Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04179 (MnSOD)
 2,777 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present study was undertaken to determine if in vitro exposure to mercuric chloride produces reactive oxygen species (ROS) in the synaptosomes prepared from various regions of rat brain. The effects of in vivo exposure to mercury on antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities in different regions of rat brain were also investigated. Adult male Sprague-Dawley (CD) rats were dosed with 0, 1, 2.0 or 4.0 mg HgCl2/kg body weight, for 7 days. One week after the last dose, animals were sacrificed by decapitation, their brains were removed and dissected and frozen in dry ice prior to measuring the activities of these enzymes. The results demonstrated that in vitro exposure to mercury produced a concentration-dependent increase of ROS in different regions of the rat brain. In vivo exposure to mercury produced a significant decrease of total SOD, Cu, Zn-SOD and Mn-SOD activities in the cerebellum of rats treated with different doses of mercury. SOD activity did not vary significantly in cerebral cortex and brain stem. GPx activity declined in a dose-dependent manner in the cerebellum with a significant reduction in animals receiving the 4 mg HgCl2/kg body weight. The activity of GPx increased in the brain stem while unchanged in the cerebral cortex. The results demonstrate that inorganic mercury decreased SOD activity significantly in the cerebellum while GPx activity was affected in both cerebellum and brain stem. Therefore, it can be concluded that oxidative stress may contribute to the development of neurodegenerative disorders caused by mercury intoxication.
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PMID:Mercuric chloride-induced reactive oxygen species and its effect on antioxidant enzymes in different regions of rat brain. 917 12

Alterations in gene expression, protein content and enzyme activity of brain Mn-SOD following mercuric chloride (HgCl2) exposure were examined in ICR male mice. Subcutaneous administration of HgCl2 (1 mg Hg/kg) resulted in a significant increase (4-fold) in the brain Mn-SOD content at 6 h after injection while the total mercury concentration was about 0.11 microg/g of brain. The enhancement of Mn-SOD protein caused by HgCl2 was completely abolished by pretreatment with dexamethasone (3 mg/kg) 1 h prior to HgCl2 administration, suggesting involvement of inflammation in inorganic mercury-induced increase in the antioxidant enzyme. This increase in level of Mn-SOD content coincided with a substantial rise in the enzyme activity; however, Northern blot analysis revealed that the induction of protein level was not due to that of its gene expression. The results of the present study indicate that mouse brain Mn-SOD appears to undergo post-translational modification by the environmental toxic metal, and induction of the antioxidant enzyme could be of an initial response to the metal-induced oxidative stress.
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PMID:Post-transcriptional elevation of mouse brain Mn-SOD protein by mercuric chloride. 937 88

Two major superoxide dismutases (SODs; SODs I and II) were found in the crude enzyme extract of wheat seedlings after heat treatment, ammonium sulfate fractionation, anionic exchange chromatography, and gel permeation chromatography. The purification fold for SODs I and II were 154 and 98, and the yields were 11 and 2.4%, respectively. SOD I was further characterized. It was found that SOD I from wheat seedlings is a homodimer, with a subunit molecular mass of 23 kDa. Isoelectric focusing electrophoresis (IEF) and zymogram staining results indicated that the isoelectric point of SOD I is 3.95. It belongs to the MnSOD category due to the fact that it was insensitive to KCN or hydrogen peroxide inhibitor. This MnSOD from wheat seedlings was found to be stable over pH 7-9, with an optimum pH of 8, but was sensitive to extreme pH, particularly to acidic pH. It was stable over a wide range of temperatures (5-50 degrees C). Thermal inactivation of wheat seedling MnSOD followed first-order reaction kinetics, and the temperature dependence of rate constants was in agreement with the Arrhenius equation. The activation energy for thermal inactivation of wheat seedling MnSOD in the temperature range of 50-70 degrees C was found to be 150 kJ/mol. HgCl2 and SDS at a concentration of 1.0 mM significantly inhibited enzyme activity. Chemical modification agents, including diethyl pyrocarbonate (2.5 mM) and Woodward's reagent K (50 mM), significantly inhibited the activity of wheat seedling SOD, implying that imidazole groups from histidine and carboxyl groups from aspartic acid and glutamic acid are probably located at or near the active site of the enzyme.
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PMID:Isolation and characterization of superoxide dismutase from wheat seedlings. 1869 93