| Autor: |
A, Majerník, P, Smigán, M, Greksák |
| Rok vydání: |
1997 |
| Předmět: |
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| Zdroj: |
Biochemistry and molecular biology international. 43(1) |
| ISSN: |
1039-9712 |
| Popis: |
The ability of the cells of Mb. thermoautotrophicum strain delta H to generate a proton gradient (driven by a concentration gradient of sodium ions) at pH 6.8 as well as at pH 8 was demonstrated. The electrogenic Na+/H+ antiport responsible for this process was shown to be inhibited by EIPA and also by DCCD. Artificially increasing of intracellular concentration of Ca2+ in these cells enhanced the Na+/H+ antiport activity, while the lowering of external Ca2+ by EGTA significantly decreased this activity. The apparent K(m) values for Na+ about 14 and 3 mM at pH 6.8 and 8, respectively, and Vmax about 214 (pH 6.8) and 155 (pH 8) delta Q/min per mg of cell proteins, respectively, were calculated. It is concluded that the described processes are mediated by the Na+/H+ antiporter which might be a clue to the adaptive bioenergetic behaviour of the cells of Mb. thermoautotrophicum strain delta H under the different physiological conditions. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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