What is the structure and function of catalase enzyme?

Catalase is a tetrameric enzyme composed of four identical subunits, each containing a heme group that facilitates its catalytic activity. Its primary function is to catalyze the decomposition of hydrogen peroxide (H₂O₂) into water and oxygen, thereby protecting cells from oxidative damage caused by this reactive oxygen species. The enzyme operates efficiently by using a two-step mechanism, which includes the formation of a compound I intermediate. Catalase is found in nearly all living organisms exposed to oxygen, highlighting its critical role in cellular defense mechanisms.