The Cu⁺² complexes of the 1-16 and the 1-20 fragments of the Alzheimer’s disease-related ß-amyloid peptide (CuAß) show significant oxidative activities toward a catechol-like substrate trihydroxylbenzene and plasmid DNA cleavage. The latter reflects possible oxidative stress to biological macromolecules, yielding supporting data to the pathological role of these soluble Aß fragments. The former exhibits enzyme-like kinetics and is dependent on [H₂O₂], exhibiting k_cat of 0.066 s^–1 (6000 folds higher than the reaction without CuAß) and k_cat/K_m of 37.2 M^–1s^–1 under saturating [H₂O₂] of ~0.24%. This kinetic profile is consistent with metal-centered redox chemistry for the action of CuAß. A mechanism is proposed by the use of the catalytic cycle of dinuclear catechol oxidase as a working model. Trihydroxylbenzene is also oxidized by CuAß aerobically without H₂O₂, affording rate constants of 6.50 × 10^–3s^–1 and 3.25 M^–1s^–1. This activity is also consistent with catechol oxidase action in the absence of H₂O₂, wherein the substrate binds and reduces the Cu²⁺ center first, followed by O₂ binding to afford the µ-²:²-peroxo intermediate which oxidizes a second substrate to complete the catalytic cycle. A tetragonally distorted octahedral metal coordination sphere with three coordinated His side chains and some specific H-bonding interactions is concluded from the electronic spectrum of CuAß, hyperfine-shifted ¹H NMR spectrum of CoAß, and molecular mechanics calculations. The results presented here are expected to add further insight into the chemistry of metallo-Aß which may assist better understanding of the neuropathology of Alzheimer’s disease.