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Plant Physiology logoLink to Plant Physiology
. 1997 Aug;114(4):1413–1419. doi: 10.1104/pp.114.4.1413

In Vivo and in Vitro Studies of Glucose-6-Phosphate Dehydrogenase from Barley Root Plastids in Relation to Reductant Supply for NO2- Assimilation.

D P Wright 1, H C Huppe 1, D H Turpin 1
PMCID: PMC158434  PMID: 12223780

Abstract

Pyridine nucleotide pools were measured in intact plastids from roots of barley (Hordeum vulgare L.) during the onset of NO2- assimilation and compared with the in vitro effect of the NADPH/NADP ratio on the activity of plastidic glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49) from N-sufficient or N-starved roots. The NADPH/NADP ratio increased from 0.9 to 2.0 when 10 mM glucose-6-phosphate was supplied to intact plastids. The subsequent addition of 1 mM NaNO2 caused a rapid decline in this ratio to 1.5. In vitro, a ratio of 1.5 inactivated barley root plastid G6PDH by approximately 50%, suggesting that G6PDH could remain active during NO2- assimilation even at the high NADPH/NADP ratios that would favor a reduction of ferredoxin, the electron donor of NO2- reductase. Root plastid G6PDH was sensitive to reductive inhibition by dithiothreitol (DTT), but even at 50 mM DTT the enzyme remained more than 35% active. In root plastids from barley starved of N for 3 d, G6PDH had a substantially reduced specific activity, had a lower Km for NADP, and was less inhibited by DTT than the enzyme from N-sufficient root plastids, indicating that there was some effect of N starvation on the G6PDH activity in barley root plastids.

