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)

Cultures of Methylomonas J, an aerobic methylotrophic bacterium, were grown both in Mn-rich and Fe-rich media. Crude extracts of the cultures from the Mn-rich and Fe-rich medium showed a specific activity of 12.2 and 0.6 units/mg by a cytochrome c-xanthine oxidase method and 19.4 and 1.3 units/mg by an ESR method, respectively. We isolated Mn-SOD and Fe-SOD from the bacteria grown in the Mn-rich and Fe-rich mediums, respectively. Specific activity and metal contents of the Mn-enzyme were 2,250 units/mg/g-atom Mn and Mn = 0.98 and Fe = 0.12 (g-atoms/mol dimer), while those of the Fe-enzyme were 61 units/mg/g-atom Fe and Mn = 0.02 and Fe = 1.08. No difference of physicochemical properties of the Fe- and Mn-enzymes were detected. Furthermore, enzyme activity was restored by dialysis of an apoprotein obtained from the Fe-enzyme with either manganese sulfate or ferrous ammonium sulfate.
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PMID:Isolation of Mn-SOD and low active Fe-SOD from Methylomonas J; consisting of identical proteins. 190 19

O2-generation rate (Vo2-) in microsomal, mitochondrial and nuclei liver membranes was measured by ESR method, by accumulation of stable nitroxide radicals. These Vo2- values were compared with Cu, ZnSOD and MnSOD activities after 2 hours ischemia and 24 hours reoxygenation. O2- radicals generated by electron transfer chains are concluded to damage mainly during the ischemia, but not the reoxygenation.
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PMID:[Membranes of subcellular organelles as the source of superoxide radicals in liver ischemia]. 239 90

Cu/Zn-superoxide dismutase (Cu/Zn-SOD) has been shown to modulate the autoxidation of a variety of phenoic compounds, including 1,4-hydroquinone (HQ), a benzene-derived metabolite. The acceleration of autoxidation of HQ by Cu/Zn-SOD results in the production of 1,4-benzoquinone (BQ). It has been proposed that the chemical mechanism involved in the Cu/Zn-SOD-catalyzed autoxidation of HQ may be occur through either its conventional activity as a superoxide:superoxide oxidoreductase or as a semiquinone:superoxide oxidoreductase. However, Cu/Zn-SOD-accelerated oxidation of HQ has not been resolved experimentally. In this study, with ESR spectroscopy we investigated further the chemical reactions involved in the SOD-accelerated oxidation of HQ. In phosphate-buffered saline (PSB), HQ underwent a slow autoxidation to BQ, which was accelerated by Cu/Zn-SOD, Mn-SOD, or Fe-SOD with similar efficiency. In contrast, among free metals, only Cu(II) strongly mediated the oxidation of HQ to BQ. Mn(II) exhibited a slight capacity to oxidize HQ, whereas neither FE(II) nor FE(III) was capable of modulating the autoxidation of HG. The presence of either form of SOD also dramatically enhanced the formation of semiquinone anion radicals SQ-. from HQ. The SOD-accelerated oxidation of HQ was also accompanied by the generation of H202. In PBS containing bovine serum albumin (BSA) (PBS/BSA), HQ did not undergo autoxidation to SQ-., and as such the presence of SOD was unable to induce the formation of either SQ-. or BQ or the consumption of O2. The addition of 10 microM BQ to HQ (100 or 1000 microM) in PBS/BSA resulted in the formation of SQ-. and initiated a slow rate of oxidation of HQ to BQ. In this case, the presence of Cu/Zn-SOD strongly accelerated the oxidation of HQ to SQ-. and BQ and the utilization of O2. Furthermore, the enhancement by Cu/Zn-SOD of the generation of SQ-. or BQ from HQ in PBS/BSA was extensively inhibited under anaerobic conditions. The enhancement of SQ-. generation from HQ by all three forms of SOD does not support the possibility that Cu/Zn-SOD can oxidize SQ-. to BQ. Taken together, this study demonstrates that unlike free copper, Cu/Zn-SOD does not directly interact with HQ to cause its oxidation to BQ. Rather, the autoxidation of HQ to SQ-. is a prerequisite for the enhancing capacity of Cu/Zn-SOD, and the dismutation of superoxide anion radicals generated from the SQ-. in the presence of O2 appears to be the underlying mechanism responsible for the enhancement by Cu/Zn-SOD of the oxidation of HQ.
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PMID:Role of Cu/Zn-superoxide dismutase in xenobiotic activation. I. Chemical reactions involved in the Cu/Zn-superoxide dismutase-accelerated oxidation of the benzene metabolite 1,4-hydroquinone. 864 79

