Transmembrane electrostatically localized protons (TELP) theory has been recently recognized as an important addition over the classic Mitchell’s chemiosmosis; thus, the proton motive force (pmf) is largely contributed from TELP near the membrane. As an extension to this theory, a novel phenomenon of mitochondrial thermotrophic function is now characterized by biophysical analyses of pmf in relation to the TELP concentrations at the liquid-membrane interface. This leads to the conclusion that the oxidative phosphorylation also utilizes environmental heat energy associated with the thermal kinetic energy (kBT) of TELP in mitochondria.
Fig: The values of total pmf, local pmf and classic pmf in mitochondria calculated as a function of membrane potential ΔψΔψ using the newly formulated pmf expression (Eqs. 2−4) in comparison with the minimally required pmf (156 mV) for ATP synthesis and with the redox potential chemical energy upper limit (228 mV).
The local pmf is now calculated to be in a range from 300 to 340 mV while the classic pmf (which underestimates the total pmf) is in a range from 60 to 210 mV in relation to a range of membrane potentials from 50 to 200 mV. Depending on TELP concentrations in mitochondria, this thermotrophic function raises pmf significantly by a factor of 2.6 to sixfold over the classic pmf. Therefore, mitochondria are capable of effectively utilizing the environmental heat energy with TELP for the synthesis of ATP, i.e., it can lock heat energy into the chemical form of energy for cellular functions.
Lee, J.W. Mitochondrial energetics with transmembrane electrostatically localized protons: do we have a thermotrophic feature?. Sci Rep 11, 14575 (2021). https://doi.org/10.1038/s41598-021-93853-x