The oxidation of
myoglobin was monitored by transmission spectroscopy in isolated, superfused preparations of rat diaphragms. In its deoxygenated form, during
anoxia,
myoglobin was oxidized by adding
hydrogen peroxide (1.0 mM) to its ferryl form (FeIV). On the other hand,
peroxide-induced formation of
ferrylmyoglobin was not observed when the perfusate contained
oxygen.
Ferrylmyoglobin was visualized after its derivatization with
Na2S to form
sulfmyoglobin. Depending on the time of addition, ascorbate (4.0 mM) or
ergothioneine (2.0 mM) either prevented the formation of or dissipated
ferrylmyoglobin. These agents are known to be
reductants of this hypervalent form of
myoglobin. In addition to providing the first demonstration of
ferrylmyoglobin in skeletal muscle, these observations are consistent with the concept that oxidation of
myoglobin to hypervalent states might be an important event in the initiation of muscle damage associated with
anoxia and reoxygenation. The rapid reduction of
myoglobin would prevent peroxidatic alterations of essential cellular constituents by
ferrylmyoglobin.