Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30044 (antioxidant enzyme)
 8,037 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chronic benzaldehyde exposure is known to cause central nervous system (CNS) disturbances. Previous studies have shown that benzaldehyde causes the formation of reactive oxygen species (ROS) in rat synaptosomal fractions. Benzaldehyde has also been implicated in ROS formation in the CNS of rats treated with toluene. We have found that benzaldehyde effectively inactivates the antioxidant enzyme glutathione peroxidase (Ki approximately 15 microM), but has no effect on the other antioxidant enzymes tested: catalase, superoxide dismutase, and glutathione reductase. This effect has been found to be specific to benzaldehyde since other structurally related and unrelated aldehydes tested were found to be devoid of inactivating capacity toward glutathione peroxidase. Since glutathione peroxidase is the main enzyme responsible for removal of hydrogen peroxide and organic hydroperoxides in brain, its inactivation by benzaldehyde may be a main contributor to the observed ROS formation and the observed neurotoxicity caused by either benzaldehyde or toluene exposure.
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PMID:Inactivation of glutathione peroxidase by benzaldehyde. 897 63

Normal cells are protected by antioxidant enzymes from the toxic effects of high concentrations of reactive oxygen species generated during cellular metabolism. Even though cancer cells generate reactive oxygen species, it has been demonstrated biochemically that antioxidant enzyme levels are low in most animal and human cancers. However, a few cancer types have been found to have elevated levels of antioxidant enzymes, particularly manganese superoxide dismutase. Morphologic studies of animal and human cancer have confirmed that although the majority of tumor cell types from several organ systems have low antioxidant enzymes, adenocarcinomas may have elevated manganese superoxide dismutase and catalase levels. However, all cancers examined to date have some imbalance in antioxidant enzyme levels compared with the cell of origin. Antioxidant enzyme importance in cancer genesis has been difficult to evaluate in early cancerous lesions using biochemical techniques because such lesions are small and therefore below the level of detection. Using immunohistochemical techniques, early lesions of human and animal cancers were demonstrated to have low antioxidant enzymes, thus suggesting a role for these enzymes both in the genesis of cancer and the malignant phenotype. All but one human cancer cell type (the granular cell variant of human renal adenocarcinoma) examined showed both low catalase and glutathione peroxidase levels, suggesting that most cancer cell types cannot detoxify hydrogen peroxide. Our results to date are used to propose new cancer therapies based on modulation of cellular redox state.
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PMID:Antioxidant enzyme levels in cancer. 915 Nov 41

Antioxidant enzyme expression was determined in rat pancreatic islets and RINm5F insulin-producing cells on the level of mRNA, protein, and enzyme activity in comparison with 11 other rat tissues. Although superoxide dismutase expression was in the range of 30% of the liver values, the expression of the hydrogen peroxide-inactivating enzymes catalase and glutathione peroxidase was extremely low, in the range of 5% of the liver. Pancreatic islets but not RINm5F cells expressed an additional phospholipid hydroperoxide glutathione peroxidase that exerted protective effects against lipid peroxidation of the plasma membrane. Regression analysis for mRNA and protein expression and enzyme activities from 12 rat tissues revealed that the mRNA levels determine the enzyme activities of the tissues. The induction of cellular stress by high glucose, high oxygen, and heat shock treatment did not affect antioxidant enzyme expression in rat pancreatic islets or in RINm5F cells. Thus insulin-producing cells cannot adapt the low antioxidant enzyme activity levels to typical situations of cellular stress by an upregulation of gene expression. Through stable transfection, however, we were able to increase catalase and glutathione peroxidase gene expression in RINm5F cells, resulting in enzyme activities more than 100-fold higher than in nontransfected controls. Catalase-transfected RINm5F cells showed a 10-fold greater resistance toward hydrogen peroxide toxicity, whereas glutathione peroxidase overexpression was much less effective. Thus inactivation of hydrogen peroxide through catalase seems to be a step of critical importance for the removal of reactive oxygen species in insulin-producing cells. Overexpression of catalase may therefore be an effective means of preventing the toxic action of reactive oxygen species.
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PMID:Relation between antioxidant enzyme gene expression and antioxidative defense status of insulin-producing cells. 935 19

