katalaza

Katalaza (commonly spelled catalase in English) is a heme-containing enzyme that catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is broadly distributed in aerobic organisms, including animals, plants, fungi and many bacteria, and is a major component of cellular antioxidant defenses.

The enzyme typically exists as a tetramer of four identical subunits, each containing a heme prosthetic group. Catalytic activity is very high, allowing rapid removal of hydrogen peroxide generated by metabolic processes and peroxisomal oxidases. In many eukaryotic cells catalase is localized to peroxisomes, organelles specialized for oxidative reactions and detoxification.

Katalaza is important in physiology and microbiology. In clinical contexts, impaired catalase activity is associated with the rare condition acatalasia, which can lead to increased susceptibility to oxidative damage. In laboratory microbiology, the catalase test—observation of bubbling when hydrogen peroxide is added—helps distinguish bacterial genera (for example, catalase-positive Staphylococcus vs. catalase-negative Streptococcus).

Biochemically, catalase interacts with small-molecule inhibitors such as 3-amino-1,2,4-triazole and is regulated at the transcriptional level by oxidative stress signals. Industrial and research applications include removal of residual hydrogen peroxide in food and textile processing, and use in biosensors and biocatalysis. The human gene encoding catalase is commonly referred to by the symbol CAT.