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. 1999 Jan 1;113(1):7–16. doi: 10.1085/jgp.113.1.7

Figure 3.

Figure 3

Effect of tonic block on accessibility of site 1304. Tonic block of F1304C (•) was evaluated by dividing the peak current obtained from infrequent depolarizations to −20 from −120 mV in the presence of 0.1, 0.5, 1.0, 2.0, 4.0, or 8.0 mM lidocaine by the peak current in the absence of drug (n = 4 for each point). These data were fit to a binding curve with a hill coefficient of 1.0, giving a K d of 1.9 mM. Also shown in the graph is the modification rate of F1304C with 8 μM MTS-ET at −120 mV in the presence of 0.5 (n = 4), 1.0 (n = 10), 2.0 (n = 8), or 4.0 (n = 10) mM lidocaine divided by the rate measured without lidocaine present (n = 4) (○). The rates were measured using the protocol shown in Fig. 2 A. A fit to the modification rate data gives a K a of 6.6 mM.