The flow method of reaction rate measurement has been adapted to the determination of the rate of diffusion of water into the human red cell. In seven experiments the half-time for diffusion exchange has been found to be 4.2 ± 1.1 msec., which is equivalent to a diffusion flow of 8.6 x 10–9 ml. H2O/(sec., red cell). This figure has been compared with the rate of water entrance under an osmotic pressure gradient, and has been found to be smaller by a factor of 2.5. The difference between these two rates of water entrance has been interpreted as indicating the presence of water-filled channels in the membrane. An estimate of the equivalent radius of these channels (on the assumption of uniform right cylindrical pores) leads to a value of 3.5 Å, which is viewed as an operational description of the resistance offered by the membrane to the passage of water.
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November 20 1957
THE RATE OF EXCHANGE OF TRITIATED WATER ACROSS THE HUMAN RED CELL MEMBRANE
C. V. Paganelli
,
C. V. Paganelli
From the Biophysical Laboratory of Harvard Medical School, Boston
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A. K. Solomon
A. K. Solomon
From the Biophysical Laboratory of Harvard Medical School, Boston
Search for other works by this author on:
C. V. Paganelli
From the Biophysical Laboratory of Harvard Medical School, Boston
A. K. Solomon
From the Biophysical Laboratory of Harvard Medical School, Boston
Received:
May 03 1957
Online Issn: 1540-7748
Print Issn: 0022-1295
Copyright, 1957, by The Rockefeller Institute for Medical Research
1957
J Gen Physiol (1957) 41 (2): 259–277.
Article history
Received:
May 03 1957
Citation
C. V. Paganelli, A. K. Solomon; THE RATE OF EXCHANGE OF TRITIATED WATER ACROSS THE HUMAN RED CELL MEMBRANE . J Gen Physiol 20 November 1957; 41 (2): 259–277. doi: https://doi.org/10.1085/jgp.41.2.259
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