A cytochrome that can pump sodium ion
| Autor: | Bassey J.S. Efiok, Dale A. Webster |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Hemeprotein
Cytochrome Stereochemistry Sodium Biophysics Respiratory chain chemistry.chemical_element Biological Transport Active Lithium Biochemistry Multienzyme Complexes NADH NADPH Oxidoreductases Na+/K+-ATPase Molecular Biology Ion transporter biology Chemistry Escherichia coli Proteins Cell Membrane NADH dehydrogenase NADH Dehydrogenase Oxidoreductases N-Demethylating Cell Biology biology.organism_classification Cytochrome b Group Bacteria Aerobic Kinetics biology.protein Cytochromes Vitreoscilla |
| Zdroj: | Biochemical and biophysical research communications. 173(1) |
| ISSN: | 0006-291X |
| Popis: | Previous studies have shown that the bacterium, Vitreoscilla , generates a respiratory-driven Δψ Na+ . Two major respiratory electron transport proteins, NADH dehydrogenase (NADH:Quinone oxidoreductase), and cytochrome o terminal oxidase are candidates for the electrogenic Na + pumping that mediates the Δψ Na+ formation. The NADH oxidase activity of the membranes was enhanced more by Na + than by Li + . The NADH:Quinone oxidoreductase activity in the respiratory chain was enhanced by Na + and Li + , whereas the quinol oxidase activity of cytochrome o was enhanced specifically by Na + , and not by Li + , K + , or choline. Purified cytochrome o , reconstituted into Na + -loaded liposomes in the right-side-out orientation, catalyzed a net Na + extrusion when energized with Q 1 H 2 1 . In non-loaded inside-out proteoliposomes, this cytochrome catalyzed a net uptake of 22 Na + when energized with ascorbate/TMPD. Both Na + -pumping activities were inhibited by CN − . These results are consistent with the Vitreoscilla cytochrome o being a redox-driven Na + pump. |
| Databáze: | OpenAIRE |
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