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Transmembrane electron transport in ascorbate-loaded plasma membrane vesicles from higher plants involves a b-type
H Asard1, N Horemans, R J Caubergs
1Department of Biology, University of Antwerp RUCA, Belgium.
FEBS Letters
|July 20, 1992
Summary
A high-potential b-type cytochrome likely mediates plasma membrane electron transport. Intra-vesicular ascorbate reduced the cytochrome, which was then oxidized by ferricyanide, suggesting its role in electron transfer.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- Plasma membrane electron transport is crucial for cellular processes.
- The role of specific cytochromes in this pathway remains under investigation.
Purpose of the Study:
- To investigate the potential involvement of a high-potential b-type cytochrome in plasma membrane electron transport.
Main Methods:
- Utilized ascorbate-loaded membrane vesicles.
- Analyzed cytochrome reduction and oxidation using absorption spectroscopy.
- Employed ascorbate oxidase and vesicle washing to confirm reduction source.
- Monitored kinetics of cytochrome response to ferricyanide addition.
Main Results:
- The b-type cytochrome was found to be approximately 89% reduced in the preparations.
- Reduction was confirmed to be mediated by intra-vesicular ascorbate.
- Ferricyanide addition caused rapid cytochrome oxidation followed by slower re-reduction, indicating a sequential electron transfer process.
Conclusions:
- The observed kinetics and reduction/oxidation patterns strongly suggest that the b-type cytochrome acts as a mediator in transmembrane electron transfer.