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. 1992 Sep;100(1):184–190. doi: 10.1104/pp.100.1.184

Transport Processes and Corresponding Changes in Metabolite Levels in Relation to Starch Synthesis in Barley (Hordeum vulgare L.) Etioplasts 1

Olaf Batz 1, Renate Scheibe 1, H Ekkehard Neuhaus 1
PMCID: PMC1075535  PMID: 16652944

Abstract

Intact etioplasts with an intactness of 85% and with a cytosolic and a mitochondrial contamination of less than 10% were isolated from 8-d-old dark-grown barley (Hordeum vulgare) leaves. These plastids contained starch equivalent to 21.5 μmol of glucose per mg protein. From various likely precursors applied to isolated etioplasts, only dihydroxyacetone phosphate (DHAP) had significant effects on metabolite levels and on the internal ATP/ADP ratio. The concentration dependence of DHAP uptake exhibited saturation characteristics with half saturation at 0.36 mm DHAP and a maximal velocity of 6.6 μmol mg−1 of protein h−1. The transport was significantly inhibited by inorganic phosphate, pyridoxal-5′-phosphate, and 4,4′-diisothiocyano-2,2′-stilbenedisulfonate. The rate of glucose-6-phosphate uptake was much lower and not saturable up to a concentration of 10 mm. Exogenously applied [14C]DHAP was incorporated into starch at a rate of 0.14 μmol of DHAP mg−1 of protein h−1. Enzyme activities required to convert DHAP into starch were found to be present in etioplasts. Furthermore, enzymes generating ATP from DHAP for ADPglucose synthesis were also detected. Finally, a scheme is presented suggesting DHAP uptake to serve both as carbon skeleton and as energy source for starch synthesis, mediated by a translocator with properties similar to those of the triose phosphate translocator from chloroplasts.

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Selected References

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  1. Cockburn W., Goh C. J., Avadhani P. N. Photosynthetic Carbon Assimilation in a Shootless Orchid, Chiloschista usneoides (DON) LDL: A Variant on Crassulacean Acid Metabolism. Plant Physiol. 1985 Jan;77(1):83–86. doi: 10.1104/pp.77.1.83. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Echeverria E., Boyer C. D., Thomas P. A., Liu K. C., Shannon J. C. Enzyme activities associated with maize kernel amyloplasts. Plant Physiol. 1988 Mar;86(3):786–792. doi: 10.1104/pp.86.3.786. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Entwistle G., Rees T. A. Enzymic capacities of amyloplasts from wheat (Triticum aestivum) endosperm. Biochem J. 1988 Oct 15;255(2):391–396. doi: 10.1042/bj2550391. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Fliege R., Flügge U. I., Werdan K., Heldt H. W. Specific transport of inorganic phosphate, 3-phosphoglycerate and triosephosphates across the inner membrane of the envelope in spinach chloroplasts. Biochim Biophys Acta. 1978 May 10;502(2):232–247. doi: 10.1016/0005-2728(78)90045-2. [DOI] [PubMed] [Google Scholar]
  5. Flügge U. I., Heldt H. W. Specific labelling of a protein involved in phosphate transport of chloroplasts by pyridoxal-5'-phosphate. FEBS Lett. 1977 Oct 1;82(1):29–33. doi: 10.1016/0014-5793(77)80878-8. [DOI] [PubMed] [Google Scholar]
  6. Heldt H. W., Sauer F. The inner membrane of the chloroplast envelope as the site of specific metabolite transport. Biochim Biophys Acta. 1971 Apr 6;234(1):83–91. doi: 10.1016/0005-2728(71)90133-2. [DOI] [PubMed] [Google Scholar]
  7. Kruckeberg A. L., Neuhaus H. E., Feil R., Gottlieb L. D., Stitt M. Decreased-activity mutants of phosphoglucose isomerase in the cytosol and chloroplast of Clarkia xantiana. Impact on mass-action ratios and fluxes to sucrose and starch, and estimation of Flux Control Coefficients and Elasticity Coefficients. Biochem J. 1989 Jul 15;261(2):457–467. doi: 10.1042/bj2610457. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Mohabir G., John P. Effect of temperature on starch synthesis in potato tuber tissue and in amyloplasts. Plant Physiol. 1988 Dec;88(4):1222–1228. doi: 10.1104/pp.88.4.1222. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Piazza G. J., Smith M. G., Gibbs M. Characterization of the Formation and Distribution of Photosynthetic Products by Sedum praealtum Chloroplasts. Plant Physiol. 1982 Dec;70(6):1748–1758. doi: 10.1104/pp.70.6.1748. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Schäfer G., Heber U. Glucose transport into spinach chloroplasts. Plant Physiol. 1977 Aug;60(2):286–289. doi: 10.1104/pp.60.2.286. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Sowokinos J. R. Pyrophosphorylases in Solanum tuberosum: I. Changes in ADP-Glucose and UDP-Glucose Pyrophosphorylase Activities Associated with Starch Biosynthesis during Tuberization, Maturation, and Storage of Potatoes. Plant Physiol. 1976 Jan;57(1):63–68. doi: 10.1104/pp.57.1.63. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Winter K., Foster J. G., Edwards G. E., Holtum J. A. Intracellular Localization of Enzymes of Carbon Metabolism in Mesembryanthemum crystallinum Exhibiting C(3) Photosynthetic Characteristics or Performing Crassulacean Acid Metabolism. Plant Physiol. 1982 Feb;69(2):300–307. doi: 10.1104/pp.69.2.300. [DOI] [PMC free article] [PubMed] [Google Scholar]

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