, Volume 149, Issue 1, pp 48–51

The mechanism of the control of carbon fixation by the pH in the chloroplast stroma

Studies with acid mediated proton transfer across the envelope
  • U. I. Flügge
  • M. Freisl
  • H. W. Heldt


The salts of several weak acids have been used to render the envelope permeable to protons. In order to investigate the role of stromal pH changes in the light regulation of CO2 fixation, formate, octanoate, nitrite, and glyoxylate have been tried as tools to reverse the light-dependent alkalization of the stroma. For this purpose, the decrease of the stromal pH in illuminated spinach chloroplasts, as caused by the addition of these substances or by instantaneous lowering of the pH in the medium, has been compared with the corresponding decrease of CO2 fixation and the change of stromal metabolite levels. It appears from out data that formate and octanoate are suited best to obtain a specific inhibition of CO2 fixation by lowering the stromal pH. The measurement of the corresponding metabolite levels indicates that this inhibition is primarily due to an inhibition of fructose- and sedoheptulose bisphosphatase. It is concluded that these two enzymes are important regulatory steps for the light control of CO2 fixation.

Key words

Chloroplast CO2 fixation Fructose 1.6-bisphosphatase Proton transfer Sedoheptulose 1.7-bisphosphatase Spinacia 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Baier, D., Latzko, E. (1975) Properties and regulation of C-1-fructose-1,6-diphosphatase from spinach chloroplasts. Biochim. Biophys. Acta 396, 141–148Google Scholar
  2. Buchanan, B.B., Wolosiuk, R.A., Schürmann, P. (1979) Thioredoxin and enzyme regulation. Trends Biochem. Sci. 4, 93–96Google Scholar
  3. Enser, U., Heber, U. (in print) Metabolic regulation by pH gradients. Biochim. Biophys. ActaGoogle Scholar
  4. Gimmler, H., Schäfer, G., Heber, U. (1975) Low permeability of the chloroplast envelope towards cations. In: 3rd Int. Congr. Photosynth., pp. 1381–1392, Avron, M., ed. North Holland, AmsterdamGoogle Scholar
  5. Heber, U., Enser, U., Weiss, E., Ziem, U., Giersch, C. (in print) Regulation of the photosynthetic carbon cycle, phosphorylation and electron transport in illuminated intact chloroplasts. Proc. of the ICN-UCLA Symposium Covalent and non-covalent modulation of protein function. Atkinson, D.A., ed.Google Scholar
  6. Heldt, H.W., Werdan, K., Milovancev, M., Geller, G. (1973) Alkalization of the chloroplast stroma caused by light dependent proton flux into the thylakoid space. Biochim. Biophys. Acta 314, 224–241PubMedGoogle Scholar
  7. Heldt, H.W., Flügge, U.I., Fliege, R. (1978) The influence of illumination on the transport of 3-phosphoglycerate across the chloroplast envelope. In: Mechanism of proton and calcium pumps, pp. 105–114, Avron, M., Azzone, G.F., Metcalfe, J., Quagliariello, E., Siliprandi, N., eds. North Holland, AmsterdamGoogle Scholar
  8. Kaiser, W.M., Bassham, J.A. (1979) Levels of metabolites in chloroplasts and medium during light-dark transition. Plant Physiol. 63, 105–108Google Scholar
  9. Lilley, R. McC., Chon, C.J., Mosbach, A., Heldt, H.W. (1977) The distribution of metabolites between spinach chloroplasts and medium during photosynthesis in vitro. Biochim. Biophys. Acta 460, 259–272Google Scholar
  10. Lorimer, G.H., Badger, M.R., Heldt, H.W. (1978) The activation of ribulose-1.5-biphosphate carboxylase-oxigenase. In: Photosynthetic carbon assimilation, pp. 283–306. Plenum Publishing Co., New York LondonGoogle Scholar
  11. Portis, A.R., Chon, C.J., Mosbach, A., Heldt, H.W. (1977) Fructose- and sedoheptulose bisphosphatase: The sites of a possible control of CO2 fixation by light dependent changes of the stromal Mg2+ concentration. Biochim. Biophys. Acta 461, 313–325Google Scholar
  12. Preiss, J., Biggs, M., Greenberg, E. (1967) The effect of magnesium ion concentration on the pH optimum of the spinach leaf alkaline fructose diphosphatase. J. Biol. Chem. 242, 2292–2294Google Scholar
  13. Purczeld, P., Chon, C.J., Portis, A.R., Heldt, H.W., Heber, U. (1978) The mechanism of the control of carbon fixation by the pH in the chloroplast stroma. Biochim. Biophys. Acta 501, 531–544Google Scholar
  14. Werdan, K., Heldt, H.W., Milovancev, M. (1975) The role of the pH in the regulation of carbon fixation in the chloroplast stroma. Biochim. Biophys. Acta 396, 276–292Google Scholar

Copyright information

© Springer-Verlag 1980

Authors and Affiliations

  • U. I. Flügge
    • 1
  • M. Freisl
    • 1
  • H. W. Heldt
    • 1
  1. 1.Institut für Physiologische Chemie, Physikalische Biochemie und ZellbiologieUniversität MünchenMünchen 2Federal Republic of Germany
  2. 2.Lehrstuhl für Biochemie der Pflanze der Universität GöttingenGöttingenFederal Republic of Germany

Personalised recommendations