On the other hand, N-truncated Aβ(4–42)is another ATCUN-containing species at the brain that arises fromnonspecific proteolytic cleavage of APP, and it constitutes ∼50–60%of amyloid plaques in AD patients.58−60 Although its physiologicalrole is still unknown, emerging evidence shows that Aβ(4–X)can take Cu2+ from Aβ(1–X), forming redox-silentCu2+-Aβ(4–X) species, that might provide redox-protectivefunctions in the brain.63,64,83 Our results indicate that TP* does not remove the metal from theCu2+-Aβ(4–X) species; hence, it would notdisrupt the formation of redox-inert Cu2+-Aβ(4–X)complexes. Here, APP is linked to Alzheimer disease.