Prooxidant activity of Aβ42. (A) Phospholipid loss in the presence of Aβ42 (0.5 μM, American Peptide, open symbols), Cu(II) (0.5 μM), and/or ascorbate (50 μM). (B) Effects of catalase (1000 units/mL), BHT (7.5 μM), DTPA (10 μM), and anaerobic conditions on Aβ42-mediated lipid loss at 120 min. (C) Effects of preincubating Aβ42 (rPeptide) with increasing copper concentrations (0.5, 2, 10 μM) on lipid loss. (D) Effects of Aβ variants on lipid loss (M35OX–methionine sulfoxide, M35V, H13A, and H14A Aβ42 with single residue changes). Note that two of the experiments in panels A and C represent identical conditions but different commercial sources of Aβ42.