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Sample records for acid dehydrogenase activity

  1. Potentiation of insulin release in response to amino acid methyl esters correlates to activation of islet glutamate dehydrogenase activity

    Kofod, Hans; Lernmark, A; Hedeskov, C J

    1986-01-01

    Column perifusion of mouse pancreatic islets was used to study the ability of amino acids and their methyl esters to influence insulin release and activate islet glutamate dehydrogenase activity. In the absence of L-glutamine, L-serine and the methyl ester of L-phenylalanine, but neither L-phenyl...

  2. Mechanisms of activation of muscle branched-chain alpha-keto acid dehydrogenase during exercise in man

    Van Hall, Gerrit; MacLean, D A; Saltin, B; Wagenmakers, A J

    1. Exercise leads to activation (dephosphorylation) of the branched-chain alpha-keto acid dehydrogenase (BCKADH). Here we investigate the effect of low pre-exercise muscle glycogen content and of branched-chain amino acid (BCAA) ingestion on the activity of BCKADH at rest and after 90 min of one......-leg knee-extensor exercise at 65% maximal one-leg power output in five subjects. 2. Pre-exercise BCAA ingestion (308 mg BCAAs (kg body wt)-1) caused an increased muscle BCAA uptake, a higher intramuscular BCAA concentration and activation of BCKADH both at rest (9 +/- 1 versus 25 +/- 5% for the control and...... BCAA test, respectively) and after exercise (27 +/- 4 versus 54 +/- 7%). 3. At rest the percentage active BCKADH was not different, 6 +/- 2% versus 5 +/- 1%, in the normal and low glycogen content leg (392 +/- 21 and 147 +/- 34 mumol glycosyl units (g dry muscle)-1, respectively). The post...

  3. Genetic analysis of central carbon metabolism unveils an amino acid substitution that alters maize NAD-dependent isocitrate dehydrogenase activity.

    Nengyi Zhang

    Full Text Available BACKGROUND: Central carbon metabolism (CCM is a fundamental component of life. The participating genes and enzymes are thought to be structurally and functionally conserved across and within species. Association mapping utilizes a rich history of mutation and recombination to achieve high resolution mapping. Therefore, applying association mapping in maize (Zea mays ssp. mays, the most diverse model crop species, to study the genetics of CCM is a particularly attractive system. METHODOLOGY/PRINCIPAL FINDINGS: We used a maize diversity panel to test the CCM functional conservation. We found heritable variation in enzyme activity for every enzyme tested. One of these enzymes was the NAD-dependent isocitrate dehydrogenase (IDH, E.C. 1.1.1.41, in which we identified a novel amino-acid substitution in a phylogenetically conserved site. Using candidate gene association mapping, we identified that this non-synonymous polymorphism was associated with IDH activity variation. The proposed mechanism for the IDH activity variation includes additional components regulating protein level. With the comparison of sequences from maize and teosinte (Zea mays ssp. Parviglumis, the maize wild ancestor, we found that some CCM genes had also been targeted for selection during maize domestication. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate the efficacy of association mapping for dissecting natural variation in primary metabolic pathways. The considerable genetic diversity observed in maize CCM genes underlies heritable phenotypic variation in enzyme activities and can be useful to identify putative functional sites.

  4. Branched chain amino acid transaminase and branched chain alpha-ketoacid dehydrogenase activity in the brain, liver and skele­tal muscle of acute hepatic failure rats

    Takei,Nobuyuki

    1985-02-01

    Full Text Available Branched chain amino acid (BCAA transaminase activity increased in both the mitochondrial and supernatant fractions of brain from hepatic failure rats, in which a partial hepatectomy was performed 24h following carbon tetrachloride (CCl4 administration, although the activity of liver and skeletal muscle was the same as in control rats. The elevation of mitochondrial BCAA transaminase activity in liver-injured rats was partly due to increased activity of brain specific Type III isozyme. Branched chain alpha-ketoacid (BCKA dehydrogenase in the brain homogenates was not significantly altered in acute hepatic failure rats, while the liver enzyme activity was markedly diminished. BCKA dehydrogenase activity in the brain homogenates was inhibited by adding ATP to the assay system, and was activated in vitro by preincubating the brain homogenate at 37 degrees C for 15 min. These findings suggest that brain BCAA catabolism is accelerated in acute hepatic failure rats.

  5. Characterization of activity and binding mode of glycyrrhetinic acid derivatives inhibiting 11β-hydroxysteroid dehydrogenase type 2.

    Kratschmar, Denise V; Vuorinen, Anna; Da Cunha, Thierry; Wolber, Gerhard; Classen-Houben, Dirk; Doblhoff, Otto; Schuster, Daniela; Odermatt, Alex

