The protonmotive force and respiratory control

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COST Action CA15203 (2016-2021): MitoEAGLE
Evolution-Age-Gender-Lifestyle-Environment: mitochondrial fitness mapping

The protonmotive force and respiratory control

OXPHOS-coupled energy cycles. From Gnaiger 2014 MitoPathways.

» WG1 Action - WG1 MITOEAGLE protocols, terminology, documentation: Standard operating procedures and user requirement document: Protocols, terminology, documentation

» WG1 Project application

Capacities of the electron transfer system, oxidative phosphorylation and resting LEAK respiration (ETS, OXPHOS, LEAK) and four-compartmental OXPHOS model. (i) Capacity of the ETS module, E, in the noncoupled state, generating the protonmotive force, Δp_mt. OXPHOS capacity, P, is partitioned into (ii) the dissipative LEAK component, L (disspation of Δp_mt), and (iii) the free OXPHOS capacity, ≈P=P-L (energy conversion driven by Δp_mt). If ≈P is limited by the capacity of the phosphorylation system, then (iv) the apparent ETS excess capacity, ExP=E-P, is available to drive coupled processes other than phosphorylation without competing with ATP production. Free divided by total ETS capacity, ≈E/E, is the ETS coupling efficiency. Free divided by total OXPHOS capacity, ≈P/P, is the OXPHOS coupling efficiency. From Gnaiger 2014 MitoPathways.

Mitochondrial respiratory coupling control - a conceptual perspective on terminology

Scope of MITOEAGLE publication: Respiratory states

• Target a broad audience – also the new generation
• List of terms including historical terms; abbreviations (mtDNA, mt to abbreviate mitochondr*); OXPHOS capacity versus State 3 (discuss saturating ADP/Pi .. concentrations)
• Scientific terminology should be general and platform independent - demands of the working groups

Structure

1. From bioenergetics to mitochondrial physiology - historical view
2. The mitochondrial respiratory system
3. Rates and states - Units (important for a database); analogous to electic terms: Flow [C.s-1]; Flux [C.s-1.m-2]; Rate (?)
4. Intact cells, mt preparation and normalization
5. Coupling states: mt-preparations and intact cells
6. Pathway states: mt-preparations and intact cells
7. References

Journal

• Int J Biochem Cell Biol (W Koopman will be the new editor); Open Access is a requirement

Action

» Pre-publication: Mitochondrial respiratory control states

» MitoPedia: Respiratory control ratios

» MitoPedia: SUIT

References

• Cohen ER, Cvitas T, Frey JG, Holmström B, Kuchitsu K, Marquardt R, Mills I, Pavese F, Quack M, Stohner J, Strauss HL, Takami M, Thor HL (2008) Quantities, Units and Symbols in Physical Chemistry, IUPAC Green Book, 3rd Edition, 2nd Printing, IUPAC & RSC Publishing, Cambridge. - »Bioblast link«
• Gnaiger E (1993) Nonequilibrium thermodynamics of energy transformations. Pure Appl Chem 65:1983-2002. - »Bioblast link«
• Gnaiger 2014 MitoPathways
• International Union of Biochemistry and Molecular Biology: Recommendations for terminology and databases for biochemical thermodynamics. - »Open Access«
• International Union of Biochemistry (1981) Symbolism and terminology in enzyme kinetics. - »Open Access«
• Lemieux H, Blier PU, Gnaiger E (2017) Remodeling pathway control of oxidative phosphorylation by temperature in the heart. bioRxiv doi10.1101/103457. - »Bioblast link«
• Miller 1991 Scientific American Library

• http://www.nature.com/cdd/journal/v16/n1/full/cdd2008150a.html
• http://www.nature.com/cdd/journal/v20/n7/full/cdd201327a.html

Next steps

Mitochondrial respiratory pathway control - substrates and inhibitors

Switch to pathway-related nomenclature instead of enzyme-linked terminology (N/NS/S versus CI/CI+II/CII)