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The allosteric ATP‐inhibition of cytochrome c oxidase activity is reversibly switched on by cAMP‐dependent phosphorylation
Author(s) -
Bender Elisabeth,
Kadenbach Bernhard
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)01773-1
Subject(s) - allosteric regulation , cytochrome c oxidase , phosphorylation , biochemistry , dephosphorylation , chemistry , atp synthase , protein kinase a , oxidase test , phosphatase , protein subunit , adenosine triphosphate , uncoupling agents , heme a , enzyme , biophysics , oxidative phosphorylation , biology , gene
In previous studies the allosteric inhibition of cytochrome c oxidase at high intramitochondrial ATP/ADP‐ratios via binding of the nucleotides to the matrix domain of subunit IV was demonstrated. Here we show that the allosteric ATP‐inhibition of the isolated bovine heart enzyme is switched on by cAMP‐dependent phosphorylation with protein kinase A of subunits II (and/or III) and Vb, and switched off by subsequent incubation with protein phosphatase 1. It is suggested that after cAMP‐dependent phosphorylation of cytochrome c oxidase mitochondrial respiration is controlled by the ATP/ADP‐ratio keeping the proton motive force Δ p low, and the efficiency of energy transduction high. After Ca 2+ ‐induced dephosphorylation this control is lost, accompanied by increase of Δ p , slip of proton pumping (decreased H + /e − stoichiometry), and increase of the rate of respiration and ATP‐synthesis at a decreased efficiency of energy transduction.