    2011-05-01

    Modulation of intracellular glucocorticoid availability is considered as a promising strategy to treat glucocorticoid-dependent diseases. 18β-Glycyrrhetinic acid (GA), the biologically active triterpenoid metabolite of glycyrrhizin, which is contained in the roots and rhizomes of licorice (Glycyrrhiza spp.), represents a well-known but non-selective inhibitor of 11β-hydroxysteroid dehydrogenases (11β-HSDs). However, to assess the physiological functions of the respective enzymes and for potential therapeutic applications selective inhibitors are needed. In the present study, we applied bioassays and 3D-structure modeling to characterize nine 11β-HSD1 and fifteen 11β-HSD2 inhibiting GA derivatives. Comparison of the GA derivatives in assays using cell lysates revealed that modifications at the 3-hydroxyl and/or the carboxyl led to highly selective and potent 11β-HSD2 inhibitors. The data generated significantly extends our knowledge on structure-activity relationship of GA derivatives as 11β-HSD inhibitors. Using recombinant enzymes we found also potent inhibition of mouse 11β-HSD2, despite significant species-specific differences. The selected GA derivatives potently inhibited 11β-HSD2 in intact SW-620 colon cancer cells, although the rank order of inhibitory potential differed from that obtained in cell lysates. The biological activity of compounds was further demonstrated in glucocorticoid receptor (GR) transactivation assays in cells coexpressing GR and 11β-HSD1 or 11β-HSD2. 3D-structure modeling provides an explanation for the differences in the selectivity and activity of the GA derivatives investigated. The most potent and selective 11β-HSD2 inhibitors should prove useful as mechanistic tools for further anti-inflammatory and anti-cancer in vitro and in vivo studies. Article from the Special issue on Targeted Inhibitors. PMID:21236343

  6. Regulation of human class I alcohol dehydrogenases by bile acids

    Langhi, Cédric; Pedraz-Cuesta, Elena; Haro, Diego; Marrero, Pedro F; Rodríguez, Joan C.

    2013-01-01

    Class I alcohol dehydrogenases (ADH1s) are the rate-limiting enzymes for ethanol and vitamin A (retinol) metabolism in the liver . Because previous studies have shown that human ADH1 enzymes may participate in bile acid metabolism, we investigated whether the bile acid-activated nuclear receptor farnesoid X receptor (FXR) regulates ADH1 genes. In human hepatocytes, both the endogenous FXR ligand chenodeoxycholic acid and synthetic FXR-specific agonist GW4064 increased ADH1 mRNA, protein, and ...

  7. Fatty acids and the regulation of pyruvate dehydrogenase interconversion

    Stewart, Melanie Ann.

    1997-01-01

    This thesis presents evidence for a novel mechanism of regulation of pyruvate dehydrogenase (PDH) kinase by fatty acids and also results of a study of muscle triacylglycerol concentration. In animals regulation of PDH complex activity is central to the selection of respiratory fuels and to the conservation of glucose during carbohydrate deprivation. The principal means of regulation of PDH complex is interconversion of phosphorylated (inactive) and dephosphorylated (active) fo...

  8. Retinoic acid response element in the human alcohol dehydrogenase gene ADH3: implications for regulation of retinoic acid synthesis.

    Duester, G; Shean, M L; McBride, M S; Stewart, M J

    1991-01-01

    Retinoic acid regulation of one member of the human class I alcohol dehydrogenase (ADH) gene family was demonstrated, suggesting that the retinol dehydrogenase function of ADH may play a regulatory role in the biosynthetic pathway for retinoic acid. Promoter activity of human ADH3, but not ADH1 or ADH2, was shown to be activated by retinoic acid in transient transfection assays of Hep3B human hepatoma cells. Deletion mapping experiments identified a region in the ADH3 promoter located between...

  9. Aminotransferase and glutamate dehydrogenase activities in lactobacilli and streptococci.

    Peralta, Guillermo Hugo; Bergamini, Carina Viviana; Hynes, Erica Rut

    2016-01-01

    Aminotransferases and glutamate dehydrogenase are two main types of enzymes involved in the initial steps of amino acid catabolism, which plays a key role in the cheese flavor development. In the present work, glutamate dehydrogenase and aminotransferase activities were screened in twenty one strains of lactic acid bacteria of dairy interest, either cheese-isolated or commercial starters, including fifteen mesophilic lactobacilli, four thermophilic lactobacilli, and two streptococci. The strains of Streptococcus thermophilus showed the highest glutamate dehydrogenase activity, which was significantly elevated compared with the lactobacilli. Aspartate aminotransferase prevailed in most strains tested, while the levels and specificity of other aminotransferases were highly strain- and species-dependent. The knowledge of enzymatic profiles of these starter and cheese-isolated cultures is helpful in proposing appropriate combinations of strains for improved or increased cheese flavor. PMID:27266631

  10. Leucine-induced activation of translational initiation is partly regulated by the branched-chain α-keto acid dehydrogenase complex in C2C12 cells

    Branched-chain amino acid leucine has been shown to activate the translational regulators through the mammalian target of rapamycin. However, the leucine's effects are self-limiting because leucine promotes its own disposal by an oxidative pathway. The irreversible and rate-limiting step in the leucine oxidation pathway is catalyzed by the branched-chain α-keto acid dehydrogenase (BCKDH) complex. The complex contains E1 (α2β2), E2, and E3 subunits, and its activity is abolished by phosphorylation of the E1α subunit by BCKDH kinase. The relationship between the activity of BCKDH complex and leucine-mediated activation of the protein translation was investigated using the technique of RNA interference. The activity of BCKDH complex in C2C12 cell was modulated by transfection of small interfering RNA (siRNA) for BCKDH E2 subunit or BCKDH kinase. Transfection of siRNAs decreased the mRNA expression and protein amount of corresponding gene. Suppression of either E2 subunit or kinase produced opposite effects on the cell proliferation and the activation of translational regulators by leucine. Suppression of BCKDH kinase for 48 h resulted in decreasing cell proliferation. In contrast, E2 suppression led to increased amount of total cellular protein. The phosphorylation of p70 S6 kinase by leucine was increased in E2-siRNA transfected C2C12 cells, whereas the leucine's effect was diminished in kinase-siRNA transfected cells. These results suggest that the activation of the translational regulators by leucine was partly regulated by the activity of BCKDH complex

