Cell Respiration is Controlled by ATP, an Allosteric Inhibitor of Cytochrome‐c Oxidase

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Abstract
The activity of cytochrome‐c oxidase, the terminal enzyme of the mitochondria) respiratory chain, is known to be regulated by the substrate pressure, i.e. the ferro‐/ferricytochrome c ratio, by the oxygen concentration, and by the electrochemical proton gradient ΔμH+ across the inner mitochondrial membrane. Here we describe a further mechanism of ‘respiratory control’ via allosteric inhibition of cytochrome‐c oxidase by ATP, which binds to the matrix domain, of subunit IV. The cooperativity between cytochrome‐c‐binding sites in the dimeric enzyme complex is mediated by cardiolipin, which is essential for cooperativity of the enzyme within the lipid membrane.