Abstract
Glucose-6-phosphate dehydrogenase (G6PDH) is the key enzyme of the oxidative pentose phosphate pathway supplying reducing power (as NADPH) in non-photosynthesizing cells. We have examined in detail the redox regulation of the plastidial isoform predominantly present in Arabidopsis green tissues (AtG6PDH1) and found that its oxidative activation is strictly dependent on plastidial thioredoxins (Trxs) that show differential efficiencies. Light/dark modulation of AtG6PDH1 was reproduced in vitro in a reconstituted ferredoxin/Trx system using f-type Trx allowing to propose a new function for this Trx isoform co-ordinating both reductive (Calvin cycle) and oxidative pentose phosphate pathways.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Arabidopsis / cytology
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Arabidopsis / enzymology
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Arabidopsis Proteins / chemistry
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism*
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Chloroplast Thioredoxins / genetics
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Chloroplast Thioredoxins / metabolism*
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Chloroplasts / enzymology*
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Cysteine / metabolism
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Darkness
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Ferredoxins / metabolism
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Glucosephosphate Dehydrogenase / chemistry
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Glucosephosphate Dehydrogenase / genetics
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Glucosephosphate Dehydrogenase / metabolism*
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Isoenzymes / chemistry
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Isoenzymes / genetics
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Isoenzymes / metabolism
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Light
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Models, Molecular
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Oxidation-Reduction
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Protein Structure, Tertiary
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
Substances
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Arabidopsis Proteins
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Chloroplast Thioredoxins
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Ferredoxins
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Isoenzymes
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Recombinant Proteins
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Glucosephosphate Dehydrogenase
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Cysteine