Advancements in the Analytical Quantification of Nitroxidative Stress Biomarker 3-Nitrotyrosine in Biological Matrices

Voltammetric Studies of 3‐Nitro‐tyrosine Electro‐oxidation at Solid Electrodes and its Interaction with DNA

“…In all samples analyzed (columns 2–4 and 6–8), Figure 10, a significant decrease in the EtBr fluorescence was detected, when compared to control samples (columns 1 and 5), indicating the difficulty of EtBr marker intercalation on the dsDNA molecule, due to previous interaction of 3‐NO 2 ‐Tyr. These results are in good agreement with the voltammetric data that also signalled that 3‐NO 2 ‐Tyr‐dsDNA interaction, Section 3.2.1 , occurs causing conformational variations on the secondary structure of DNA, thus being able to interfere in several important biochemical processes of the DNA molecule in‐vivo and possibly as already reported in the literature causing some types of pathologies [1–6].…”

“…Oxidative stress (OS) can occur in‐vivo , as a consequence of the suppression of the antioxidant system and/or an imbalance in the redox state, producing an excess of reactive nitrogen (RNS) and oxygen (ROS) species, which may cause irreversible oxidative damage to important biomolecules, such as proteins and nucleic acids, leading to many pathological processes [1–3]. Thus, it is extremely important to establish the chemical properties of these altered biomolecules, as well as to use them as biomarkers of OS, distinguishing the healthy from the pathological state [1–3]. 3‐nitro‐tyrosine (3‐NO 2 ‐Tyr), Scheme 1, is generated in the human body due to excess of RNS and can be found freely or in proteins.…”

“…3‐nitro‐tyrosine (3‐NO 2 ‐Tyr), Scheme 1, is generated in the human body due to excess of RNS and can be found freely or in proteins. Its physicochemical properties are quite different compared to tyrosine (Tyr), regarding, for example, solubility, phenol group pka (3‐NO 2 ‐Tyr, pka=7.1 and Tyr, pka=10), redox and spectrophotometric properties [1–6]. The presence of 3‐NO 2 ‐Tyr in the human body has been associated with numerous diseases, such as cancer, diabetes, Alzheimer's, celiac disease and various neurodegenerative diseases [1–6].…”

“…Free and protein‐bound 3‐NO 2 ‐Tyr are relatively stable products and can be considered important biomarkers of general oxidative stress or specific disease states [2, 3, 14], giving rise to many analytical methods to quantify 3‐NO 2 ‐Tyr [2, 3, 14–28]. The most common technique for this is the use of high performance liquid chromatography (HPLC), with ultraviolet‐visible (UV‐Vis), mass spectrometry, fluorescence or an electrochemical detector, as chromatographic detectors in general have good sensitivity and specificity [2].…”

Urinary Oxidative Stress Biomarkers in Workers of a Titanium Dioxide Based Pigment Production Plant

“…This oxidation process can also involve lipids and proteins: For proteins, it implies the introduction of functional groups that could alter their functionality and metabolism. One of the most important biomarker of protein oxidation is 3-Nitrotyrosine (3-NO 2 Tyr), an oxidation product of tyrosine, an amino acid found in most proteins, produced in the reaction with NO or NO 3 [12]. Local biological effects in the respiratory system and increased levels of oxidative products of nucleic acids and proteins were found in the exhaled breath condensate of the (nano)TiO 2 workers in a study on 36 male workers examined over 2012 and 2013, and this effect was lower in less exposed workers [13].…”