H2O2 and {radical dot}NO scavenging by Mycobacterium leprae truncated hemoglobin O

Paolo Ascenzi, Elisabetta De Marinis, Massimo Coletta, Paolo Visca

Research output: Contribution to journalArticle

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 languageEnglish
Pages (from-to)197-201
Number of pages5
JournalBiochemical and Biophysical Research Communications
Volume373
Issue number2
DOIs
Publication statusPublished - 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

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