title: Electrochemical proton gradient of Brevibacterium linens and its relationship to phenylalanine transport.
abstract: The proton motive force generated by Brevibacterium linens was determined by the accumulation of radiolabelled tetraphenylphosphonium for transmembrane potential (delta psi) and by the accumulation of benzoate ions for the H+ chemical gradient (delta pH). In resting cells at pH 8.0, the delta psi was 172 +/- 10 mV while delta pH was 9 mV. The additions of valinomycin to B. linens in the presence of 100 mM exogenous potassium reduced the delta psi and led to a drastic inhibition of phenylalanine transport. These findings are consistent with the hypothesis that a membrane potential is essential for active phenylalanine transport in B. linens cells at pH 8.0. Phenylalanine transport in these cells (halotolerant strain) did not depend on the presence of Na+.
mesh_terms: D001693:Biological Transport, Active / Q000187:drug effects; D001951:Brevibacterium / Q000378:metabolism*; D004734:Energy Metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008094:Lithium / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D010649:Phenylalanine / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D011522:Protons; D012964:Sodium / Q000494:pharmacology; D014634:Valinomycin / Q000494:pharmacology
chemical_list: D011522:Protons; D014634:Valinomycin; D010649:Phenylalanine; D008094:Lithium; D012964:Sodium; D011188:Potassium