  11. INFLUENCE OF SELECTED PHARMACEUTICALS ON ACTIVATED SLUDGE DEHYDROGENASE ACTIVITY

    Agnieszka Tomska

    2016-06-01

    The aim of this work was to evaluate the effect of selected antibiotics - sulfanilamide and erythromycin on activated sludge dehydrogenase activity with use of trifenyltetrazolinum chloride (TTC test. Dehydrogenases activity is an indicator of biochemical activity of microorganisms present in activated sludge or the ability to degrade organic compounds in waste water. TTC test is particularly useful for the regularity of the course of treatment, in which the presence of inhibitors of biochemical reactions and toxic compounds are present. It was observed that the dehydrogenase activity decreases with the increase of a antibiotics concentration. The lowest value of the dehydrogenase activity equal to 32.4 μmol TF / gMLSS obtained at sulfanilamide concentration 150mg / l. For this sample, an inhibition of dehydrogenase activity was 31%.

  12. Response of cytokinin pool and cytokinin oxidase/dehydrogenase activity to abscisic acid exhibits organ specificity in peas

    Vaseva, I.; Todorova, D.; Malbeck, Jiří; Trávníčková, Alena; Macháčková, Ivana

    2008-01-01

    Roč. 30, č. 2 (2008), s. 151-155. ISSN 0137-5881 Institutional research plan: CEZ:AV0Z50380511 Keywords : Abscisic acid * Cytokinins * Cytokinin Subject RIV: EF - Botanics Impact factor: 0.807, year: 2008

  13. Effect of alkyl polyglucoside and nitrilotriacetic acid combined application on lead/pyrene bioavailability and dehydrogenase activity in co-contaminated soils.

    Chen, Tingru; Liu, Xiaoyan; Zhang, Xinying; Chen, Xiao; Tao, Kaiyun; Hu, Xiaoxin

    2016-07-01

    At present, few research focus on the phytoremediation for organic pollutants and heavy metals enhanced by surfactants and chelate agents in the combined contaminated soils or sediments. In this study, the effect of a novel combined addition of alkyl polyglucoside (APG) and nitrilotriacetic acid (NTA) into pyrene and lead (Pb) co-contaminated soils on bioaccessiblity of pyrene/Pb and dehydrogenase activities (DHA) was studied. Through the comparison of the results with the alone and combined application, synergistic effect on bioaccessiblity of pyrene and Pb was found while APG and NTA was applied together. Results also indicated a significant promotion on the DHA in mixed addition of APG and NTA. In addition, correlation and principal component analysis were performed to better understand the relationship among APG/NTA, bioaccessiblity of pyrene/Pb and the DHA. Results showed that APG and NTA can affect DHA directly by themselves but also can affect DHA indirectly by changing bioaccessible pyrene and exchangeable Pb. PMID:27085066

  14. Alcohol dehydrogenase activity in immobilized yeast cells

    A method for the immobilization of Saccharomyces cerevisiae was developed and the activity of alcohol dehydrogenase of the immobilized cells was determined. The treatment of the yeast cells with 1 % toluene followed by irradiation with acrylamide and bisacrylamide resulted in a high activity of alcohol dehydrogenase in the immobilized cells. The enzyme of the immobilized cells was stable in the pH range of 7.5 - 8.0 and the optimum pH opposed to be 8.5. Although the immobilized cells showed a rather low level of thermostability, it is suggested that they could be used for a long period of time at a temperature of 27 deg C. The immobilized cells did not exhibit any loss in the enzyme activity when stored at 4 deg C or -20 deg C. (author)

  15. Cloning and expression of bacterial genes coding amino acid dehydrogenases (oxidoreductases)

    Full text: The synthesis of 15N-labeled amino acids from the corresponding α-ketoacids can be accomplished in vitro using bacterial NAD-dependent amino acid dehydrogenases. The example of alanine dehydrogenase (AlaDH) and leucine dehydrogenase (LeuDH) will be presented here. Both enzymes belong to NAD dependent oxidoreductase family. AlaDH or L-alanine NAD-oxidoreductase (EC 1.4.1.1) promotes the reversible oxidative deamination of L-alanine to pyruvate (pyruvic acid). LeuDH or L-leucine NAD-oxidoreductase (EC 1.4.1.9) catalyses the reversible oxidative deamination of many related L-amino acids to corresponding α-ketoacids. The bacterial genes encoding AlaDH from Bacillus subtilis and LeuDH from Bacillus stearothermophilus were cloned separately in pET21b vector, and overexpressed in Escherichia coli BL21(DE3) strain. The [15N]L-alanine was synthesized by reductive amination of pyruvate, in the presence of 15NH4Cl, NADH, AlaDH and glucose dehydrogenase. The [15N]L-leucine, [15N]L-isoleucine, [15N]L-norleucine, [15N]L-valine and [15N]L-norvaline were produced in the same conditions using LeuDH, as a catalyst, and α- ketoisocaproate, DL-α-keto-β-methyl-n-valerate, α-ketocaproate, α-ketoisovalerate and α-ketovalerate, respectively, as substrates. In all cases, the reaction mixtures included glucose dehydrogenase for NADH regeneration with glucose as electron donor. The NADH renewal is more convenient with glucose dehydrogenase than other methods described before using formate dehydrogenase or alcohol dehydrogenase. The glucose dehydrogenase is very active and do not inhibit 15N-labeled amino acid synthesis. As determined by mass spectroscopy, the 15N-labeled amino acids were synthesized with yields between 60% and 95%. Our results demonstrate the usefulness of recombinant amino acid dehydrogenases for in vitro synthesis of 15N-labeled amino acids. (author)

