Some novel aspects of the relationship between the amino acid gradient and the sodium electrochemical gradient in mouse ascites tumour cells.
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.
Eddy
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Department of Biochemistry and Applied Molecular Biology, University of Manchester Institute of Science and Technology, U.K.
Hopkins
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Johnson
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D000465:Algorithms; D000596:Amino Acids / Q000378:metabolism*; D000621:Aminoisobutyric Acids / Q000378:metabolism; D000818:Animals; D001201:Ascites / Q000378:metabolism; D001693:Biological Transport, Active; D004563:Electrochemistry; D007555:Isoxazoles / Q000494:pharmacology; D051379:Mice; D009374:Neoplasms, Experimental / Q000378:metabolism*; D009550:Nigericin / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*; D014407:Tumor Cells, Cultured / Q000378:metabolism
D000596:Amino Acids; D000621:Aminoisobutyric Acids; D007555:Isoxazoles; C100049:2-aminoisobutyric acid; C013633:oxonol V; D012964:Sodium; D009550:Nigericin