On the origin of the limited control of mitochondrial respiration by the adenine nucleotide translocator

Abstract

A thermodynamic control theory previously developed has been applied to mitochondrial oxidative phosphorylation with emphasis on the role of Δ \\ ̃ gm H and coupling and within the paradigm of delocalized chemiosmotic coupling. The basis for the observed distribution of flux control over the participating enzymes is shown to lie in the relative magnitudes of so-called Δ μ h elasticity coefficients, i.e., the Δ μ h dependencies of the different mitochondrial processes. In particular the relatively strong Δ μ h dependence of mitochondrial respiration is responsible for the significant role of the adenine nucleotide translocator in the control of oxidative phosphorylation. Uncoupling decreases the control exerted by this translocator on respiration but increases that exerted on phosporylation.