Relationships between nitric oxide, nitroxyl ion, nitrosonium cation and peroxynitrite

Area of Science:

• Biochemistry
• Chemical Biology
• Physiology

Background:

• Nitric oxide (NO) exists in three distinct redox states: nitroxyl ion (NO-), NO radical (NO.), and nitrosonium ion (NO+).
• Nitroxyl ion (NO-) is a key species with significant biological implications, yet its chemistry and roles are less understood compared to NO.

Purpose of the Study:

• To provide a comprehensive review of the chemistry and biology of nitroxyl ion (NO-).
• To discuss biochemical and chemical methods for NO- formation and detection.
• To explore the reactions of NO- with various biological and chemical entities, and its role in physiological processes.

Main Methods:

• Literature review of biochemical and chemical studies.
• Analysis of reaction mechanisms involving NO-.
• Discussion of methods for generating and detecting NO- in solution.
• Assessment of NO- interactions with NO., thiols, heme iron, and dioxygen.

Main Results:

• Biochemical pathways for NO- formation and methods to demonstrate its intermediacy are detailed.
• Chemical methods for generating NO- are presented.
• Key reactions of NO- with NO., thiols, heme iron, and dioxygen are reviewed.
• The reaction of NO- with dioxygen is identified as a significant source of peroxynitrite, with potential influence from NO- spin state.

Conclusions:

• Nitroxyl ion (NO-) plays a crucial role in biological systems, with its chemistry and interactions being vital for physiological functions.
• S-nitrosothiols and metal nitrosyl complexes serve as important carriers of the nitrosonium ion (NO+) under physiological conditions.
• Understanding the distinct chemistry of NO-, NO., and NO+ is essential for comprehending various biological redox processes and signaling pathways.