The allosteric ATP‐inhibition of cytochrome c oxidase activity is reversibly switched on by cAMP‐dependent phosphorylation
Year: 2000
Type: article
Abstract: 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 Deltap low, and the efficiency of energy transduction high. After Ca(2+)-induced dephosphorylation this control is lost, accompanied by increase of Deltap, 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.
Source: FEBS Letters
Authors: Elisabeth Bender, Bernhard Kadenbach
Institution: Philipps University of Marburg
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W2050688382