An exploration of how the thermodynamic efficiency of bioenergetic membrane systems varies with c-subunit stoichiometry of F₁F₀ ATP synthases.Recently the F0 portion of the bovine mitochondrial F1F0-ATP synthase was shown to contain eight 'c' subunits (n = 8).  This surprised many in the field, as previously, the only other mitochondrial F0 (for yeast) was shown to have ten 'c' subunits.  The metabolic implications of 'c' subunit copy number explored in this paper lead to several surprising conclusions: (1) Aerobically respiring E. coli (n = 10) and animal mitochondria (n = 8) both have very high F1F0 thermodynamic efficiencies of ≈90% under typical conditions, whereas efficiency is only ≈65% for chloroplasts (n = 14).  (3) Finally, the thermodynamic efficiency of oxidative phosphorylation is not lower than that of substrate level phosphorylation, as previously believed.  The overall thermodynamic efficiencies of oxidative phosphorylation, glycolysis, and the citric acid cycle are ≈80% in all three processes.
THERM