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Uncoupler-stimulated Na+ pump and its possible role in the halotolerant bacterium, Ba.
Uncoupler-stimulated Na+ pump and its possible role in the halotolerant bacterium, Ba.
- Source :
-
Archives of biochemistry and biophysics [Arch Biochem Biophys] 1984 Mar; Vol. 229 (2), pp. 640-9. - Publication Year :
- 1984
-
Abstract
- In cells of Ba1 suspended in K salt as the osmoticum, the respiratory rate declined by 80% between the pH values of 6.5 and 8.5. Catalytic amounts of Na+ ions prevented this drop. The possibility that Na+ exerted its effect by an influence on proton fluxes across the membrane (Na+/H+ exchange) was explored. Addition of catalytic amounts of Na+ ions to cells respiring at pH 8.5 elicited an influx of protons and, as a result, the delta pH across the membrane became diminished. delta psi (membrane potential) was not affected by Na+. At pH 6.5, Na+ caused no proton influx. FCCP (carbonylcyanide-p-trifluoromethoxyphenylhydrazone) collapsed delta psi, but the Na+-dependent proton influx observed at pH 8.5 became enhanced, leading to an inversion of delta pH (more acid inside). When a Na salt was used as the osmoticum, delta pH of reversed polarity was generated by respiration also in the absence of FCCP. Respiring, inverted membrane vesicles responded to a Na+ pulse essentially as the intact cells. Based on the above and some additional findings it is suggested that these Na+-dependent effects are suited to prevent a raise in the intracellular pH over the level which hinders the respiratory activity. It may also play a role in the regulation of intracellular Na salt content.
- Subjects :
- Adenosine Triphosphate metabolism
Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone pharmacology
Ethanol pharmacology
Hot Temperature
Kinetics
Oxidative Phosphorylation drug effects
Oxygen Consumption drug effects
Potassium Cyanide pharmacology
Sodium pharmacology
Sodium-Hydrogen Exchangers
Bacteria metabolism
Carrier Proteins metabolism
Sodium metabolism
Uncoupling Agents pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 0003-9861
- Volume :
- 229
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Archives of biochemistry and biophysics
- Publication Type :
- Academic Journal
- Accession number :
- 6322699
- Full Text :
- https://doi.org/10.1016/0003-9861(84)90197-8