Comparison of superoxide with other reducing agents in the biological production of hydroxyl radicals

Abstract

Iron-EDTA catalysed OH. production from H2O2 and ascorbate by a mechanism largely independent of superoxide. When ascorbate and superoxide were both present, the ascorbate mechanism was more important than superoxide as a source of OH., and would appear to be more significant biologically. The 1-electron reduction of O2 produces O2-., and occurs in a wide range of both chemical and metabolic processes. Superoxide appears to be toxic to living systems, as the enzyme superoxide dismutase, which breaks it down, is an essential constituent of all organisms that utilize O2.