Table 1.

Energetic consequences of catalytic activity determined according to the Rate Isotherm for a reaction proceeding at a fixed net rate of 10 mM s−1.

ATPaseATP synthase
rf/rbrf (mM s−1)rb (mM s−1)ΔGdiss= RTln(rf/rb) (kJ mol−1)PMFa (mV)efficiency (%)PMFb (mV)efficiency (%)
1.01101010000.026155.3899.95155.5499.95
1.11101000.246154.7099.51156.2399.51
111116.177136.2587.65174.6789.00
10110.10.111.889118.5076.22192.4380.79
10310.010010.0100117.795100.1364.41210.7973.75
10410.0010.00123.72781.6952.55229.2467.82
  • aThe PMF in this column shows that generated from ATP hydrolysis (assuming a free energy gradient of ΔGATP=−50 kJ mol−1) in the face of the given free energy dissipation, ΔGdiss, determined according to the Rate Isotherm. It is calculated as PMF=(ΔGATPGdiss)/nF, where F is the Faraday constant and n=3.3˙H+/ATP. The corresponding thermodynamic efficiency is calculated as (ΔGATPGdiss)/ΔGATP. bThe PMF in this column is that required to synthesize ATP against its free energy gradient of 50 kJ mol−1 in the face of the given free energy dissipation, ΔGdiss, determined according to the Rate Isotherm. It is calculated as PMF=(ΔGATP−ΔGdiss)/nF. The corresponding thermodynamic efficiency is calculated as ΔGATP/(nF×PMF) or ΔGATP/(ΔGATP−ΔGdiss).