Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q8NEX9 (reductase)
 26,410 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sulfate-reducing bacteria, Desulfovibrio vulgaris, strain Miyazaki, were grown on either sulfate, sulfite, or thiosulfate as the terminal electron acceptor. Better growth was observed on sulfite and less growth on thiosulfate than on sulfate. Enzyme levels of adenylylsulfate (APS) reductase [EC 1.8.99.2], reductant-activated inorganic pyrophosphatase [EC 3.6.1.1], sulfite reductase [EC 1.8.99.1] (desulfoviridin), hydrogenase [EC 1.12.2.1], and Mg2+-activated ATPase [EC 3.6.1.3] were compared in crude extracts of these cells at various stages of growth. 1) The specific activity of APS reductase in sulfite-grown cells was only one-fourth that in sulfate-grown cells throughout growth. Thiosulfate-grown cells had an activity intermediate between those of sulfate- and sulfite-grown cells. 2) Cells grown on sulfite had lower specific activity of reductant-activated inorganic pyrophosphatase than cells grown on sulfate or thiosulfate. 3) The specific activity of sulfite reductase (desulfoviridin) was highest in sulfite-grown cells. The sulfite medium gave the enzyme in high yield as well as with high specific activity. 4) The specific activities of hydrogenase and Mg2+-ATPase were not significantly altered by electron acceptors in the growth medium.
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PMID:Biochemical studies on sulfate-reducing bacteria. XIV. Enzyme levels of adenylylsulfate reductase, inorganic pyrophosphatase, sulfite reductase, hydrogenase, and adenosine triphosphatase in cells grown on sulfate, sulfite, and thiosulfate. 17 50

Microsomal fractions of cells isolated from chick epiphyseal cartilage catalyzed the synthesis of prostaglandins from radiolabeled delta8,11,14-eicosatrienoic and from arachidonic acids. In addition, the microsomal supernatants contained both 15-hydroxyprostaglandin dehydrogenase and prostaglandin 15-keto delta13,14-reductase activities. Two major classes of prostaglandins (E and F) were synthesized; however, a major product which chromatographically behaves as PGA was also isolated. Synthetase activities were analyzed for pH optima and response to known stimulators and inhibitors of prostaglandin systhesis. The different activators had varying stimulatory effects on prostaglandin synthesis; the anti-inflammatory drugs were all strongly inhibitory. Synthetase activity in the growth plate was highest in the zone of hypertrophy, declining substantially in the more heavily calcified regions. Degradative enzyme activities were highest in the zone of maturation and significantly lower in the adjacent hypertrophic zone. The net effect of these opposing activities would be to elevate prostaglandin levels at the zone of hypertrophy, a finding which suggests that prostaglandins may play a role in the modulation of epiphyseal cartilage metabolism.
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PMID:Biosynthesis and metabolism of prostaglandins in chick epiphyseal cartilage. 41 62

Adenylyl sulfate (APS) reductase, the key enzyme of the dissimilatory sulfate respiration, catalyzes the reduction of APS (the activated form of sulfate) to sulfite with release of AMP. A spectroscopic study was carried out with the APS reductase purified from the extremely thermophilic sulfate-reducing archaebacterium Archaeoglobus fulgidus DSM 4304. Combined ultraviolet/visible spectroscopy and low temperature electron paramagnetic resonance (EPR) studies were used in order to characterize the active centers and the reactivity towards AMP and sulfite of this enzyme. The A. fulgidus APS reductase is an iron-sulfur flavoprotein containing two distinct [4Fe-4S] clusters (Centers I and II) very similar to the homologous enzyme from Desulfovibrio gigas. Center I, which has a high redox potential, is reduced by AMP and sulfite, and Center II has a very negative redox potential.
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PMID:Spectroscopic studies on APS reductase isolated from the hyperthermophilic sulfate-reducing archaebacterium Archaeglobus fulgidus. 165 11

