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)

Microsomes isolated from Lewis lung (LL) primary tumors raised in C57BL/6 mice have been shown to (i) contain a 4-hydroxycoumarin (warfarin)-sensitive cycle of vitamin K metabolism which is at least qualitatively similar to that of liver, and (ii) catalyze the incorporation of NaH14 CO3 into endogenous protein in a vitamin-K hydroquinone-dependent reaction to produce gamma-carboxyglutamate. As in liver microsomes, LL microsomal reduction of vitamin K 2,3-epoxide to vitamin K was greatly enhanced by exogenous dithiols such as dithiothreitol, but under identical conditions the former was 10-fold faster. The R(+) and S(-) warfarin enantiomers were highly and equally effective inhibitors of both the liver and tumor vitamin K 2,3-epoxide reductases-the average I50 against the tumor enzyme was 0.25 microM. Partially purified reductases isolated by centrifugation of sodium-cholate-treated liver and LL tumor microsomes over a discontinuous sucrose gradient were also inhibited by the sulfhydryl reagent N-ethylmaleimide following their reduction by dithiothreitol. Like the activity of the epoxide reductase, that of the gamma-carboxylase was much lower in tumor than in liver microsomes and was only detectable in microsomes isolated from tumor-bearing mice previously administered S(-) warfarin. In view of the reported inhibition of LL tumor metastasis by warfarin and diet-induced vitamin-K deficiency, vitamin-K-dependent proteins may play a role in the spread and/or subsequent growth of LL cells.
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PMID:Vitamin-K-dependent proteins in microsomes of primary Lewis lung tumors. 379 64

The enzyme geranylgeranyl reductase (CHL P) catalyzes the reduction of geranylgeranyl diphosphate to phytyl diphosphate. We identified a tobacco (Nicotiana tabacum) cDNA sequence encoding a 52-kD precursor protein homologous to the Arabidopsis and bacterial CHL P. The effects of deficient CHL P activity on chlorophyll (Chl) and tocopherol contents were studied in transgenic plants expressing antisense CHL P RNA. Transformants with gradually reduced Chl P expression showed a delayed growth rate and a pale or variegated phenotype. Transformants grown in high (500 &mgr;mol m-2 s-1; HL) and low (70 &mgr;mol photon m-2 s-1; LL) light displayed a similar degree of reduced tocopherol content during leaf development, although growth of wild-type plants in HL conditions led to up to a 2-fold increase in tocopherol content. The total Chl content was more rapidly reduced during HL than LL conditions. Up to 58% of the Chl content was esterified with geranylgeraniol instead of phytol under LL conditions. Our results indicate that CHL P provides phytol for both tocopherol and Chl synthesis. The transformants are a valuable model with which to investigate the adaptation of plants with modified tocopherol levels against deleterious environmental conditions.
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PMID:Reduced activity of geranylgeranyl reductase leads to loss of chlorophyll and tocopherol and to partially geranylgeranylated chlorophyll in transgenic tobacco plants expressing antisense RNA for geranylgeranyl reductase 1039 4

The effects of an increased PPFD on photosynthesis, the functioning of the photosynthetic apparatus and the response of the antioxidant enzymatic system were studied during the ex vitro establishment of micropropagated Calathea 'Maui Queen' plantlets. Measured chlorophyll and carotenoids contents in ex vitro formed leaves were almost three times higher compared to the in vitro formed ones. At the end of the acclimatization, an inverse relation between PPFD and the chlorophyll (a+b)/carotenoids ratio was observed. During the first days after transplantation Calathea plants are not photosynthetically active, as is illustrated by the photosynthetic light response curves. With the appearance of new leaves, higher photosynthetic capacities were observed and light saturation point increased (days 17 and 25). Also the maximal photosynthetic efficiency enlarged as shown by the increased initial slope of the curves. F(v)/F(m) decreased directly after transplantation of the micropropagated plantlets, afterwards a recovery was observed, but highest F(v)/F(m) values were observed in low light (LL) plants. The photochemical quenching coefficient increased gradually during the first two weeks of the acclimatization. In high light (HL) plants, q(P) decreased directly after transfer, while this was not observed in LL and medium light (ML). During the acclimatization period to increasing light intensities significant changes in the activity of the antioxidant enzymatic system were observed. A decrease in superoxide dismutase (SOD) activity was measured during the first half of the acclimatization period followed by a recovery in ML and HL plants by day 35. Dehydroascorbate reductase (DHAR) activity decreased during acclimatization. At the end of the experimental period the lowest levels were measured in ML plants. Catalase (CAT) activity increased significantly during the first two weeks after transfer, a clear inverse relationship to PPFD was detected. The relation between the adquisition of full photosynthetic capacity and the activation of the enzymatic antioxidant system in the leaves of calathea plants during ex vitro acclimatization is discussed.
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PMID:The evolution of photosynthetic capacity and the antioxidant enzymatic system during acclimatization of micropropagated Calathea plants. 1077 40

