Redox chain
A redox chain is a concatenation of several redox reactions with the purpose of “passing through” electrons that are released in a certain first redox reaction by means of various subsequent redox cycles up to a second redox reaction, where these electrons then reduce the relevant recipient molecule. Redox chains are important components of numerous biochemical mechanisms, for example photosynthesis or the respiratory chain .
procedure
A chemical reaction reduces a molecule at a certain point , which then reduces another molecule in a second redox reaction and is itself oxidized again in the process. The electron recipient of the second redox reaction now repeats the same thing in a further redox reaction with another recipient molecule, etc., until the electrons finally reach the end of the chain and there, in a final redox reaction, reduce the final recipient molecule.
Significance for the organism
In the chloroplasts, this electron transfer is used to transport H + ions against the concentration gradient from the stroma into the thylakoid space or to generate such a concentration gradient in the first place. The resulting proton gradient then creates a flow of electrons because the H + ions tend to migrate back from the high to the low substance concentration. The only point of passage is a tunnel protein, the ATP synthase , and while the H + ions flow through the ATP synthase, they give off energy that is used to form ATP.
See also
Individual evidence
- ^ PB Crowley, M. Ubbink: Close encounters of the transient kind: protein interactions in the photosynthetic redox chain investigated by NMR spectroscopy. In: Accounts of chemical research. Volume 36, Number 10, October 2003, pp. 723-730, ISSN 0001-4842 . doi : 10.1021 / ar0200955 . PMID 14567705 .
- ↑ TE DeCoursey: Interactions between NADPH oxidase and voltage-gated proton channels: why electron transport depends on proton transport. In: FEBS letters. Volume 555, Number 1, November 2003, pp. 57-61, ISSN 0014-5793 . PMID 14630319 .