.26 ± 0.07	2.6 ± 0.9	1.2 ± 0.4
DEAA	6,600 ± 440	2,700 ± 130	2,780 ± 280	4.2 ± 0.2	1.5 ± 0.1	1.5 ± 0.2
DEHA	8,660 ± 320	1,920 ± 370	3,240 ± 260	6.5 ± 2.7	3.5 ± 1.6	2.1 ± 0.8
STX parameters
DEKA	5.70 ± 0.39	1.19 ± 0.04	0.91 ± 0.59	0.022 ± 0.003	19 ± 3	24 ± 16
DERA	399 ± 17	17.5 ± 4.3	131 ± 40	0.73 ± 0.11	42 ± 12	5.6 ± 1.9

K_d^L was obtained from the fit of the toxin titration at low simulation frequency (1/30 Hz) to Eq. 1. K_d^H1 was estimated from an exponential fit of K_d versus stimulation interval as in Fig. 6. K_d^H2 and k_off^H were obtained from a fit to Eq. 4 of observed time constant of use-dependent enhanced block versus toxin concentration as in Fig. 8 B. k_on^H1 and k_on^H2 were calculated from the ratio of k_off^H to K_d^H1 and K_d^H2, respectively. Error estimates are reported from statistics of nonlinear fits in SigmaPlot.

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