Membrane adenosine triphosphatase as a participant in the active transport of sodium and potassium in the human erythrocyte.
Membrane adenosine triphosphatase as a participant in the active transport of sodium and potassium in the human erythrocyte.
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DOI：
10.1016/s0021-9258(19)76884-7
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发表时间：
1960-06
期刊：
影响因子：
--
通讯作者：
R. Post;C. R. Merritt;C. R. Kinsolving;C. Albright
中科院分区：
文献类型：
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作者：
R. Post;C. R. Merritt;C. R. Kinsolving;C. Albright
METHODSTransport of Sodium and Potassium in Intact Cells-Sodium and potassium transport in intact cells was measured with the method reported previously (7) with slight modifications. In this method net transport was determined from the changes in the cation contents of the cells with time. Cation contents were measured by flame photometry and were referred to cell Hb measured optically as cyanmethemoglobin. One liter of normal cells contains 5 mmoles of Hb. Active transport is expressed as the sum of sodium movement outward plus potassium movement inward. The movements are calculated from the differences of relatively large contents so that the larger movements of sodium (7) are more precisely determined and are weighted more heavily in the final estimate of transport rate. Corrections for simultaneous passive transport were made by incubating identical cell suspensions with ouabain, 2.5 X 10-Gm, which stops active transport specifically (10, 11). The changes in cell contents during incubation introduced small differences in the membrane electrochemical potential gradients between the test and control cells. These were neglected. The passive permeability of erythrocyte membranes to sodium and potassium ions in our experience usually lies between 0.01 and 0.02 mmole (5 mmoles of Hb)-1 hour-lmM-l expressed as the ratio of change in rate of net movement to change in external concentration. An improved incubation solution which gave a more uniform rate of active transport and less passive transport was used. The solution, pH 7.6, had the following composition:
