Article ; Online: A protet-based, protonic charge transfer model of energy coupling in oxidative and photosynthetic phosphorylation.
Advances in microbial physiology
2021 Volume 78, Page(s) 1–177
Abstract: Textbooks of biochemistry will explain that the otherwise endergonic reactions of ATP synthesis can be driven by the exergonic reactions of respiratory electron transport, and that these two half-reactions are catalyzed by protein complexes embedded in ... ...
Abstract | Textbooks of biochemistry will explain that the otherwise endergonic reactions of ATP synthesis can be driven by the exergonic reactions of respiratory electron transport, and that these two half-reactions are catalyzed by protein complexes embedded in the same, closed membrane. These views are correct. The textbooks also state that, according to the chemiosmotic coupling hypothesis, a (or the) kinetically and thermodynamically competent intermediate linking the two half-reactions is the electrochemical difference of protons that is in equilibrium with that between the two bulk phases that the coupling membrane serves to separate. This gradient consists of a membrane potential term Δψ and a pH gradient term ΔpH, and is known colloquially as the protonmotive force or pmf. Artificial imposition of a pmf can drive phosphorylation, but only if the pmf exceeds some 150-170mV; to achieve in vivo rates the imposed pmf must reach 200mV. The key question then is 'does the pmf generated by electron transport exceed 200mV, or even 170mV?' The possibly surprising answer, from a great many kinds of experiment and sources of evidence, including direct measurements with microelectrodes, indicates it that it does not. Observable pH changes driven by electron transport are real, and they control various processes; however, compensating ion movements restrict the Δψ component to low values. A protet-based model, that I outline here, can account for all the necessary observations, including all of those inconsistent with chemiosmotic coupling, and provides for a variety of testable hypotheses by which it might be refined. |
---|---|
MeSH term(s) | Adenosine Triphosphate/metabolism ; Electron Transport ; Oxidative Phosphorylation ; Oxidative Stress ; Photophosphorylation ; Proton-Motive Force ; Protons |
Chemical Substances | Protons ; Adenosine Triphosphate (8L70Q75FXE) |
Language | English |
Publishing date | 2021-04-16 |
Publishing country | England |
Document type | Journal Article ; Research Support, Non-U.S. Gov't |
ZDB-ID | 174-0 |
ISSN | 2162-5468 ; 0065-2911 |
ISSN (online) | 2162-5468 |
ISSN | 0065-2911 |
DOI | 10.1016/bs.ampbs.2021.01.001 |
Database | MEDical Literature Analysis and Retrieval System OnLINE |
Full text online
More links
Kategorien
In stock of ZB MED Cologne/Königswinter
Zs.A 366: Show issues | Location: Je nach Verfügbarkeit (siehe Angabe bei Bestand) bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular Jg. 1995 - 2021: Lesesall (1.OG) ab Jg. 2022: Lesesaal (EG) |
Order via subito
This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.