Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A cDNA clone encoding ascorbate peroxidase (AP, EC 1.11.1.11) was isolated from a phage lambda gt11 library of cDNA from Arabidopsis thaliana by immunoscreening with monoclonal antibodies against the enzyme, and then sequenced. The cDNA insert hybridized to a 1.1 kb poly(A)+ RNA from leaves of A. thaliana. Genomic hybridization suggests that the cDNA obtained here corresponds to a single-copy gene. The N-terminal amino acid sequence of Arabidopsis AP was determined by protein sequencing of the immunochemically purified enzyme, and proved to be homologous to the N-terminal amino acid sequence of the chloroplastic AP of spinach. The predicted amino acid sequence of the mature AP of A. thaliana, deduced from the nucleotide sequence, consists of 249 amino acid residues, which is 34% homologous with cytochrome c peroxidase of yeast, but less homologous with other plant peroxidases. Amino acid residues at the active site of yeast cytochrome c peroxidase are conserved in the amino acid sequence of Arabidopsis AP. The poly(dG-dT) sequence, which is a potential Z-DNA-forming sequence, was found in the 3' untranslated region of the cDNA.
Plant Mol Biol 1992 Feb
PMID:Cloning and sequencing of a cDNA encoding ascorbate peroxidase from Arabidopsis thaliana. 155 44

The response of Raphanus sativus to salinity has been investigated. Salt-responsive proteins were detected by comparative 2D-PAGE analysis. Three polypeptides of 22, 28 and 28.5 kDa were isolated and subjected to microsequencing. The P22 possesses homology with members of the Kunitz family of trypsin inhibitor; the P28.5 is homologous to ascorbate peroxidase of several plant species while P28 did not exhibit significant homology with sequences archived in available databases.
Cell Mol Biol (Noisy-le-grand) 1994 Feb
PMID:Identification by 2D-page analysis of salt-stress induced proteins in radish (Raphanus sativus). 800 38

The effects of ozone or sulfur dioxide on antioxidant enzymes were investigated in Arabidopsis thaliana. Plants were fumigated with 0.1-0.15 ppm ozone or sulfur dioxide up to about 1 week in an environment-controlled chamber. Both pollutants increased the activities of ascorbate peroxidase and guaiacol peroxidase in leaves, but had little effect on the activities of superoxide dismutase, catalase, monodehydroascorbate reductase, dehydroascorbate reductase or glutathione reductase. Ozone was more effective than sulfur dioxide in increasing the activities of the peroxidases. Ascorbate peroxidase activity increased 1.8-fold without a lag period during fumigation with 0.1 ppm ozone, while guaiacol peroxidase activity increased 4.4-fold with a 1-day lag. Expression of the APX1 gene encoding cytosolic ascorbate peroxidase was further investigated. Its protein levels in leaves exposed to 0.1 ppm ozone for 4 or 8 days were 1.5-fold higher than in controls. Both ozone and sulfur dioxide elevated APX1 mRNA levels in leaves at 4 and 7 days, whereas at 1 day only ozone was effective. The induction of APX1 mRNA levels by ozone (3.4- to 4.1-fold) was more prominent than that by sulfur dioxide (1.6- to 2.6-fold). The APX1 mRNA level increased by day and decreased by night. Exposure of plants to 0.1 ppm ozone enhanced the APX1 mRNA level within 3 h, which showed a diurnal rhythm similar to that of the control. These results demonstrate that near-ambient concentrations of ozone as well as similar concentrations of sulfur dioxide can induce APX1 gene expression in A. thaliana.
Plant Mol Biol 1995 Nov
PMID:Expression of Arabidopsis cytosolic ascorbate peroxidase gene in response to ozone or sulfur dioxide. 853 47

