Which bacterial enzyme neutralizes hydrogen peroxide?
Hydrogen peroxide is unavoidable byproduct of flavoprotein oxidases such as NADH oxidase and autoxidation of menaquinones generating reactive oxygen stress capable of hydroxyl radical formation via Fenton reaction damaging iron-sulfur clusters and DNA. Aerobic bacteria depend on extremely efficient enzymatic detoxification. Catalase is tetrameric heme enzyme containing heme b active site where first H2O2 oxidizes ferric heme to Compound I ferryl oxo porphyrin radical, second H2O2 reduces Compound I releasing water and dioxygen. Catalytic rate is among highest known about ten million molecules
Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 12: Catalase Function and Hydrogen Peroxide Neutralization.
