Table I.

Parameters of the Voltage Dependence of Fast Inactivation

Channel		v1/2 *		ah *		n *
WT		−47.5 ± 0.9		4.7 ± 0.4		10
1R2Q		−52.6 ± 0.7‡		3.7 ± 0.2‡		3
1R2K		−57.4 ± 0.9‡		4.4 ± 0.2		5
1K4Q		−51.2 ± 1.2‡		4.3 ± 0.2‡		7
1K4R		−51.2 ± 0.7‡		4.3 ± 0.4		3
2R2Q		−55.6 ± 0.9‡		3.9 ± 0.7‡		3
2R2K		−47.9 ± 2.7		4.3 ± 0.1‡		4
2K4Q		−53.2 ± 1.6‡		4.1 ± 0.6‡		8
2K4R		−48.6 ± 1.4		4.4 ± 0.1		4
3R2Q		−56.0 ± 1.3‡		3.8 ± 0.4‡		5
3R2K		−54.8 ± 1.5‡		5.5 ± 0.9‡		4
3R4Q		−50.7 ± 1.0‡		4.7 ± 0.3		6
3R4K		−51.7 ± 1.0‡		4.6 ± 0.2		4
4R2Q		−48.1 ± 0.4		4.2 ± 0.1‡		3
4R2K		−47.2 ± 1.5		4.8 ± 0.2		5
4R4Q		−47.3 ± 1.7		5.0 ± 0.5		7
4R4K		−40.5 ± 0.7‡		4.6 ± 0.3		3
1K4Q:2K4Q		−54.8 ± 0.9‡		4.2 ± 0.4‡		8
3R4Q:4R4Q		−64.9 ± 3.4‡		8.0 ± 0.5‡		7

^*v_1/2 and a_h are the half-maximal voltage and slope factor for fast inactivation as determined by least-squares fits of the data (n = number of separate determinations) to a two-state Boltzmann function as described in materials and methods.  

^‡Values significantly different from WT, with a probability <0.05 resulting from random variation (based on Student's unpaired t test).