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Non-equilibrium thermodynamic sensitivity of oxidative phosphorylation
1Pharmakologisches Institut der Universität Bern, Switzerland.
Proceedings. Biological Sciences
|June 22, 1991
Summary
This study introduces a new method to analyze oxidative phosphorylation dynamics. It reveals that the phosphate potential is most stable against fluctuating ATP use at a specific coupling degree, enhancing cellular energy buffering.
Area of Science:
- Biochemistry
- Bioenergetics
- Thermodynamics
Background:
- Oxidative phosphorylation is crucial for cellular energy production.
- Understanding its dynamic properties, especially ATP utilization sensitivity, is vital.
- Current methods for analyzing these dynamics are computationally intensive.
Purpose of the Study:
- To develop a novel method for analyzing the dynamic properties of oxidative phosphorylation.
- To investigate the sensitivity of the phosphate potential to fluctuating cellular ATP utilization.
- To determine the optimal degree of coupling for kinetic stability and thermodynamic efficiency.
Main Methods:
- Developed an eigenvalue sensitivity analysis method.
- Utilized an experimentally supported non-equilibrium thermodynamic model.
- Applied the method to parameters characteristic of liver in starved rats in vivo.
Main Results:
- The sensitivity of oxidative phosphorylation to fluctuating ATP utilization is minimal at a degree of coupling (q) of 0.95.
- This degree of coupling provides high buffering of the phosphate potential against fluctuating energy demands.
- The optimal degree of coupling for economic net ATP production (q_eff) is consistent with the value for minimal sensitivity.
Conclusions:
- The phosphate potential is highly buffered at q = 0.95, indicating significant kinetic stability.
- Simultaneous maximization of kinetic stability and thermodynamic efficiency occurs at the same degree of coupling.
- This finding suggests a potential regulatory mechanism for cellular energy homeostasis.