TABLE I.

Single H⁺ Channel Conductance (γ_H) and Maximum Open Probability (P_max) at Different pH

pHo//pHi	γH	P max
	mean ± SEM (n)	mean ± SEM (n)
	fS
7.5//6.5	37.4 ± 4.0 (19)	0.746 ± 0.027 (17)
6.5//6.5	38.3 ± 4.3 (3)	0.60 (1)
7.5//5.5	138.9 ± 7.5 (13)	0.954 ± 0.014 (10)
7.5//5.0	220 (2)	0.95 (2)
7.5//4.1	400 (1)	0.97 (1)

Estimates of γ_H and N were obtained from y-g_H plots (Fig. 6) and were based on the total H⁺ current variance (σ_H ²). If calculated using only the Lorentzian variance (σ_L ²), then the estimates of γ_H are about 20% lower, whereas the estimates of N are unaffected (Fig. 12).