Carbonyl formation on a copper-bound prion protein fragment, PrP23-98, associated with its dopamine oxidase activity.

The amino-terminal part of prion protein (PrP), containing a series of octapeptide repeats with the consensus sequence PHGGGWGQ, has been implicated in the binding of copper ion. This region possesses amino acid residues susceptible to oxidation, such as histidine, lysine, arginine and proline. In this study, we have investigated copper-catalyzed oxidation of an N-terminal part of human PrP, PrP23-98, that was prepared by the recombinant DNA technique. Carbonyl formations on copper-bound PrP23-98 induced by dopamine and L-ascorbate were analyzed kinetically, and it was found that the redox cycling of PrP23-98-bound copper, especially induced by dopamine, was coupled to the formation of carbonyls on the protein.