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Selected References

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  1. Anderson L. E., Ng T. C., Park K. E. Inactivation of pea leaf chloroplastic and cytoplasmic glucose 6-phosphate dehydrogenases by light and dithiothreitol. Plant Physiol. 1974 Jun;53(6):835–839. doi: 10.1104/pp.53.6.835. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Borchert S., Harborth J., Schunemann D., Hoferichter P., Heldt H. W. Studies of the Enzymic Capacities and Transport Properties of Pea Root Plastids. Plant Physiol. 1993 Jan;101(1):303–312. doi: 10.1104/pp.101.1.303. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1016/0003-2697(76)90527-3. [DOI] [PubMed] [Google Scholar]
  4. Buchanan B. B. Regulation of CO2 assimilation in oxygenic photosynthesis: the ferredoxin/thioredoxin system. Perspective on its discovery, present status, and future development. Arch Biochem Biophys. 1991 Jul;288(1):1–9. doi: 10.1016/0003-9861(91)90157-e. [DOI] [PubMed] [Google Scholar]
  5. Farr T. J., Huppe H. C., Turpin D. H. Coordination of Chloroplastic Metabolism in N-Limited Chlamydomonas reinhardtii by Redox Modulation (I. The Activation of Phosphoribulosekinase and Glucose-6-Phosphate Dehydrogenase Is Relative to the Photosynthetic Supply of Electrons). Plant Physiol. 1994 Aug;105(4):1037–1042. doi: 10.1104/pp.105.4.1037. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Fickenscher K., Scheibe R. Purification and properties of the cytoplasmic glucose-6-phosphate dehydrogenase from pea leaves. Arch Biochem Biophys. 1986 Jun;247(2):393–402. doi: 10.1016/0003-9861(86)90598-9. [DOI] [PubMed] [Google Scholar]
  7. Graeve K., von Schaewen A., Scheibe R. Purification, characterization, and cDNA sequence of glucose-6-phosphate dehydrogenase from potato (Solanum tuberosum L.). Plant J. 1994 Mar;5(3):353–361. doi: 10.1111/j.1365-313x.1994.00353.x. [DOI] [PubMed] [Google Scholar]
  8. Green L. S., Yee B. C., Buchanan B. B., Kamide K., Sanada Y., Wada K. Ferredoxin and ferredoxin-NADP reductase from photosynthetic and nonphotosynthetic tissues of tomato. Plant Physiol. 1991;96:1207–1213. doi: 10.1104/pp.96.4.1207. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Hirasawa M., Chang K. T., Knaff D. B. Characterization of a ferredoxin:NADP+ oxidoreductase from a nonphotosynthetic plant tissue. Arch Biochem Biophys. 1990 Jan;276(1):251–258. doi: 10.1016/0003-9861(90)90035-w. [DOI] [PubMed] [Google Scholar]
  10. Hirasawa M., Sung J. D., Malkin R., Zilber A., Droux M., Knaff D. B. Evidence for the presence of a [2Fe-2S] ferredoxin in bean sprouts. Biochim Biophys Acta. 1988 Jul 6;934(2):169–176. doi: 10.1016/0005-2728(88)90179-x. [DOI] [PubMed] [Google Scholar]
  11. Hong Z. Q., Copeland L. Isoenzymes of glucose 6-phosphate dehydrogenase from the plant fraction of soybean nodules. Plant Physiol. 1991 Jul;96(3):862–867. doi: 10.1104/pp.96.3.862. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Huppe H. C., Farr T. J., Turpin D. H. Coordination of Chloroplastic Metabolism in N-Limited Chlamydomonas reinhardtii by Redox Modulation (II. Redox Modulation Activates the Oxidative Pentose Phosphate Pathway during Photosynthetic Nitrate Assimilation). Plant Physiol. 1994 Aug;105(4):1043–1048. doi: 10.1104/pp.105.4.1043. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Huppe H. C., Turpin D. H. Appearance of Novel Glucose-6-Phosphate Dehydrogenase Isoforms in Chlamydomonas reinhardtii during Growth on Nitrate. Plant Physiol. 1996 Apr;110(4):1431–1433. doi: 10.1104/pp.110.4.1431. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Lendzian K., Bassham J. A. Regulation of glucose-6-phosphate dehydrogenase in spinach chloroplasts by ribulose 1,5-diphosphate and NADPH/NADP+ ratios. Biochim Biophys Acta. 1975 Aug 11;396(2):260–275. doi: 10.1016/0005-2728(75)90040-7. [DOI] [PubMed] [Google Scholar]
  15. Morigasaki S., Takata K., Sanada Y., Wada K., Yee B. C., Shin S., Buchanan B. B. Novel forms of ferredoxin and ferredoxin-NADP reductase from spinach roots. Arch Biochem Biophys. 1990 Nov 15;283(1):75–80. doi: 10.1016/0003-9861(90)90614-5. [DOI] [PubMed] [Google Scholar]
  16. Morigasaki S., Takata K., Suzuki T., Wada K. Purification and Characterization of a Ferredoxin-NADP Oxidoreductase-Like Enzyme from Radish Root Tissues. Plant Physiol. 1990 Jul;93(3):896–901. doi: 10.1104/pp.93.3.896. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Scheibe R., Geissler A., Fickenscher K. Chloroplast glucose-6-phosphate dehydrogenase: Km shift upon light modulation and reduction. Arch Biochem Biophys. 1989 Oct;274(1):290–297. doi: 10.1016/0003-9861(89)90441-4. [DOI] [PubMed] [Google Scholar]
  18. Smith R. G., Gauthier D. A., Dennis D. T., Turpin D. H. Malate- and pyruvate-dependent Fatty Acid synthesis in leucoplasts from developing castor endosperm. Plant Physiol. 1992 Apr;98(4):1233–1238. doi: 10.1104/pp.98.4.1233. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Suzuki A., Oaks A., Jacquot J. P., Vidal J., Gadal P. An electron transport system in maize roots for reactions of glutamate synthase and nitrite reductase : physiological and immunochemical properties of the electron carrier and pyridine nucleotide reductase. Plant Physiol. 1985 Jun;78(2):374–378. doi: 10.1104/pp.78.2.374. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. von Schaewen A., Langenkämper G., Graeve K., Wenderoth I., Scheibe R. Molecular characterization of the plastidic glucose-6-phosphate dehydrogenase from potato in comparison to its cytosolic counterpart. Plant Physiol. 1995 Dec;109(4):1327–1335. doi: 10.1104/pp.109.4.1327. [DOI] [PMC free article] [PubMed] [Google Scholar]

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