Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.7.1.2 (nitrate reductase)
 3,861 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The incubation of peroxynitrite (PN)-pretreated histone III-S (NH) with Escherichia coli nitrate reductase (cytochrome, NADPH/GSH-independent) and that of NADPH-treated NH (NHNADPH) with liver cytochrome P-450 reductase (NADPH-dependent) resulted in decreased 3-nitrotyrosine immunoreactivity found in Western blot analysis. Additionally, increased nitrate was noted as an end product of these reactions. These findings imply that varied enzymatic denitration/modification of NO/PN-reacted protein, either with or without a reductant, may be important in regulating related signal transduction cascade(s) and relieving oxidative stress.
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PMID:Protein denitration/modification by Escherichia coli nitrate reductase and mammalian cytochrome P-450 reductase. 1181 90

Phosphorylation is an ubiquitous regulatory mechanism governing the activity, subcellular localization, and intermolecular interactions of proteins. To identify a broad range of phosphoproteins from Zea mays, we enriched phosphopeptides from Zea mays leaves using titanium dioxide microcolumns and then extensively fractionated and identified the phosphopeptides by mass spectrometry. A total of 165 unique phosphorylation sites with a putative role in biological processes were identified in 125 phosphoproteins. Most of these proteins are involved in metabolism, including carbohydrate and protein metabolism. We identified novel phosphorylation sites on translation initiation factors, splicing factors, nucleolar RNA helicases, and chromatin-remodeling proteins such as histone deacetylases. Intriguingly, we also identified phosphorylation sites on several proteins associated with photosynthesis, and we speculate that these sites may be involved in carbohydrate metabolism or electron transport. Among these phosphoproteins, phosphoenolpyruvate carboxylase and NADH: nitrate reductase (NR) which catalyzes the rate-limiting and regulated step in the pathway of inorganic nitrogen assimilation were identified. A conserved phosphorylation site was found in the cytochrome b5 heme-binding domain of NADH: nitrate reductase, suggesting that NADH: nitrate reductase is phosphorylated by the same protein kinase or highly related kinases. These data demonstrate that the pathways that regulate diverse processes in plants are major targets of phosphorylation.
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PMID:Large-scale analysis of phosphorylated proteins in maize leaf. 2105 13

The activities of mammalian DNA and histone methyltransferases are regulated by post-translational modifications such as phosphorylation and sumoylation; however, it is unclear how the activities of these enzymes are regulated at the post-translational level in plants. Here, we demonstrate that the DNA methylation activity of Arabidopsis CHROMOMETHYLASE 3 (CMT3) is positively regulated by the E3 SUMO ligase AtSIZ1. The methylation level of the Arabidopsis genome, including transposons, was significantly lower in the siz1-2 mutant than in wild-type plants. CMT3 was sumoylated by the E3 ligase activity of AtSIZ1 through a direct interaction, and the DNA methyltransferase activity of CMT3 was enhanced by this modification. In addition, the methylation levels of a large number of genes, including the nitrate reductase gene NIA2, were lower in siz1-2 and cmt3 plants than in wild-type plants. Furthermore, the CHG methylation activity of CMT3 was specific for NIA2and not NIA1 (the other nitrate reductase gene in Arabidopsis), indicating that CMT3 selectively regulates the CHG methylation levels of target genes. Taken together, our results indicate that the sumoylation of CMT3 is critical for its role in the control of gene expression and that AtSIZ1 positively controls the epigenetic repression of CMT3-mediated gene expression.
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PMID:Arabidopsis CMT3 activity is positively regulated by AtSIZ1-mediated sumoylation. 2639 5