  16. Carbohydrate metabolism during prolonged exercise and recovery: interactions between pyruvate dehydrogenase, fatty acids, and amino acids

    Mourtzakis, Marina; Saltin, B.; Graham, T.;

    2006-01-01

    During prolonged exercise, carbohydrate oxidation may result from decreased pyruvate production and increased fatty acid supply and ultimately lead to reduced pyruvate dehydrogenase (PDH) activity. Pyruvate also interacts with the amino acids alanine, glutamine, and glutamate, whereby the decline...... activity (P < 0.05) and increased PDH kinase 4 mRNA (P < 0.05) during exercise and recovery. At 1 h of exercise, pyruvate production was greatest and was closely linked to glutamate, which was the predominant amino acid taken up during exercise and recovery. Alanine and glutamine were also associated with...... pyruvate metabolism, and they comprised 68% of total amino-acid release during exercise and recovery. Thus reduced pyruvate production was primarily associated with reduced carbohydrate oxidation, whereas the greatest production of pyruvate was related to glutamate, glutamine, and alanine metabolism in...

  17. Evolution of D-lactate dehydrogenase activity from glycerol dehydrogenase and its utility for D-lactate production from lignocellulose.

    Wang, Qingzhao; Ingram, Lonnie O; Shanmugam, K T

    2011-11-22

    Lactic acid, an attractive, renewable chemical for production of biobased plastics (polylactic acid, PLA), is currently commercially produced from food-based sources of sugar. Pure optical isomers of lactate needed for PLA are typically produced by microbial fermentation of sugars at temperatures below 40 °C. Bacillus coagulans produces L(+)-lactate as a primary fermentation product and grows optimally at 50 °C and pH 5, conditions that are optimal for activity of commercial fungal cellulases. This strain was engineered to produce D(-)-lactate by deleting the native ldh (L-lactate dehydrogenase) and alsS (acetolactate synthase) genes to impede anaerobic growth, followed by growth-based selection to isolate suppressor mutants that restored growth. One of these, strain QZ19, produced about 90 g L(-1) of optically pure D(-)-lactic acid from glucose in < 48 h. The new source of D-lactate dehydrogenase (D-LDH) activity was identified as a mutated form of glycerol dehydrogenase (GlyDH; D121N and F245S) that was produced at high levels as a result of a third mutation (insertion sequence). Although the native GlyDH had no detectable activity with pyruvate, the mutated GlyDH had a D-LDH specific activity of 0.8 μmoles min(-1) (mg protein)(-1). By using QZ19 for simultaneous saccharification and fermentation of cellulose to D-lactate (50 °C and pH 5.0), the cellulase usage could be reduced to 1/3 that required for equivalent fermentations by mesophilic lactic acid bacteria. Together, the native B. coagulans and the QZ19 derivative can be used to produce either L(+) or D(-) optical isomers of lactic acid (respectively) at high titers and yields from nonfood carbohydrates. PMID:22065761

  18. Overexpression of malate dehydrogenase in transgenic alfalfa enhances organic acid synthesis and confers tolerance to aluminum.

    Tesfaye, M; Temple, S J; Allan, D L; Vance, C P; Samac, D A

    2001-12-01

    Al toxicity is a severe impediment to production of many crops in acid soil. Toxicity can be reduced through lime application to raise soil pH, however this amendment does not remedy subsoil acidity, and liming may not always be practical or cost-effective. Addition of organic acids to plant nutrient solutions alleviates phytotoxic Al effects, presumably by chelating Al and rendering it less toxic. In an effort to increase organic acid secretion and thereby enhance Al tolerance in alfalfa (Medicago sativa), we produced transgenic plants using nodule-enhanced forms of malate dehydrogenase and phosphoenolpyruvate carboxylase cDNAs under the control of the constitutive cauliflower mosaic virus 35S promoter. We report that a 1.6-fold increase in malate dehydrogenase enzyme specific activity in root tips of selected transgenic alfalfa led to a 4.2-fold increase in root concentration as well as a 7.1-fold increase in root exudation of citrate, oxalate, malate, succinate, and acetate compared with untransformed control alfalfa plants. Overexpression of phosphoenolpyruvate carboxylase enzyme specific activity in transgenic alfalfa did not result in increased root exudation of organic acids. The degree of Al tolerance by transformed plants in hydroponic solutions and in naturally acid soil corresponded with their patterns of organic acid exudation and supports the concept that enhancing organic acid synthesis in plants may be an effective strategy to cope with soil acidity and Al toxicity. PMID:11743127

  19. Malate dehydrogenase activity in human seminal plasma and spermatozoa homogenates

    Hulya Leventerler

    2013-08-01

    Full Text Available Purpose: Malate Dehydrogenase is an important enzyme of the Krebs cycle, most cells require this enzyme for their metabolic activity. We evaluated the Malate Dehydrogenase (NAD/NADP activity in human seminal plasma and sperm homogenates in normozoospermic, fertile and infertile males. Also glucose and fructose concentrations were determined in the seminal plasma samples. Material and Methods: Malate Dehydrogenase (NAD/NADP activity in human seminal plasma and sperm homogenates of normozoospermic and infertile males was determined by spectrophotometric method. Semen analysis was considered according to the WHO Criteria. Results: Malat Dehydrogenase-NAD value in seminal plasma (the mean ± SD, mU/ml of asthenoteratospermic (40.0±25.7 and azospermic (38.0±43.6 groups were significantly lower than normozoospermic, (93.9±52.1 males. Malat Dehydrogenase-NAD value in sperm homogenates (the mean ± SD, mU/ 20x106 sperm of teratospermic group (136.8±61.8 was significantly higher compared to the normozoospermic (87.3±26.5 males. Glucose concentration (mg/dl in asthenoteratospermic (4.0±1.4 and azospermic (15.4±6.4 groups were significantly higher than fertile (2.0±2.1 males. Also fructose concentration (mg/dl in asthenoteratospermic (706.6±143.3 and azospermic (338.1±228.2 groups were significantly high compared to the normozoospermic (184.7±124.8 group. Conclusion: Sperm may be some part of the source of Malat Dehydrogenase activity in semen. Malat Dehydrogenase activity in seminal plasma has an important role on energy metabolism of sperm. Intermediate substrates of Krebs cycle might have been produced under the control of Malat Dehydrogenase and these substrates may be important for sperm motility and male infertility. [Cukurova Med J 2013; 38(4.000: 648-658

