Table I. Phenotypic analyses of yeast strains used^a.

Strains	Doubling time (min)	% of rho– cells in cultures	Uncoupled respiration rate (nmol of O/min/mg of protein)b	ATP/Oc	ATPase activityd
					– oligomycine	+ oligomycine (%)	inhibition
Wild type	150	0.9 ± 0.2	1199 ± 42	1.09 ± 0.13	4.98 ± 0.10	0.67 ± 0.02	87
ΔATP20	221	40.0 ± 2.4	795 ± 50	1.22 ± 0.04	6.61 ± 0.04	3.68 ± 0.09	44
ΔTIM11	229	40.9 ± 1.1	868 ± 24	0.89 ± 0.03	5.79 ± 0.29	2.99 ± 0.03	48
ΔATP18	456	11.1 ± 0.8	1380 ± 130	0.79 ± 0.06	2.83 ± 0.02	2.15 ± 0.06	24

^aYeast cells were grown at 28°C on complete medium containing lactate as carbon source. rho^– production in cultures was measured on glycerol plates supplemented with 0.1% glucose. Mitochondria were prepared from protoplasts.

^bUncoupled respiration rates were determined in the presence of 3 µM CCCP (carbonyl cyanide m-chlorophenylhydrazone).

^cATP/O ratios were determined with NADH as substrate.

^dATPase activities and the sensitivity to the F₀ inhibitor oligomycin were measured at pH 8.4 in the presence of 0.375% Triton X-100 to remove the natural inhibitor IF₁.

^eUnits: µmol of Pi/min/mg of protein.