Desferrioxamine as an Electron Donor. Inhibition of Membranal Lipid Peroxidation Initiated by H₂0₂ –Activated Metmyoglobin and Other Peroxidizing Systems

Abstract

Desferoxamine (DFO) involvement in several peroxidative systems was studied. These sytems included: a) membranal lipid peroxidation initiated by H₂O₂-activated metmyoglobin (or methemoglobin); b) phenol-red oxidation by activated metmyoglobin or horseradish peroxidase (HRP): c) β-carotene-linoleate couple oxidation stimulated by lipoxygenase or hemin. Desferrioxamine was found to inhibit all these systems but not ferrioxamine (FO). Phenol-red oxidation by H₂0₂-horseradish peroxidase was inhibited competitively with DFO. Kinetic studies using the spectra changes in the Soret region of metmyoglobin suggest a mechanism by which H₂0₂ reacts with the iron-heme to form an intermediate of oxy-ferryl myoglobin that subsequently reacts with DFO to return the activated compound to the resting state. These activities of DFO resemble the reaction of other electron donors.

Key Words:

• Desferrioxamine
• membranal lipid peroxidation
• phenol-red oxidation
• ^β-carotene oxidation
• H₂O₂-activated metmyoglobin
• hemin. lipoxygenase