Intrinsic uncoupling of mitochondrial proton pumps. 1. Non-ohmic conductance cannot account for the nonlinear dependence of static head respiration on Delta mu similar to sub(H)

The passive membrane conductane L sub(H) super(1) of rat liver mitochondria has been measured and compared with the quanity nJ sub(e) super(sh)/ Delta mu similar to sub(H) super(s) super(h)(n = H super(+)/e stoichiometry; J sub(e) super(sh) = rate of electron transfer in static head) over a Delta mu...

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Bibliographic Details
Published in:Biochemistry (Easton) 1986-01, Vol.25 (4), p.760-767
Main Authors: Zoratti, M, Favaron, M, Pietrobon, D, Azzone, G F
Format: Article
Language:English
Subjects:
liver
mitochondria
protons
rats
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Summary:The passive membrane conductane L sub(H) super(1) of rat liver mitochondria has been measured and compared with the quanity nJ sub(e) super(sh)/ Delta mu similar to sub(H) super(s) super(h)(n = H super(+)/e stoichiometry; J sub(e) super(sh) = rate of electron transfer in static head) over a Delta mu similar to sub(H) range. The two curves approach each other only in the lower part of the range, while they sharply diverge at large values of Delta mu similar to sub(H). Thus nJ sub(e) super(sh)/ Delta mu similar to sub(H) super(s) super(s) super(h) cannot be considered to be a measure of L sub(H) super(1) in the upper Delta mu similar to sub(H) region. Only a fraction of the static head electron flow is accounted for by futile proton cycling via leaks. Contaminating open membrane fragments or completely leaky mitochondria can be responsible for only a small part of the residual rate of oxygen consumption. The authors conclude that a large part of static head respiration must have yet another cause and propose it to be intrinsic uncoupling of the respiratory chain enzymes.
ISSN:0006-2960