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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
2
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pubmed:dateCreated |
1976-4-2
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pubmed:abstractText |
The number of protons ejected during electron transport per pair of electrons per energy-conserving site (the H+/site ratio) was measured in rat liver mitochondria by three different methods under conditions in which transmembrane movements of endogenous phosphate were minized or eliminated. (1) In the Ca2+ pulse method, between 3.5 and 4.0 molecules of 3-hydroxybutyrate and 1.75 to 2.0 Ca2+ ions were accumulated per 2 e- per site during Ca2+ induced electron transport in the presence of rotenone, when measured under conditions in which movements of endogenous phosphate were negligible. Since entry of 3-hydroxybutyrate requires its protonation to the free acid these data correspond to an H+/site ratio of 3.5-4.0 (2) In the oxygen pulse method addition of known amounts of oxygen to anaerobic mitochondria in the presence of substrate yielded H+/site ratios of 3.0 when phosphate transport was eliminated by addition of N-ethylmaleimide or by anaerobic washing to remove endogenous phosphate. In the absence of such measures the observed H+/site ratio was 2.0. (3) In the reductant pulse method measurement of the initial steady rates of H+ ejection and oxygen consumption by mitochondria in an aerobic medium after addition of substrate gave H+/site near 4.0 in the presence of N-ethylmaleimide; in the absence of the inhibitor the observed ratio was only 2.0. These and other experiments reported indicate that the values of 2.0 earlier obtained for the H+/site ratio by Mitchell and Moyle [Biochem J. (1967) 105, 1147-1162] and others were underestimates due to the unrecognized masking of H+ ejection by movements of endogenous phosphate. The results presented here show that the H+/site ratio of mitochondrial electron transport is at least 3.0 and may be as high as 4.0.
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-1176454,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-13771349,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-16742541,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-241748,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-4144294,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-4222981,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-4330063,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-4357710,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-4364542,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-4452361,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-4749276,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-4822505,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-4881885,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-4922961,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-4965707,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-5222551,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-5368333,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-5479384,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-5551630,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-5649935,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1061146-5776240
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Feb
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pubmed:issn |
0027-8424
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
73
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
437-41
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pubmed:dateRevised |
2010-9-3
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pubmed:meshHeading |
pubmed-meshheading:1061146-Animals,
pubmed-meshheading:1061146-Calcium,
pubmed-meshheading:1061146-Electron Transport,
pubmed-meshheading:1061146-Ethylmaleimide,
pubmed-meshheading:1061146-Mitochondria, Liver,
pubmed-meshheading:1061146-Oxygen Consumption,
pubmed-meshheading:1061146-Phosphates,
pubmed-meshheading:1061146-Protons,
pubmed-meshheading:1061146-Rats,
pubmed-meshheading:1061146-Rotenone,
pubmed-meshheading:1061146-Valinomycin
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pubmed:year |
1976
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pubmed:articleTitle |
Stoichiometric relationship between energy-dependent proton ejection and electron transport in mitochondria.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.
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