There is a need for the selective derivatization and enrichment of posttranslational protein modifications from tissue samples. This chapter describes a method for the selective derivatization of 3-nitrotyrosine (after reduction to 3-amino-tyrosine) and 3,4-dihydroxyphenylalanine with benzylamine derivatives to yield 6-amino- and 6-benzylamine-substituted benzoxazoles, which display characteristic fluorescence properties. The methodology can be expanded to other substituted benzylamines, which carry functional groups for affinity enrichment.
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http://dx.doi.org/10.1016/S0076-6879(08)01202-0 | DOI Listing |
Talanta
November 2021
Department of Food Science, University of Copenhagen, Rolighedsvej 26, 1958, Frederiksberg C, Denmark; Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark.
A targeted UHPLC-MS/MS isotopic dilution method has been developed for the simultaneous quantification of 18 different free and protein-bound aromatic amino acid oxidation products in food and biological matrices. All analytes, including critical isomeric pairs of Tyr, o-Tyr, m-Tyr, and dioxyindolylalanine diastereomers were chromatographically resolved to obtain high selectivity, without the need for derivatizing or ion pairing agents. The results of method validation showed adequate retention time reproducibility [0.
View Article and Find Full Text PDFRedox Biol
September 2020
Dept. of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark. Electronic address:
The precise characterization and quantification of oxidative protein damage is a significant challenge due to the low abundance, large variety, and heterogeneity of modifications. Mass spectrometry (MS)-based techniques at the peptide level (proteomics) provide a detailed but limited picture due to incomplete sequence coverage and imperfect enzymatic digestion. This is particularly problematic with oxidatively modified and cross-linked/aggregated proteins.
View Article and Find Full Text PDFChemistry
August 2019
State Key Laboratory of Applied Organic Chemistry &, College of Chemistry and Chemical Engineering, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, 730000, China.
Herein, a strategy for the selective derivatization of 3-nitrotyrosine-containing proteins using the classic azo coupling reaction as the key step is described. This novel approach featured multiple advantages and was successfully applied to detect picomole levels of protein tyrosine nitration in biological samples.
View Article and Find Full Text PDFBiomed Chromatogr
December 2018
Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic.
Although reactive oxygen/nitrogen species (ROS/RNS) have a fundamental role in physiological processes, enhanced ROS/RNS production induced by exogenous sources, including drugs and other xenobiotics, may result in serious damage to biomolecules. Oxidative/nitrosative stress is being intensively investigated and might be responsible for a variety of health side effects. The present liquid chromatography-tandem mass spectrometry (LC-MS/MS) method provides reliable and accurate simultaneous measurement of malondialdehyde (MDA) and 3-nitrotyrosine (3-NT) in cultured human hepatoma (HepG2) cells.
View Article and Find Full Text PDFJ Vis Exp
July 2017
Pharmasan Labs, Inc.; NeuroScience, Inc.
Free 3-nitrotyrosine (3-NT) has been extensively used as a possible biomarker for oxidative stress. Increased levels of 3-NT have been reported in a wide variety of pathological conditions. However, existing methods lack the sufficient sensitivity and/or specificity necessary to measure the low endogenous level of 3-NT reliably and are too cumbersome for clinical applications.
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