Mass spectrometric quantification of 3-nitrotyrosine, ortho-tyrosine, and o,o′-dityrosine in brain tissue of 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine-treated mice, a model of oxidative stress in Parkinson's disease. - Pennathur,S.; Jackson-Lewis,V.; Przedborski,S.; Heinecke,J.W. (J Biol Chem, 1999)