Simultaneous detection and quantification of 3-nitrotyrosine and 3-bromotyrosine in human urine by stable isotope dilution liquid chromatography tandem mass spectrometry.

Abstract

Nitration and bromination of proteins, giving rise to the respective 3-nitrotyrosine (3NT) and 3-bromotyrosine (3BT), are implicated in asthma, allergic inflammatory disorders, and cancer. We have developed an isotope dilution liquid chromatography electrospray ionization tandem mass spectrometry (LC/MS/MS) assay for simultaneous analysis of protein-bound 3NT and 3BT in human urine. The detection limits (S/N=3) were 10 pg (44 fmol) for 3NT and 5.0 pg (19 fmol) for 3BT injected on-column. The average levels of protein-bound 3NT and 3BT in 23 healthy individuals were 9.7 +/- 11.0 (mean +/- S.D.) in 10(5) tyrosine and 4.4 +/- 3.9 (mean +/- S.D.) in 10(3) tyrosine, respectively, using this highly sensitive LC/MS/MS under the selective reaction monitoring mode. Furthermore, the levels of urinary 3NT and 3BT show a statistically significant correlation (R(2) = 0.55, p = 0.0065, n=23). The high specificity and accuracy of this LC/MS/MS method render it a valuable tool in measurement of 3NT and 3BrT in the human urinary protein as promising noninvasive biomarkers for protein tyrosine nitration and bromination in vivo.

• Authors: Hauh-Jyun Candy Chen, Wei-Loong Chiu
• Journal: Toxicology letters (Toxicol Lett) Vol. 181 Issue 1 Pg. 31-9 (Sep 2008) ISSN: 0378-4274 [Print] Netherlands
• PMID: 18652882 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 3-nitrotyrosine
• Tyrosine
• 3-bromotyrosine

Topics

• Calibration
• Chromatography, Liquid
• Humans
• Radioisotope Dilution Technique
• Sensitivity and Specificity
• Tandem Mass Spectrometry
• Tyrosine (analogs & derivatives, urine)