Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (682 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
The process by which electrons are transported from a reduced substrate to molecular oxygen. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Transport, Electron; Respiratory Chain; Chain, Respiratory; Chains, Respiratory; Respiratory Chains.
Where it fits in the MeSH classification
- Broader topics
- Biochemical Phenomena; Oxidation-Reduction; Metabolic Networks and Pathways
Related concepts
- Electrons
- Oxygen
Research landscape
PubMed indexes 30,676 records tagged with the MeSH heading “Electron Transport” (counts retrieved 2026-10-29). 4,250 of them (13.9%) were published from 2020 onward, and the busiest period so far is through 1999 with 11,374 records.
Reviews account for 3,435 records (11.2%) and meta-analyses for 3. Randomized controlled trials number 8 (0.0%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 11,374 |
| 2000-2009 | 6,285 |
| 2010-2019 | 8,767 |
| 2020 onward | 4,250 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 3,435 | 11.2% |
| Meta-analyses | 3 | 0.0% |
| Randomized controlled trials | 8 | 0.0% |
Method: PubMed query "Electron Transport"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-29.
Reading the evidence in molecular biology
Molecular biology establishes mechanisms through controlled experiments, often in simplified systems such as purified proteins, cultured cells or model organisms. Such work can show what is possible in a defined system, but whether a pathway matters in a whole organism or in human disease needs further evidence. Check the experimental system, whether findings were reproduced by independent groups, and whether the authors tested the mechanism directly or inferred it from correlation.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Structure and function of mitochondrial membrane protein complexes | 2015 | Review article Design not recorded in structured metadata | 475 | cc by PMID 26515107 · DOI · PMC4625866 |
| Mitochondrial DNA Depletion in Respiratory Chain-Deficient Parkinson Disease Neurons | 2016 | Research article Design not recorded in structured metadata | 209 | cc by PMID 26605748 · DOI · PMC4819690 |
| Oncogenic pathways and the electron transport chain: a dangeROS liaison | 2020 | Review article Design not recorded in structured metadata | 174 | cc by PMID 31819197 · DOI · PMC7052168 |
| Electron transfer in multicentre redox proteins: from fundamentals to extracellular electron transfer | 2025 | Review article Design not recorded in structured metadata | 5 | cc by PMID 39714013 · DOI · PMC12203936 |
Structure and function of mitochondrial membrane protein complexes [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Biological energy conversion in mitochondria is carried out by the membrane protein complexes of the respiratory chain and the mitochondrial ATP synthase in the inner membrane cristae.
- Closing excerpt
- This review places these advances in the context of what is already known, and discusses the fundamental questions that remain open but can now be approached.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (81 words)
Biological energy conversion in mitochondria is carried out by the membrane protein complexes of the respiratory chain and the mitochondrial ATP synthase in the inner membrane cristae. Recent advances in electron cryomicroscopy have made possible new insights into the structural and functional arrangement of these complexes in the membrane, and how they change with age. This review places these advances in the context of what is already known, and discusses the fundamental questions that remain open but can now be approached.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 26515107 · DOI · PMC4625866
Mitochondrial DNA Depletion in Respiratory Chain-Deficient Parkinson Disease Neurons [2]
Abstract reading summary — source excerpts
- Opening excerpt
- ObjectiveTo determine the extent of respiratory chain abnormalities and investigate the contribution of mtDNA to the loss of respiratory chain complexes (CI-IV) in the substantia nigra (SN) of idiopathic Parkinson disease (IPD) patients at the single-neuron level.
- Closing excerpt
- These deficiencies are possibly a consequence of the interplay between nDNA and mtDNA-encoded factors mechanistically connected via TFAM.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (245 words)
ObjectiveTo determine the extent of respiratory chain abnormalities and investigate the contribution of mtDNA to the loss of respiratory chain complexes (CI-IV) in the substantia nigra (SN) of idiopathic Parkinson disease (IPD) patients at the single-neuron level.MethodsMultiple-label immunofluorescence was applied to postmortem sections of 10 IPD patients and 10 controls to quantify the abundance of CI-IV subunits (NDUFB8 or NDUFA13, SDHA, UQCRC2, and COXI) and mitochondrial transcription factors (TFAM and TFB2M) relative to mitochondrial mass (porin and GRP75) in dopaminergic neurons. To assess the involvement of mtDNA in respiratory chain deficiency in IPD, SN neurons, isolated with laser-capture microdissection, were assayed for mtDNA deletions, copy number, and presence of transcription/replication-associated 7S DNA employing a triplex real-time polymerase chain reaction (PCR) assay.ResultsWhereas mitochondrial mass was unchanged in single SN neurons from IPD patients, we observed a significant reduction in the abundances of CI and II subunits. At the single-cell level, CI and II deficiencies were correlated in patients. The CI deficiency concomitantly occurred with low abundances of the mtDNA transcription factors TFAM and TFB2M, which also initiate transcription-primed mtDNA replication. Consistent with this, real-time PCR analysis revealed fewer transcription/replication-associated mtDNA molecules and an overall reduction in mtDNA copy number in patients. This effect was more pronounced in single IPD neurons with severe CI deficiency.InterpretationRespiratory chain dysfunction in IPD neurons not only involves CI, but also extends to CII. These deficiencies are possibly a consequence of the interplay between nDNA and mtDNA-encoded factors mechanistically connected via TFAM.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 26605748 · DOI · PMC4819690
Oncogenic pathways and the electron transport chain: a dangeROS liaison [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Driver mutations in oncogenic pathways, rewiring of cellular metabolism and altered ROS homoeostasis are intimately connected hallmarks of cancer.
