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. 1973 Dec;70(12 Pt 1-2):3730–3734. doi: 10.1073/pnas.70.12.3730

Oxaloacetate as the Hill Oxidant in Mesophyll Cells of Plants Possessing the C4-Dicarboxylic Acid Cycle of Leaf Photosynthesis

Marvin L Salin 1, Wilbur H Campbell 1, Clanton C Black Jr 1
PMCID: PMC427316  PMID: 16592125

Abstract

Isolated mesophyll cells from leaves of plants that use the C4 dicarboxylic acid pathway of CO2 fixation have been used to demonstrate that oxaloacetic acid reduction to malic acid is coupled to the photochemical evolution of oxygen through the presumed production of NADPH. The major acid-stable product of light-dependent CO2 fixation is shown to be malic acid. In the presence of phosphoenolpyruvate and bicarbonate the stoichiometry of CO2 fixation into acid-stable products to O2 evolution is shown to be near 1.0. Thus oxaloacetic acid acts directly as the Hill oxidant in mesophyll cell chloroplasts. The experiments are taken as a firm demonstration that the C4 dicarboxylic acid cycle of photosynthesis is the major pathway for the fixation of CO2 in mesophyll cells of plants having this pathway.

Keywords: CO2 fixation, uncoupler, photochemical reactions, electron transport, O2 evolution

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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