Regulation of Plant Pyruvate Dehydrogenase Complex by Phosphorylation 1
AUTOR(ES)
Rubin, Paul M.
RESUMO
The ATP-dependent inactivation of the pyruvate dehydrogenase complex (PDC) was examined using ruptured mitochondria and partially purified pyruvate dehydrogenase complex isolated from broccoli and cauliflower (Brassica oleracea) bud mitochondria. The ATP-dependent inactivation was temperature- and pH-dependent. [32P]ATP experiments show a specific transphosphorylation of the γ-PO4 of ATP to the complex. The phosphate attached to the PDC was labile under mild alkaline but not under mild acidic conditions. The inactivated-phosphorylated PDC was not reactivated by 20 mm MgCl2, dialysis, Sephadex G-25 treatment, apyrase action, or potato acid phosphatase action. However, partially purified bovine heart PDC phosphatase catalyzed the reactivation and dephosphorylation of the isolated plant PDC. The ATP-dependent inactivation-phosphorylation of the PDC was inhibited by pyruvate. It is concluded that the ATP-dependent inactivation-phosphorylation of broccoli and cauliflower mitochondrial PDC is catalyzed by a PDC kinase. It is further concluded that the PDC from broccoli and cauliflower mitochondria is capable of interconversion between an active (dephosphorylated) and an inactive (phosphorylated) form.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=542541Documentos Relacionados
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