An Arabidopsis 14-3-3 protein, AFT1, was used as a 'bait' in the two-hybrid system to identify its interacting proteins. One of the candidate proteins, APX3, was identified as a putative peroxisomal membrane-bound ascorbate peroxidase. Ascorbate peroxidases are important defense enzymes that protect plant cells from oxidative stress damage. DNA blot analysis indicates that APX3 is encoded by a single-copy gene in the Arabidopsis genome. RNA blot analyses show that APX3 transcript levels increase slightly in response to cold, UV light, and treatments with hydrogen peroxide and paraquat. The activity of APX3 in Arabidopsis may be controlled in two ways: its enzymatic activity through protein-protein interactions and its transcription by transcriptional or posttranscriptional regulation.
Plant Mol Biol 1997 Aug
PMID:Cloning and expression of an Arabidopsis gene encoding a putative peroxisomal ascorbate peroxidase. 929 Jun 48

We investigated the behavior of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APx), in potato tubers during storage at low temperature. SOD activity increased temporarily within 3 weeks and was higher at 1 degree C than at 20 degrees C. APx activity also increased more at low (1 degree C) than at higher temperatures (5 and 20 degrees C). The contents of ascorbic acid (AsA), which is the substrate of APx, decreased immediately within 3 weeks and then gradually decreased until 15 weeks. The activity of CAT, the other enzyme which can scavenge hydrogen peroxide, decreased once in the first six weeks and thereafter increased to 15 weeks. Thus, the enhancement of the active oxygen-scavenging system that was induced by low temperature in potato tubers could result not only in a decrease of AsA but also in combined increases in APx and CAT activity whose manners were different.
Biochem Mol Biol Int 1998 Apr
PMID:Ascorbate peroxidase and catalase cooperate for protection against hydrogen peroxide generated in potato tubers during low-temperature storage. 958 85

To understand the coordinated functions of the different classes of defense-related genes expressed in plant disease resistance, the expression patterns of pathogenesis related (PR) protein genes and genes involved in antioxidation and the production of secondary metabolites were examined. The expression patterns of the respective defense-related genes were monitored following TMV infection or salicylic acid treatment. Northern blot analyses showed that PR genes such as PR-1, beta-1,3-glucanase and chitinase were strongly induced in tobacco leaves upon TMV infection or salicylic acid treatment. 3-Hydroxy-3-methylglutaryl CoA reductase (HMGR) and phenylalanine ammonialyase (PAL), involved in isoprenoid and phenylpropanoid biosynthesis, respectively, were mildly induced at the late stage of normal hypersensitive response (HR) or after salicylic acid treatment when compared with the PR-gene expressions. However, in acute HR, they were strongly expressed at the early stage. Interestingly, the expression of the antioxidative genes, anionic peroxidase and ascorbate peroxidase, were inversely expressed following TMV infection and salicylic acid treatment. Differential expression of 3 groups of genes involved in plant defense responses are discussed in relation to different signal transduction pathways.
Mol Cells 1998 Aug 31
PMID:Coordinated expression of defense-related genes by TMV infection or salicylic acid treatment in tobacco. 974 24

In cultured soybean cells, a transient ethylene burst in the pre-stationary phase was followed by an induction of ascorbate peroxidase (AsPOX) in the stationary phase. Treatment of cells with the ethylene antagonist, silver thiosulfate (STS), resulted in the suppression of enzyme activity. Application of the ethylene releasing agent 2-chloroethylphosphonic acid (CEPA) in the medium led to an increased enzyme activity when treated in the pre-stationary phase. On the contrary, a remarkable inhibitory effect on enzyme activity was elicited by 1,3-dimethyl-2-thiourea (DMTU), trapping the hydrogen peroxide generated when treated in the stationary phase. Likewise, a steady level of AsPOX transcript was reduced by STS treatment. Furthermore, its effect appeared to be more rapid and prominent during the pre-stationary phase. It is suggested that the induction of AsPOX in cultured soybean cells during the stationary phase could result, at least in part, by the hydrogen peroxide generated as a result of preceding ethylene production.
Mol Cells 1999 Apr 30
PMID:Induction of ascorbate peroxidase by ethylene and hydrogen peroxide during growth of cultured soybean cells. 1034 Apr 71

