Table 1.

ΔpH, Δψ, Δμ̃_H⁺, and ATP content in cell suspensions of H. halophilus at different external pH values^a

pHe	Mean value ± SD for:
	pHi	ΔpH	Δψ (mV)	Δμ̃H+ (mV)	ATP (nmol/mg)
6.6	6.52 ± 0.07	−0.08 ± 0.07	−194 ± 9	−190 ± 13	1.5 ± 0.1
7.4	7.24 ± 0.06	−0.19 ± 0.06	−201 ± 9	−190 ± 13	3.8 ± 0.2
8.0	7.41 ± 0.12	−0.59 ± 0.12	−218 ± 4	−183 ± 11	3.2 ± 0.3
8.5	7.86 ± 0.08	−0.64 ± 0.08	−220 ± 5	−182 ± 10	2.8 ± 0.2
8.9	7.98 ± 0.02	−0.96 ± 0.02	−188 ± 12	−133 ± 13	1.3 ± 0.3

^aCell suspensions were incubated in 0.05 M Tris-HCl, pH 7.5, containing 0.05 M MgSO₄ and 1 M NaCl. The bioenergetics parameters were determined as described in Materials and Methods. pH_e, external pH; pH_i, internal pH.