Kemmler W, Löffler G
Diabetologia. 1977 May;13(3):235-8. doi: 10.1007/BF01219705.
Shifts in the distribution of the monovalent cations Na+ and K+ between the extra- and intracellular space seem to be important for the secretory response of the beta-cell. An attempt was therefore made to study the enzyme responsible for monovalent cation transport, the (NaK)-activated ATPase. In the presence of NaN3 as inhibitor of the mitochondrial Mg-ATPase, a NaK-ATPase with a specific activity of 72 mU X mg protein-1 could be demonstrated in crude membrane preparations of rat pancreatic islets. The enzyme, which was inactive in the absence of Mg++, needed both Na+ and K+ for activation and was inhibited by ouabain and PCMB. The main part of the NaK-ATPase was localized in the microsomal fraction. Glucose, sulphonylureas, somatostatin and diazoxide were without effect on NaK-ATPase.
单价阳离子Na⁺和K⁺在细胞外和细胞内空间之间的分布变化似乎对β细胞的分泌反应很重要。因此，人们试图研究负责单价阳离子转运的酶，即（钠钾）激活的ATP酶。在NaN₃作为线粒体Mg-ATP酶抑制剂存在的情况下，在大鼠胰岛的粗膜制剂中可以证明一种比活性为72 mU·mg蛋白⁻¹的钠钾ATP酶。该酶在没有Mg²⁺时无活性，需要Na⁺和K⁺两者来激活，并被哇巴因和对氯汞苯甲酸抑制。钠钾ATP酶的主要部分定位于微粒体部分。葡萄糖、磺酰脲类、生长抑素和二氮嗪对钠钾ATP酶没有影响。