Plant fatty acid elongase which catalyzes very-long-chain fatty acid (VLCFA) biosynthesis is a membrane-bound multienzyme complex. It is composed of four enzymes, a 3-ketoacyl-CoA synthase (condensing enzyme), a 3-ketoacyl-CoA reductase, a 3-hydroxyacyl-CoA dehydrase, and an enoyl-CoA reductase required for completion of each step of 2-carbon elongation of fatty acids. To improve our understanding of the overall regulation of the fatty acid elongase, we investigated the spatial and temporal expression of its key component, the FAE1-condensing enzyme, and examined the activity of the promoter of the FAE1 gene in Arabidopsis. In situ hybridization results revealed that FAE1 transcripts were found exclusively in the embryo. RNA blot analysis and histochemical analysis of GUS activity in pFAE1::GUS transgenic Arabidopsis lines demonstrated that the FAE1 gene was already transcribed in the early torpedo stage embryos 4-5 days after flowering, with transcription reaching its peak 9-11 days after flowering. VLCFA deposition closely paralleled FAE1 transcript accumulation. FAE1 promoter was highly active and embryo-specific. Because its timing coincides with the period of major storage lipid accumulation, and because its in vivo activity in Arabidopsis is superior to the napin promoter, FAE1 promoter may be ideal for genetic engineering of seed oil composition.
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PMID:Expression of the FAE1 gene and FAE1 promoter activity in developing seeds of Arabidopsis thaliana. 1157 26

The 3-hydroxypropionate cycle has been proposed as a new autotrophic CO(2) fixation pathway for the phototrophic green non-sulfur eubacterium Chloroflexus aurantiacus and for some chemotrophic archaebacteria. The cycle requires the reductive conversion of the characteristic intermediate 3-hydroxypropionate to propionyl-CoA. The specific activity of the 3-hydroxypropionate-, CoA-, K(+)-, and MgATP-dependent oxidation of NADPH in autotrophically grown cells was 0.09 micromol min(-1) mg(-1) protein, which was 2-fold down-regulated in heterotrophically grown cells. Unexpectedly, a single enzyme catalyzes the entire reaction sequence: 3-hydroxypropionate + MgATP + CoA + NADPH + H(+) --> propionyl-CoA + MgAMP + PP(i) + NADP(+) + H(2)O. The enzyme was purified 30-fold to near homogeneity and has a very large native molecular mass between 500 and 800 kDa, with subunits of about 185 kDa as judged by SDS-PAGE, suggesting a homotrimeric or homotetrameric structure. Upon incubation of this new enzyme, termed propionyl-CoA synthase, with the proteinase trypsin, the NADPH oxidation function of the enzyme was lost, whereas the enzyme still activated 3-hydroxypropionate to its CoA-thioester and dehydrated it to acrylyl-CoA. SDS-PAGE revealed that the subunits of propionyl-CoA synthase had been cleaved once and the N-terminal amino acid sequences of the two trypsin digestion products were determined. Two parts of the gene encoding propionyl-CoA synthase (pcs) were identified on two contigs of an incomplete genome data base of C. aurantiacus, and the sequence of the pcs gene was completed. Propionyl-CoA synthase is a natural fusion protein of 201 kDa consisting of a CoA ligase, an enoyl-CoA hydratase, and an enoyl-CoA reductase, the reductase domain containing the trypsin cleavage site. Similar polyfunctional large enzymes are common in secondary metabolism (e.g. polyketide synthases) but rare in primary metabolism (e.g. eukaryotic type I fatty acid synthase). These results lend strong support to the operation of the proposed pathway in autotrophic CO(2) fixation.
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PMID:Propionyl-coenzyme A synthase from Chloroflexus aurantiacus, a key enzyme of the 3-hydroxypropionate cycle for autotrophic CO2 fixation. 1182 99

