Target sizes of human erythrocyte membrane Ca2+-ATPase and Mg2+-ATPase activities in the presence and absence of calmodulin
| Autor: | Mogens Nielsen, Klaus Gietzen, Lin Hymel |
|---|---|
| Rok vydání: | 1985 |
| Předmět: |
Calmodulin
Macromolecular Substances ATPase Protein subunit Biophysics Calcium-Transporting ATPases Biology Biochemistry chemistry.chemical_compound Humans Adenosine Triphosphatases chemistry.chemical_classification Erythrocyte Membrane Dose-Response Relationship Radiation Cell Biology Molecular Weight Calcium ATPase Kinetics EGTA Membrane Enzyme chemistry biology.protein Protein quaternary structure Ca(2+) Mg(2+)-ATPase |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Biomembranes. 815:461-467 |
| ISSN: | 0005-2736 |
| DOI: | 10.1016/0005-2736(85)90374-8 |
| Popis: | We have investigated the subunit structure of Ca2+-transport ATPase in human erythrocyte membranes using radiation inactivation analysis. All inactivation data were linear on a semilog plot down to at least 20% of the control activity. We found a target size for the calmodulin-dependent Ca2+-ATPase activity of 331 kDa, consistent with the presence of this enzyme as a dimer in calmodulin-depleted ghosts. Membranes which had been saturated with calmodulin before irradiation yielded a a similar size of 317 kDa, implying that activation of Ca2+-transport ATPase by calmodulin does not involve significant change in oligomeric structure. Basal (calmodulin-independent) Ca2+-ATPase activity corresponded to a size of 290 kDa, suggesting that this activity resides in the same, or similar-sized, complex as the calmodulin-dependent activity. Mg2+-ATPase activity, however, was found to reside in a smaller complex of 224 kDa, which proved to be statistically distinct from the target size of Ca2+-ATPase activity. It would appear that Mg2+-ATPase is a distinct entity whose function is likely unrelated to the Ca2+-transport ATPase. |
| Databáze: | OpenAIRE |
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