Figure 3.

FAD-linked PS1L166P and PS1G384A mutations did not restore Aβ42-to-Aβ40–converting activity of ACE. (A) Fibroblasts were transfected with empty vector or PS1WT or PS1 mutant plasmids. Recombinant ACE proteins, NCT, PS1, and α-tubulin were detected by Western blotting. (B) F-, N-, and C-ACE purified from WT and PS1-KO fibroblasts or PS1-KO fibroblasts transfected with PS1WT or PS1 mutant were mixed with synthetic Aβ42 and incubated at 37°C for 2 h. Western blots of the mixtures were probed with anti-Aβ40 and anti-Aβ42 antibodies. (C) Quantification of Aβ40 converted from Aβ42. PS1L166P and PS1G384A did not restore the Aβ42-to-Aβ40–converting activity of F-ACE and N-ACE proteins, whereas PS WT and PS1ΔE9 restored this activity. Values represent the mean ± SD; n = 3; *, p < 0.05, **, p < 0.01. NS, not significant, Holm-Sidak’s multiple comparisons test.