In plants ascorbate peroxidase (APX) is an important H2O2-detoxifying enzyme. The expression of APX is rapidly induced in response to stresses that result in the accumulation of reactive oxygen species (ROS). We have recently reported that the steady-state level of transcripts encoding cytosolic APX (cAPX) is dramatically induced during the hypersensitive response (HR) of tobacco plants infected with tobacco mosaic virus (TMV). Because cAPX expression is closely linked to the production of ROS in plant cells, studying the regulation cAPX mRNA can reveal some of the signal transduction events associated with ROS metabolism during the HR. Analysis of cAPX mRNA induction during the HR suggested that the expression of cAPX is under the control of the HR signal transduction pathway. The activation of cAPX expression followed signaling events such as changes in protein phosphorylation and induction of ion fluxes. Expression of cAPX was suppressed under conditions of low oxygen pressure, and could only be mimicked by enhancing the intracellular generation of ROS. Interestingly, salicylic acid (SA), which is thought to be involved in ROS metabolism during the HR, did not affect the induction of cAPX mRNA during TMV-induced HR. Using cAPX expression as a marker for the production of ROS, it is suggested that SA may not be involved in the formation of ROS during the HR of tobacco to TMV, and that ROS may not be involved in the induction of the pathogenesis-related protein, PR-1, during this process.
Plant Mol Biol 1999 Mar
PMID:Signals controlling the expression of cytosolic ascorbate peroxidase during pathogen-induced programmed cell death in tobacco. 1034 7

Arabidopsis thaliana was transformed with the codA gene from Arthrobacter globiformis. This gene encodes choline oxidase, an enzyme that converts choline to glycinebetaine. The photosynthetic activity, monitored in terms of chlorophyll fluorescence, of transformed plants was more tolerant to light stress than that of wild-type plants. This enhanced tolerance to light stress was caused by acceleration of the recovery of the photosystem II (PS II) complex from the photo-inactivated state. The transformed plants synthesized glycinebetaine, but no changes were detected in the relative levels of membrane lipids or in the relative levels of fatty acids in the various membrane lipids. Transformation with the codA gene increased levels of H2O2, a by-product of the reaction catalyzed by choline oxidase, by only 50% to 100% under stress or non-stress conditions. The activity of ascorbate peroxidase and, to a lesser extent, that of catalase in transformed plants were significantly higher than in the wild-type plants. These observations suggest that H2O2 produced by choline oxidase in the transformed plants might have stimulated the expression of H2O2 scavenging enzymes, with resultant maintenance of the level of H2O2 within a certain limited range. It appears that glycinebetaine produced in vivo, but not changes in membrane lipids or in the level of H2O2, protected the PS II complex in transformed plants from damage due to light stress.
Plant Mol Biol 1999 May
PMID:Enhanced tolerance to light stress of transgenic Arabidopsis plants that express the codA gene for a bacterial choline oxidase. 1041 6

This report describes the characterisation of a gene (APX20) from tomato plants that encodes a cytosolic isoform of ascorbate peroxidase which is involved in the detoxification of intracellular H2O2. Expression analysis of promoter-GUS fusions in transgenic plants reveals that the gene is under strict developmental control, becoming transcriptionally active in cells which are apparently undergoing mechanical stimulation generated during the different phases of growth. We show that the APX20 gene contains a large 5' leader intron which is required to confer constitutive gene expression in leaves, but not in other organs of the plant. Based on these observations, we propose that the observed transcriptional regulation of this gene may constitute a basic mechanism for deployment of antioxidative defences in plants, which act to limit the deleterious effects of H2O2 generated during normal plant development.
Mol Gen Genet 1999 Sep
PMID:Developmental regulation of a cytosolic ascorbate peroxidase gene from tomato plants. 1051 16


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