Demonstration of acid—base phosphorylation in chromatophores in the presence of a K<sup>+</sup> diffusion potential

Leiser, Margarita; Gromet-Elhanan, Zippora

doi:10.1016/0014-5793(74)80658-7

Cited by 31 publications

(15 citation statements)

References 18 publications

(7 reference statements)

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“…PMS in all cases was 50 PM. The PMS-supported phosphorylation activity of the control was 600 Fmol ATP formed/h X mg Bchl a double additive effect [22,23] creating a lightinduced ApH and a superimposed potassium diffusion potential in the dark, whereas in the presence of SCNthe ApH' was almost totally the result of a lightinduced ApH. It must also be remembered that the ApH' produced in the presence of valinomycin + K' is lower than that measured in the presence of other lipophilic anions [25,26].…”

Section: Elsevierjnorth-holland Biomedical Pressmentioning

confidence: 95%

“…Post-illumination ATP synthesis was measured according to [22,23], in the presence of either 1 r_1M valinomycin + 100 mM KC1 added in the light stage or in the dark, or in the presence of 10 mM NaSCN.…”

Section: Rhodospirillum Rubrummentioning

confidence: 99%

“…However, a difference is readily apparent; thus, when PMS + valinomycin + K+ were present during pre-illumination, no inhibition was detected, whereas for SCN-under the same conditions, the dark ATP synthesis activity was strongly dependent on the pre-illumination time. The reason for such a difference is not obvious considering that under both conditions a stimulation of the H' uptake [22,23] is produced as a consequence of the ability of both substances to decrease the membrane potential. Moreover, both of them stimulate post-illumination ATP synthesis [22,23].…”

Section: Elsevierjnorth-holland Biomedical Pressmentioning

confidence: 99%

“…The reason for such a difference is not obvious considering that under both conditions a stimulation of the H' uptake [22,23] is produced as a consequence of the ability of both substances to decrease the membrane potential. Moreover, both of them stimulate post-illumination ATP synthesis [22,23]. When valinomycin + K' were added in the dark stage and thus inducing a potassium diffusion potential [23], an inhibition of dark ATP synthesis was again observed by pre-illuminating the membrane, at pH 6.0, in the presence of PMS.…”

Section: Elsevierjnorth-holland Biomedical Pressmentioning

confidence: 99%

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PMS photo‐inhibition in Rhodospirillum rubrum membranes in the presence of permeant entities affecting either the Δψ or the Δ pH components of the protonmotive force

1978

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Section: Elsevierjnorth-holland Biomedical Pressmentioning

confidence: 95%

Section: Rhodospirillum Rubrummentioning

confidence: 99%

Section: Elsevierjnorth-holland Biomedical Pressmentioning

confidence: 99%

Section: Elsevierjnorth-holland Biomedical Pressmentioning

confidence: 99%

See 2 more Smart Citations

PMS photo‐inhibition in Rhodospirillum rubrum membranes in the presence of permeant entities affecting either the Δψ or the Δ pH components of the protonmotive force

1978

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“…Leiser and Gromet-Elhanan [8] have reported that ATP can be formed in Rhodospirillum rubrum chromatophores under energization by an artificially imposed K+-diffusion potential alone or together with a ApH. A pH jump alone only gave rise to very little formation of ATP.…”

Section: Introductionmentioning

confidence: 99%

Demonstration of ΔpH‐ and Δψ‐induced synthesis of inorganic pyrophosphate in chromatophores from Rhodospirillum rubrum

