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Cytochrome c550 from Pseudomonas aeruginosa
1Fachgebiet Technische Biochemie, Institut für Biotechnologie der Technischen Universität Berlin, Federal Republic of Germany.
The Biochemical Journal
|January 1, 1993
Summary
Pseudomonas aeruginosa synthesizes a novel cytochrome c550 when grown on ethanol. This cytochrome is crucial for electron transfer in the ethanol oxidation pathway, linking ethanol dehydrogenase to oxygen respiration.
Area of Science:
- Microbiology
- Biochemistry
- Electron Transport
Background:
- Pseudomonas aeruginosa utilizes various substrates for growth.
- Ethanol metabolism involves specific enzymes and electron transport chains.
Purpose of the Study:
- To characterize a soluble c-type cytochrome induced during ethanol growth in P. aeruginosa.
- To elucidate the role of this cytochrome in the electron transport chain linked to quinoprotein ethanol dehydrogenase.
Main Methods:
- Purification of the soluble c-type cytochrome.
- Spectroscopic analysis (alpha-absorption band at 550 nm).
- Biochemical assays to determine molecular mass, pI, midpoint potential, and electron transfer activity.
- Enzyme activity assays with membrane particles and inhibitors.
Main Results:
- A homogeneous soluble c-type cytochrome (cytochrome c550) was purified with a molecular mass of 15 kDa and pI of 4.8.
- Cytochrome c550 has a midpoint potential of 280 mV and mediates electron transfer between quinoprotein ethanol dehydrogenase and ferricyanide.
- Oxygen consumption linked to quinoprotein ethanol dehydrogenase requires cytochrome c550, indicating its role in the respiratory chain.
- Inhibition studies suggest involvement of a cytochrome bc1-like complex in electron transport to oxygen.
Conclusions:
- Cytochrome c550 is a key component in the Pseudomonas aeruginosa ethanol oxidation pathway.
- It facilitates electron transfer from ethanol dehydrogenase to the respiratory chain, ultimately to oxygen.
- The findings reveal a novel aspect of respiratory metabolism in P. aeruginosa.