Abstract
The reversible and stable binding of dioxygen to the heme iron (II) is the basis of myoglobin and hemoglobin functions. During reversible oxygen binding, however, the oxygenated form of myoglobin or hemoglobin is oxidized easily to the ferric (III) met-form with generation of the superoxide anion. Thus, stability property of each oxygenated form is of particular importance in vivo, since the iron (III) species cannot bind dioxygen and is therefore physiologically inactive. With special emphasis on the possible roles of the distal histidine, this overview represents a compendium for the molecular mechanism of autoxidation for myoglobin and hemoglobin molecules.
