Table I.

Parameters for the Modified Woodhull Equation (Eq. 3) Measured in BK Channels

Channel		Unitary conductance		Divalent cation		N		zd		K d(F)(0)
		pS								mM
1		262		Sr2+		0.74		0.45		58
2		224		Sr2+		0.75		0.51		60
3		250		Sr2+		0.73		0.48		63
				Ca2+		0.68		0.50		46
				Mg2+		0.71		0.50		39
4		178		Sr2+		0.69		0.45		209
				Ca2+		0.66		0.41		126
				Mg2+		0.70		0.47		105