About the Electron Transport Chain Calculator
The Electron Transport Chain Calculator is a scientifically rigorous, web-based bioenergetics tool that models the mitochondrial electron transport chain (ETC) and calculates ATP yield, proton pumping, oxygen consumption, and coupling efficiency from NADH and FADH₂ oxidation. Based on the chemiosmotic theory of Peter Mitchell (Nobel Prize 1978) and the P/O ratios established by Hinkle et al. (1991), the Electron Transport Chain Calculator implements the exact stoichiometry of Complexes I–IV and ATP synthase.
Used by researchers in mitochondrial biology, pharmacology, and metabolic engineering, this tool quantifies the efficiency of oxidative phosphorylation (OXPHOS) and predicts the impact of proton leak, uncouplers, and respiratory inhibitors.
Electron Transport Chain Complexes
The ETC consists of four membrane protein complexes:
Complex I (NADH:ubiquinone oxidoreductase)
- Pumps 4 H⁺ per NADH
- Transfers 2e⁻ to ubiquinone (Q)
- Inhibited by rotenone
Complex II (Succinate dehydrogenase)
- No proton pumping
- FADH₂ → Q
- Inhibited by malonate
Complex III (Q-cytochrome c oxidoreductase)
- Q-cycle: 4 H⁺ per 2e⁻
- Inhibited by antimycin A
Complex IV (Cytochrome c oxidase)
- 2 H⁺ pumped + 2 H⁺ consumed per 2e⁻
- 4e⁻ reduce O₂ to 2 H₂O
- Inhibited by cyanide
Importance of ETC Efficiency
The ETC generates ~90% of cellular ATP:
- 1 glucose → ~25–28 ATP via ETC
- 1 palmitate → ~106 ATP
- Proton leak: 20–30% of basal metabolism
- ROS production at Complexes I and III
When and Why You Should Use This Calculator
Use the Electron Transport Chain Calculator when:
- Modeling mitochondrial ATP production
- Predicting effects of uncouplers (DNP, FCCP)
- Studying mitochondrial diseases (Complex I deficiency)
- Teaching bioenergetics and respiration
- Designing metabolic interventions
Clinical Applications:
- Leigh syndrome (Complex I)
- Parkinson’s (Complex I inhibition)
- Cancer (altered P/O ratios)
- Aging (increased proton leak)
User Guidelines for Accurate Results
To ensure precision:
- Use measured NADH/FADH₂ flux from ¹³C-MFA
- Adjust P/O ratios for tissue type
- Include proton leak for in vivo conditions
- Validate with glucose:
- 10 NADH + 2 FADH₂ → ~28 ATP
- P/O = 2.5/1.5
Purpose and Research Applications
This calculator enables:
- Quantitative bioenergetics modeling
- Drug screening for ETC inhibitors
- Metabolic control analysis
- Integration with genome-scale models
Interpretation of Results
Key outputs include:
- ATP yield: From OXPHOS only
- Protons pumped: Total H⁺ translocated
- O₂ consumption: Respiratory rate
- Coupling efficiency: % of protons used for ATP
Limitations and Advanced Considerations
Model assumptions:
- Steady-state electron flow
- No reverse electron transport
- Standard proton stoichiometry
- Neglects supercomplexes
References and Further Reading
- Mitchell P. (1961). Coupling of phosphorylation to electron transfer. Nature.
- Hinkle PC, et al. (1991). P/O ratios of mitochondrial OXPHOS. Biochemistry.
- Brand MD. (1997). Regulation analysis of energy metabolism. J Exp Biol.
- Nicholls DG, Ferguson SJ. (2013). Bioenergetics 4. Academic Press.
- Rich PR. (2003). The molecular machinery of Keilin's respiratory chain. Biochem Soc Trans.
For agricultural applications of plant respiration, visit Agri Care Hub. Learn more about the bioenergetic engine on the Electron Transport Chain Calculator Wikipedia page.