Changes of total water and sucrose space accompanying induced ion uptake or phosphate swelling of rat liver mitochondria |
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| Authors: | E. J. Harris and K. Van Dam |
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| Affiliation: | Department of Biophysics, University College London, Gower Street, London, W.C. 1, and Laboratory of Biochemistry, B.C.P. Jansen Institute, University of Amsterdam, Plantage Muidergracht, Amsterdam, The Netherlands |
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| Abstract: | 1. Total water exchangeable with tritiated water and sucrose space were measured in rat liver mitochondria during the uptake of K(+) induced by valinomycin and the release caused by nigericin. The K(+) content and the sucrose-inaccessible water rose and fell together. 2. Swelling resulting from phosphate addition in a medium of high K(+) concentration was associated mainly with increased sucrose-accessible water, which carried dissolved K(+). This change was reversed by addition of ATP. 3. The response of the sucrose-inaccessible space to changed osmolarity was qualitatively that expected if the mitochondrial K(+) is assumed to be present in this space with a univalent anion. 4. It is brought out that the light-scattering method fails to distinguish between changes in sucrose space and in sucrose-inaccessible space, which in the present experiments could be altered respectively by phosphate (in high K(+) solution) and by cation uptake induced by antibiotic. |
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