Sweadner K J
J Biol Chem. 1979 Jul 10;254(13):6060-7.
The brain contains two distinct molecular forms of the (Na,K)-ATPase (sodium and potassium ion-stimulated adenosine triphosphatase). They can be resolved by gel electrophoresis in sodium dodecyl sulfate, and can be identified by sodium-dependent, potassium-sensitive phosphorylation by [gamma-32P]ATP. They are present in the brain of every animal species examined, while only one molecular form is detected in the other organs examined. They are located in different kinds of cells within the brain, and can be physically separated while fully active by gentle tissue fractionation procedures. One is the only (Na,K)-ATPase of brain non-neuronal cells (astrocytes), while the other is the only (Na,K)-ATPase of axolemma (plasma membrane of myelinated axons). They differ in at least one kinetic parameter: the affinity for the specific inhibitor strophanthidin. They have similar one-dimensional peptide maps, but differ in their sensitivity to digestion by trypsin and in the number or reactivity of sulfhydryl groups. It is anticipated that they will be found to play functionally different roles in the complex ion transport mechanisms of the brain.
大脑中存在两种不同分子形式的（钠，钾）-ATP酶（钠和钾离子刺激的腺苷三磷酸酶）。它们可以通过十二烷基硫酸钠凝胶电泳分离，并且可以通过[γ-32P]ATP的钠依赖性、钾敏感性磷酸化来鉴定。在每一种被检测的动物物种的大脑中都存在它们，而在其他被检测的器官中只检测到一种分子形式。它们位于大脑内不同类型的细胞中，并且可以通过温和的组织分级分离程序在完全活跃时进行物理分离。一种是大脑非神经元细胞（星形胶质细胞）唯一的（钠，钾）-ATP酶，而另一种是轴膜（有髓轴突的质膜）唯一的（钠，钾）-ATP酶。它们至少在一个动力学参数上有所不同：对特异性抑制剂毒毛旋花子苷的亲和力。它们具有相似的一维肽图，但在对胰蛋白酶消化的敏感性以及巯基的数量或反应性方面有所不同。预计它们将在大脑复杂的离子转运机制中发挥功能不同的作用。
