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Regulation of the Phosphorylation of Mitochondrial Pyruvate Dehydrogenase Complex in Situ  Effects of Respiratory Substrates and Calcium

Regulation of the Phosphorylation of Mitochondrial Pyruvate Dehydrogenase Complex in Situ... Abstract The activity of the pyruvate dehydrogenase complex (PDC), as controlled by reversible phosphorylation, was studied in situ with mitochondria oxidizing dfifferent substrates. PDCs from both plant and animal tissues were inactivated when pyruvate became limiting. The PDC did not inactivate in the presence of saturating levels of pyruvate. Calcium stimulated reactivation of PDC in chicken heart but not pea (Pisum sativum L.) leaf mitochondria. With pea leaf mitochondria oxidizing malate, inactivation of PDC was pH dependent corresponding to the production of pyruvate via malic enzyme. When pea leaf mitochondria oxidized succinate or glycine, PDC was inactivated. This inactivation was reversed by the addition of pyruvate. Reactivation by pyruvate was enhanced by the addition of thiamine pyrophosphate, as previously observed with nonrespiring mitochondria. These results indicate a major role for pyruvate in regulating the covalent modification of the PDC. 1 This research was supported in part by the Missouri Agriculture Experimental Station, National Science Foundation grant DMB-8506473 and the Food for the 21st Century Program. This is journal report 10468 from the Missouri Agricultural Experiment Station. This content is only available as a PDF. © 1988 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Plant Physiology Oxford University Press

Regulation of the Phosphorylation of Mitochondrial Pyruvate Dehydrogenase Complex in Situ  Effects of Respiratory Substrates and Calcium

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References (21)

Publisher
Oxford University Press
Copyright
Copyright © 2021 American Society of Plant Biologists
ISSN
0032-0889
eISSN
1532-2548
DOI
10.1104/pp.88.4.1031
Publisher site
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Abstract

Abstract The activity of the pyruvate dehydrogenase complex (PDC), as controlled by reversible phosphorylation, was studied in situ with mitochondria oxidizing dfifferent substrates. PDCs from both plant and animal tissues were inactivated when pyruvate became limiting. The PDC did not inactivate in the presence of saturating levels of pyruvate. Calcium stimulated reactivation of PDC in chicken heart but not pea (Pisum sativum L.) leaf mitochondria. With pea leaf mitochondria oxidizing malate, inactivation of PDC was pH dependent corresponding to the production of pyruvate via malic enzyme. When pea leaf mitochondria oxidized succinate or glycine, PDC was inactivated. This inactivation was reversed by the addition of pyruvate. Reactivation by pyruvate was enhanced by the addition of thiamine pyrophosphate, as previously observed with nonrespiring mitochondria. These results indicate a major role for pyruvate in regulating the covalent modification of the PDC. 1 This research was supported in part by the Missouri Agriculture Experimental Station, National Science Foundation grant DMB-8506473 and the Food for the 21st Century Program. This is journal report 10468 from the Missouri Agricultural Experiment Station. This content is only available as a PDF. © 1988 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Journal

Plant Physiology – Oxford University Press

Published: Dec 1, 1988

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