Breathing air exposes humans and other mammals to various toxic agents including oxidative contaminants associated with fine particles of less than 2.5 micron which may be deposited in the deep lung and have been implicated in the increased morbidity and mortality correlated with air pollution. Oxidative damage from inhaled particles may include damage to DNA, thereby adversely affecting the immunosurveillance provided by alveolar macrophages. Using the rat alveolar macrophage cell line NR8383, we demonstrated that cell proliferation was inhibited by exogenous hydrogen peroxide, an oxidant naturally produced in cellular respiration and phagocytosis. Mercaptosuccinate, a specific inhibitor of the antioxidant enzyme glutathione peroxidase, also inhibited cell growth. Genes known to be coordinatively regulated in response to growth arrest and DNA damage, GADD45 and GADD153, were induced compared to the housekeeping gene beta-ACTIN by equitoxic doses of hydrogen peroxide and mercaptosuccinate. Hydrogen peroxide treatment of cells in which glutathione peroxidase was inhibited by mercaptosuccinate resulted in even greater induction of both GADD genes. This approach using the NR8383 alveolar macrophage cell line provides a model for studying genotoxicity at the mechanistic level at which stress-responsive genes involved in growth arrest and DNA-damage response are modulated.
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PMID:NR8383 alveolar macrophage toxic growth arrest by hydrogen peroxide is associated with induction of growth-arrest and DNA damage-inducible genes GADD45 and GADD153. 935 15

Nephron loss leads to increased production of reactive oxygen intermediates. We measured the effect of carvedilol, a beta-blocking drug with radical scavenging properties, on renal function, glomerulosclerosis, antioxidant enzyme status and in vivo hydrogen peroxide (H2O2) production in rats with chronic renal failure caused by 5/6 nephrectomy (remnant kidney) and compared results to data obtained with propranolol, a beta-blocking drug without scavenging characteristics. Carvedilol and propranolol were administered during 11 weeks following reduction of nephron number. Kidneys were examined using enzymatic and histological techniques. Both carvedilol and propranolol decreased systolic blood pressure. Compared to propranolol, carvedilol offered some additional beneficial effects on renal function, particularly with regard to glomerulosclerosis. Lipid peroxidation, evaluated by malonaldehyde and 4-hydroxynonenal concentration in cortex homogenates, was decreased in carvedilol-treated rats only. Superior beneficial effect of carvedilol treatment is not linked to a significant up-regulation of the activities of the remnant kidney antioxidant enzymes (catalase, glutathione peroxidase and superoxide dismutase) or to a decreased in vivo H2O2 production.
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PMID:Carvedilol protects against glomerulosclerosis in rat remnant kidney without general changes in antioxidant enzyme status. A comparative study of two beta-blocking drugs, carvedilol and propanolol. 937 27

Reduction-oxidation (redox) plays a critical role in NF-kappaB activation. Diverse stimuli appear to utilize reactive oxygen species (e.g. hydrogen peroxide) as common effectors for activating NF-kappaB. Antioxidants govern intracellular redox status, and many such molecules can reduce H2O2. However, functionally, it does appear that different antioxidants are variously selective for redox regulation of certain transcription factors such as NF-kappaB. For NF-kappaB, thioredoxin has been described to be a more potent antioxidant than either glutathione or N-acetylcysteine. Thioredoxin peroxidase is the immediate enzyme that links reduction of H2O2 to thioredoxin. Several putative human thioredoxin peroxidases have been identified using recursive sequence searches/alignments with yeast or prokaryotic enzymes. None has been characterized in detail for intracellular function(s). Here, we describe a new human thioredoxin peroxidase, antioxidant enzyme AOE372, identified by virtue of its protein-protein interaction with the product of a proliferation association gene, pag, which is also a thiol-specific antioxidant. In human cells, AOE372 defines a redox pathway that specifically regulates NF-kappaB activity via a modulation of IkappaB-alpha phosphorylation in the cytoplasm. We show that AOE372 activity is regulated through either homo- or heterodimerization with other thiol peroxidases, implicating subunit assortment as a mechanism for regulating antioxidant specificities. AOE372 function suggests thioredoxin peroxidase as an immediate regulator of H2O2-mediated activation of NF-kappaB.
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PMID:Regulatory role for a novel human thioredoxin peroxidase in NF-kappaB activation. 938 42

The present experiments were done to elucidate the roles of thioredoxin and thioredoxin reductase system in defense against hydrogen peroxide (H2O2) in Escherichia coli. The thioredoxin-deficient mutant (trxA) was more sensitive to H2O2 than was the wild-type strain, when challenged in the stationary and exponentially growing phase. Thioredoxin reductase-deficient mutant (trxB) in the stationary phase also exhibited increased sensitivity, compared with the wild-type strain. These results indicated that reduced form of thioredoxin is required for defense against H2O2, possibly by scavenging radicals generated in the cells. In contrast, the trxB mutant in the growing phase had higher survival after exposure to H2O2 than the wild-type strain. The acquirement of resistance related to increased capacity for removing H2O2 in the trxB mutant and was not observed in a catalase-negative background. Furthermore, enhanced expression of the katG :: lacZ gene occurred in the mutant. Therefore, it was concluded that oxidized form of thioredoxin confers H2O2 resistance on E. coli cells by increasing activity to remove H2O2, which was brought about by enhanced induction of the katG-coded catalase/hydroperoxidase I at the transcriptional level. In addition, this resistance to H2O2 correlated well with reduced amount of DNA damage caused by H2O2, determined by the induction level of the recA :: lacZ fusion gene after treatment with H2O2.
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PMID:Different mechanisms of thioredoxin in its reduced and oxidized forms in defense against hydrogen peroxide in Escherichia coli. 955 67

