Subcellular distribution of enzymes of the oxidative pentose phosphate pathway in root and leaf tissues

Debnam, Phillip; Emes, Michael J.

doi:10.1093/jxb/50.340.1653

Cited by 80 publications

(34 citation statements)

References 19 publications

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“…In addition, given that NADPH is not easily transported across membranes but, rather, operates through indirect shuttle systems, all these NADP-dehydrogenases usually have different isozymes which are localized in the different subcellular compartments. Although the localization of some of these NADPdehydrogenases in the different organelles has been described in different plant species (Gálvez and Gadal, 1995;Corpas et al, 1998Corpas et al, , 1999Debnam and Emes, 1999;Hodges et al, 2003;Kruger and von Schaewen, 2003;Leterrier et al, 2007), the availability of genomes in higher plants such as Arabidopsis thaliana and Oryza sativa has facilitated a more systematic analysis of different NADP-dehydrogenases (Chi et al, 2004;Wakao and Benning, 2005;Wheeler et al, 2005).…”

Section: Subcellular Nadp-dehydrogenase Compartmentalization As a Nadmentioning

confidence: 99%

NADPH-generating dehydrogenases: their role in the mechanism of protection against nitro-oxidative stress induced by adverse environmental conditions

Corpas

Barroso

2014

Front. Environ. Sci.

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NADPH is an essential reductive coenzyme in biosynthetic processes such as cell growth, proliferation, and detoxification in eukaryotic cells. It is required by antioxidative systems such as the ascorbate-glutathione cycle and is also necessary for the generation of superoxide radicals by plant NADPH oxidases and for the generation of nitric oxide (NO) by L-arginine-dependent nitric oxide synthase. This coenzyme is principally re-generated by a group of NADP-dehydrogenases enzymes including glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH), both belonging to the pentose phosphate pathway, the NADP-malic enzyme (NADP-ME), and NADP-isocitrate dehydrogenase (NADP-ICDH). In this study, current perspectives on these enzymes in higher plants under different stress situations are reviewed and it is also pointed out that this group of NADPH-generating dehydrogenases is a key element in supporting the mechanism of response to nitro-oxidative stress situations.

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Section: Subcellular Nadp-dehydrogenase Compartmentalization As a Nadmentioning

confidence: 99%

NADPH-generating dehydrogenases: their role in the mechanism of protection against nitro-oxidative stress induced by adverse environmental conditions

Corpas

Barroso

2014

Front. Environ. Sci.

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“…ADPglucose pyrophosphorylase (AGPase), aldolase, enolase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphofructokinase, phosphoglucose isomerase, phosphoglycerate kinase, pyruvate kinase and triose-phosphate isomerase were assayed as detailed in Fernie et al (2001b); cytosolic fructose 1,6-bisphosphatase (cFBPase) was assayed as described Kruger and Beevers (1984); maximal and selective activities of sucrose phosphate synthase (SPS) were assessed following the protocol of Reimholz et al (1994) and UDPglucose pyrophosphorylase (UGPase) activity was determined as described by Sweetlove et al (1996). Rubisco was assayed as detailed in Sharkey et al (1991), NADP + -specific GAPDH as detailed in Leegood and Walker (1980), phosphoribulokinase as described in Haake et al (1998) and transketolase as detailed in Debnam and Emes (1999).…”

Section: Enzyme Analysismentioning

confidence: 99%

Carbon assimilation and metabolism in potato leaves deficient in plastidial phosphoglucomutase

