TABLE 1.

A comparison of optimized parameters for the five-state kinetic model shown in Fig. 4 A

Model parameters	Oocyte	HEK Cell	Experimental
α (s−1)	0.31	0.16	–
β (s−1)	3.6	9.83	–
Kon (μM−1s−1)	0.096	0.32	–
Koff (s−1)	0.18	4.59	–
EC50 (μM)	0.80	2.15	2.11 ± 0.15
Slope	2.37	2.09	2.08 ± 0.10
τdeact (s) at 1 μM	26.4	10.7	11.0 ± 0.44
τact (s) at 1 μM*	5.83	6.46	5.9 ± 0.45
10–90% rise time (s)	12.8	14.2	13.0 ± 2.30
τact (s) at 30 μM*	0.55	0.18	0.16 ± 0.01
10–90% rise time (s)	1.2	0.4	0.38 ± 0.05

The parameters for the receptors expressed in oocytes system were taken from Chang and Weiss (4), but the calculations were done with our software implementation.

^*The activation kinetics is clearly complex, demonstrating a sigmoidal activation as expected for a channel with multiple cascading states; therefore, the monoexponential fit listed is only an approximation of the true activation kinetics, which in theory is always a sum of four exponentials with time constants corresponding to the inverse of the nonzero eigenvalues of the Q-matrix. The 10–90% rise time was determined from the sum of four exponentials.