An electrochemical potential difference for protons (μH+) across the membrane of bacterial chromatophores was induced by an artificially generated pH difference (pH) and a K+/valinomycin diffusion potential, φ. The initial rate of ATP synthesis was measured with a rapid‐mixing quenched‐flow apparatus in the time range between 70 ms and 30 s after the acid–base transition. The rate of ATP synthesis depends exponentially on pH;. Increasing diffusion potentials shift the pH dependency to lower pH values. Diffusion potentials were calculated from the Goldman equation. Using estimated permeability coefficients, the rate of ATP synthesis depends only on the electrochemical potential difference of protons irrespective of the relative contribution of pH and φ. Copyright © 1991, Wiley Blackwell. All rights reserved
TURINA P., MELANDRI B.A., GRABER P. (1991). ATP synthesis in chromatophores driven by artificially induced ion gradients. EUROPEAN JOURNAL OF BIOCHEMISTRY, 196(1), 225-229 [10.1111/j.1432-1033.1991.tb15808.x].
ATP synthesis in chromatophores driven by artificially induced ion gradients
TURINA P.;MELANDRI B. A.;
1991
Abstract
An electrochemical potential difference for protons (μH+) across the membrane of bacterial chromatophores was induced by an artificially generated pH difference (pH) and a K+/valinomycin diffusion potential, φ. The initial rate of ATP synthesis was measured with a rapid‐mixing quenched‐flow apparatus in the time range between 70 ms and 30 s after the acid–base transition. The rate of ATP synthesis depends exponentially on pH;. Increasing diffusion potentials shift the pH dependency to lower pH values. Diffusion potentials were calculated from the Goldman equation. Using estimated permeability coefficients, the rate of ATP synthesis depends only on the electrochemical potential difference of protons irrespective of the relative contribution of pH and φ. Copyright © 1991, Wiley Blackwell. All rights reservedI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
