Table 1.
Stability constants K for the block of binding components channels formed by C2II and Iota b by chloroquine and related aminoquinolinium salts in lipid bilayer membranes a. * The results of similar titration experiments performed with C2IIa channels and chloroquine are given for comparison.
| Chloroquine Analog | K/103 M−1 | KS/µM | K/103 M−1 | KS/µM |
|---|---|---|---|---|
| - | C2II | Iota b | ||
| Chloroquine | 110 * | 9.1 * | 7.1 ± 1.7 | 140 |
| C 23 | 1.5 ± 0.4 | 710 | 0.82 ± 0.21 | 1200 |
| C 164 | 18.5 ± 2.5 | 54 | 0.39 ± 0.13 | 2400 |
| C 268 | 198 ± 15 | 5.1 | 2.5 ± 0.4 | 400 |
| C 280 | 6200 ± 40 | 0.16 | 12.5 ± 2.1 | 80 |
a The data represent means ± SD of at least three individual titration experiments. The membranes were formed from diphytanoyl phosphatidylcholine/n-decane. The aqueous phase contained 150 mM KCl, 10 mM MES-KOH, pH 6, and about 10 ng/mL activated C2II or about 20 ng/mL Iota b; T = 20 °C. * The stability constant K for binding of chloroquine to C2IIa channels is given for comparison and was taken from Bachmeyer et al. (2003) [45].