Parameters of HA1383-, HA1568- and HA486-induced current noise in PA63channels.

k1 and k-1 were derived from a fit of the corner frequencies as a function of the ligand concentration. K is the stability constant for ligand binding derived from the ratio k1/k-1. The data represent means of at least three individual experiments with the same substrate. Membranes were formed from diphytanoyl phosphatidylcholine/n-decane. The aqueous phase contained 150 mM KCl, 10 mM MES, pH 6.0, and about 1 ng/ml PA63 on the cis-side; T = 20°C. The data for chloroquine are given for comparison and were taken from [31].