3-Chlorotyrosine

3-Chlorotyrosine

Simultaneous determination of 3-chlorotyrosine and 3-nitrotyrosine in human plasma by direct analysis in real time-tandem mass spectrometry.[Pubmed:26579479]

Acta Pharm Sin B. 2015 Sep;5(5):482-6.

A novel method for the simultaneous determination of 3-nitrotyrosine (NT) and 3-Chlorotyrosine (CT) in human plasma has been developed based on direct analysis in real time-tandem mass spectrometry (DART-MS/MS). Analysis was performed in the positive ionization mode using multiple reaction monitoring (MRM) of the ion transitions at m/z 216.2/170.1 for CT, m/z 227.2/181.1 for NT and m/z 230.2/184.2 for the internal standard, d (3)-NT. The assay was linear in the ranges 0.5-100 mug/mL for CT and 4-100 mug/mL for NT with corresponding limits of detection of 0.2 and 2 mug/mL. Intra- and inter-day precisions and accuracies were respectively <15% and +/-15%. Matrix effects were also evaluated. The method is potentially useful for high throughput analysis although sensitivity needs to be improved before it can be applied in clinical research.

Simultaneous Measurement of 3-Chlorotyrosine and 3,5-Dichlorotyrosine in Whole Blood, Serum and Plasma by Isotope Dilution HPLC-MS-MS.[Pubmed:26977104]

J Anal Toxicol. 2016 May;40(4):264-71.

Chlorine is a public health concern and potential threat due to its high reactivity, ease and scale of production, widespread industrial use, bulk transportation, massive stockpiles and history as a chemical weapon. This work describes a new, sensitive and rapid stable isotope dilution method for the retrospective detection and quantitation of two chlorine adducts. The biomarkers 3-Chlorotyrosine (Cl-Tyr) and 3,5-dichlorotyrosine (Cl2-Tyr) were isolated from the pronase digest of chlorine exposed whole blood, serum or plasma by solid-phase extraction (SPE), separated by reversed-phase HPLC and detected by tandem mass spectrometry (MS-MS). The calibration range is 2.50-1,000 ng/mL (R2 >/= 0.998) with a lowest reportable limit (LRL) of 2.50 ng/mL for both analytes, an accuracy of >/=93% and an LOD of 0.443 ng/mL for Cl-Tyr and 0.396 ng/mL for Cl2-Tyr. Inter- and intra-day precision of quality control samples had coefficients of variation of

Simultaneous measurement of protein-bound 3-chlorotyrosine and homocitrulline by LC-MS/MS after hydrolysis assisted by microwave: application to the study of myeloperoxidase activity during hemodialysis.[Pubmed:22967600]

Talanta. 2012 Sep 15;99:603-9.

A high degree of uremia is common in patients with end-stage renal disease and has been linked to the development of chronic inflammation and cardiovascular diseases. In conditions where transplantation is not possible, uremia can be reduced by hemodialysis although the repeated interventions have been implicated in loss of renal function, partially as a result of chronic inflammation and/or oxidative stress processes. In this context, it has been suggested that myeloperoxidase (MPO) can contribute to the oxidative stress during hemodialysis and to the cardiovascular risk. Protein damages due to MPO activity have never been assessed during hemodialysis although two of its reaction products, 3-Chlorotyrosine and homocitrulline, are of interest. Indeed, the first one is a specific product of MPO activity and the formation of the second one could be catalyzed by MPO. In order to analyze these products in plasma proteins, a total hydrolysis method followed by liquid chromatography mass spectrometry analysis was developed. Different conditions of hydrolysis were tested and the optimized procedure was assessed for complete hydrolysis and artifactual chlorination. Finally, the method was used for analyzing 3-Chlorotyrosine and homocitrulline in plasma proteins during a hemodialysis session in fifteen patients and data were related to measurements of MPO concentration and activity. Both increases in MPO activity and protein-bound 3-Chlorotyrosine were observed, highlighting the involvement of MPO in oxidative stress during hemodialysis and further demonstrating the link between hemodialysis and cardiovascular diseases.

High plasma thiocyanate levels modulate protein damage induced by myeloperoxidase and perturb measurement of 3-chlorotyrosine.[Pubmed:22609005]

Free Radic Biol Med. 2012 Jul 1;53(1):20-9.

Smokers have an elevated risk of atherosclerosis but the origin of this elevated risk is incompletely defined, though increasing evidence supports a role for the oxidant-generating enzyme myeloperoxidase (MPO). In previous studies we have demonstrated that smokers have elevated levels of thiocyanate ions (SCN(-)), relative to nonsmokers, and increased thiol oxidation, as SCN(-) is a favored substrate for MPO, and the resulting hypothiocyanous acid (HOSCN) targets thiol groups rapidly and selectively. In this study we show that increased HOSCN formation by MPO diminishes damage to nonthiol targets on both model proteins and human plasma proteins. Thus high SCN(-) levels protect against HOCl- and MPO-mediated damage to methionine, tryptophan, lysine, histidine, and tyrosine residues on proteins. Furthermore, levels of the HOCl-mediated marker compound 3-Chlorotyrosine and the cross-linked product dityrosine are decreased. Plasma protein 3-Chlorotyrosine levels induced by HOCl exposure in nonsmokers are elevated over the levels detected in smokers when exposed to identical oxidative insult (P<0.05), and a strong inverse correlation exists between plasma SCN(-) levels and 3-Chlorotyrosine concentrations (r=0.6182; P<0.0001). These correlations were also significant for smokers (r=0.2724; P<0.05) and nonsmokers (r=0.4141; P<0.01) when analyzed as individual groups. These data indicate that plasma SCN(-) levels are a key determinant of the extent and type of protein oxidation induced by MPO on isolated and plasma proteins and that smoking status and resulting high SCN(-) levels can markedly modulate the levels of the widely used biomarker compound 3-Chlorotyrosine.