TY - JOUR
T1 - Respiratory Control and the Proton Electrochemical Gradient in Mitochondria
AU - Padan, Etana
AU - Rottenberg, Hagai
PY - 1973/12
Y1 - 1973/12
N2 - The relationship between the rate of electron transport and the proton electrochemical gradient ΔH across the inner membranes of rat liver mitochondria was investigated. ΔH was calculated from ΔPH as measured by 14C‐labeled 5,5‐dimethyl‐2, 4‐oxazolidine dione distribution and from Δφ as measured by 42K distribution (in the presence of valinomycin). When mitochondria are in state 3, i.e. during phosphorylation, ΔH was only 5 m V less than in state 4, while respiration increased 3.5‐fold. In the presence of uncoupler, respiration was the same as in state 3, but ΔH was reduced by 22 m V with dinitrophenol, 28 m V with KCI + valinomycin and 60 m V with gramicidin. In the presence of valinomycin, when uncoupling increases by increasing KCl concentration, there was a linear relationship between ΔH and the rate of respiration. These results are in agreement with the suggestion that in uncoupled systems the respiratory rate is controlled by ΔH. However, the phosphorylation reaction controls the respiratory rate directly and not through its effect on ΔH. This conclusion is not compatible with the chemiosmotic model of oxidative phosphorylation.
AB - The relationship between the rate of electron transport and the proton electrochemical gradient ΔH across the inner membranes of rat liver mitochondria was investigated. ΔH was calculated from ΔPH as measured by 14C‐labeled 5,5‐dimethyl‐2, 4‐oxazolidine dione distribution and from Δφ as measured by 42K distribution (in the presence of valinomycin). When mitochondria are in state 3, i.e. during phosphorylation, ΔH was only 5 m V less than in state 4, while respiration increased 3.5‐fold. In the presence of uncoupler, respiration was the same as in state 3, but ΔH was reduced by 22 m V with dinitrophenol, 28 m V with KCI + valinomycin and 60 m V with gramicidin. In the presence of valinomycin, when uncoupling increases by increasing KCl concentration, there was a linear relationship between ΔH and the rate of respiration. These results are in agreement with the suggestion that in uncoupled systems the respiratory rate is controlled by ΔH. However, the phosphorylation reaction controls the respiratory rate directly and not through its effect on ΔH. This conclusion is not compatible with the chemiosmotic model of oxidative phosphorylation.
UR - http://www.scopus.com/inward/record.url?scp=0015748249&partnerID=8YFLogxK
U2 - 10.1111/j.1432-1033.1973.tb03212.x
DO - 10.1111/j.1432-1033.1973.tb03212.x
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C2 - 4131256
AN - SCOPUS:0015748249
SN - 0014-2956
VL - 40
SP - 431
EP - 437
JO - European Journal of Biochemistry
JF - European Journal of Biochemistry
IS - 2
ER -