IMMUNOHISTOCHEMICAL DETECTION OF DITYROSINE IN LIPOFUSCIN PIGMENTS INTHE AGED HUMAN BRAIN

Lipofuscin is a yellowish brown fluorescent pigment which is sequester ed within cytoplasmic granules during aging. To examine the contributi on of protein oxidation to lipofuscin accumulation, we performed immun ohistochemical detection of dityrosine, which is considered one of the specific markers for protein oxidation, in lipofuscin in the aged hum an brain using an antibody specific to dityrosine. By characterization using competitive enzyme-linked immunosorbent assay, the specificity of the antibody to dityrosine was confirmed, None of the other tyrosin e-related compounds such as L-tyrosine, 3-nitrotyrosine, 3-chlorotyros ine, or 3,4-dihydroxyphenylalanine cross-reacted with the antibody. Th e anti-dityrosine antibody reacted with lipofuscin granules in the pyr amidal neurons of the aged human brain, The results suggest that prote in oxidation by free radicals and/or peroxidases may play an important role in lipofuscin accumulation. (C) 1998 Federation of European Bioc hemical Societies.