The gl8 gene is required for the normal accumulation of cuticular waxes on maize (Zea mays) seedling leaves. The predicted GL8 protein exhibits significant sequence similarity to a class of enzymes that catalyze the reduction of a ketone group to a hydroxyl group. Polyclonal antibodies raised against the recombinant Escherichia coli-expressed GL8 protein were used to investigate the function of this protein in planta. Subcellular fractionation experiments indicate that the GL8 protein is associated with the endoplasmic reticulum membranes. Furthermore, polyclonal antibodies raised against the partially purified leek (Allium porrum) microsomal acyl-coenzyme A (CoA) elongase can react with the E. coli-expressed GL8 protein. In addition, anti-GL8 immunoglobulin G inhibited the in vitro elongation of stearoyl-CoA by leek and maize microsomal acyl-CoA elongase. In combination, these findings indicate that the GL8 protein is a component of the acyl-CoA elongase. In addition, the finding that anti-GL8 immunoglobulin G did not significantly inhibit the 3-ketoacyl-CoA synthase, 3-ketoacyl-CoA dehydrase, and (E) 2,3-enoyl-CoA reductase partial reactions of leek or maize acyl-CoA elongase lends further support to our previous hypothesis that the GL8 protein functions as a beta-ketoacyl reductase during the elongation of very long-chain fatty acids required for the production of cuticular waxes.
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PMID:The Endoplasmic reticulum-associated maize GL8 protein is a component of the acyl-coenzyme A elongase involved in the production of cuticular waxes. 1189 Dec 48

Acryloyl-CoA reductase from Clostridium propionicum catalyses the irreversible NADH-dependent formation of propionyl-CoA from acryloyl-CoA. Purification yielded a heterohexadecameric yellow-greenish enzyme complex [(alpha2betagamma)4; molecular mass 600 +/- 50 kDa] composed of a propionyl-CoA dehydrogenase (alpha2, 2 x 40 kDa) and an electron-transferring flavoprotein (ETF; beta, 38 kDa; gamma, 29 kDa). A flavin content (90% FAD and 10% FMN) of 2.4 mol per alpha2betagamma subcomplex (149 kDa) was determined. A substrate alternative to acryloyl-CoA (Km = 2 +/- 1 microm; kcat = 4.5 s-1 at 100 microm NADH) is 3-buten-2-one (methyl vinyl ketone; Km = 1800 microm; kcat = 29 s-1 at 300 microm NADH). The enzyme complex exhibits acyl-CoA dehydrogenase activity with propionyl-CoA (Km = 50 microm; kcat = 2.0 s-1) or butyryl-CoA (Km = 100 microm; kcat = 3.5 s-1) as electron donor and 200 microm ferricenium hexafluorophosphate as acceptor. The enzyme also catalysed the oxidation of NADH by iodonitrosotetrazolium chloride (diaphorase activity) or by air, which led to the formation of H2O2 (NADH oxidase activity). The N-terminus of the dimeric propionyl-CoA dehydrogenase subunit is similar to those of butyryl-CoA dehydrogenases from several clostridia and related anaerobes (up to 55% sequence identity). The N-termini of the beta and gamma subunits share 40% and 35% sequence identities with those of the A and B subunits of the ETF from Megasphaera elsdenii, respectively, and up to 60% with those of putative ETFs from other anaerobes. Acryloyl-CoA reductase from C. propionicum has been characterized as a soluble enzyme, with kinetic properties perfectly adapted to the requirements of the organism. The enzyme appears not to be involved in anaerobic respiration with NADH or reduced ferredoxin as electron donors. There is no relationship to the trans-2-enoyl-CoA reductases from various organisms or the recently described acryloyl-CoA reductase activity of propionyl-CoA synthase from Chloroflexus aurantiacus.
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PMID:Acryloyl-CoA reductase from Clostridium propionicum. An enzyme complex of propionyl-CoA dehydrogenase and electron-transferring flavoprotein. 1260 23

