Peroxynitrite scavenging by ferryl sperm whale myoglobin and human hemoglobin

Paolo Ascenzi, Elisabetta De Marinis, Alessandra di Masi, Chiara Ciaccio, Massimo Coletta

Research output: Contribution to journalArticlepeer-review

Abstract

Globins protect from the oxidative and nitrosative cell damage. Here, kinetics of peroxynitrite scavenging by ferryl sperm whale myoglobin (Mb{single bond}Fe(IV){double bond, long}O) and human hemoglobin (Hb{single bond}Fe(IV){double bond, long}O), between pH 5.8 and 8.3 at 20.0 °C, are reported. In the absence of CO2, values of the second-order rate constant for peroxynitrite scavenging by Mb{single bond}Fe(IV){double bond, long}O and Hb{single bond}Fe(IV){double bond, long}O (i.e., for Mb{single bond}Fe(III) and Hb{single bond}Fe(III) formation; kon) are 4.6 × 104 M-1 s-1 and 3.3 × 104 M-1 s-1, respectively, at pH 7.1. Values of kon increase on decreasing pH with pKa values of 6.9 and 6.7, this suggests that the ONOOH species reacts preferentially with Mb{single bond}Fe(IV){double bond, long}O and Hb{single bond}Fe(IV){double bond, long}O. In the presence of CO2 (=1.2 × 10-3 M), values of kon for peroxynitrite scavenging by Mb{single bond}Fe(IV){double bond, long}O and Hb{single bond}Fe(IV){double bond, long}O are essentially pH-independent, the average kon values are 7.1 × 104 M-1 s-1 and 1.2 × 105 M-1 s-1, respectively. As a whole, Mb{single bond}Fe(IV){double bond, long}O and Hb{single bond}Fe(IV){double bond, long}O, obtained by treatment with H2O2, undertake within the same cycle H2O2 and peroxynitrite detoxification.

Original languageEnglish
Pages (from-to)27-31
Number of pages5
JournalBiochemical and Biophysical Research Communications
Volume390
Issue number1
DOIs
Publication statusPublished - Dec 4 2009

Keywords

  • Effect of CO
  • Ferric hemoglobin formation
  • Ferric myoglobin formation
  • Ferryl hemoglobin reduction
  • Ferryl myoglobin reduction
  • Kinetics
  • Peroxynitrite scavenging

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Cell Biology
  • Molecular Biology

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