Cookies help us deliver our services. By using our services, you agree to our use of cookies. More information

Pallag 2022 MitoFit Proline

From Bioblast

MitoFit Preprints         MitoFit Preprints        
Gnaiger 2019 MitoFit Preprints
Gnaiger MitoFit Preprints 2020.4
        MitoFit DOI Data Center         MitoPedia: Preprints         Bioenergetics Communications

Pallag 2022 MitoFit Proline

Publications in the MiPMap
Pallag G, Nazarian S, Ravasz D, Bui D, Komlódi T, Doerrier C, Gnaiger E, Seyfried TN, Chinopoulos C (2022) Proline oxidation leading to high electron flow through reduction of ubiquinone supports ATP production by F1FO-ATPase in mitochondria with inhibited Complex I. published in

» MitoFit Preprints 2022.01.v3.

MitoFit pdf

Proline oxidation leading to high electron flow through reduction of ubiquinone supports ATP production by F1FO-ATPase in mitochondria with inhibited Complex I

MitoFit Prep 2022.1.v3. (2022) MitoFit Prep


Version 3 (v3) 2022-03-07 doi:10.26124/mitofit:2022-0001.v3
Version 2 (v2) 2022-03-03 doi:10.26124/mitofit:2022-0001.v2
Version 1 (v1) 2022-03-02 doi:10.26124/mitofit:2022-0001 - »Link to all versions«

In mitochondria expressing proline dehydrogenase (ProDH), oxidation of proline to pyrroline-5-carboxylate (P5C) leads to transfer of electrons to ubiquinone supporting Complexes CIII and CIV, in turn generating the protonmotive force. Further catabolism of P5C forms glutamate that fuels the citric acid cycle yielding reducing equivalents sustaining oxidative phosphorylation. However, P5C and glutamate catabolism depend on CI activity due to NAD+ requirement. The extent of proline oxidation was established in isolated mitochondria of various mouse tissues by means of simultaneously measuring oxygen consumption, membrane potential, NADH and ubiquinone redox state using the NextGen-O2k (Oroboros Instruments) and correlated to ProDH activity and F1FO-ATPase directionality. In CI-inhibited mouse liver and kidney mitochondria exhibiting high levels of proline oxidation and ProDH activity, catabolism of proline generated a sufficiently high membrane potential maintaining F1FO-ATPase operation in forward mode. This was not observed when either CIII or CIV was inhibited, nor during anoxia. Fueling CIII and CIV with duroquinone partially reproduced the effects of proline. Excess glutamate could not reproduce the effects of proline, arguing that they are due to processes upstream of glutamate conversion from proline. The ProDH inhibitors L-tetrahydro-2-furoic acid and to lesser extent S-5-oxo-2-tetrahydrofurancarboxylic acid abolished all effects conferred by proline. It is concluded that proline catabolism through ProDH generates sufficient CIII and CIV proton pumping, supporting ATP production by F1FO-ATPase even when CI is inhibited.

Keywords: proline dehydrogenase, OXPHOS, substrate-level phosphorylation, quinone Bioblast editor: Tindle-Solomon L O2k-Network Lab: AT Innsbruck Oroboros, HU Budapest Chinopoulos C

ORCID: ORCID.pngPallag Gergely, ORCID.pngNazarian Sara, ORCID.pngRavasz Dora, ORCID.pngBui David, ORCID.pngKomlodi Timea, ORCID.pngDoerrier Carolina, ORCID.pngGnaiger Erich, ORCID.pngSeyfried Thomas N, ORCID.pngChinopoulos Christos

Data availability

Original files are available Open Access at Zenodo repository: (in preparation)



Template NextGen-O2k.jpg
This work was supported by grants from NKFIH ([TKP2021-EGA-25], FIKP-61822-64888-EATV, VEKOP 2.3.3-15-2016-00012, 2017-2.3.4-TET-RU-2017-00003, KH129567, and K135027) to C.C. and from the project NextGen-O2k (Oroboros Instruments) which has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement Nº 859770.

Labels: MiParea: Respiration, Instruments;methods 

Organism: Mouse  Tissue;cell: Heart, Nervous system, Liver, Kidney  Preparation: Isolated mitochondria 

Regulation: Q-junction effect  Coupling state: LEAK, OXPHOS  Pathway: N, S, NS, Other combinations, ROX  HRR: Oxygraph-2k, NextGen-O2k