AJP - Cell Physiology, Vol 259, Issue 6 C995-C997, Copyright © 1990 by American Physiological Society
Reduction of ferrylmyoglobin in rat diaphragm
L. Eddy, A. Arduini and P. Hochstein
Institute for Toxicology, University of Southern California, Los Angeles 90033.
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.
