Nitrotyrosine as a new marker for endogenous nitrosation and nitration

Area of Science:

• Biochemistry
• Analytical Chemistry
• Toxicology

Background:

• 3-nitrotyrosine (NTTYR) is a marker for exposure to nitrosating or nitrating agents.
• Accurate quantification of NTTYR in biological samples is crucial for exposure assessment.

Purpose of the Study:

• To develop a sensitive and selective method for analyzing 3-nitrotyrosine (NTTYR) in proteins and its urinary metabolites.
• To apply the developed method for kinetic studies and in vivo NTTYR formation assessment.
• To evaluate NTTYR and its metabolites as biomarkers for endogenous nitrosation and nitration.

Main Methods:

• Gas chromatography-thermal energy analysis was employed for the sensitive and selective quantification of NTTYR.
• Kinetic studies were performed on free and protein-bound tyrosine.
• In vivo studies involved administering tetranitromethane to rats and analyzing plasma proteins and hemoglobin for NTTYR.
• Urinary metabolites of NTTYR were isolated, identified, and quantified in rats and humans.

Main Results:

• A dose-dependent increase in NTTYR was observed in rat plasma proteins and hemoglobin after tetranitromethane injection.
• 3-nitro-4-hydroxyphenylacetic acid (NHPA) and 3-nitro-4-hydroxyphenyllactic acid were identified as major urinary metabolites of NTTYR in rats.
• NHPA was detected in human urine samples, indicating NTTYR exposure.
• The developed method demonstrated sensitivity and selectivity for NTTYR and its metabolites.

Conclusions:

• Gas chromatography-thermal energy analysis provides a reliable method for analyzing NTTYR in proteins and its urinary metabolites.
• NTTYR and its metabolites can serve as valuable biomarkers for endogenous nitrosation and nitration.
• The findings support the use of NTTYR analysis for monitoring exposure to nitrating and nitrosating agents.