Synthesis of ATP induced in pea chloroplasts by single turnover flashes

Galmiche, J.M.; Girault, G.

doi:10.1016/0014-5793(82)80718-7

Cited by 11 publications

(5 citation statements)

References 32 publications

(33 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We already reported [11] that ATP synthesis after a group of two flashes, t o ms apart, was more than twice that observed after a single flash when flashes and flash groups were fired at the same frequency, 0.1 Hz. That was particularly obvious at external pH 7.…”

Section: H +/Atp Value After a Group Of Two Flashes As A Function Of mentioning

confidence: 88%

“…Procedures were essentially the same as those reported in Ref. 11. Type B chloroplasts [12] with active ATP synthase were prepared from preilluminated leaves of pea seedlings.…”

Section: Methodsmentioning

confidence: 99%

“…Chloroplasts prepared from preilluminated leaves have an active ATP synthase [10,11]. With these chloroplasts we followed, by monitoring the luminescence of the luciferin-luciferase system, the ATP synthesis on separate flashes or groups of flashes [11], given at a frequency of 0.1 Hz. This method offered the convenience of measuring the actual flash-induced ATP synthesis corrected for the dark hydrolysis of ATP.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the concomitant proton efflux across the membrane could also be determined from the first derivative of the dark decay of the absorbance changes at 515 nm, AA515, as a function of time [7]. We already [11] reported variations in the yield of ATP synthesized per flash as a function of the external pH and of the dark period, tD, between two successive flashes of the flash group. The synthesis of ATP was generally independent on the number of flashes already fired.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Flash-induced ATP synthesis in pea chloroplasts in relation to proton flux

Lemaire¹,

Girault²,

Galmiche³

1985

Biochimica et Biophysica Acta (BBA) - Bioenergetics

Self Cite

View full text Add to dashboard Cite

Chloroplasts extracted from preilluminated pea seedling leaves have an active ATP synthase. Single turnover flashes induce ATP synthesis in these chloroplasts. This synthesis has been measured by the luminescence of the luciferin-luciferase assay system and the absorbance changes at 515 nm monitored to determine the concomitant proton flux through the ATP-synthase. Variations in the ratio H +/ATP are observed and can be explained by the way ATP synthase is operating. The newly synthesized ATP molecules remain bound to the enzyme, and have variable probabilities to be hydrolysed or released from the enzyme, dependent upon the energized state of the membranes. The lowest value found for the ratio, H +/ATP, is 1.90 + 0.55, which should be very close to the true value.

show abstract

Section: H +/Atp Value After a Group Of Two Flashes As A Function Of mentioning

confidence: 88%

“…Procedures were essentially the same as those reported in Ref. 11. Type B chloroplasts [12] with active ATP synthase were prepared from preilluminated leaves of pea seedlings.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Flash-induced ATP synthesis in pea chloroplasts in relation to proton flux

Lemaire¹,

Girault²,

Galmiche³

1985

Biochimica et Biophysica Acta (BBA) - Bioenergetics

Self Cite

View full text Add to dashboard Cite

show abstract

“…Our estimation of ApH is based on the calibration value of 0.015 pH unit per flash using atebrin with the same chloroplasts [4]. Calibration of ApH induced by a single turnover flash in freeze-thawed chloroplasts [14] as well as an estimation of ApH per flash in fresh chloroplasts [9] yielded values higher than 0.015 pH unit.…”

Section: Accumulation Of Transmembrane Z2~phmentioning

confidence: 99%

Dependence of energization of thylakoids on frequency of exciting flashes in intact chloroplasts

1987

View full text Add to dashboard Cite

We investigated the frequency-dependence of the flash-induced electrochromic absorbance change, ΔA515, and of the pH-indicating absorbance change of neutral red in isolated intact chloroplasts. The energization pattern of thylakoids depended strongly on the frequency (f) of the exciting flashes, tested between 0.05 and 2 s(-1). When the frequency was increased from 0.1 to 1 s(-1) the total initial change and the slow rise of ΔA515 decreased by about 30% and 70%, respectively, and both the slow rise and decay were considerably accelerated. These changes were fully reversible, even after prolonged excitation at 1 s(-1), if the frequency was decreased again to 0.1 s(-1). Accumulation of an appreciable transmembrane electric field strength could not be detected in any of our experiments, at high frequency, since the decay of ΔA515 was considerably accelerated when the frequency was increased. In contrast, ΔpH significantly increased at higher frequencies of the exciting flashes. In the steady-state (after about 100 flashes) ΔpH was about 0.5-0.8 pH unit higher than in the dark or at low frequencies. In the presence of nigericin or dithionite, both of which prevented accumulation of protons in the lumen, the total initial change in ΔA515 at f=1 s(-1) relative to that at f=0.1 s(-1) decreased to a similar extent as in the control. The proportion of the slow rise relative to the initial amplitude, however, did not decrease. Our data support the suggestion that ΔpH controls the amplitude of the slow rise of ΔA515. However, contrary to a previous statement (B. Bouges-Bouquet (1981) Biochim. Biophys. Acta 535, 327-340), we show that the ΔpH effect cannot be accounted for by variation of the rate of this kinetic component of ΔA515.

show abstract