LOCALIZATION OF NA+-K+-ATPASE IN CELLS OF RAT KIDNEY CORTEX - STUDY ON ISOLATED PLASMA MEMBRANES
LOCALIZATION OF NA+-K+-ATPASE IN CELLS OF RAT KIDNEY CORTEX - STUDY ON ISOLATED PLASMA MEMBRANES
复制标题
DOI：
10.1007/bf00586614
复制
发表时间：
1971-01-01
影响因子：
4.5
通讯作者：
KINNESAF.E
中科院分区：
文献类型：
--
作者：
KINNE, R;SCHMITZ, JE;KINNESAF.E
通过连续和不连续蔗糖梯度离心和无载体连续电泳，对大鼠肾皮质质膜组分进行了细分。在不同的组分中，碱性磷酸酶和氨基肽酶，刷状缘膜中存在的酶，以及Mg++-ATP酶，Na+−K+-ATP酶，5′-核苷酸酶，酸性磷酸酶和葡萄糖-6-磷酸酶的活性被测定。碱性磷酸酶，氨基肽酶和5′-核苷酸酶的分布是相同的，表明这些酶在刷状缘膜中的定位。Na+−K+-ATP酶的分布与所研究的任何酶都不相同。使用无载体连续电泳可以获得与皮层匀浆相比碱性磷酸酶富集15倍的组分，而Na+−K+-ATP酶的比活性降低至起始材料的三分之一。另一方面，可以分离出Na+−K+-ATP酶比活性比匀浆高16倍的组分。这些组分中没有碱性磷酸酶的富集，因此可以得出结论，Na+−K+-ATP酶既不存在于刷状缘膜中，也不存在于溶酶体或内质网中。Na+−K+-ATP酶最可能的定位是细胞质膜的基底内折叠。
Plasma membrane fractions of rat kidney cortex were subdivided by centrifugation on a continuous and a discontinuous sucrose gradient and by carrier free continuous electrophoresis. In the different fractions the activity of alkaline phosphatase and aminopeptidase, enzymes which are present in the brushborder membrane, as well as Mg++-ATPase, Na+−K+-ATPase, 5′-nucleotidase, acid phosphatase and glucose-6-phosphatase were determined.The distribution of alkaline phosphatase, aminopeptidase and 5′-nucleotidase is identical, indicating the localization of these enzymes in the brushborder membrane. Na+−K+-ATPase does not show an identical distribution with any of the enzymes studied.Using carrier free continuous electrophoresis fractions can be obtained which are enriched in alkaline phosphatase by a factor of 15 when compared to the cortex homogenate, whereas the specific activity of Na+−K+-ATPase is reduced to one third of the starting material. On the other hand fractions can be isolated in which the specific activity of Na+−K+-ATPase is 16 times higher than in the homogenate. No enrichment of alkaline phosphatase occurs in these fractions.It is therefore concluded that the Na+−K+-ATPase is not present in the brushborder membrane nor in the lysosomes or endoplasmatic reticulum. The most probable localization of the Na+−K+-ATPase are the basal infoldings of the plasma membranes of the cells.