  20. In vitro inhibition of 10-formyltetrahydrofolate dehydrogenase activity by acetaldehyde

    Mun, Ju-Ae; Doh, Eunjin; Min, Hyesun

    2008-01-01

    Alcoholism has been associated with folate deficiency in humans and laboratory animals. Previous study showed that ethanol feeding reduces the dehydrogenase and hydrolase activity of 10-formyltetrahydrofolate dehydrogenase (FDH) in rat liver. Hepatic ethanol metabolism generates acetaldehyde and acetate. The mechanisms by which ethanol and its metabolites produce toxicity within the liver cells are unknown. We purified FDH from rat liver and investigated the effect of ethanol, acetaldehyde an...

  1. Assessment of toxicity using dehydrogenases activity and mathematical modeling.

    Matyja, Konrad; Małachowska-Jutsz, Anna; Mazur, Anna K; Grabas, Kazimierz

    2016-07-01

    Dehydrogenase activity is frequently used to assess the general condition of microorganisms in soil and activated sludge. Many studies have investigated the inhibition of dehydrogenase activity by various compounds, including heavy metal ions. However, the time after which the measurements are carried out is often chosen arbitrarily. Thus, it can be difficult to estimate how the toxic effects of compounds vary during the reaction and when the maximum of the effect would be reached. Hence, the aim of this study was to create simple and useful mathematical model describing changes in dehydrogenase activity during exposure to substances that inactivate enzymes. Our model is based on the Lagergrens pseudo-first-order equation, the rate of chemical reactions, enzyme activity, and inactivation and was created to describe short-term changes in dehydrogenase activity. The main assumption of our model is that toxic substances cause irreversible inactivation of enzyme units. The model is able to predict the maximum direct toxic effect (MDTE) and the time to reach this maximum (TMDTE). In order to validate our model, we present two examples: inactivation of dehydrogenase in microorganisms in soil and activated sludge. The model was applied successfully for cadmium and copper ions. Our results indicate that the predicted MDTE and TMDTE are more appropriate than EC50 and IC50 for toxicity assessments, except for long exposure times. PMID:27021434

  2. NAD(H recycling activity of an engineered bifunctional enzyme galactose dehydrogenase/lactate dehydrogenase

    2006-03-01

    Full Text Available A chimeric bifunctional enzyme composing of galactose dehydrogenase (galDH; from Pseudomonas fluorescens and lactate dehydrogenase (LDH; from Bacillus stearothermophilus was successfully constructed. The chimeric galDH/LDH possessed dual characteristics of both galactose dehydrogenase and lactate dehydrogenase activities while exhibiting hexameric rearrangement with a molecular weight of approximately 400 kDa. In vitro observations showed that the chimeric enzyme was able to recycle NAD with a continuous production of lactate without any externally added NADH. Two fold higher recycling rate (0.3 mM/h than that of the native enzyme was observed at pH values above 8.5. Proximity effects became especially pronounced during the recycling assay when diffusion hindrance was induced by polyethylene glycol. All these findings open up a high feasibility to apply the NAD(H recycling system for metabolic engineering purposes e.g. as a model to gain a better understanding on the molecular proximity process and as the routes for synthesizing of numerous high-value-added compounds.

  3. Construction of Mutant Glucose Oxidases with Increased Dye-Mediated Dehydrogenase Activity

    Koji Sode

    2012-11-01

    Full Text Available Mutagenesis studies on glucose oxidases (GOxs were conducted to construct GOxs with reduced oxidase activity and increased dehydrogenase activity. We focused on two representative GOxs, of which crystal structures have already been reported—Penicillium amagasakiense GOx (PDB ID; 1gpe and Aspergillus niger GOx (PDB ID; 1cf3. We constructed oxygen-interacting structural models for GOxs, and predicted the residues responsible for oxidative half reaction with oxygen on the basis of the crystal structure of cholesterol oxidase as well as on the fact that both enzymes are members of the glucose/methanol/choline (GMC oxidoreductase family. Rational amino acid substitution resulted in the construction of an engineered GOx with drastically decreased oxidase activity and increased dehydrogenase activity, which was higher than that of the wild-type enzyme. As a result, the dehydrogenase/oxidase ratio of the engineered enzyme was more than 11-fold greater than that of the wild-type enzyme. These results indicate that alteration of the dehydrogenase/oxidase activity ratio of GOxs is possible by introducing a mutation into the putative functional residues responsible for oxidative half reaction with oxygen of these enzymes, resulting in a further increased dehydrogenase activity. This is the first study reporting the alteration of GOx electron acceptor preference from oxygen to an artificial electron acceptor.

