Cohn 1953 J Biol Chem

Cohn M (1953) A study of oxidative phosphorylation with O18-labeled inorganic phosphate. J Biol Chem 201:735-50.

» PMID: 13061412 Open Access

Cohn M (1953) J Biol Chem

Abstract: A new reaction which occurs in oxidative phosphorylation associated with the electron transport system has been observed in rat liver mitochondria with α-ketoglutarate, β-hydroxybutyrate, and succinate as substrates. This reaction manifests itself by a replacement of O18 with normal oxygen in inorganic phosphate labeled with O18 and parallels the phosphorylation which is associated with the oxidation. The number of molecules of inorganic phosphate which participate in this reaction, calculated on the basis that a monoester of phosphate is involved, is several times higher than the number of high energy phosphate bonds that can be formed. The reaction does not occur at the substrate level oxidation of α-ketoglutarate and the evidence suggests that it occurs at every step in the electron transport system.

This phosphate turnover reaction occurs only when phosphorylation is proceeding. Dinitrophenol suppresses the reaction. The omission of Mg++ or adenylic acid also suppresses the reaction. The reaction is abolished when succinate oxidation is catalyzed by a succinic oxidase preparation containing no phosphorylating system. The possibility that the reaction is due to a direct reaction of ATP, hydrolytic or otherwise, is eliminated. Various mechanisms which are consistent with the findings are discussed. • Keywords: Oxidative phosphorylation, O18-labelled inorganic phosphate, phosphate turnover reaction

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Organism: Rat  Tissue;cell: Liver  Preparation: Isolated mitochondria 

Regulation: ATP; ADP; AMP; PCr"ATP; ADP; AMP; PCr" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property., Substrate  Coupling state: OXPHOS 

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