Catalase is an antioxidant enzyme that has been shown to inhibit apoptotic or necrotic neuronal death induced by hydrogen peroxide. We report the purification of a contaminating antiapoptotic activity from a commercial bovine liver catalase preparation by following its ability to inhibit apoptosis when applied extracellularly in multiple death paradigms. The antiapoptotic activity was identified by protein microsequencing as arginase, a urea cycle and nitric oxide synthase-regulating enzyme, and confirmed by demonstrating the presence of antiapoptotic activity in a >97% pure preparation of recombinant arginase. The pluripotency of recombinant arginase was demonstrated by its ability to inhibit apoptosis in multiple paradigms including rat cortical neurons induced to die by glutathione depletion and oxidative stress, by 100 nM staurosporine treatment, or by Sindbis virus infection. The protective effects of arginase in these apoptotic paradigms, in contrast to previous studies on excitotoxic neuronal necrosis, are independent of nitric oxide synthase inhibition. Rather, arginase-induced depletion of arginine leads to inhibition of protein synthesis, resulting in cell survival. Because inhibitors of nitric oxide synthesis and of protein synthesis have been shown to decrease necrotic and apoptotic death, respectively, in animal models of stroke and spinal cord injury, arginine-depleting enzymes, capable of simultaneously inhibiting protein synthesis and nitric oxide generation, may be propitious therapeutic agents for acute neurological diseases. Furthermore, our results suggest caution in attributing the cytoprotective effects of some catalase preparations to catalase.
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PMID:Purification of a multipotent antideath activity from bovine liver and its identification as arginase: nitric oxide-independent inhibition of neuronal apoptosis. 959 89

The cytoplasmic copper-zinc superoxide dismutase (Cu, Zn SOD; SOD-1) is an abundant and well-conserved intracellular antioxidant enzyme which has been implicated in a number of oxidative stress mediated phenomena, especially Down Syndrome, in which SOD-1 activity is increased due to triplication of chromosome 21 containing the gene and, in hereditary amyotrophic lateral sclerosis, in which the gene is mutated. Overexpression of SOD-1 could theoretically, therefore, lead to increased vulnerability to oxidative stress in two distinct manners: increasing steady-state hydrogen peroxide levels or increasing toxic side reactions. We used two mouse neuronal culture systems--one in which the murine chromosome containing SOD-1 is triplicated and one in which human SOD-1 is a transgene--to test the effect of overexpression of this enzyme on antioxidant status in general and specifically on glutamate mediated oxidative stress. We found that SOD-1 overexpression increases antioxidant status at the same time it decreases vulnerability to glutamate.
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PMID:Effects of overexpression of the cytoplasmic copper-zinc superoxide dismutase on the survival of neurons in vitro. 963 90

In response to the attack of reactive oxygen species, the skin has developed a complex antioxidant defense system including among others the manganese-superoxide dismutase (MnSOD). MnSOD dismutates the superoxide anion (O2*-) derived from the reduction of molecular oxygen to hydrogen peroxide (H2O2), which is detoxified by glutathione peroxidase to water and molecular oxygen. We have addressed the question whether MnSOD is inducible upon UVA irradiation and whether repetitive UV exposure, as practiced for the light-hardening during phototherapy of various photodermatoses, can even enhance the adaptive antioxidant response. Single exposure of four different strains of fibroblasts to UVA irradiation resulted in a dose- and time-dependent increase in specific MnSOD mRNA levels. Interestingly, repetitive UVA exposure at days 1, 2, and 3 at a dose rate of 200 kJ per m2 resulted in a 5-fold induction of specific MnSOD mRNA levels following the third UVA exposure. Similar results were obtained for MnSOD activity. This adaptive response in terms of upregulation of the antioxidant enzyme MnSOD correlates with the protection against high UV doses, if cells were preexposed to sublethal UV doses. Importantly, MnSOD substantially differed between the tested individuals in both mRNA and activity levels. Taken together, we here provide evidence for the increasing induction of MnSOD upon repetitive UVA irradiation that may contribute to the effective adaptive UVA response of the skin during light hardening in phototherapy. Interindividual differences in the inducibility of MnSOD might account for differences in the susceptibility to develop photodermatologic disorders related to photosensitivity, photoaging, and skin cancer. The molecular basis for interindividual differences in the inducibility of antioxidant enzymes remains to be elucidated.
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PMID:Adaptive antioxidant response of manganese-superoxide dismutase following repetitive UVA irradiation. 988 57


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