Proteinl-Dopa as an Index of Hydroxyl Radical Attack on Protein Tyrosine

Simultaneous determination of tyrosine, phenylalanine and deoxyguanosine oxidation products by liquid chromatography–tandem mass spectrometry as non-invasive biomarkers for oxidative damage

“…Oxidized phenylalanine derivatives (m-and o-tyrosine) and oxidized tyrosine derivatives (o,o -dityrosine, 3-nitrotyrosine, 3-chlorotyrosine, and 3,4-dihydroxyphenylalanine (dopa)) have been suggested as promising biomarkers for oxidative damage to proteins [25][26][27][28][29]. 8-OHdG has been shown to be a biomarker for oxidative damage to DNA [30,31].…”

Endogenous 3,4-Dihydroxyphenylalanine and Dopaquinone Modifications on Protein Tyrosine

“…Among several HO ⅐ -mediated oxidative modifications, the protein tyrosine modification 3,4-dihydroxyphenylalanine (DOPA) has been reported as a major product and index of HO ⅐ attack on tyrosine residues in proteins ( Fig. 1) (27,28). DOPA is also formed on protein tyrosine residues via controlled enzymatic pathways through enzymes such as tyrosinase or tyrosine hydroxylase (28).…”

“…1) (27,28). DOPA is also formed on protein tyrosine residues via controlled enzymatic pathways through enzymes such as tyrosinase or tyrosine hydroxylase (28). Once formed, proteinbound DOPA has the potential to initiate further oxidative reactions through binding and reducing transition metals or through redox cycling between catechol and quinone (dopaquinone) forms (29,30).…”

“…Moreover, elevated levels of protein-bound DOPA have been reported in several diseases, including atherosclerosis, cataracts, and myocardial disease, and in PD patients undergoing levodopa therapy (26,(32)(33)(34)(35)(36). However, the specific DOPAmodified proteins, which could provide mechanistic knowledge of the progression of these diseases, have not been identified (27,28). The ability to identify site-specific protein modifications should lead to a better understanding of the role of DOPA modification in disease pathologies as well as new molecular signatures or therapeutic targets for diseases.…”

An electrochemical biosensor for the detection of tyrosine oxidation induced by Fenton reaction

“…Dityrosine, as one of important biomarkers for oxidative stress of tyrosine formed in the process of protein post-translational modification, can be generated by peroxidase-catalyzed mechanism (Giulivi et al, 2003), or by reaction with the reactive nitrogen species. Dopa is usually used as an index of tyrosine with direct attack of hydroxyl radicals (Cohen et al, 1998). Increases of tyrosine oxidation product level in oxidatively damaged protein have been associated with 0956-5663/$ -see front matter © 2010 Elsevier B.V. All rights reserved.…”