Kinetic mechanism and substrate specificity of glutathione peroxidase activity of ebselen (PZ51). 1988

M Maiorino, and A Roveri, and M Coassin, and F Ursini
Department of Biological Chemistry, University of Padova, Italy.

The glutathione peroxidase activity of ebselen (PZ51) was studied using different hydroperoxidic substrates. The single progression curves obtained in the spectrophotometric test were processed by a computer to fit the integrated rate equation that describes the ping pong reaction of the Se glutathione peroxidase. Ebselen catalyzes the GSH peroxidase reaction with a mechanism that appears kinetically identical to the mechanism of the enzymes. The inactivation of the catalytic properties of ebselen by iodoacetate suggests that a selenol moiety is involved. Among the substrates tested, the best hydroperoxidic substrates are the hydroperoxy derivatives of phosphatidyl choline. Ebselen is active also on membrane hydroperoxides as does phospholipid hydroperoxide glutathione peroxidase but not glutathione peroxidase.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D008054 Lipid Peroxides Peroxides produced in the presence of a free radical by the oxidation of unsaturated fatty acids in the cell in the presence of molecular oxygen. The formation of lipid peroxides results in the destruction of the original lipid leading to the loss of integrity of the membranes. They therefore cause a variety of toxic effects in vivo and their formation is considered a pathological process in biological systems. Their formation can be inhibited by antioxidants, such as vitamin E, structural separation or low oxygen tension. Fatty Acid Hydroperoxide,Lipid Peroxide,Lipoperoxide,Fatty Acid Hydroperoxides,Lipid Hydroperoxide,Lipoperoxides,Acid Hydroperoxide, Fatty,Acid Hydroperoxides, Fatty,Hydroperoxide, Fatty Acid,Hydroperoxide, Lipid,Hydroperoxides, Fatty Acid,Peroxide, Lipid,Peroxides, Lipid
D005979 Glutathione Peroxidase An enzyme catalyzing the oxidation of 2 moles of GLUTATHIONE in the presence of HYDROGEN PEROXIDE to yield oxidized glutathione and water. Cytosolic Glutathione Peroxidase,Glutathione Lipoperoxidase,Selenoglutathione Peroxidase,Glutathione Peroxidase, Cytosolic,Lipoperoxidase, Glutathione,Peroxidase, Glutathione,Peroxidase, Selenoglutathione
D006861 Hydrogen Peroxide A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials. Hydrogen Peroxide (H2O2),Hydroperoxide,Oxydol,Perhydrol,Superoxol,Peroxide, Hydrogen
D000975 Antioxidants Naturally occurring or synthetic substances that inhibit or retard oxidation reactions. They counteract the damaging effects of oxidation in animal tissues. Anti-Oxidant,Antioxidant,Antioxidant Activity,Endogenous Antioxidant,Endogenous Antioxidants,Anti-Oxidant Effect,Anti-Oxidant Effects,Anti-Oxidants,Antioxidant Effect,Antioxidant Effects,Activity, Antioxidant,Anti Oxidant,Anti Oxidant Effect,Anti Oxidant Effects,Anti Oxidants,Antioxidant, Endogenous,Antioxidants, Endogenous
D001393 Azoles Five membered rings containing a NITROGEN atom. Azole
D012643 Selenium An element with the atomic symbol Se, atomic number 34, and atomic weight 78.97. It is an essential micronutrient for mammals and other animals but is toxic in large amounts. Selenium protects intracellular structures against oxidative damage. It is an essential component of GLUTATHIONE PEROXIDASE. Selenium-80,Selenium 80
D013379 Substrate Specificity A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts. Specificities, Substrate,Specificity, Substrate,Substrate Specificities
D016566 Organoselenium Compounds Organic compounds which contain selenium as an integral part of the molecule. Compounds, Organoselenium
D054833 Isoindoles Benzopyrroles with the nitrogen at the number two carbon, in contrast to INDOLES which have the nitrogen adjacent to the six-membered ring. Isoindole

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