Eddy A A, Hopkins P, Johnson E
Department of Biochemistry and Applied Molecular Biology, University of Manchester Institute of Science and Technology, U.K.
Biophys Chem. 1988 Feb;29(1-2):119-25. doi: 10.1016/0301-4622(88)87031-5.
Accumulation of 2-aminoisobutyrate by mouse ascites tumour cells was studied in circumstances where nigericin reversed the normal direction of the Na+ concentration gradient. The membrane potential (delta psi) was assayed using oxonol V as a voltage-sensitive probe. The amino acid gradient (delta mu A) that formed did not significantly exceed the likely magnitude of the Na+ electrochemical gradient when this was in the range 2-6 kJ mol-1. When delta-Na mu increased up to 11 kJ mol-1, delta mu A was almost constant at 7-8 kJ mol-1. The observations indicate that when delta psi is large changes in cellular [Na+] in the range 16-80 mM scarcely affect delta mu A.