- Closing excerpt
- In this review, we focus on the ETC as a source of ROS and its modulation by oncogenic pathways, which generates a vicious cycle that resets ROS levels to a higher homoeostatic set point, sustaining the cancer cell phenotype.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (143 words)
Driver mutations in oncogenic pathways, rewiring of cellular metabolism and altered ROS homoeostasis are intimately connected hallmarks of cancer. Electrons derived from different metabolic processes are channelled into the mitochondrial electron transport chain (ETC) to fuel the oxidative phosphorylation process. Electrons leaking from the ETC can prematurely react with oxygen, resulting in the generation of reactive oxygen species (ROS). Several signalling pathways are affected by ROS, which act as second messengers controlling cell proliferation and survival. On the other hand, oncogenic pathways hijack the ETC, enhancing its ROS-producing capacity by increasing electron flow or by impinging on the structure and organisation of the ETC. In this review, we focus on the ETC as a source of ROS and its modulation by oncogenic pathways, which generates a vicious cycle that resets ROS levels to a higher homoeostatic set point, sustaining the cancer cell phenotype.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 31819197 · DOI · PMC7052168
Electron transfer in multicentre redox proteins: from fundamentals to extracellular electron transfer [4]
Abstract reading summary — source excerpts
- Opening excerpt
- Multicentre redox proteins participate in diverse metabolic processes, such as redox shuttling, multielectron catalysis, or long-distance electron conduction.
- Closing excerpt
- In this new frontier of biological electron transfer, which can extend over distances that exceed the size of the individual multicentre redox proteins by orders of magnitude, current experimental data are still unable, in most cases, to provide discrimination between incoherent conduction by heme orbitals and coherent band conduction.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (213 words)
Multicentre redox proteins participate in diverse metabolic processes, such as redox shuttling, multielectron catalysis, or long-distance electron conduction. The detail in which these processes can be analysed depends on the capacity of experimental methods to discriminate the multiple microstates that can be populated while the protein changes from the fully reduced to the fully oxidized state. The population of each state depends on the redox potential of the individual centres and on the magnitude of the interactions between the individual redox centres and their neighbours. It also depends on the interactions with binding sites for other ligands, such as protons, giving origin to the redox-Bohr effect. Modelling strategies that match the capacity of experimental methods to discriminate the contributions of individual centres are presented. These models provide thermodynamic and kinetic characterization of multicentre redox proteins. The current state of the art in the characterization of multicentre redox proteins is illustrated using the case of multiheme cytochromes involved in the process of extracellular electron transfer. In this new frontier of biological electron transfer, which can extend over distances that exceed the size of the individual multicentre redox proteins by orders of magnitude, current experimental data are still unable, in most cases, to provide discrimination between incoherent conduction by heme orbitals and coherent band conduction.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 39714013 · DOI · PMC12203936
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Chemiosmotic coupling in oxidative and photosynthetic phosphorylation [5]
- Research article Extracellular electron transfer mechanisms between microorganisms and minerals [6]
- Research article Proton-coupled electron transfer [7]
- Research article Proton-coupled electron transfer [8]
- Research article Respiratory metabolism: glycolysis, the TCA cycle and mitochondrial electron transport [9]
- Research article Microbial electrosynthesis - revisiting the electrical route for microbial production [10]
References
- Kühlbrandt W. Structure and function of mitochondrial membrane protein complexes. . 2015. PMID 26515107 · DOI · PMC4625866
- Grünewald A, Rygiel KA, Hepplewhite PD, Morris CM, Picard M, Turnbull DM. Mitochondrial DNA Depletion in Respiratory Chain-Deficient Parkinson Disease Neurons. . 2016. PMID 26605748 · DOI · PMC4819690
- Raimondi V, Ciccarese F, Ciminale V. Oncogenic pathways and the electron transport chain: a dangeROS liaison. . 2020. PMID 31819197 · DOI · PMC7052168
- Bayar B, Soares R, Nalakath H, Alves A, Paquete CM, Louro RO. Electron transfer in multicentre redox proteins: from fundamentals to extracellular electron transfer. . 2025. PMID 39714013 · DOI · PMC12203936
- Mitchell P. Chemiosmotic coupling in oxidative and photosynthetic phosphorylation. Biol Rev Camb Philos Soc. 1966. PMID 5329743 · DOI
- Shi L, Dong H, Reguera G, Beyenal H, Lu A, Liu J, et al.. Extracellular electron transfer mechanisms between microorganisms and minerals. Nat Rev Microbiol. 2016. PMID 27573579 · DOI
- Weinberg DR, Gagliardi CJ, Hull JF, Murphy CF, Kent CA, Westlake BC, et al.. Proton-coupled electron transfer. Chem Rev. 2012. PMID 22702235 · DOI
- Huynh MH, Meyer TJ. Proton-coupled electron transfer. Chem Rev. 2007. PMID 17999556 · DOI · PMC3449329
- Fernie AR, Carrari F, Sweetlove LJ. Respiratory metabolism: glycolysis, the TCA cycle and mitochondrial electron transport. Curr Opin Plant Biol. 2004. PMID 15134745 · DOI
- Rabaey K, Rozendal RA. Microbial electrosynthesis - revisiting the electrical route for microbial production. Nat Rev Microbiol. 2010. PMID 20844557 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-29.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.