Peroxidase-hydrogen peroxide system (None)

The peroxidase-hydrogen peroxide system is a ubiquitous biochemical system found across biological organisms including plants, animals, and microorganisms. Peroxidases are enzymes that catalyze the oxidation of various substrates using hydrogen peroxide or other peroxides as electron acceptors[1][2][4]. The majority (approximately 84%) of known peroxidase enzymes are haem-containing enzymes[1]. These enzymes are classified into multiple superfamilies and classes. Non-animal peroxidases include Class I (intracellular peroxidases such as cytochrome c peroxidase, catalase peroxidases, and ascorbate peroxidase), Class II (extracellular fungal peroxidases including lignin peroxidase and manganese peroxidase), and Class III (secreted plant peroxidases)[1][3]. Animal peroxidases constitute a separate superfamily with more complex subclassification[3]. The system plays critical roles in cellular detoxification, with enzymes like catalase converting excess H₂O₂ to water and oxygen, while other peroxidases oxidize phenols, formic acid, formaldehyde, and alcohols through peroxidation reactions[2]. In biological systems, hydrogen peroxide is produced through various metabolic pathways including glucose oxidation by glucose oxidase, superoxide dismutase activity, and peroxisomal fatty acid catabolism[2]. The system has important physiological functions but can also be toxic through the Fenton reaction, which generates hydroxyl radicals that cause irreversible oxidative damage to DNA, proteins, and lipids[2].

Other names

Peroxidase systemH₂O₂-peroxidase system

The system operates through peroxidase-catalyzed oxidation reactions where hydrogen peroxide serves as the electron acceptor, converting various substrates to radicals through sequential one-electron transfer steps