3nitrotyrosine

3-nitrotyrosine is a nitro-derivative of the amino acid tyrosine in which a nitro group (-NO2) is attached at the 3-position of the aromatic ring. The compound can exist as the free amino acid or as a post-translational modification on tyrosine residues within proteins. Its chemical formula is C9H10N2O5 and its molecular weight is about 226.19 g/mol. It is commonly referred to as 3-nitrotyrosine or 3-nitro-L-tyrosine.

Formation and occurrence: 3-nitrotyrosine is produced by nitration of tyrosine residues through reactive nitrogen species, most commonly peroxynitrite, formed by the rapid reaction of nitric oxide with superoxide. Other nitrating species such as nitrogen dioxide can also contribute. Nitration tends to occur under inflammatory or oxidative stress conditions and can modify protein structure and function.

Biological and clinical relevance: 3-nitrotyrosine is widely used as a marker of nitrosative stress in tissues and bodily fluids. Elevated levels have been reported in various diseases, including cardiovascular disease, neurodegenerative disorders (for example, Alzheimer’s disease), chronic inflammation, and aging. The presence of 3-nitrotyrosine can alter protein activity, enzyme kinetics, or receptor signaling, potentially contributing to pathophysiology, though it is often viewed as a biomarker rather than a sole causal factor.

Detection and analysis: 3-nitrotyrosine can be detected by immunoassays using specific anti-nitrotyrosine antibodies, or quantified by mass spectrometry-based proteomics and by chromatographic methods such as HPLC with electrochemical detection. Care is taken to minimize artifactual formation during sample handling.