Adenylylsulphate (adenosine-5'-phosphosulphate, APS) reductase from the extremely thermophilic sulphate-reducing archaeon Archaeoglobus fulgidus is an iron-sulphur flavoprotein containing one non-covalently bound flavin group, eight non-haem iron and six labile sulphide atoms per molecule. Reevaluation of the enzyme structure revealed the presence of two different subunits with molecular masses of 80 and 18.5 kDa. The subunits are arranged in an alpha 2 beta subunit structure. We have cloned and sequenced a 2.7 kb segment of DNA containing the genes for the alpha and beta subunits, which we designate aprA and aprB, respectively. The two genes are separated by 17 bp and localized in the order aprBA. While a putative promoter could not be identified in the vicinity of aprBA a probable termination signal was found just downstream of the translation stop codon of aprA. The codon usage for aprBA shows strong preferences for G and C in the third codon position. aprA encodes a 73.3 kDa polypeptide, which shows significant overall similarities with the flavoprotein subunits of the succinate dehydrogenases from Escherichia coli and Bacillus subtilis and the corresponding flavoprotein of E. coli fumarate reductase. Part of the homologous peptide stretches could be assigned to domains that are involved in the binding of the substrate or of the FAD prosthetic group. aprB encodes a 17.1 kDa polypeptide representing an iron-sulphur protein, seven cysteine residues of which are arranged in two clusters typical of ligands of the iron-sulphur centres in ([Fe3S4][Fe4S4]) 7-Fe ferredoxins.
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PMID:Adenylylsulphate reductase from the sulphate-reducing archaeon Archaeoglobus fulgidus: cloning and characterization of the genes and comparison of the enzyme with other iron-sulphur flavoproteins. 808 92

5'-Adenylylsulfate (APS) reductase (EC 1.8.99.-) catalyzes the reduction of activated sulfate to sulfite in plants. The evidence presented here shows that a domain of the enzyme is a glutathione (GSH)-dependent reductase that functions similarly to the redox cofactor glutaredoxin. The APR1 cDNA encoding APS reductase from Arabidopsis thaliana is able to complement the cysteine auxotrophy of an Escherichia coli cysH [3'-phosphoadenosine-5'-phosphosulfate (PAPS) reductase] mutant, only if the E. coli strain produces glutathione. The purified recombinant enzyme (APR1p) can use GSH efficiently as a hydrogen donor in vitro, showing aKm[GSH] approximately of 0.6 mM. Gene dissection was used to express separately the regions of APR1p from amino acids 73-327 (the R domain), homologous with microbial PAPS reductase, and from amino acids 328-465 (the C domain), homologous with thioredoxin. The R and C domains alone are inactive in APS reduction, but the activity is partially restored by mixing the two domains. The C domain shows a number of activities that are typical of E. coli glutaredoxin rather than thioredoxin. Both the C domain and APR1p are highly active in GSH-dependent reduction of hydroxyethyldisulfide, cystine, and dehydroascorbate, showing a Km[GSH] in these assays of approximately 1 mM. The R domain does not show these activities. The C domain is active in GSH-dependent reduction of insulin disulfides and ribonucleotide reductase, whereas APR1p and R domain are inactive. The C domain can substitute for glutaredoxin in vivo as demonstrated by complementation of an E. coli mutant, underscoring the functional similarity between the two enzymes.
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PMID:Glutaredoxin function for the carboxyl-terminal domain of the plant-type 5'-adenylylsulfate reductase. 965 99

A gene was cloned from Burkholderia cepacia DBO1 that is homologous with Escherichia coli cysH encoding 3'-phosphoadenylylsulfate (PAPS) reductase. The B. cepacia gene is the most recent addition to a growing list of cysH homologs from a diverse group of sulfate-assimilating bacteria whose products show greater homology to plant 5'-adenylylsulfate (APS) reductase than they do to E. coli CysH. The evidence reported here shows that the cysH from one of the species, Pseudomonas aeruginosa, encodes APS reductase. It is able to complement an E. coli cysH mutant and a cysC mutant, indicating that the enzyme is able to bypass PAPS, synthesized by the cysC product. Insertional knockout mutation of P. aeruginosa cysH produced cysteine auxotrophy, indicating its role in sulfate assimilation. Purified P. aeruginosa CysH expressed as a His-tagged recombinant protein is able to reduce APS, but not PAPS. The enzyme has a specific activity of 5.8 micromol. min(-1). mg of protein(-1) at pH 8.5 and 30 degrees C with thioredoxin supplied as an electron donor. APS reductase activity was detected in several bacterial species from which the novel type of cysH has been cloned, indicating that this enzyme may be widespread. Although an APS reductase from dissimilatory sulfate-reducing bacteria is known, it shows no structural or sequence homology with the assimilatory-type APS reductase reported here. The results suggest that the dissimilatory and assimilatory APS reductases evolved convergently.
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PMID:Identification of a new class of 5'-adenylylsulfate (APS) reductases from sulfate-assimilating bacteria. 1061 72

