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Myoglobin scavenges peroxynitrite without being significantly nitrated

Susanna Herold1, Kalinga Shivashankar, Martin Mehl

  • 1Laboratorium für Anorganische Chemie, Eidgenössische Technische Hochschule, ETH Hönggerberg, CH-8093 Zürich, Switzerland. herold@inorg.chem.ethz.ch

Biochemistry
|November 6, 2002
PubMed

Insights

Myoglobin and hemoglobin react with peroxynitrite. The heme center in myoglobin efficiently scavenges peroxynitrite, protecting the protein from nitration and preserving mitochondrial respiration.

Area of Science:

  • Biochemistry
  • Protein Chemistry
  • Oxidative Stress

Background:

  • Peroxynitrite is a reactive nitrogen species implicated in cellular damage.
  • Hemoglobin (Hb) and myoglobin (Mb) are heme proteins involved in oxygen transport.
  • Understanding protein susceptibility to oxidative modification is crucial for cellular protection mechanisms.

Purpose of the Study:

  • To investigate the nitration of hemoglobin and myoglobin by peroxynitrite.
  • To determine the role of different protein forms and the heme center in peroxynitrite reactions.
  • To explore the protective function of oxyMb against cellular damage.

Main Methods:

  • Treatment of various forms of Hb and Mb with peroxynitrite.
  • High-Performance Liquid Chromatography (HPLC) analysis.
  • Acid hydrolysis and Pronase digestion of proteins.
  • Quantification of 3-nitrotyrosine and other nitrated amino acids.

Main Results:

  • Oxy forms of Hb and Mb showed minimal 3-nitrotyrosine formation.
  • Met-forms and apo-forms exhibited higher nitration levels.
  • Tryptophan residues were also found to be nitrated to a detectable extent.
  • The heme center of Mb acted as an efficient peroxynitrite scavenger.

Conclusions:

  • The heme center of myoglobin protects the globin moiety from peroxynitrite-induced nitration.
  • OxyMb may play a role in preventing mitochondrial damage by scavenging peroxynitrite.
  • This mechanism offers a protective pathway against irreversible inhibition of enzymes like cytochrome c oxidase.

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