Ouabain-sensitive Na+,K+-ATPase in the plasma membrane of Leishmania mexicana
| Autor: | Karl Dawidowicz, Vincenza Cervino, Gustavo Benaim, Pimali Felibertt, Roldán Bermúdez, F. Dagger, Reinaldo Marín, Teresa Proverbio |
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| Rok vydání: | 1995 |
| Předmět: |
Intracellular Fluid
Sodium ATPase Sodium-Potassium-Exchanging ATPase Leishmania mexicana chemistry.chemical_element Ouabain parasitic diseases medicine Animals Vanadate Enzyme Inhibitors Na+/K+-ATPase Molecular Biology biology Cell Membrane biology.organism_classification Kinetics chemistry Biochemistry Potassium biology.protein Parasitology Vanadates Intracellular medicine.drug |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 0166-6851 |
| Popis: | The mechanism responsible for the regulation of intracellular Na+ and K+ concentrations in trypanosomatids is unknown. In higher eukaryotes a ouabain-sensitive Na+,K(+)-ATPase located in the plasma membrane is the main mechanism for the regulation of the intracellular concentrations of Na+ and K+, while in trypanosomatids there are conflicting evidences about the existence of this type of ATPase. By the use of a highly enriched plasma membrane fraction, we showed that an ouabain-sensitive Na+,K(+)-ATPase is present in L. mexicana. The affinity of the enzyme for Na+ and K+ is similar to that reported for the mammalian Na+,K(+)-ATPase, showing also the same kinetic parameters regarding the relative concentration of those cations that give the optimal activity. Vanadate (10 microM) fully inhibits the ATPase activity, suggesting that the enzyme belongs to the P-type family of ionic pumps. The enzyme is sensitive to ouabain and other cardiac glycosides. These cardiac glycosides do not show any appreciable effect on the higher Mg(2+)-ATPase activity present in the same preparation. By the use of [3H]ouabain, we also show in this report that the binding of the inhibitor to the enzyme was specific. Taken together, these results demonstrate that an ouabain-sensitive Na+,K(+)-ATPase is present in the plasma membrane of Leishmania mexicana. Therefore, this Na+,K(+)-ATPase should participate in the intracellular regulation of these cations in Leishmania. |
| Databáze: | OpenAIRE |
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