ATP synthesis catalyzed by the purified erythrocyte Ca-ATPase in the absence of calcium gradients.
ATP synthesis catalyzed by the purified erythrocyte Ca-ATPase in the absence of calcium gradients.
复制标题
在没有钙梯度的情况下，纯化的红细胞 Ca-ATP 酶催化 ATP 合成。
DOI：
10.1021/bi00307a009
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发表时间：
1984
期刊：
影响因子：
2.9
通讯作者：
E. Carafoli
中科院分区：
文献类型：
--
作者：
M. Chiesi;M. Zurini;E. Carafoli
用钙调素亲和层析法分离红细胞Ca ~（2+）转运ATP酶。研究了ATP酶的逆向反应。磷酸化的溶解酶的Pi需要镁和抑制钙和钒酸在微摩尔浓度范围内。只有在含有高二甲基亚砜浓度（大于25%）的培养基中才能获得大量的磷酸酶，以减少磷酸化位点的水活性。以这种方式形成的磷酸酶不能磷酸化ADP。然而，在磷酸化的制剂中加入Ca 2+离子和二甲基亚砜稀释（水活度跳跃）后，获得了一种高度反应性的磷酸酶物种，它可以将磷酸盐以接近化学计量的量转移到ADP以形成ATP。
The Ca2+-transporting ATPase of erythrocytes was isolated by calmodulin affinity chromatography. The backward reaction of the ATPase was investigated. The phosphorylation of the solubilized enzyme by Pi required Mg and was inhibited by Ca and vanadate in the micromolar concentration range. Significant amounts of phosphoenzyme could be obtained only in a medium containing high dimethyl sulfoxide concentrations (greater than 25%) in order to diminish water activity at the phosphorylation site. The phosphoenzyme formed in this way could not phosphorylate ADP. However, upon addition of Ca2+ ions and dilution of dimethyl sulfoxide in the phosphorylated preparation (water activity jump), a highly reactive phosphoenzyme species was obtained which could transfer phosphate in nearly stoichiometric amounts to ADP to form ATP.