At antipyretic and analgesic doses, salicylate has no antiplatelet or anti-inflammatory effects, unlike typical inhibitors of the prostaglandin H synthases (PGHSs). We demonstrated that salicylate inhibits PGHS-1 and -2 with a potency inversely related to ambient hydroperoxide concentrations. Salicylate inhibition of PGHS-1 was prevented by 12-hydroperoxyeicosatetraenoic acid (12-HPETE). Increa...

Pregnancy places increased demands on the mother to provide adequate nutrition to the growing conceptus. A number of micronutrients function as essential cofactors for or themselves acting as antioxidants. Oxidative stress is generated during normal placental development; however, when supply of antioxidant micronutrients is limited, exaggerated oxidative stress within both the placenta and mat...

Transgenic mice overexpressing Cu/Zn superoxide dismutase (hSod1Tg(+/0)) or catalase (hCatTg(+/0)) and knockout mice underexpressing manganese superoxide dismutase (Sod2(+/)(-)) or glutathione peroxidase-1 (Gpx1(-/-)) were used to study the effect of antioxidant enzymes on cell-mediated low density lipoprotein (LDL) oxidation and oxidized LDL (oxLDL)-induced apoptosis. Incubation of LDL with mo...

Based on the concept that activated oxygen species are causally involved in Adriamycin toxicity, endogenous antioxidant defenses are expected to be important determinants of cellular Adriamycin tolerance. We have tested this prediction by making use of an oxygen-resistant variant subline of Chinese hamster ovary cells (CHOr), which is characterized by increased levels of glutathione, copper- an...

Copper- and zinc-containing superoxide dismutase, manganese-containing superoxide dismutase, catalase, and glutathione peroxidase form the primary enzymic defense against toxic oxygen reduction metabolites. Such metabolites have been implicated in the damage brought about by ionizing radiation, as well as in the effects of several cytostatic compounds. These enzymes were analyzed in 31 differen...

Oxidative stress is the hallmark of several pathologies like arthritis, hypertension and many neurodegenerative disorders such as Parkinson's and Alzheimer's diseases. In this scenario, antioxidant compounds can play a pivotal role in treating these severe pathologies. The synthesis of molecules able to mimic physiologically-relevant proteins is nowadays of particular interest. Several transiti...

BACKGROUND A decreased expression of glutathione peroxidase mRNA, an antioxidant enzyme, was previously observed in thyroid anaplastic carcinomas. METHODS To clarify the expression of antioxidant-related enzymes in thyroid anaplastic carcinomas, the expression levels of catalase, copper and zinc superoxide dismutase and manganese superoxide dismutase mRNA in 85 benign and malignant thyroid ti...

BACKGROUND Floudas et al. (Science 336: 1715) established that lignin-degrading fungi appeared at the end of Carboniferous period associated with the production of the first ligninolytic peroxidases. Here, the subsequent evolution of these enzymes in Polyporales, where most wood-rotting fungi are included, is experimentally recreated using genomic information. RESULTS With this purpose, we an...

Manganese peroxidase (MnP) is a heme-containing enzyme produced by white-rot fungi and is part of the extracellular lignin degrading system in these organisms. MnP is unique among Mn binding enzymes in its ability to bind and oxidize Mn(II) and efficiently release Mn(III). Initial site-directed mutagenesis studies identified the residues E35, E39, and D179 as the Mn binding ligands. However, an...

The aim of this study is the evaluation of the enzymatic action of the ligninolytic enzyme manganese peroxidase (MnP), through a suitable addition of H(2)O(2), as a feasible system for the in vitro degradation of complex structures. For this purpose, a highly recalcitrant polymeric dye (Poly R-478) was selected as a model compound. An amperometric technique was used to determine the H(2)O(2) re...