Figure 2. Effects of the compounds on metal-free and metal-induced Aβ aggregation.

(a) Amino acid sequences of Aβ₄₀ and Aβ₄₂. (b) Scheme of the inhibition experiment: freshly prepared Aβ (25 μM) in the presence or absence of Cu(II) (blue, 25 μM) or Zn(II) (green, 25 μM) was mixed without (lane C) or with compounds (1–4; 50 μM) and incubated at 37 °C with constant agitation for 24 h. (c) Gel/western blot analysis of the MW distribution of the resulting Aβ₄₀ and Aβ₄₂ species using anti-Aβ antibody (6E10). (d) Morphologies of the Aβ₄₀ aggregates after treatment with 1–4 as observed using TEM (scale bar, 200 nm). (e,f) Ability of 2 (50 μM), compared with 1, to modulate the aggregation pathway of Aβ₄₀ (25 μM) in the presence of various amounts of Cu(II) (left) or Zn(II) (right) (left, 50 μM; middle, 100 μM; right, 200 μM), monitored by gel/western blots.