Peroxidase as an Oxygenase**Abbreviations and conventionsPeroxidase: The word “peroxidase” refers only to plant peroxidases, and usually that from horse-radish; animal and yeast peroxidases are referred to by specific names (lactoperoxidase, verdoperoxidase, cytochrome c peroxidase, etc.)Hemoprotein nomenclature: “Hemoglobin” refers to the ferrous derivative, and “methemoglobin” to the ferric form; similarly with myoglobin; “peroxidase” is, however, the ferric form, with “ferroperoxidase” used for the ferrous compound. Derivatives of these compounds are named correspondingly.“Oxidatic” refers to reactions where the hydrogen acceptor is molecular oxygen; “peroxidatic” to reactions where that acceptor is hydrogen peroxide; “catalatic” to the reaction where both donor and acceptor are hydrogen peroxide, and oxygen is therefore evolved.Horse-radish peroxidase, HRP; turnip peroxidase, TP; dihydroxyfumaric acid (previously misnamed dioxymaleic acid), DHF; peroxidase donors, AH2 and BH2; free radicals, AH, DHF, etc.; indoleacetic acid, IAA; peroxidase peroxide compounds I, II, and III, Compounds I, II, and III, respectively.