Table 1.

Amplitudes of proton uptake measured at pH 7.5 on formation of Q_A⁻ and Q_B⁻

Strains	H+/QA−*			H+/QB−, first flash†			H+/QB, second flash†			Total first and second flashes
	Fast	Slow	Total	Fast	Slow	Total	Fast	Slow	Total
Wild type‡	0.16	—	0.16	0.70	—	0.70	1.30	—	1.30	2.00
L212Q	0.16	—	0.16	0.63	—	0.63	0.90	0.42	1.32	1.95
L212A	0.14	—	0.14	0.55	—	0.55	1.45	—	1.45	2.00
L212A-L213A	0.15	0.15	0.30	0.45	0.55	1.00	0.20	0.75	0.95	1.95
AA+M231L§	0.18	—	0.18	0.90	—	0.90	1.05	—	1.05	1.95
AA+M43D	0.15	—	0.15	1.00	—	1.00	0.75	0.15	0.90	1.90
AA+M5D	0.15	0.10	0.25	0.30	0.75	1.05	0.20	0.85	1.05	2.10
AA+M247Y	0.30	0.18	0.48	0.25	0.70	0.95	0.15	1.00	1.15	2.10

The standard deviation is 0.03 for the H⁺/Q_A⁻ measurements and 0.05 on each flash for the H⁺/Q_B measurements. “Fast” refers to components faster than ≈25 ms. 

^*Terbutryn added. 

^† Excess quinone present. 

^‡ Wild-type residues are L212E, L213D, M5N, M43N, M231R, and M247A. 

^§ AA = L212A-L213A.