Highly active adenylylsulfate (APS) reductase was isolated under N(2)/H(2) from sulfate-reducing and sulfide-oxidizing bacteria and archaea. It was a 1:1 alphabeta-heterodimer of molecular mass approximately 95 kDa, and two subunits (alpha approximately 75, beta approximately 20 kDa). The specific activity was 11-14 micromol (min mg)(-1); cofactor analysis revealed 0.96+/-0.05 FAD, 7.5+/-0.1 Fe and 7.9+/-0.25 S(2-). The photochemically reduced enzyme had a multiline EPR spectrum resulting from two interacting [4Fe-4S] centers. The properties of the different APS reductases were remarkably similar, although the enzyme is involved in different metabolic pathways and was isolated from phylogenetically far separated organisms. A structural model is proposed, with FAD bound to the alpha-subunit, and two [4Fe-4S] centers located in close proximity on the beta-subunit.
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PMID:Adenylylsulfate reductases from archaea and bacteria are 1:1 alphabeta-heterodimeric iron-sulfur flavoenzymes--high similarity of molecular properties emphasizes their central role in sulfur metabolism. 1080 60

5'-Adenylylsulfate (APS) reductase was characterized in diverse marine algae. A cDNA encoding APS reductase from Enteromorpha intestinalis (EAPR) was cloned by functional complementation of an Escherichia coli cysH mutant. The deduced amino acid sequence shows high homology with APS reductase (APR) from flowering plants. Based on the probable transit peptide cleavage site the mature protein is 45.7 kD. EAPR expressed as a His-tagged recombinant protein catalyzes reduced glutathione-dependent reduction of APS to sulfite, exhibiting a specific activity of approximately 40 micromol min(-1) mg protein(-1) and Michealis-Menten kinetic constants of approximately 1.4 mM for reduced glutathione and approximately 6.5 microM for APS. APR activity and expression were studied in relation to the production of 3-dimethylsulfoniopropionate (DMSP), a sulfonium compound produced by many marine algae. A diverse group of DMSP-producing species showed extremely high enzyme activity (up to 400 times that found in flowering plants). Antibodies raised against a conserved peptide of APR strongly cross-reacted with a protein of 45 kD in several chlorophytes but insignificantly with chromophytes. In the chlorophyte Tetraselmis sp., APR activity varies significantly during the culture cycle and does not follow the changes in cellular DMSP content. However, a positive correlation was found between cell-based APR activity and specific growth rate.
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PMID:Characterization of sulfate assimilation in marine algae focusing on the enzyme 5'-adenylylsulfate reductase. 1088 58

Two genes for the sulfate assimilation pathway in Aspergillus terreus were cloned. The genes sAT (coding for PAPS-reductase) and sCT (coding for ATP-sulfurylase) form a small gene cluster. Both genes are similar to their homologs in A. nidulans (sA and sC), Penicillium chrysogenum (aps) and Saccharomyces cerevisiae (MET3 and MET16). In the coding sequence of the sCT gene, a typical non-functional APS-kinase-like domain is present. The sCT gene is expressed in A. nidulans, but its expression there is less sensitive to methionine level than in the original species. Two regions 5' upstream of sAT were found to be similar to those of sA.
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PMID:Sulfate assimilation in Aspergillus terreus: analysis of genes encoding ATP-sulfurylase and PAPS-reductase. 1105 45

5'-Adenylyl sulfate (APS) reductase (EC 1.8.4.9) catalyzes a key reaction in the plant sulfate assimilation pathway leading to the synthesis of cysteine and the antioxidant glutathione. In Arabidopsis thaliana APS reductase is encoded by a family of three genes. In vitro biochemical studies revealed that the enzyme product derived from one of them (APR1) is activated by oxidation, probably through the formation of a disulfide bond. The APR1 enzyme is 45-fold more active when expressed in a trxB strain of Escherichia coli than in a trxB(+) wild type. The enzyme is inactivated in vitro by treatment with disulfide reductants and is reactivated with thiol oxidants. Redox titrations show that the regulation site has a midpoint potential of -330 mV at pH 8.5 and involves a two-electron redox reaction. Exposure of a variety of plants to ozone induces a rapid increase in APS reductase activity that correlates with the oxidation of the glutathione pool and is followed by an increase in free cysteine and total glutathione. During the response to ozone, the level of immunodetectable APS reductase enzyme does not increase. Treatment of A. thaliana seedlings with oxidized glutathione or paraquat induces APS reductase activity even when transcription or translation is blocked with inhibitors. The results suggest that a posttranslational mechanism controls APS reductase. A model is proposed whereby redox regulation of APS reductase provides a rapidly responding, self-regulating mechanism to control the glutathione synthesis necessary to combat oxidative stress.
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PMID:Regulation of the plant-type 5'-adenylyl sulfate reductase by oxidative stress. 1146 67


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