Collect. Czech. Chem. Commun.
2000, 65, 297-325
https://doi.org/10.1135/cccc20000297
Heme Peroxidases: Structure, Function, Mechanism and Involvement in Activation of Carcinogens. A Review
Marie Stiborováa,*, Markéta Mikšanováa, Václav Martíneka and Eva Freib
a Department of Biochemistry, Charles University, 128 40 Prague 2, Czech Republic
b Department of Molecular Toxicology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
Abstract
Peroxidases are enzymes playing an important role in large and diverse numbers of physiological processes in organisms including human. We have attempted in this article to summarize and review the important structural and catalytic properties of principal classes of heme peroxidases as well as their biological functions. Major reactions catalyzed by these enzymes (a conventional peroxidase cycle, reactions using O2 and halogenations) and their mechanism are reviewed, too. Moreover, the reaction mechanisms by which peroxidases are implicated in bioactivation of xenobiotic chemicals are presented. Numerous chemicals including protoxicants and procarcinogens are metabolized by equally numerous chemical reactions catalyzed by peroxidases. The unifying theme is the radical nature of the oxidations. The direct conventional peroxidase reaction forming reactive species is generally responsible for the activation of procarcinogenic substrates of peroxidases. The subsequent formation of a superoxide anion radical and peroxy radicals is necessary for activation of chemicals that are poor substrates for peroxidases. The significance of studies concerning the reactions catalyzed by peroxidases is underlined in the present review article. A review with 166 references.
Keywords: Peroxidases; Enzyme structure and function; Reaction mechanisms; Carcinogens; Heme proteins; Porphyrins; Prostaglandins; Oxidations.
References: 166 live references.
