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Cited by 397Photosynthetic Processes and MechanismsPlant nutrient uptake and metabolismATP Synthase and ATPases Research

The DOI matches its Crossref record; 27 of the 27 references it cites were found in a registry or an index.

The role of pH in the regulation of carbon fixation in the chloroplast stroma. Studies on CO2 fixation in the light and dark

Werdan, Karl, Heldt, Hans W., Milovancev, Mirjana·1975·Biochimica et Biophysica Acta (BBA) - Bioenergetics
DOI 10.1016/0005-2728(75)90041-9
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Abstract

1. The pH in the stroma and in the thylakoid space has been measured in a number of chloroplast preparations in the dark and in the light at 20 degrees C. Illumination causes a decrease of the pH in the thylakoid space by 1.5 and an increase of the pH in the stroma by almost 1 pH unit. 2. CO2 fixation is shown to be strongly dependent on the pH in the stroma. The pH optimum was 8.1, with almost zero activity below pH 7.3.Phosphoglycerate reduction, which is a partial reaction of CO2 fixation, shows very little pH dependency. 3. Low concentrations of the uncoupler m-chlorocarbonylcyanide phenylhydrazone (CCCP) inhibit CO2 fixation without affecting phosphoglycerate reduction. This inhibition of CO2 fixation appears to be caused by reversal of light induced alkalisation in the stroma by CCCP. 4. Methylamine has a very different effect compared to CCCP. Increasing concentrations of methylamine inhibit CO2 fixation and phosphoglycerate reduction to the same extent. The light induced alkalisation of the stroma appears not to be significantly inhibited by methylamine, but the protons in the thylakoid space are neutralized. The inhibition of CO2 fixation by higher concentrations of methylamine is explained by an inhibition of photophosphorylation. It appears that methylamine does not abolish proton transport. 5. It is shown that intact chloroplasts are able to fix CO2 in the dark, yielding 3-phosphoglycerate. This requires the addition of dihydroxyacetone phosphate as precursor of ribulosemonophosphate and also to supply ATP, and the addition of oxaloacetate for reoxidation of the NADPH in the stroma. 6. Dark CO2 fixation in the presence of dihydroxyacetone phosphate and oxaloacetate has the same pH dependency as CO2 fixation in the light. This demonstrates that CO2 fixation in the dark is not possible, unless the pH in the medium is artificially raised to pH 8.8.

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Crossref · 10.1016/0005-2728(75)90041-9

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Research works printed but not linked: 1

  1. Hind, 1974, 71, 1484

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Metadata

Authors
Werdan, K., Heldt, H. W., & Milovancev, M.
Affiliations
Ludwig-Maximilians-Universität München (DE)
ORCID
Werdan, Karl
Venue
Biochimica et Biophysica Acta (BBA) - Bioenergetics
Publisher
Elsevier BV
Published
1975-08
Volume
396
Issue
2
Pages
276-292
ISSN
0005-2728 (ISSN-L)
DOI
10.1016/0005-2728(75)90041-9
OpenAlex
W2019784795
Cited by
391
References
27
Citations by year
2026: 7 · 2025: 3 · 2024: 6 · 2023: 10 · 2022: 7 · 2021: 9 · 2020: 10 · 2019: 4 · 2018: 7 · 2017: 8 · 2016: 6 · 2015: 9 · 2014: 7 · 2013: 4 · 2012: 7
FWCI
7.35
Type
journal article
Language
en
Open access
closed
Licence
www.elsevier.com/tdm/userlicense/1.0/ (tdm)
Locations
  • Biochimica et Biophysica Acta (BBA) - Bioenergetics (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Photosynthetic Processes and Mechanisms
  • Life Sciences › Agricultural and Biological Sciences › Plant Science › Plant nutrient uptake and metabolism
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › ATP Synthase and ATPases Research
Keywords
CO2 fixation, dark CO2 fixation, dihydroxyacetone phosphate, oxaloacetate, proton transport
MeSH terms
Adenosine Triphosphate, Bicarbonates, Carbon Dioxide, Carbonyl Cyanide m-Chlorophenyl Hydrazone, Chloroplasts, Darkness, Dihydroxyacetone Phosphate, Dithiothreitol, Glyceric Acids, Hydrogen-Ion Concentration, Kinetics, Light, Malates, Methylamines, Organoids, Oxaloacetates, Oxygen

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Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).

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