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Verdoheme formation in Proteus mirabilis catalase
Pierre Andreoletti1, Jean-Marie Mouesca, Patrice Gouet
1INSERM U866, Dijon, France. pierre.andreoletti@u-bourgogne.fr
Biochimica Et Biophysica Acta
|April 28, 2009
Summary
Verdoheme formation, a heme oxidation product that inactivates catalase, originates from Compound I, not Compound II. This autocatalytic process likely occurs in vivo.
Area of Science:
- Biochemistry
- Enzymology
Background:
- Heme oxidative degradation is well-studied in peroxidases, but less so in catalases.
- Verdoheme formation, a heme oxidation product, leads to catalase inactivation.
Purpose of the Study:
- Investigate the pathway of verdoheme formation in Proteus mirabilis catalase.
- Determine the origin of verdoheme formation in relation to catalase reactional intermediates.
Main Methods:
- Verdoheme generation using peracetic acid.
- Analysis via mass spectrometry and spectrophotometry.
- Kinetic studies of catalase intermediates and inhibitors.
Main Results:
- Verdoheme formation follows Compound I, not Compound II.
- NADPH inhibits verdoheme formation, while dithiothreitol does not prevent Compound II formation.
- Protein radicals facilitate verdoheme generation, and heme oxidation is linked to enzyme catalysis.
Conclusions:
- The verdoheme formation pathway originates from Compound I.
- Autocatalytic verdoheme formation is likely to occur in vivo.
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