Catalase and peroxidase (CAT/POX)

Catalase and peroxidases are a diverse group of heme-containing enzymes that play a fundamental role in cellular redox homeostasis by regulating the levels of reactive oxygen species (ROS). Catalase is primarily responsible for the rapid dismutation of hydrogen peroxide into water and oxygen, serving as a critical defense mechanism against oxidative damage and lipid peroxidation (Source: NIH/StatPearls). Peroxidases utilize hydrogen peroxide to catalyze the oxidation of various substrates, contributing to biological processes such as thyroid hormone synthesis and the oxidative burst in neutrophils (Source: UniProt). In clinical medicine, the bacterial bifunctional enzyme catalase-peroxidase (KatG) is a major therapeutic target as it is required to activate the anti-tuberculosis drug isoniazid; consequently, mutations in this enzyme are a leading cause of drug-resistant tuberculosis (Source: PubMed). Deficiencies in human catalase are associated with acatalasemia, which can lead to increased susceptibility to type 2 diabetes and oral gangrene (Source: PubChem). Therapeutic strategies involving these enzymes include the development of catalase mimetics to treat inflammatory conditions and the use of enzyme inhibitors to sensitize cancer cells to oxidative stress-induced death (Source: Peer-reviewed journals).

Other names

HydroperoxidaseHeme peroxidaseCatalasePeroxidaseCatalase-peroxidaseKatG

The primary mechanism involves the enzymatic decomposition of hydrogen peroxide into water and molecular oxygen (catalase activity) or the use of hydrogen peroxide to oxidize various organic and inorganic substrates (peroxidase activity). In the context of pharmacology, the bacterial enzyme KatG oxidizes the prodrug isoniazid into an active isonicotinyl-NAD adduct, which inhibits the synthesis of mycolic acids essential for the bacterial cell wall (Source: PubMed).