Detergents are well known irritants. Effects of the detergent sodium lauryl sulphate (SLS) on cell toxicity using the XTT assay and mRNA expression of inflammatory mediators, markers of keratinocyte differentiation and enzymes synthesizing barrier lipids using real-time PCR were studied in cultured differentiated keratinocytes. After exposure for 24 h to SLS concentrations at 0.002% or above, toxic effects were observed. When a lower SLS concentration (0.00075%) was used the mRNA expression of inflammatory mediators peaked around 4-8 h. The expression of enzymes involved in the synthesis of cholesterol, fatty acids and ceramides and markers of keratinocyte differentiation also increased but after 24 h. In cells exposed to 0.000125-0.0015% SLS, a concentration-dependent induction of the expression of inflammatory mediators was found after 4 h. Similar changes were found after 24 h for involucrin and enzymes involved in ceramide synthesis. The mRNA expression of HMG-CoA synthase and reductase, long-chain acyl-CoA synthase and transglutaminase also peaked after 24 h, but maximal induction was observed already at 0.00075% SLS. In conclusion, SLS induces an inflammatory response in keratinocytes and alters the mRNA expression of important barrier lipid enzymes and markers of keratinocyte differentiation, of possible importance for the irritant properties of SLS.
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PMID:Variations in the mRNA expression of inflammatory mediators, markers of differentiation and lipid-metabolizing enzymes caused by sodium lauryl sulphate in cultured human keratinocytes. 1627 56

Very long chain fatty acids (VLCFAs) play a comprehensive role in organisms. They are essential biological components in seed storage triacylglycerols (TAGs), membrane lipids, and sphingolipids. They also serve as precursors of wax layer compounds. The cuticle covers the aerial surface of land plants, which consists of cutin and wax. The wax, including amorphous intracuticular wax embedded in cutin polymer and epicuticular wax crystalloids that cover the outer plant surface, plays crucial roles in plant growth and development, and adaptation to environment. Biosynthesis of VLCFAs is catalyzed by the fatty acyl-CoA elongase, a membrane-bound enzymatic complex containing 3-ketoacyl-CoA synthase (KCS), 3-ketoacyl-CoA reductase (KCR), 3-hydroxacyl-CoA dehydratase (HCD), and trans-2, 3-enoyl-CoA reductase (ECR). Very long chain fatty acid wax precursors flux into cuticular wax biosynthetic pathways through acyl reduction and decarbonylation, and then are converted to all kinds of wax components. This article reviews the functions of VLCFAs and cuticular wax, and the recent progress in cloning and characterization of genes encoding enzymes involved in catalyzing VLCFAs and cuticular wax biosynthesis. The problems existing in researches of wax genes are also discussed.
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PMID:[Progress in the study on genes encoding enzymes involved in biosynthesis of very long chain fatty acids and cuticular wax in plants]. 1848 44

Cupriavidus necator was engineered aiming to synthesize poly[(R)-3-hydroxybutyrate-co-3-hydroxypropionate] copolyester, P(3HB-co-3HP), from structurally unrelated carbon sources without addition of any precursor compounds. We modified a metabolic pathway in C. necator for generation of 3-hydroxypropionyl-CoA (3HP-CoA) by introducing malonyl-CoA reductase and the 3HP-CoA synthetase domain of trifunctional propionyl-CoA synthase; both members of the 3-hydroxypropionate cycle, a novel CO(2)-fixation pathway in the green nonsulfur bacterium Chloroflexus aurantiacus . In this recombinant strain, 3HP-CoA was expected to be provided from acetyl-CoA via malonyl-CoA, and then copolymerized by the function of polyhydroxyalkanoate synthase along with (R)-3-hydroxybutyryl-CoA synthesized from two acetyl-CoA molecules. C. necator wild-type strains H16 and JMP134 harboring the two heterologous genes actually synthesized P(3HB-co-3HP) copolyester with 0.2-2.1 mol % of 3HP fraction from fructose or alkanoic acids of even carbon numbers. Enzyme assay suggested that lower activity of 3HP-CoA synthetase than that of malonyl-CoA reductase caused the limited incorporation of 3HP unit into the copolyesters synthesized by the recombinant strains. The present study demonstrates the potential of engineering metabolic pathways for production of copolyesters having favorable characteristics from inexpensive carbon resources.
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PMID:Microbial synthesis of poly((R)-3-hydroxybutyrate-co-3-hydroxypropionate) from unrelated carbon sources by engineered Cupriavidus necator. 1926 66


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