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Plant Physiology 75:548-553 (1984) © 1984 American Society of Plant Biologists Control of Photosynthetic Sucrose Synthesis by Fructose 2,6-Bisphosphate 1I. Coordination of CO2 Fixation and Sucrose SynthesisLehrstuhl für Biochemie der Pflanze, Universität Göttingen, Untere Karspüle 2, 3400 Göttingen, Federal Republic of Germany
A mechanism is proposed for a feed-forward control of photosynthetic sucrose synthesis, which allows withdrawal of carbon from the chloroplast for sucrose synthesis to be coordinated with the rate of carbon fixation. (a) Decreasing the rate of photosynthesis of spinach (Spinacia oleracea, U.S. hybrid 424) leaf discs by limiting light intensities or CO2 concentrations leads to a 2-to 4-fold increase in fructose 2,6-bisphosphate. (b) This increase can be accounted for by lower concentrations of metabolites which inhibit the synthesis of fructose 2,6-bisphosphate, such as dihydroxyacetone phosphate and 3-phosphoglycerate. (c) Thus, as photosynthesis decreases, lower levels of dihydroxyacetone phosphate should inhibit the cytosolic fructose bisphosphatase via simultaneously lowering the concentration of the substrate fructose 1,6-bisphosphate, and raising the concentration of the inhibitor fructose 2,6-bisphosphate.
1 Supported by the Deutsche Forschungsgemeinschaft. This article has been cited by other articles:
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