Thermogenic activity of Ca2+-ATPase from skeletal muscle heavy sarcoplasmic reticulum:: The role of ryanodine Ca2+ channel
Thermogenic activity of Ca2+-ATPase from skeletal muscle heavy sarcoplasmic reticulum:: The role of ryanodine Ca2+ channel
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DOI：
10.1016/j.bbamem.2007.03.016
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发表时间：
2007-06-01
影响因子：
3.4
通讯作者：
de Meis, Leopoldo
中科院分区：
文献类型：
--
作者：
Arruda, Ana Paula;Nigro, Mariana;de Meis, Leopoldo
肌浆网Ca 2 + ATP酶1（SERCA 1）能够以这样的方式处理来自ATP水解的能量，以确定用于Ca 2+转运的能量包和转化为热的部分。在这项工作中，我们测量了SERCA 1在两个肌浆网（SR）部分中的产热：富含SERCA的轻组分（LSR）和含有SERCA和ryanodine Ca 2+通道的重组分（HSR）。我们证实，虽然HSR切割ATP的速度比LSR快，释放的热量在ATP水解过程中由HSR小于LSR测量。因此，与LSR相比，HSR切割的每摩尔ATP释放的热量（Δ H-cal）较低。在HSR中，加入5 mM Mg 2+或钌红，关闭兰尼碱Ca 2+通道的条件，促进ATP酶活性降低，但ATP水解过程中释放的热量几乎保持不变。在此条件下，ATP水解的Δ H-cal值显著增加。Mg ~（2+）和钌红对LSR无影响。因此，我们得出结论，热的产生SERCA 1取决于该酶插入的SR的区域，在HSR中，ATP水解的Δ H-cal的SERCA 1取决于是否兰尼碱钙通道是打开或关闭。(c)2007 Elsevier B. V.保留所有权利。
The sarcoplasmic reticulum Ca2+ ATPase 1 (SERCA 1) is able to handle the energy derived from ATP hydrolysis in such a way as to determine the parcel of energy that is used for Ca2+ transport and the fraction that is converted into heat. In this work we measured the heat production by SERCA 1 in the two sarcoplasmic reticulum (SR) fractions: the light fraction (LSR), which is enriched in SERCA and the heavy fraction (HSR), which contains both the SERCA and the ryanodine Ca2+ channel. We verified that although HSR cleaved ATP at faster rate than LSR, the amount of heat released during ATP hydrolysis by HSR was smaller than that measured by LSR. Consequently, the amount of heat released per mol of ATP cleaved (Delta H-cal) by HSR was lower compared to LSR. In HSR, the addition of 5 mM Mg2+ or ruthenium red, conditions that close the ryanodine Ca2+ channel, promoted a decrease in the ATPase activity, but the amount of heat released during ATP hydrolysis remained practically the same. In this condition, the Delta H-cal values of ATP hydrolysis increased significantly. Neither Mg2+ nor ruthenium red had effect on LSR. Thus, we conclude that heat production by SERCA 1 depends on the region of SR in which the enzyme is inserted and that in HSR, the Delta H-cal of ATP hydrolysis by SERCA 1 depends on whether the ryanodine Ca2+ channel is opened or closed. (c) 2007 Elsevier B.V. All rights reserved.