Figures 3B, C show the various VMtrC values and how the thermionic efficiency changes with those changes in VMQ. The general trend seen is that the efficiency rises with more negative VMQ, but the higher VMtrC reduces efficiency given the same VMQ. Thus, there is a balance that is required between increasing either VMtrC or VMQ.
To describe how increased MQ potential could improve the thermionic efficiency, the effect of menaquinone potential (VMQ) on the EET system movement in protons across the membrane was investigated (figure 3D). By raising the fuphill the menaquinone potential shifts in its position between VNADH and VO2, which causes more NADH reduction and then increasing the thermionic efficiency. Also, proton movement ar MQ standard potential is shown in figure 3E. The increase in proton limits, where increasing the proton limits favour thermionic efficiencies particularly at lower membrane potentials is seen.
Menaquinone potential could be affected by another parameter such as Temperature.
Figure 3F, G investigates the temperature effect on the efficiency of the system at various menaquinone potential with and without proton limitation, respectively. limits in proton movements (5 per electron) are introduced in Figure 3F, unsurprisingly at lower temperatures (hence lower membrane potentials), we get a reduced thermionic efficiency. Any increases seen in both the VMQ at standard and at the lower potential were accompanied by a roughly 1.4% change in efficiency at around 302K and 326K respectively. For the lower potential, staying at room temperature offers the maximum efficiency, while at the standard potential, the rise in efficiency occurs at around 326K.
In the case of no proton movement limitation, at -35mV of VMQ there is a rise in temperature. However, at more favorable menaquinone potentials this is not the case. Hence any temperature dependence is dependent on how the membrane potential affects the overall thermionic efficiency.