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THERMAL UNCOUPLING OF THE CA2+-TRANSPORTING ATPASE IN SARCOPLASMIC-RETICULUM - CHANGES IN SURFACE-PROPERTIES OF LIGHT VESICLESстатья
Информация о цитировании статьи получена из
Scopus,
Web of Science
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
- Авторы: GEIMONEN E., BATRUKOVA MA, RUBTSOV AM
- Журнал: European Journal of Biochemistry
- Том: 225
- Номер: 1
- Год издания: 1994
- Первая страница: 347
- Последняя страница: 354
- DOI: 10.1111/j.1432-1033.1994.00347.x
- Аннотация: It is known that the light fraction of rabbit skeletal muscle sarcoplasmic reticulum vesicles can release Ca2+ from the intravesicular space, although the Ca2+-conductive channels are present only in the heavy fraction of sarcoplasmic reticulum vesicles. To study the possible pathways of the Ca2+ leakage from light vesicles we have used a short-term treatment for 4.5 min at 45 degrees C which quickly decreases the efficiency of Ca2+-transporting ATPase operation without any visible effects on the hydrolytic activity of the Ca2+-ATPase in the membranes. The treatment of the vesicles decreased the negative membrane surface potential created by the Ca2+-ATPase. Comparative titration of control and heat-treated preparations of light sarcoplasmic reticulum vesicles by K+, Na+, Mg2+, and Ca2+ revealed clear differences in their surface properties. The short-term heating resulted in release of Ca2+ from the vesicles previously loaded with Ca-45(2+), which indicates an increase in passive membrane permeability to Ca2+. Study of Ca2+-ATPase protein arrangement in the membrane indicated that the heat treatment induced protein oligomerization and some of the Ca2+-ATPase molecules acquired intermolecular and intramolecular covalent bonds. From these data, we have concluded that the changes in the surface and structure properties of the vesicle membranes after the short-term heat treatment were the result of clustering of the Ca2+-ATPase molecules. This protein rearrangement may create channels for calcium leakage from light sarcoplasmic reticulum vesicles.
- Добавил в систему: Рубцов Александр Михайлович