Abstract
Kinetics of ferric Mycobacterium leprae truncated hemoglobin O (trHbO{single bond}Fe(III)) oxidation by H2O2 and of trHbO{single bond}Fe(IV){double bond, long}O reduction by {radical dot}NO and NO2 - are reported. The value of the second-order rate constant for H2O2-mediated oxidation of trHbO{single bond}Fe(III) is 2.4 × 103 M-1 s-1. The value of the second-order rate constant for {radical dot}NO-mediated reduction of trHbO{single bond}Fe(IV){double bond, long}O is 7.8 × 106 M-1 s-1. The value of the first-order rate constant for trHbO{single bond}Fe(III){single bond}ONO decay to the resting form trHbO{single bond}Fe(III) is 2.1 × 101 s-1. The value of the second-order rate constant for NO2 --mediated reduction of trHbO{single bond}Fe(IV){double bond, long}O is 3.1 × 103 M-1 s-1. As a whole, trHbO{single bond}Fe(IV){double bond, long}O, generated upon reaction with H2O2, catalyzes {radical dot}NO reduction to NO2 -. In turn, {radical dot}NO and NO2 - act as antioxidants of trHbO{single bond}Fe(IV){double bond, long}O, which could be responsible for the oxidative damage of the mycobacterium. Therefore, Mycobacterium leprae trHbO could be involved in both H2O2 and {radical dot}NO scavenging, protecting from nitrosative and oxidative stress, and sustaining mycobacterial respiration.
Original language | English |
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Pages (from-to) | 197-201 |
Number of pages | 5 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 373 |
Issue number | 2 |
DOIs | |
Publication status | Published - Aug 22 2008 |
Keywords
- HO and NO scavenging
- Kinetics
- Mycobacterium leprae truncated hemoglobin O
- Nitrosative and oxidative stress
ASJC Scopus subject areas
- Biochemistry
- Biophysics
- Molecular Biology