Studies on sarcoplasmic reticulum from slow-twitch muscle
Studies on sarcoplasmic reticulum from slow-twitch muscle
复制标题
慢肌肌浆网的研究
DOI：
10.1007/bf00711942
复制
发表时间：
1982
影响因子：
2.7
通讯作者：
M. G. Sarzała
中科院分区：
文献类型：
--
作者：
E. Zubrzycka;B. Korczak;H. Osińska;M. G. Sarzała
采用差速离心和蔗糖密度梯度离心的方法，从兔慢缩肌肌浆网（SR）膜中分离出囊泡。在一些实验中，囊泡进一步分级加载草酸钙，然后在蔗糖密度梯度离心分离的囊泡的蛋白质组成是复杂的，不同于快缩肌囊泡的蛋白质组成。然而，其他蛋白质成分，这也是目前在快收缩肌SR囊泡，已被确定：钙离子依赖的ATP酶，钙螯合蛋白，160 000分子量的糖蛋白和53 000分子量的糖蛋白。在慢收缩肌SR囊泡中，Ca2+依赖性ATP酶和钙螯合蛋白的量要低几倍。慢收缩肌SR囊泡在与快收缩肌SR相似的条件下表现出活性钙转运、Ca2+依赖性ATP酶活性和磷酸化中间体的形成。然而，当以每毫克总蛋白表达时，比从快速收缩骨骼肌中分离的SR囊泡中的类似活性低几倍。当以每毫克分子量为105000的ATP酶表示相同的酶活性时，两种囊泡的酶活性值非常接近，表明慢收缩肌SR囊泡的钙转运速率慢可能与膜上的钙转运ATP酶含量低有关。
SummaryVesicles were isolated from membranes of the sarcoplasmic reticulum (SR) of rabbit slow-twitch muscle by differential and sucrose density gradient centrifugation after homogenization. In some experiments, the vesicles were further fractionated by loading them with calcium oxalate followed by centrifugation in a sucrose density gradient.Protein composition of the isolated vesicles was complex and differed from the protein composition of fast-twitch muscle vesicles. However, other protein components, which were also present in fast-twitch muscle SR vesicles, have been identified: Ca2+-dependent ATPase, calsequestrin, 160 000 molecular weight glycoprotein and 53 000 molecular weight glycoprotein. The amount of the Ca2+-dependent ATPase and calsequestrin was several times lower in the slow-twitch muscle SR vesicles. This has been observed in both the original and the loaded vesicles.The slow-twitch muscle SR vesicles showed active calcium transport, Ca2+-dependent ATPase activity, and the formation of the phosphorylated intermediate under conditions similar to those established for fast-twitch muscle SR. However, these activities, when expressed per mg of total protein, were several times lower than the analogous activities in the SR vesicles isolated from fast-twitch skeletal muscle. When the same enzyme activities were expressed per mg of the 105 000 molecular weight ATPase, the values obtained were very similar in both kinds of vesicles.The results indicate that the slow rate of calcium transport, found in slow-twitch muscle SR vesicles, may be related to a low content of the calcium-transporting ATPase in the membrane.
影响因子：
6.5
作者：
W. R. Morrison;L. Smith
通讯作者：
W. R. Morrison;L. Smith