Lytovchenko

Bieberich

Willmitzer

et al. 2002

Planta

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We have previously described the generation of transgenic potato ( Solanum tuberosum L. cv. Desiree) lines expressing the S. tuberosum plastidial phosphoglucomutase ( StpPGM) gene in the antisense orientation under the control of the 35S promoter and characterised heterotrophic metabolism in these lines [E. Tauberger et al. (2000) Plant J 23:43-53]. The aim of the current work was to examine the role of plastidial phosphoglucomutase (pPGM, EC 5.4.2.2) in photosynthetic carbon partitioning. Here we characterise the metabolism of leaves of the same lines and show that reducing the activity of this enzyme has profound effects on carbon partitioning, characterised by a strong (up to 50%) reduction in the rate of starch accumulation accompanied by a minor reduction in the rate of sucrose accumulation. Gas-exchange and (14)CO(2)-feeding experiments revealed that the transgenic lines exhibited a decreased rate of photosynthesis and a corresponding reduced assimilation of radiolabel into starch, even in lines exhibiting only a minor decrease in pPGM activity. In illuminated leaves, decreasing the amount of pPGM resulted in decreased amounts of triose-phosphates, hexose-phosphates and inorganic phosphate without changes in the level of 3-phosphoglycerate. Most importantly, the deduced ratio of phosphoesters to inorganic phosphate increased, indicating the likelihood that photosynthesis was phosphate-limited in these lines. Determination of a more complete metabolic profile of leaf material from these lines revealed a large number of changes in the levels of amino and organic acids, consistent with an inhibition of triose-phosphate export from the chloroplast, but little change in the energy status of the transformants. We discuss the implications of these changes with respect to both consequences of inhibiting starch synthesis and of inhibiting photosynthesis, and conclude that a high activity of pPGM is required both to prevent phosphate limitation of photosynthesis and for co-ordination of plastidially and cytosolically compartmented photosynthetic metabolism.

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“…The Calvin cycle is localized in plastids. There are some uncertainties about the localization of the oxidative pentose phosphate pathway, which takes place in the cytoplasm in animal cells and fungi, whereas the complete pathway in plants is only localized to chloroplasts according to Schnarrenberger et al (1995), Debnam and Emes (1999), and Henkes et al (2001). All plant transketolase enzymes of the Calvin cycle and the oxidative pentose phosphate pathway reported so far are nuclear encoded, and transported into the chloroplasts (Flechner et al 1996;Teige et al 1998;Henkes et al 2001;Gerhardt et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Subcellular localization and enzymatic properties of differentially expressed transketolase genes isolated from the desiccation tolerant resurrection plant Craterostigma plantagineum

Willige

Kutzer

Tebartz

et al. 2008

Planta

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The desiccation tolerant resurrection plant Craterostigma plantagineum encodes three classes of transketolase transcripts, which are distinguished by their gene structures and their expression patterns. One class, represented by tkt3, is constitutively expressed and two classes, represented by tkt7 and tkt10, are upregulated upon rehydration of desiccated C. plantagineum plants. The objective of this work was to characterize the differentially expressed transketolase isoforms with respect to subcellular localization and enzymatic activity. Using GFP fusion constructs and enzymatic activity assays, we demonstrate that C. plantagineum has novel forms of transketolase which localize not to the chloroplast, but mainly to the cytoplasm and which are distinct in the enzymatic properties from the transketolase enzymes active in the Calvin cycle or oxidative pentose phosphate pathway. A transketolase preparation from rehydrated leaves was able to synthesize the unusual C8 carbon sugar octulose when glucose-6-phosphate and hydroxy-pyruvate were used as acceptor and donor molecules in in vitro assays. This suggests that a transketolase catalyzed reaction is likely to be involved in the octulose biosynthesis in C. plantagineum.

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Subcellular distribution of enzymes of the oxidative pentose phosphate pathway in root and leaf tissues

Cited by 80 publications

References 19 publications

NADPH-generating dehydrogenases: their role in the mechanism of protection against nitro-oxidative stress induced by adverse environmental conditions

NADPH-generating dehydrogenases: their role in the mechanism of protection against nitro-oxidative stress induced by adverse environmental conditions

Carbon assimilation and metabolism in potato leaves deficient in plastidial phosphoglucomutase

Subcellular localization and enzymatic properties of differentially expressed transketolase genes isolated from the desiccation tolerant resurrection plant Craterostigma plantagineum

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