31P NMR magnetization transfer study of the control of ATP turnover in Saccharomyces cerevisiae
| Autor: | Jonathan G. Sheldon, Kevin M. Brindle, Simon-Peter Williams, Alexandra M. Fulton |
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| Rok vydání: | 1996 |
| Předmět: |
Multidisciplinary
Magnetic Resonance Spectroscopy ATP synthase biology Chemiosmosis Glyceraldehyde-3-Phosphate Dehydrogenases Phosphorus Isotopes Saccharomyces cerevisiae Catalysis Mitochondria Oxygen Phosphoglycerate Kinase Adenosine Triphosphate Biochemistry biology.protein Translocase Glycolysis ATP–ADP translocase P/O ratio Flux (metabolism) Mitochondrial ADP ATP Translocases ATP synthase alpha/beta subunits Research Article |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America. 93(13) |
| ISSN: | 0027-8424 |
| Popis: | 31P NMR magnetization transfer measurements have been used to measure the steady state flux between Pi and ATP in yeast cells genetically modified to overexpress an adenine nucleotide translocase isoform. An increase in Pi -> ATP flux and apparent ratio of moles of ATP synthesized/atoms of oxygen consumed (P:O ratio), when these cells were incubated with glucose, demonstrated that the reactions catalyzed by the translocase and F1F0 ATP synthase were readily reversible in vivo. However, when the same cells were incubated with ethanol alone, translocase overexpression had no effect on the measured Pi -> ATP flux or apparent P:O ratio, suggesting that the synthase was now operating irreversibly. This change was accompanied by an increase in the intracellular ADP concentration. These observations are consistent with a model proposed for the kinetic control of mitochondrial ATP synthesis, which was based on isotope exchange measurements with isolated mammalian mitochondria [LaNoue, K. F., Jeffries, F. M. H. & Radda, G. K. (1986) Biochemistry 25, 7667-7675]. |
| Databáze: | OpenAIRE |
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