ABSTRACT
ACKNOWLEDGMENTS 552
ABBREVIATIONS AND DEFINITIONS 552 REFERENCES 553
Hydrogen peroxide is a toxic molecule, able to both oxidize and reduce organic substrates. Unfortunately, hydrogen peroxide is produced in bi ological systems, both through the partial reduction of dioxygen by ox idases and by the disproportionation of superoxide by superoxide dismutases. Consequently, aerobic organisms have needed to evolve mechanisms for hydrogen peroxide detoxification. This is most often ac complished by the disproportionation of H20 2 to H20 and 0 2, the socalled catalase reaction [Eq. (1)].