Oxidized proteins in Alzheimer's plasma

The levels of oxidatively modified proteins were examined in blood from Alz heimer's disease (AD) patients, non-AD controls, and AD relatives, Oxidativ e modification was measured by reacting the protein carbonyls with 2,4-dini trophenyl hydrazine (DNPH). The total oxidized proteins were determined by HPLC, while specific protein oxidation was assessed from Western blots of e lectrophoretic gels using antibody to the DNP derivatives. Statistically si gnificant elevations (P < 0.05) of total oxidized proteins were observed in both AD subjects and AD relatives when compared with non-AD controls. More over, a protein band (e.g., MW = 78-kDa) was uniquely oxidized in the plasm a of AD subjects. Furthermore, this protein from AD subjects was more susce ptible to in vitro oxidation. These data suggest that such oxidized protein s may be useful as biomarkers for the detection and evaluation of AD. (C) 2 000 Academic Press.