  4. Purification of a branched-chain keto acid dehydrogenase from Pseudomonas putida.

    Sokatch, J R; McCully, V; Roberts, C M

    1981-01-01

    We purified branched-chain keto acid dehydrogenase to a specific activity of 10 mumol/min per mg of protein from Pseudomonas putida grown on valine. The purified enzyme was active with 2-ketoisovalerate, 2-ketoisocaproate, and 2-keto-3-methylvalerate in a ratio of 1.0:0.8:0.7 but showed no activity with either pyruvate or 2-ketoglutarate. There were four polypeptides in the purified enzyme (molecular weights, 49,000, 46,000, 39,000, and 37,000). The purified enzyme was deficient in the specif...

  5. 9-O-acetylated sialic acids differentiating normal haematopoietic precursors from leukemic stem cells with high aldehyde dehydrogenase activity in children with acute lymphoblastic leukaemia.

    Chowdhury, Suchandra; Chandra, Sarmila; Mandal, Chitra

    2014-10-01

    Childhood acute lymphoblastic leukaemia (ALL) originates from mutations in haematopoietic progenitor cells (HPCs). For high-risk patients, treated with intensified post-remission chemotherapy, haematopoietic stem cell (HSC) transplantation is considered. Autologous HSC transplantation needs improvisation till date. Previous studies established enhanced disease-associated expression of 9-O-acetylated sialoglycoproteins (Neu5,9Ac2-GPs) on lymphoblasts of these patients at diagnosis, followed by its decrease with clinical remission and reappearance with relapse. Based on this differential expression of Neu5,9Ac2-GPs, identification of a normal HPC population was targeted from patients at diagnosis. This study identifies two distinct haematopoietic progenitor populations from bone marrow of diagnostic ALL patients, exploring the differential expression of Neu5,9Ac2-GPs with stem cell (CD34, CD90, CD117, CD133), haematopoietic (CD45), lineage-commitment (CD38) antigens and cytosolic aldehyde dehydrogenase (ALDH). Normal haematopoietic progenitor cells (ALDH(+)SSC(lo)CD45(hi)Neu5,9Ac2 -GPs(lo)CD34(+)CD38(-)CD90(+)CD117(+)CD133(+)) differentiated into morphologically different, lineage-specific colonies, being crucial for autologous HSC transplantation while leukemic stem cells (ALDH(+)SSC(lo)CD45(lo)Neu5,9Ac2 -GPs(hi)CD34(+)CD38(+)CD90(-)CD117(-)CD133(-)) lacking this ability can be potential targets for minimal residual disease detection and drug-targeted immunotherapy. PMID:25283637

  6. Identification of essential amino-acid residues in Azotobacter vinelandii isocitrate dehydrogenase by radical anions and H atoms

    Pure TPN+-specific isocitrate dehydrogenase from Azotobacter vinelandii was irradiated with H atoms generated in a γ-irradiated solution at pH 6.5. A G(-activity) = 0.12 +- 0.01 was found. At the same time no corresponding loss in free sulfhydryls was observed. These results confirmed the essentiality of methionine for the enzymatic activity as known from previous studies. Irradiation with the radical anions, (CNS)2- and Br2- generated in γ-irradiated solutions at pH 6.5, strongly inactivated isocitrate dehydrogenase with yields of G(-activity) of 2.1 and 3.9, respectively. Part of the inactivating effect, however, is due to oxidation of sulfhydryl groups. These results lead to the conclusion that tryptophan is an essential amino-acid residue to isocitrate dehydrogenase from A. vinelandii. The presence of tryptophan in the enzyme was demonstrated by pulse radiolysis

  7. Subcellular localization of branched-chain amino acid aminotransferase and lactate dehydrogenase C4 in rat and mouse spermatozoa.

    Montamat, E E; Vermouth, N T; Blanco, A

    1988-11-01

    Spermatozoa isolated from rat and mouse epididymes show a relatively high branched-chain amino acid aminotransferase (leucine aminotransferase, EC 2.6.1.6) activity. There is a significant reduction of leucine aminotransferase and of the isoenzyme C4 of lactate dehydrogenase (EC 1.1.1.27) in the gametes during their epididymal transit. Studies of patterns of liberation of the leucine aminotransferase and of the lactate dehydrogenase C4 from intact spermatozoa, treated with increasing concentrations of digitonin, indicate that both enzymes have the same dual subcellular location, i.e. in the cytosol and in the mitochondria. PMID:3214422

  8. Dimerization and enzymatic activity of fungal 17β-hydroxysteroid dehydrogenase from the short-chain dehydrogenase/reductase superfamily

    Kristan Katja

    2005-12-01

    Full Text Available Abstract Background 17β-hydroxysteroid dehydrogenase from the fungus Cochliobolus lunatus (17β-HSDcl is a member of the short-chain dehydrogenase/reductase (SDR superfamily. SDR proteins usually function as dimers or tetramers and 17β-HSDcl is also a homodimer under native conditions. Results We have investigated here which secondary structure elements are involved in the dimerization of 17β-HSDcl and examined the importance of dimerization for the enzyme activity. Sequence similarity with trihydroxynaphthalene reductase from Magnaporthe grisea indicated that Arg129 and His111 from the αE-helices interact with the Asp121, Glu117 and Asp187 residues from the αE and αF-helices of the neighbouring subunit. The Arg129Asp and His111Leu mutations both rendered 17β-HSDcl monomeric, while the mutant 17β-HSDcl-His111Ala was dimeric. Circular dichroism spectroscopy analysis confirmed the conservation of the secondary structure in both monomers. The three mutant proteins all bound coenzyme, as shown by fluorescence quenching in the presence of NADP+, but both monomers showed no enzymatic activity. Conclusion We have shown by site-directed mutagenesis and structure/function analysis that 17β-HSDcl dimerization involves the αE and αF helices of both subunits. Neighbouring subunits are connected through hydrophobic interactions, H-bonds and salt bridges involving amino acid residues His111 and Arg129. Since the substitutions of these two amino acid residues lead to inactive monomers with conserved secondary structure, we suggest dimerization is a prerequisite for catalysis. A detailed understanding of this dimerization could lead to the development of compounds that will specifically prevent dimerization, thereby serving as a new type of inhibitor.

