Peroxynitrite: a multifaceted oxidizing and nitrating metabolite.

Area of Science:

• Biochemistry
• Molecular Biology
• Cellular Physiology

Background:

• Peroxynitrite is a reactive oxidant formed from superoxide and nitric oxide.
• It plays a critical role in numerous physiological and pathological processes, including immune response, inflammation, cancer, neurodegeneration, vascular dysfunction, and aging.
• Its biochemistry involves complex oxidation and nitration reactions.

Purpose of the Study:

• To review recent findings on peroxynitrite's role as a metabolic mediator.
• To highlight its involvement in processes from oxidative killing to redox signaling.
• To underscore the impact of protein nitration (e.g., 3-nitrotyrosine) on cell homeostasis.

Main Methods:

• Literature review of recent findings on peroxynitrite.
• Survey of examples of nitrated proteins, specifically 3-nitrotyrosine.
• Analysis of peroxynitrite's dual role at different concentrations.

Main Results:

• Peroxynitrite acts as a metabolic mediator in diverse biological processes.
• Protein nitration, such as 3-nitrotyrosine formation, is a significant post-translational modification affecting cell homeostasis.
• High concentrations of peroxynitrite cause broad oxidation and nitration, whereas low to moderate concentrations selectively activate signal transduction pathways.

Conclusions:

• Peroxynitrite is a key mediator in both health and disease.
• Understanding its concentration-dependent effects is crucial for deciphering its biological actions.
• Further research using peroxynitrite probes and redox-based pharmacology is essential.