Catalase (CAT) is a peroxisomal enzyme that catalyzes the degradation of hydrogen peroxide (H₂O₂) to water and oxygen, protecting cells from oxidative damage 1. Beyond its primary antioxidant role, CAT promotes growth of diverse cell types including T-cells, B-cells, myeloid leukemia cells, melanoma cells, and fibroblasts 1. The enzyme functions through heme-dependent catalysis and participates in cellular detoxification of reactive oxygen species, with activity regulated in response to oxidative stress. CAT operates primarily in peroxisomes but also localizes to cytoplasm and mitochondria, where it forms protein complexes and homodimers. The enzyme exhibits NADP binding capacity and contributes to UV protection and negative regulation of apoptosis. Disease relevance is demonstrated by acatalasemia, a rare inherited disorder resulting from CAT deficiency. This genetic condition impairs the cell's capacity to neutralize hydrogen peroxide, leading to accumulation of toxic reactive oxygen species. The clinical significance of CAT extends to understanding oxidative stress-related pathologies, as adequate catalase activity is essential for maintaining cellular redox homeostasis and preventing oxidative damage to cellular components. CAT's multiple roles in cell proliferation, differentiation (particularly osteoblast development), and survival underscore its importance beyond simple detoxification.