31P NMR magnetization transfer study of the control of ATP turnover in Saccharomyces cerevisiae.
AUTOR(ES)
Sheldon, J G
RESUMO
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].
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=39034Documentos Relacionados
- 39K, 23Na, and 31P NMR studies of ion transport in Saccharomyces cerevisiae.
- 31P NMR studies of intracellular pH and phosphate metabolism during cell division cycle of Saccharomyces cerevisiae.
- Rapid ATP assays in perfused mouse liver by 31P NMR.
- Mechanisms and control of mRNA turnover in Saccharomyces cerevisiae.
- A study of the conformation of 5S RNA by 31P NMR.