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)

Thioredoxin reductase (TR) activity on primary melanomas and in surrounding skin is regulated by calcium and, therefore, TR activity can be used to measure the flux of calcium between primary tumors and their surrounding epidermis. Calcium uptake in human melanotic melanoma cell lines SKmel-23 (metastatic) and BC-PT-1 (primary) is related to the density of beta-2-adrenoceptors. The non-pigmented cell line HT-144 (metastatic), did not express beta-2-adrenoceptors, yielding a slow rate of calcium uptake compared to SKmel-23 and BC-PT-1. Cell extracts from melanotic and amelanotic melanoma tissues did not contain a phenylethanolamine-N-methyltransferase (PNMT) for the biosynthesis of epinephrine from norepinephrine and S-adenosylmethionine. However, human full-thickness skin, epidermis and cell cultures of human keratinocytes contained significant PNMT activities. Taken together, these results indicate that (a), TR can be used to monitor calcium flux between primary melanomas and their surrounding skin and vice versa and (b), calcium uptake may be regulated by stimulation of beta-2-adrenoceptors on melanotic melanomas by epinephrine synthesized in the surrounding skin.
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PMID:Calcium transport and regulation in human primary and metastatic melanoma. 132 82

Oxidation-reduction (redox) reactions comprise a subset of fundamental biochemical reactions found throughout biological systems. While redox reactions are involved in many normal cellular functions, excess oxidative potential, or oxidative stress, can lead to cellular dysfunction and injury. Multiple protective antioxidant systems have evolved to guard against the adverse consequences of oxidant stress and injury. These systems include low-molecular-weight antioxidants, such as the glutathione-glutathione disulfide redox couple; the thiol proteome, whose various oxidation states can serve as a global redox buffer; and antioxidant enzymes, such as the superoxide dismutases, catalase, peroxidredoxins, and the glutathione peroxidases. One example of an essential antioxidant enzyme whose deficiency contributes to pathobiology in the vasculature is glutathione peroxidase-3 (GPx-3), the principal antioxidant enzyme in the extracellular compartment. This enzyme catalyzes the reduction of hydrogen and lipid peroxides to water and lipid alcohols, respectively, and does so using reducing equivalents provided by glutathione. As a selenoprotein, it requires unique translational machinery for its expression, as well as adequate selenium stores; its primary site of synthesis is the renal tubule, although all nucleated cells can express low levels of the enzyme. We have previously demonstrated that a deficiency of GPx-3 leads to enhanced platelet activation, and is an independent risk factor for acute ischemic stroke in the young. We recently developed a GPx-3-deficient mouse model, and demonstrated endothelial dysfunction as well as increased platelet-dependent thrombosis in an acute ischemic stroke model. Importantly, platelet inhibitors or small-molecule superoxide and hydrogen peroxide scavengers greatly attenuated the size of the ischemic stroke and its functional consequences in this model. These data support the importance of GPx-3as a key antioxidant enzyme that functions to limit arterial thrombosis in the setting of increased oxidant stress and endothelial dysfunction. A second example of an essential antioxidant enzyme whose deficiency contributes to pathobiology in the vasculature is glutathione peroxidase-1 (GPx-1), a central intracellular antioxidant. In our efforts to uncover a mechanism for the oxidative stress of hyperhomocysteinemia, we found that elevated levels of this amino acid is associated with a decrease in the expression and activity of GPx-1 in endothelial cells. This change in expression was found to be post-translational, and we recently demonstrated that it is a consequence of hypomethylation of selenocysteine (Sec)-charged tRNA. This modification is essential for appropriate incorporation of Sec into the selenoprotein GPx-1's active site during translation. Changes in Sec-tRNA methylation are brought about by increased S-adenosylhomocysteine, which inhibits the methyltransferase required to methylate Sec-tRNA to the Um34 form. These data suggest a unique mechanism for impaired GPx-1 expression in hyperhomocysteinemic states that directly relates to impaired cellular methylation potential caused by increased S-adenosylhomocysteine accumulation.
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PMID:Redox Dysregulation in Vascular Pathobiology. 2646 4

Rice (Oryza sativa L.), a major staple food for billions of people, was assessed for its phytotoxicity of copper oxide nanoparticle (CuO NPs, size < 50 nm). Under hydroponic condition, seven days of exposure to 62.5, 125, and 250 mg/L CuO NPs significantly suppressed the growth rate of rice seedlings compared to both the control and the treatment of supernatant from 250 mg/L CuO NP suspensions. In addition, physiological indexes associated with antioxidants, including membrane damage and antioxidant enzyme activity, were also detected. Treatment with 250 mg/L CuO NPs significantly increased malondialdehyde (MDA) content and electrical conductivity of rice shoots by 83.4% and 67.0%, respectively. The activity of both catalase and superoxide dismutase decreased in rice leaves treated with CuO NPs at the concentration of 250 mg/L, while the activity of the superoxide dismutase significantly increased by 1.66 times in rice roots exposed to 125 mg/L CuO NPs. The chlorophyll, including chlorophyll a and chlorophyll b, and carotenoid content in rice leaves decreased with CuO NP exposure. Finally, to explain potential molecular mechanisms of chlorophyll variations, the expression of four related genes, namely, Magnesium chelatase D subunit, Chlorophyll synthase, Magnesium-protoporphyrin IX methyltransferase, and Chlorophyllide a oxygenase, were quantified by qRT-PCR. Overall, CuO NPs, especially at 250 mg/L concentration, could affect the growth and development of rice seedlings, probably through oxidative damage and disturbance of chlorophyll and carotenoid synthesis.
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PMID:Effects of Copper Oxide Nanoparticles on the Growth of Rice (Oryza Sativa L.) Seedlings and the Relevant Physiological Responses. 3207 21

DNMT2 is a DNA/tRNA cytosine methyltransferase that is highly conserved in structure and function in eukaryotes. In plants however, limited information is available on the function of this methyltransferase. We have previously reported that in the moss Physcomitrella patens, DNMT2 plays a crucial role in stress recovery and tRNAAsp transcription/stability under salt stress. To further investigate the role of PpDNMT2 at genome level, in this study we have performed RNA sequencing of ppdnmt2. Transcriptome analysis reveals a number of genes and pathways to function differentially and suggests a close link between PpDNMT2 function and osmotic and ionic stress tolerance. We propose PpDNMT2 to play a pivotal role in regulating salt tolerance by affecting molecular networks involved in stress perception and signal transduction that underlie maintenance of ion homeostasis in cells. We also examined interactome of PpDNMT2 using affinity purification (AP) coupled to mass spectrometry (AP-MS). Quantitative proteomic analysis reveals several chloroplast proteins involved in light reactions and carbon assimilation and proteins involved in stress response and some not implicated in stress to co-immunoprecipitate with PpDNMT2. Comparison between transcriptome and interactome datasets has revealed novel association between PpDNMT2 activity and the antioxidant enzyme Superoxide dismutase (SOD), protein turnover mediated by the Ubiquitin-proteasome system and epigenetic gene regulation. PpDNMT2 possibly exists in complex with CuZn-SODs in vivo and the two proteins also directly interact in the yeast nucleus as observed by yeast two-hybrid assay. Taken together, the work presented in this study sheds light on diverse roles of PpDNMT2 in maintaining molecular and physiological homeostasis in P. patens. This is a first report describing transcriptome and interactome of DNMT2 in any land plant.
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PMID:Transcriptome Analysis of ppdnmt2 and Identification of Superoxide Dismutase as a Novel Interactor of DNMT2 in the Moss Physcomitrella patens. 3284 34