Reversible hemichromes

The ferry 1-Fe" is slowly reduced to the met-form. If the globin structures of deoxy-, oxy-or met-forms of myoglobin are disturbed, they are reversibly or irreversibly converted into hemochrome-Fe + or hemichrome-Fe. The role of these denatured species in lipid oxidation of meat is not clear. When ferric hemin is detached from the globin, the ferryl ion can initiate lipid oxidation by hydrogen abstraction to produce a lipid radical plus a proton. Iron can also be released from hemin in the presence of hydroperoxides to participate in lipid oxidation processes. Ascorbic acid and other reducing compounds in muscle cytosol effectively inhibit lipid oxidation promoted by ferryl ions in membranes. 

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