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Artefacts in HPLC Detection of 3‐Nitrotyrosine in Human Brain Tissue
Author(s) -
Kaur Harparkash,
Lyras Leonidas,
Jenner Peter,
Halliwell Barry
Publication year - 1998
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1998.70052220.x
Subject(s) - human brain , brain tissue , chemistry , high performance liquid chromatography , chromatography , peroxynitrite , biology , biochemistry , anatomy , neuroscience , enzyme , superoxide
An HPLC method was used for quantification of 3‐nitrotyrosine (3‐NT) in human postmortem brain tissue. A peak with similar retention time to 3‐NT was detected in brain tissue from patients with Parkinson's disease, Huntington's chorea, multiple system atrophy, and Alzheimer's disease but not in control tissue. The peak was lost on reduction with dithionite, a criterion often used to identify 3‐NT. Tissue from the same neurodegenerative diseases was analysed by HPLC using a photodiode array detector in series with an amperometric electrochemical detector, but the peak was found not to be 3‐NT. The absorbance spectrum, fragmentation pattern on mass spectroscopy, and electrochemical profile of this peak do not match authentic 3‐NT. A search of the mass spectroscopy databases failed to reveal its identity. The presence of this closely eluting, dithionite‐reducible peak could confound analysis of human tissues for 3‐NT. In vitro experiments showed that high concentrations of peroxynitrite were needed to achieve detectable levels of 3‐NT in human brain tissue.