The ferroxidase reaction of ferritin reveals a diferric mu-1,2 bridging peroxide intermediate in common with other O2-activating non-heme diiron proteins

An analysis of the mechanism of ferroxidase reaction of ferritin shows that there exists a diferric mu-1,2 bridging transient peroxide intermediate similar to other O2-activating non-heme diiron proteins. This was evident in an experiment that characterized the intermediate and established the peroxodiferric assignment using the rapid freeze-quenching technique. Discrete vibrational modes were detected in the ferritin, suggesting that a single chromophore exists in a homogeneous state.