  For more than 30 years, the only enzymatic system known to catalyze the
elimination of superoxide was superoxide dismutase, SOD. SOD has been found in
almost all organisms living in the presence of oxygen, including some anaerobic
bacteria, supporting the notion that superoxide is a key and general component
of oxidative stress. Recently, a new concept in the field of the mechanisms of
cellular defense against superoxide has emerged. It was discovered that
elimination of superoxide in some anaerobic and microaerophilic bacteria could
occur by reduction, a reaction catalyzed by a small metalloenzyme thus named
superoxide reductase, SOR. Having played a major role in this discovery, we
describe here how the concept of superoxide reduction emerged and how it was
experimentally substantiated independently in our laboratory.
