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10.1023/b:jobb.0000031978.15139.49
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Título: | Functional approach to the catalytic site of the sarcoplasmic reticulum Ca(2+)-ATPase: binding and hydrolysis of ATP in the absence of Ca(2+) |
Fecha de publicación: | jun-2004 |
Cita bibliográfica: | Journal of Bioenergetics and Biomembranes. 2004 Jun;36(3):265-73.doi: 10.1023/b:jobb.0000031978.15139.49. |
ISSN: | 1573-6881 0145-479X |
Palabras clave: | Ca2+-independent ATPase activity Ca2+-ATPase mechanism Sarcoplasmic reticulum Ca2+- ATPase Muscle relaxation Rabbit skeletal muscle |
Resumen: | Isolated sarcoplasmic reticulum vesicles in the presence of Mg(2+) and absence of Ca(2+) retain significant ATP hydrolytic activity that can be attributed to the Ca(2+)-ATPase protein. At neutral pH and the presence of 5 mM Mg(2+), the dependence of the hydrolysis rate on a linear ATP concentration scale can be fitted by a single hyperbolic function. MgATP hydrolysis is inhibited by either free Mg(2+) or free ATP. The rate of ATP hydrolysis is not perturbed by vanadate, whereas the rate of p-nitrophenyl phosphate hydrolysis is not altered by a nonhydrolyzable ATP analog. ATP binding affinity at neutral pH and in a Ca(2+)-free medium is increased by Mg(2+) but decreased by vanadate when Mg(2+) is present. It is suggested that MgATP hydrolysis in the absence of Ca(2+) requires some optimal adjustment of the enzyme cytoplasmic domains. The Ca(2+)-independent activity is operative at basal levels of cytoplasmic Ca(2+) or when the Ca(2+) binding transition is impeded. |
Autor/es principal/es: | Lax Pérez, Antonio Manuel Soler Pardo, Fernando Fernandez Belda, Francisco |
Facultad/Departamentos/Servicios: | Facultades, Departamentos, Servicios y Escuelas::Departamentos de la UMU::Medicina |
URI: | http://hdl.handle.net/10201/137585 |
DOI: | 10.1023/b:jobb.0000031978.15139.49 |
Tipo de documento: | info:eu-repo/semantics/article |
Número páginas / Extensión: | 9 |
Derechos: | info:eu-repo/semantics/openAccess Attribution-NonCommercial-NoDerivatives 4.0 Internacional |
Descripción: | ©2004. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the Accepted version of a Published Work that appeared in final form in Journal of Bioenergetics and Biomembranes. To access the final edited and published work see https://doi.org/10.1023/b:jobb.0000031978.15139.49 |
Aparece en las colecciones: | Artículos: Medicina |
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