TABLE 4.

Parameters of chloroquine-induced current noise in PA₍₆₃₎ depending on the applied electric field

Side of ligand addition*	Voltage applied at the cis-side	k1 / 106 M−1s−1	k−1 / s−1	K / 103 M−1
1 M KCl
trans-side
	+10 mV/−10 mV	1.7 / 3.3	826 / 1800	2.1 / 1.8
	+20 mV/−20 mV	1.2 / 5.3	720 / 2570	1.4 / 2.1
	+30 mV	0.42	690	0.61
	+40 mV	0.14	850	0.17
	+50 mV	0.04	990	0.04
	+60 mV	N.D.	N.D.	N.D.
	+70 mV	N.D.	N.D.	N.D.
cis-side
	+10 mV	41	715	57
	+20 mV/−20 mV	54 / 35	730 / 1860	80 / 19
	+30 mV	65	760	86
	+40 mV	71	890	80
	+50 mV	74	960	77
	+60 mV	76	1200	64
	+70 mV	72	1420	51

^*The membranes were formed from diphytanoyl phosphatidylcholine n-decane. The aqueous phase contained 1 M KCl and ∼10 ng/ml PA₆₃ at the cis-side; T = 20°C. k₁ and 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 . The data represent mean of at least three individual experiments with the same ligand. The standard deviation was typically <10% of the mean value. N.D. means not detectable and indicates that the power density of the current noise could not be fitted to a Lorentzian function.