Direct evidence for non-specific peroxidase activity of ‘‘ferritin–heme” complex: possible role in the development of neurodegenerative diseases

Ferritin, as the major iron storage compound, consists of an apoferritin shell and interior ferric oxyhydroxide crystalline core. Mammalian ferritins can potentially bind heme. Thus, there is the possibility that various ‘‘ferritin–heme” systems display unexpected catalytic behavior like heme-containing enzymes. In the current study, peroxidase activity of the ‘‘ferritin–heme” complex was studied using H 2 O 2 and t -BHP as oxidant substrates and TMB, L-DOPA, serotonin, and dopamine as a reductant substrates. It was found that peroxidase activity of “ferritin–heme” complex depends on both the affinity and number of bound hemes in the ferritin–heme systems. We also discuss the importance of the peroxidase activity of various H/L ferritins in the oxidation of vital molecules as well as role of subunits ratio in neurodegeneration in vivo. Uncontrollable “heme–ferritin”-based enzyme activity as well as up-regulation of heme and ferritin may describe in part importance of peroxidase-related oxidative stress as causative pathogenesis mechanism in some neurodegenerative disorders. Graphical Abstract