对鱿鱼（佩氏枪乌贼）视神经节膜制备物中（钠+ +钾+）-ATP酶的特性研究。
Characterization of the the (Na + +K+)-ATPase in a membranous preparation from the optic ganglion of the squid (Loligo pealei).
作者信息
Breitwieser G E
出版信息
Biochim Biophys Acta. 1982 Aug 12;689(3):457-63. doi: 10.1016/0005-2736(82)90303-0.
(1) A membrane fraction enriched in (Na+ +K+)-ATPase (EC 3.6.1.3) was obtained from optic ganglia of the squid (Loligo pealei) by density gradient fractionation of membranes followed by treatment with either SDS or Brij-58. The resulting membrane had an (Na+ +K+)-ATPase specific activity of approx. 2 units/mg and was greater than 95% ouabain-sensitive. (2) The (Na+ +K+)-ATPase had a Km for ATP of 0.42 +/- 0.04 mM and a pH optimum of 7.0. It was inhibited by ouabain with a Ki of 0.32 +/- 0.04 microM. (3) Optimum monovalent cation concentrations were: 240 mM NaCl, 60 mM KCl, tested with NaCl + KCl = 300 mM. (4) The Mg2+ dependence of hydrolysis varied with the absolute ATP concentration. At 3 mM ATP, the Km for Mg2+ was 0.86 +/- 0.10 mM, and at 6 mM ATP, the Km was 1.86 +/- 0.44 mM. High levels of Mg2+ caused inhibition of hydrolysis. (5) The interactions of Na+ and K+ were examined over a range of conditions. K+ levels caused modulations in the Na+ dependence in the range of 1-150 mM. (6) The (Na+ +K+)-ATPase prepared from squid optic ganglion displays properties similar to those of the sodium pump in injected nerves.
(1) 通过对膜进行密度梯度分级分离，随后用十二烷基硫酸钠（SDS）或聚氧乙烯月桂醚（Brij - 58）处理，从鱿鱼（美洲大赤鱿）的视神经节中获得了富含（Na⁺ + K⁺）-ATP 酶（EC 3.6.1.3）的膜组分。所得膜的（Na⁺ + K⁺）-ATP 酶比活性约为 2 单位/毫克，且对哇巴因敏感的比例大于 95%。(2) 该（Na⁺ + K⁺）-ATP 酶对 ATP 的 Km 为 0.42±0.04 毫摩尔，最适 pH 为 7.0。它被哇巴因抑制，Ki 为 0.32±0.04 微摩尔。(3) 最佳单价阳离子浓度为：240 毫摩尔氯化钠，60 毫摩尔氯化钾，在氯化钠 + 氯化钾 = 300 毫摩尔的条件下进行测试。(4) 水解对镁离子的依赖性随 ATP 绝对浓度而变化。在 3 毫摩尔 ATP 时，对镁离子的 Km 为 0.86±0.10 毫摩尔，在 6 毫摩尔 ATP 时，Km 为 1.86±0.44 毫摩尔。高浓度的镁离子会导致水解受到抑制。(5) 在一系列条件下研究了钠离子和钾离子的相互作用。钾离子水平在 1 - 150 毫摩尔范围内会引起对钠离子依赖性的调节。(6) 从鱿鱼视神经节制备的（Na⁺ + K⁺）-ATP 酶表现出与注入神经中的钠泵相似的特性。
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