%0 Journal Article
%T Amyloid- -peptide reduces copper(II) to copper(I) independent of its aggregation state
%A CARLOS OPAZO
%A FRANCISCA H RUIZ
%A NIBALDO C INESTROSA
%J Biological Research
%D 2000
%I Sociedad de Biolog¨ªa de Chile
%X Alzheimer¡¯s disease (AD) is characterized by the deposition of amyloid b-peptide (A ) and neuronal degeneration in brain regions involved in learning and memory. One of the leading etiologic hypotheses regarding AD is the involvement of free radical-mediated oxidative stress in neuronal degeneration. Recent evidence suggests that metals concentrated in amyloid deposits may contribute to the oxidative insults observed in AD-affected brains. We hypothesized that A  peptide in the presence of copper enhances its neurotoxicity generating free radicals via copper reduction. In the present study, we have examined the effect of the aggregation state of amyloid- -peptide on copper reduction. In independent experiments we measured the copper-reducing ability of soluble and fibrillar A 1-40 forms by bathocuproine assays. As it was previously observed for the amyloid precursor protein (APP), the A  peptide showed copper-reducing ability. The capacity of A  to reduce copper was independent of the aggregation state. Finally, the A  peptide derived from the human sequence has a greater effect than the A  peptide derived from the rat sequence, suggesting that histidine 13 may play a role in copper reduction. In agreement with this possibility, the A  peptide reduces less copper in the presence of exogenous histidine
%K A  peptide
%K amyloid fibrils
%K copper reduction
%K oxidative damage
%K Alzheimer¡¯s Disease
%U http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000200012