EVERYDAY SCIENCE

Detailed explanation-1: -They contain oxidative enzymes, such as catalase and urate oxidase, at such high concentrations that in some cells the peroxisomes stand out in electron micrographs because of the presence of a crystalloid core (Figure 12-31).

Detailed explanation-2: -Catalase-peroxidase (KatG)4 is a bifunctional heme-dependent enzyme found in bacteria and lower eukaryotes (1), which is integral to the defense of these organisms against H2O2 toxicity (2, 3).

Detailed explanation-3: -Catalase, peroxidase, and small molecule thiol such as glutathione are major players of the peroxisomal antioxidant system [7–9].

Detailed explanation-4: -Catalases and peroxidases are ubiquitous heme enzymes that catalyze the removal of hydrogen peroxide (H(2)O(2)). Both enzymes use one molecule of hydrogen peroxide to form a high valent iron intermediate named Compound I (Cpd I).