Document Detail


Unique relationships between the rates of oxidation and phosphorylation and the protonmotive force in rat-liver mitochondria.
MedLine Citation:
PMID:  2837288     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The rate of ATP synthesis (JP) in isolated rat-liver mitochondria was strongly dependent on the magnitude of the protonmotive force (delta mu H+) across the mitochondrial inner membrane. Addition of different concentrations of various uncouplers or malonate to mitochondrial incubations in State 3 led to a depression of delta mu H+ and a concomitant decrease in JP. A unique relationship between JP and delta mu H+ was obtained, which was independent of the way in which delta mu H+ was varied. This unique relationship was observed when K+ (in the presence of valinomycin) was used as a probe for delta psi. Different relationships between JP and delta mu H+ were observed when K+ was used as a probe for delta psi and when K+ was measured after separation of the mitochondria by centrifugation without silicone oil. This led to a serious underestimation of delta psi, specifically when uncouplers were present, and non-unique flow-force relationships were thus obtained. Anomalous relationships between JP and delta mu H+ were also found when TPMP+ was used as a probe for delta psi. However, in uncoupler incubations the presence of TBP- strongly affected the TPMP+ accumulation ratio without any effect on the K+ accumulation or on JP and in the presence of TBP- unique relationships between JP and delta mu H+ were again obtained. This indicates that the accumulation of TPMP+ inside the mitochondria is not a straightforward function of delta psi but also depends on conditions like the presence of TBP- or uncouplers. We conclude that there is a unique relationship between the rate of phosphorylation and the protonmotive force in mitochondria and that under some conditions the behaviour of TPMP+ is anomalous.
Authors:
H Woelders; T van der Velden; K van Dam
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  934     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  1988 Jun 
Date Detail:
Created Date:  1988-07-19     Completed Date:  1988-07-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  123-34     Citation Subset:  IM    
Affiliation:
Laboratory of Biochemistry, University of Amsterdam, The Netherlands.
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MeSH Terms
Descriptor/Qualifier:
Adenosine Triphosphate / biosynthesis
Animals
Intracellular Membranes / physiology
Membrane Potentials*
Mitochondria, Liver / physiology*
Onium Compounds / metabolism
Oxidative Phosphorylation*
Potassium / metabolism
Protons*
Rats
Trityl Compounds / metabolism
Uncoupling Agents / pharmacology
Chemical
Reg. No./Substance:
0/Onium Compounds; 0/Protons; 0/Trityl Compounds; 0/Uncoupling Agents; 15912-74-0/triphenylmethylphosphonium; 56-65-5/Adenosine Triphosphate; 7440-09-7/Potassium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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