Strid¹,

Karlsson²,

Baltscheffsky³

1987

FEBS Letters

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It is possible to obtain synthesis of PPi by artifical ion potentials in Rhodospirillum rubrum chromatophores. PPi can be formed by K +-diffusion gradients (A ~,), H + gradients (ApH) or a combination of both. In contrast, ATP can only be synthesized by imposed A~u or d~,+dpH. For ATP formation there is also a threshold value of K + concentration below which synthesis of ATP is not possible. Such a threshold is not found for PP~ formation. Both PPi and ATP syntheses are abolished by addition of FCCP or nigericin and only marginally affected by electron transport inhibitors. The synthesis of PPi can be monitored for several minutes before it ceases, while ATP production stops within 30 s. As a result the maximal yield of PPi is 200 nmol PPi//tmol BChl, while that of ATP is no more than 25 nmol ATP/Itmol BChl. The initial rates of syntheses were 0.50/tmol PPd/lmol BChl per min and 2.0/tmol ATP/~tmol per min, respectively. These rates are approx. 50 and 20% of the respective photophosphorylation rates under saturating illumination.Acid-base jump; Bioluminescence; H +-ATPase; H +-Pyrophosphatase; K +-diffusion potential; (Rhodospirillum rubrum)

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Contribution of Membrane Potentials to Energy Conversion in Photosynthetic Membranes

Huber¹,

Rumberg²,

Siggel³

1980

Ber Bunsenges Phys Chem

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The conversion of the energy of light into the chemical energy of ATP occurs at the photosynthetic membrane with the transmembrane electrochemical gradient of protons as intermediate. The electric portion, i.e. the light‐induced change of the electric potential difference (photopotential), quickly attains a maximum of 200 mV after the onset of illumination and decreases toward the steady state for the benefit of the H+‐concentration gradient. The resulting stationary photopotential is determined by two different methods, on the one hand directly through the electrochromic absorption change of membrane pigments, on the other hand by calculating the change of the surface potential at the inner side of the membrane from the surface charge densities. The charge density in the dark state is derived from the kinetics of an electron transfer reaction in the membrane (reduction of oxidized chlorophyll‐aI) sensitive to the pH of the inner surface. Its dependence on pH is characterized by an isoelectric point of 4.8. The light‐induced change of the charges is determined from the amount of protons additionally bound to the inner membrane surface. For the calculation of surface potentials from the charge densities the conventional Gouy‐Chapman theory is modified by assuming a transverse spreading of surface charges over a layer of 20 A thickness. — The results of both the methods are similar. The stationary transmembrane photopotential is dependent on the concentration of electrolyte and exhibits a maximal value of 60–70 mV at 6 mM KCl. Under physiological conditions the contribution of the photopotential is below 20 mV and can be neglected compared to the light‐induced difference in proton concentration with respect to energetic and kinetic considerations.

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Demonstration of acid—base phosphorylation in chromatophores in the presence of a K⁺ diffusion potential

Cited by 31 publications

References 18 publications

PMS photo‐inhibition in Rhodospirillum rubrum membranes in the presence of permeant entities affecting either the Δψ or the Δ pH components of the protonmotive force

PMS photo‐inhibition in Rhodospirillum rubrum membranes in the presence of permeant entities affecting either the Δψ or the Δ pH components of the protonmotive force

Demonstration of ΔpH‐ and Δψ‐induced synthesis of inorganic pyrophosphate in chromatophores from Rhodospirillum rubrum

Contribution of Membrane Potentials to Energy Conversion in Photosynthetic Membranes

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Demonstration of acid—base phosphorylation in chromatophores in the presence of a K+ diffusion potential

Cited by 31 publications

References 18 publications

PMS photo‐inhibition in Rhodospirillum rubrum membranes in the presence of permeant entities affecting either the Δψ or the Δ pH components of the protonmotive force

PMS photo‐inhibition in Rhodospirillum rubrum membranes in the presence of permeant entities affecting either the Δψ or the Δ pH components of the protonmotive force

Demonstration of ΔpH‐ and Δψ‐induced synthesis of inorganic pyrophosphate in chromatophores from Rhodospirillum rubrum

Contribution of Membrane Potentials to Energy Conversion in Photosynthetic Membranes

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Demonstration of acid—base phosphorylation in chromatophores in the presence of a K⁺ diffusion potential