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Enterococcus faecalis glutathione reductase: purification, characterization and expression under normal and
M P Patel1, J Marcinkeviciene, J S Blanchard
1Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA.
FEMS Microbiology Letters
|September 19, 1998
Summary
This study purified glutathione reductase from Enterococcus faecalis, revealing its structure and function. Enzyme activity increased under hyperbaric oxygen, suggesting oxygen-responsive gene expression for bacterial defense.
Area of Science:
- Biochemistry
- Microbiology
- Enzymology
Background:
- Glutathione reductase is crucial for bacterial defense against oxidative stress.
- It is found in eukaryotes and Gram-negative bacteria.
Purpose of the Study:
- To purify and characterize glutathione reductase from the Gram-positive bacterium Enterococcus faecalis.
- To investigate the enzyme's response to hyperbaric oxygen conditions.
Main Methods:
- Purification using anion exchange, hydrophobic interaction, and affinity chromatography.
- N-terminal amino acid sequencing.
- Kinetic mechanism determination.
- Enzyme activity assays under hyperbaric oxygen.
Main Results:
- Homogeneous 49-kDa enzyme with 1 mol bound FAD per subunit was obtained.
- N-terminal sequence showed homology with other glutathione reductases.
- Ping-pong kinetic mechanism was identified.
- Activity increased twofold under hyperbaric O2, with a threefold induction of glutathione peroxidase.
Conclusions:
- Enterococcus faecalis glutathione reductase shares similarities with reductases from other species.
- The gene encoding glutathione reductase is oxygen-responsive.
- Glutathione synthesizing enzyme genes are not linked to oxygen-sensitive promoters.