Table I.
Effects of Zn2+ on the Forward (α) and Backward (β) Rates of Inactivation
| [Zn2+] (μM) | τ (s) | I/Imax | β (× 10−3 s−1) | α (× 10−3 s−1) | α100/α0 | |||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0 | 10 | 100 | 0 | 10 | 100 | β0 | β10 | β100 | β100/β0 | α0 | α10 | α100 | ||||||||||||||||
| 19.8°C | 1093.3 | 344.7 | 75.5 | 0.2508 | 0.1271 | 0.0516 | 0.229 | 0.369 | 0.683 | 2.98 | 0.686 | 2.532 | 12.562 | 18.31 | ||||||||||||||
| (0.2208) | (0.0971) | (0.0216) | (0.202) | (0.282) | (0.286) | 1.42 | (0.713) | (2.619) | (12.959) | 18.18 | ||||||||||||||||||
| 24.0°C | 235.4 | 67.1 | 17.8 | 0.2213 | 0.0891 | 0.0391 | 0.940 | 1.328 | 2.197 | 2.34 | 3.308 | 13.575 | 53.983 | 16.32 | ||||||||||||||
| (0.1913) | (0.0591) | (0.0091) | (0.813) | (0.881) | (0.511) | 0.63 | (3.435) | (14.022) | (55.669) | 16.21 | ||||||||||||||||||
| 28.3°C | 51.1 | 13.2 | 4.2 | 0.0908 | 0.0561 | 0.0378 | 1.777 | 4.250 | 9.000 | 5.06 | 17.792 | 71.508 | 229.095 | 12.88 | ||||||||||||||
| (0.0608) | (0.0261) | (0.0078) | (1.190) | (1.977) | (1.857) | 1.56 | (18.379) | (73.781) | (236.238) | 12.85 | ||||||||||||||||||
The table lists the slow-gating relaxation time constant (τ) calculated from Fig. 5, the noninactivated current fraction (I/Imax) obtained from Fig. 7 C, the forward (α) and the backward (β) rates of inactivation at three different temperatures, and in 0, 10, and 100 μM Zn2+. β was calculated by dividing I/Imax by τ (Eq. 1), whereas α was obtained by subtracting β from 1/τ (Eq. 2). The numbers outside the parentheses were derived from original measured current without leak subtraction. The I/Imax values in parentheses were obtained by subtracting 0.03 from the original values outside parentheses and the α's and β's in parentheses were calculated accordingly.