Rapid autoxidation of ferrous heme-Aβ complexes relevant to Alzheimer's disease.

Heme bound Aβ peptides have been reported to reduce O 2 by 2e - to H 2 O 2 which may result in oxidative stress commonly encountered in Alzheimer's disease. In this study we report the first instance of rapid freeze quench trapping and characterizing the heme(III)-O 2 ˙ - intermediate involved in the heme-Aβ induced formation of partially reduced oxygen species (PROS) in physiologically relevant aqueous medium using absorption and resonance Raman spectroscopy. The kinetics of this process indicates a key role of the Tyr10 residue, unique to human Aβ, in the generation of H 2 O 2 from O 2 .