  9. Regulation of pyruvate dehydrogenase kinase activity by protein thiol-disulfide exchange.

    Pettit, F H; Humphreys, J; Reed, L J

    1982-01-01

    Endogenous kinase activity of highly purified pyruvate dehydrogenase complex from bovine kidney is markedly inhibited by N-ethylmaleimide and by certain disulfides. Inhibition by disulfides is highly specific and is reversed by thiols. 5,5'-Dithiobis(2-nitrobenzoate) is the most potent inhibitor, showing significant inhibition at a concentration as low as 1 microM. Cystamine, oxidized glutathione, pantethine, lipoic acid, lipoamide, ergothionine, insulin, oxytocin, and vasopressin were ineffe...

  10. Microbial and xanthine dehydrogenase inhibitory activity of some flavones.

    Khobragade, C N; Bodade, Ragini G; Shinde, M S; Jaju, Deepa R; Bhosle, R B; Dawane, B S

    2008-06-01

    Xanthine dehydrogenase (XDH) is responsible for the pathological condition called Gout. In the present study different flavones synthesized from chalcone were evaluated in vitro for their inhibitory activity. Inhibitory activity of flavones on XDH was determined in terms of inhibition of uric acid synthesis from Xanthine. The enzymatic activity was found maximum at pH 7.5 and temperature 40 degrees C. The flavones 6-chloro-2-[3-(4-hydroxy-phenyl)-1-phenyl-1-H-pyrazol-4-yl]-chromen-4-one (F(1)) and 6-chloro-7methyl-2-[3-(4-chloro-phenyl)-1-phenyl-1-H-pyrazol-4-yl]-chromen-4-one(F(2)),were noncompetitive and competitive inhibitor with Ki values 1.1 and 0.22 respectively. The flavones (F(1)), (F(2)), 6-chloro-2-[3-(4-chloro-phenyl)-1phenyl-1-H-pyrazol-4-yl]-chromen-4-one(F(3)), 8-bromo-6-chloro-2-[3-(4-chloro-phenyl)-1-phenyl-1-H-pyrazol-4-yl]-chromen-4-one (F(4)), 2-[3-(4-hydroxy-phenyl)-1-phenyl-1-H-pyrazol-4-yl]-chromen-4-one (F(5)) and 6-methyl-2-[3-(4-hydroxy-phenyl)-1-phenyl-1-H-pyrazol-4-yl]-chromen-4-one (F(6)) were also screened for their antimicrobial activity, measured in terms of zone of inhibition. A broad spectrum antifungal activity was obtained against Trichoderma viridae, Candida albicans, Microsporum cannis, Penicillium chrysogenum and Fusarium moniliformae. In case of Aspergillus niger and Aspergillus flavous only spore formation was affected, while antibacterial activity was observed against Staphylococcus aureus, Bacillus subtilis and Serratia marsecens only. The flavones were further analyzed for quantitative structural activity relationship study (QSAR) by using PASS, online software to determine their Pa value. Toxicity and drug relevant properties were revealed by PALLAS software in terms of their molecular weight. Log P values were also studied. The result showed both the F(1) and F(2) flavones as antigout and therefore supports the development of novel drugs for the treatment of gout. PMID:18569337

  11. Solution structures of lipoyl domains of the 2-oxo acid dehydrogenase complexes from Azotobacter vinelandii. Implications for molecular recognition.

    Berg, A.

    1997-01-01

    The 2-oxo acid dehydrogenase complexes are large multienzyme complexes that catalyse the irreversible oxidative decarboxylation of a specific 2-oxo acid to the corresponding acyl-CoA derivative. The pyruvate dehydrogenase complex (PDHC) converts the product of the glycolysis, pyruvate, to acetyl-CoA, which enters the tricarboxylic acid cycle. The 2-oxoglutarate dehydrogenase complex (OGDHC functions in the tricarboxylic acid cycle itself by converting 2-oxoglutarate to succinyl-CoA. The branc...

  12. Novel yeast cell dehydrogenase activity assay in situ.

    Berłowska, Joanna; Kregiel, Dorota; Klimek, Leszek; Orzeszyna, Bartosz; Ambroziak, Wojciech

    2006-01-01

    The aim of this research was to develop a suitable method of succinate dehydrogenase activity assay in situ for different industrial yeast strains. For this purpose different compounds: EDTA, Triton X-100, sodium deoxycholate, digitonin, nystatin and beta-mercaptoethanol were used. The permeabilization process was controlled microscopically by primuline staining. Enzyme assay was conducted in whole yeast cells with Na-succinate as substrate, phenazine methosulfate (PMS) as electron carrier and in the presence one of two different tetrazolium salts: tetrazolium blue chloride (BT) or cyanoditolyl tetrazolium chloride (CTC) reduced during the assay. In comparabile studies of yeast vitality the amount of intracellular ATP was determined according to luciferin/luciferase method. During the succinate dehydrogenase assay in intact yeast cells without permeabilization, BT formazans were partially visualized in the cells, but CTC formazans appeared to be totally extracellular or associated with the plasma membrane. Under these conditions there was no linear relationship between formazan color intensity signal and yeast cell density. From all chemical compounds tested, only digitonin was effective in membrane permeabilization without negative influence on cell morphology. Furthermore, with digitonin-treated cells a linear relationship between formazan color intensity signal and yeast cell number was noticed. Significant decreasing of succinate dehydrogenase activity and ATP content were observed during aging of the tested yeast strains. PMID:17419290

