Human amyloid peptides Abeta1-40 and Abeta1-42 exhibit NADH oxidase activity with copper-induced oscillations and a period length of 24 min

Human amyloid beta peptides Abeta1-40 and Abeta1-42 exhibit NADH oxidase activity with regular oscillations at intervals of ca 6 min. In the presence of copper, the oscillations in Abeta1-40 and Abeta1-42 become more pronounced and now assume a period length of 24 min. In the presence of copper, the oscillations are similar to those observed with NADH oxidase activities of cell surface ECTO-NOX proteins in general including a period length of 24 min. Solutions of copper sulphate in the presence of all the reagents except for the peptides did not exhibit the oscillatory behavior. NOX proteins have been reported previously to have properties of prions and to form amyloid rods of indeterminant length similar to those formed by the 39-43 residue amyloid beta proteins (Abeta). In this report, we demonstrate a second similarity between ECTO-NOX proteins and amyloid beta, that of an oscillating NADH oxidase activity with a period length of 24 min when assayed in the presence of copper.