The superoxide-dismutase (SOD) enzyme, isolated from the halophilic halotolerant bacterium Ba1, was found to be a dimer with a molecular weight of 40 kD and a subunit weight of 23.5 kD. The partial N-terminal sequence showed significant homology to SODs isolated from various sources. Metal analysis showed that SOD from Ba1 contains manganese and iron with the following stoichiometries: 0.9 +/- 0.4 Mn/dimer and 0.6 +/- 0.2 Fe/dimer. Two bands were obtained by isoelectric-focusing, at pI of 4.45 and at 4.40. Native SOD from Ba1 at room temperature was ESR silent. An ESR spectrum of hydrated Mn(II) was obtained from denaturated enzyme. Native enzyme cooled to 97 K showed an ESR spectrum identified as being due to Fe(III). The spectrum was pH-independent. SOD from Ba1 was not inactivated by H2O2. On the basis of these observations, SOD from Ba1 was characterized as MnSOD. The excitation fluorescence spectrum of SOD from Ba1 showed four main peaks in the visible region. The effects on the spectra of KSCN, NaN3, NaF, and ascorbate were examined. Measurements of H2(17)O-nmr relaxation times T1 and T2, for solutions containing E. coli MnSOD and FeSOD, showed no paramagnetic contribution. These results support the assumption that the water molecule at the active site is strongly bound.
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PMID:Mn-superoxide dismutase from the halophilic halotolerant bacterium Ba1--isolation and active site spectroscopic studies. 898 69

Moxa smoke induced internucleosomal DNA fragmentation in human promyelocytic leukemic HL-60 cells, but not in other cell lines. The cytotoxic activity of Moxa smoke was significantly reduced by a popular antioxidant, N-acetyl-L-cysteine (NAC). Moxa smoke showed oxidation potential (measured by NO monitor) and produced carbon radical (measured by ESR spectroscopy). The addition of NAC significantly reduced both the oxidation potential and carbon radical intensity of Moxa smoke. Activity staining of polyacryamide gel electrophoresis of MnSOD revealed the possible modification of the conformation and/or activity of this enzyme at an early stage of HL-60 cell death. These data suggest that Moxa smoke induces cytotoxicity by its pro-oxidant action.
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PMID:Induction of cell death by pro-oxidant action of Moxa smoke. 1201 80

The effect of Cu plate on the cellular function was investigated by two different methods: an extraction method (Method I) and a direct contact method (Method II). In Method I, the supernatant of the culture medium, which had been pre-incubated with Cu plate, was added to mouse macrophage-like Raw 264.7 cells. This supernatant dose-dependently inhibited the proliferation and nitric oxide (NO) production by lipopolysaccharide-stimulated Raw 264.7 cells. In Method II, human promyelocytic leukemic HL-60 cells in suspension were incubated with culture medium which contained Cu plate. The direct contact with Cu plate rapidly suppressed the proliferation and MnSOD and Cu/ZnSOD activities. The suppressed proliferation and SOD activity reverted to or exceeded the control level by sodium ascorbate, whereas N-acetyl-L-cysteine (NAC) only reactivated the proliferation, but not the SOD activity. ESR spectroscopy showed that contact with Cu plate slightly diminished the hydroxyl radical (generated by Fenton reaction), without affecting the intensity of NO (produced from NOC-7) and DPPH radical. The present study suggests that two representative antioxidants, such as sodium ascorbate and NAC, protect the cells from Cu-induced cytotoxicity via different mechanisms.
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PMID:Protection by antioxidants of copper-induced decline of proliferation and SOD activity. 1581 49

The dried rhizome of Bai Zhu (Atractylodes ovata) is widely used as a Chinese herbal medicine. Two sesquiterpenolides of similar structures (atractylenolide I, AT-I; atractylenolide III, AT-III) were isolated from dried rhizome of Atractylodes ovata. Incubation of AT-I with recombinant human Cu,Zn-superoxide dismutase (rhCu,Zn-SOD) resulted in rhCu,Zn-SOD fragmentations and Zn releases. However, these were not observed in the AT-III reaction. The AT-1 showed dose-dependent cytotoxic activities (7.5, 15, and 30 microg/ml) on the human promyeloleukemic HL-60 cells while AT-III did not, and the IC50 of the former being 10.6 microg/ml (corresponding to 46 microM) on 12 h-treated cells. The results of DNA ladder and DNA contents in sub-G1 type revealed that AT-I induced apoptosis in human promyeloleukemic HL-60 cells. The cytotoxic and pharmacological mechanisms of AT-I against human promyeloleukemic HL-60 cells was investigated. The AT-I appeared to exhibit both pro-oxidant and antioxidant properties after an ESR spectrometer was used to detect hydroxyl radical productions in vitro and flow cytometry to detect intracellular ROS productions in AT-I treated cells. The AT-1 also showed dose-dependent Cu,Zn-SOD inhibitory activity in HL-60 cells treated for 12 h, confirmed by activity and immune stainings. However, catalase, Mn-SOD, and glutathione peroxidase did not apparently change activities under the same treatments. The addition of commercial rhCu,Zn-SOD (25-100 U/mL) to the AT-I-treated HL-60 cells (15 microg/ml) resulted in significant differences (p<0.01) and could reduce the AT-I cytotoxicity from 78% to 28% on HL-60 cells. It was proposed that the AT-I might work via Cu,Zn-SOD inhibition in HL-60 cells to induce apoptosis and bring about cytotoxicity.
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PMID:Pro-oxidant and cytotoxic activities of atractylenolide I in human promyeloleukemic HL-60 cells. 1662 72