Segmental heterogeneity in the biochemical properties of the Na + -K + -ATPase along the intestine of the gilthead seabream ( Sparus aurata L.)
| Autor: | Juana Rosa Cejas, M. Casariego, J. Sánchez, Eduardo Almansa, S. Cozzi, Mario Díaz |
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| Rok vydání: | 2001 |
| Předmět: |
Physiology
Sodium chemistry.chemical_element Calcium Biology Biochemistry Isozyme Ouabain chemistry.chemical_compound Adenosine Triphosphate Endocrinology Intestinal mucosa medicine Animals Magnesium Vanadate Enzyme Inhibitors Na+/K+-ATPase Ecology Evolution Behavior and Systematics Dose-Response Relationship Drug Hydrogen-Ion Concentration Sea Bream Intestines chemistry Organ Specificity Potassium Animal Science and Zoology Sodium-Potassium-Exchanging ATPase Adenosine triphosphate medicine.drug |
| Zdroj: | ResearcherID e-IEO. Repositorio Institucional Digital de Acceso Abierto del Instituto Español de Oceanografía instname |
| ISSN: | 1432-136X 0174-1578 |
| DOI: | 10.1007/s003600100206 |
| Popis: | The activity of the Na+-K+-ATPase along the intestinal mucosa of the gilthead seabream has been examined. Under optimal assay conditions, found at 35 degrees C, pH 7.5, 2-5 mM MgCl2, 5 mM ATP, 10 mM K+ and 200 mM Na+, maximal Na+-K+-ATPase activities were found in the microsomal fraction of pyloric caeca (PC) and anterior intestine (AI), which were more than two-fold the activity measured in the microsomes from the posterior intestine (PI). Na+-K+-ATPase activities from PC, AI and PI displayed similar pH dependence, optimal Mg2+/ATP and Na+/K+ ratios, affinities for Mg2+ and ATP, and inhibition by vanadate. However, considerable differences regarding sensitivity to ouabain, inhibition by calcium and responses to ionic strength were observed between segments. Thus, Na+-K+-ATPase activity from the AI was found to be ten-fold more sensitive to ouabain and calcium than the enzyme from the PC and PI and displayed distinct kinetic behaviours with respect to Na+ and K+, compared to PC and PI. Analysis of the data from the AI revealed the presence of two Na+-K+-ATPase activities endowed with distinguishable biochemical characteristics, suggesting the involvement of two different isozymes. Regional differences in Na+-K+-ATPase activities in the intestine of the gilthead seabream are compared with literature data on Na+-K+-ATPase isozymes and discussed on the basis of the physiological differences between intestinal regions. |
| Databáze: | OpenAIRE |
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