  13. Toxicity of Nitrification Inhibitors on Dehydrogenase Activity in Soils

    Ferisman Tindaon

    2011-01-01

    Full Text Available The objective of this research was to determine the effects of nitrification inhibitors (NIs such as 3,4-dimethylpyrazolephosphate=DMPP, 4-Chlor-methylpyrazole phosphate=ClMPP and dicyandiamide,DCD which might be expected to inhibit microbial activity, on dehydrogenase activity (DRA,in three different soils in laboratory conditions. Dehydrogenase activity were assessed via reduction of 2-p-Iodophenyl-3-p-nitrophenyl-5-phenyltetrazoliumchloride (INT. The toxicity and dose response curve of three NIs were quantified under laboratory conditions using a loamy clay, a sandy loam and a sandy soil. The quantitative determination of DHA was carried out spectrophotometrically. In all experiments, the influence of 5-1000 times the base concentration were examined. To evaluate the rate of inhibition with the increasing NI concentrations, dose reponse curves were presented and no observable effect level =NOEL, as well as effective dose ED10 and ED 50(10% and 50% inhibition were calculated. The NOEL for common microbial activity such as DHA was about 30–70 times higher than base concentration in all investigated soils. ClMPP exhibited the strongest influence on the non target microbial processes in the three soils if it compare to DMPP and DCD. The NOEL,ED10 and ED50 values higher in clay than in loamy or sandy soil. The NIs were generally most effective in sandy soils. The three NIs considered at the present state of knowledge as environmentally safe in use.

  14. Orthodontic Force Application in Correlation with Salivary Lactate Dehydrogenase Activity

    Erik Husin

    2013-07-01

    Full Text Available Orthodontic tooth movement generate mechanical forces to periodontal ligament and alveolar bone. The forces correlate with initial responses of periodontal tissues and involving many metabolic changes. One of the metabolic changes detected in saliva is lactate dehydrogenase (LDH activity. Objectives: To evaluate the correlation between orthodontic interrupted force application, lactate dehydrogenase activity and the distance of tooth movement. Methods: upper premolar, pre-retraction of upper canine and 1, 7, 14, 21 and 28 days post-retraction of upper canine with 100g interrupted orthodontic force. Results: duration of force (F=11.926 p 14 and 28 days post-retraction of canine. The region of retraction correlated with the distance of tooth movement (F=7.377 p=0.007. The duration of force correlated with the distance of tooth movement (F=66.554 p=0.000. retraction of canine. Conclusion: This study concluded that orthodontic interrupted force application on canine could increase the distance of tooth movement and LDH activity in saliva.

  15. Overexpression of Lactobacillus casei d-Hydroxyisocaproic Acid Dehydrogenase in Cheddar Cheese†

    Broadbent, Jeffery R.; Gummalla, Sanjay; Hughes, Joanne E.; Johnson, Mark E.; Rankin, Scott A.; Drake, Mary Anne

    2004-01-01

    Metabolism of aromatic amino acids by lactic acid bacteria is an important source of off-flavor compounds in Cheddar cheese. Previous work has shown that α-keto acids produced from Trp, Tyr, and Phe by aminotransferase enzymes are chemically labile and may degrade spontaneously into a variety of off-flavor compounds. However, dairy lactobacilli can convert unstable α-keto acids to more-stable α-hydroxy acids via the action of α-keto acid dehydrogenases such as d-hydroxyisocaproic acid dehydro...

  16. Efficient production of (R-2-hydroxy-4-phenylbutyric acid by using a coupled reconstructed D-lactate dehydrogenase and formate dehydrogenase system.

    Binbin Sheng

    Full Text Available (R-2-hydroxy-4-phenylbutyric acid [(R-HPBA] is a key precursor for the production of angiotensin-converting enzyme inhibitors. However, the product yield and concentration of reported (R-HPBA synthetic processes remain unsatisfactory.The Y52L/F299Y mutant of NAD-dependent D-lactate dehydrogenase (D-nLDH in Lactobacillus bulgaricus ATCC 11842 was found to have high bio-reduction activity toward 2-oxo-4-phenylbutyric acid (OPBA. The mutant D-nLDHY52L/F299Y was then coexpressed with formate dehydrogenase in Escherichia coli BL21 (DE3 to construct a novel biocatalyst E. coli DF. Thus, a novel bio-reduction process utilizing whole cells of E. coli DF as the biocatalyst and formate as the co-substrate for cofactor regeneration was developed for the production of (R-HPBA from OPBA. The biocatalysis conditions were then optimized.Under the optimum conditions, 73.4 mM OPBA was reduced to 71.8 mM (R-HPBA in 90 min. Given its high product enantiomeric excess (>99% and productivity (47.9 mM h(-1, the constructed coupling biocatalysis system is a promising alternative for (R-HPBA production.

  17. Soil dehydrogenase activity in the presence of chromium (III) and (VI)

    Wolińska A.; Stępniewska Z.

    2005-01-01

    The paper presents the influence of chromium forms (III) and (VI) on the soil dehydrogenase activity. Enzyme activities can be considered effective indicators of soil quality changes resulting from environmental stress or management practices. It was found that chromium compounds have detrimental effects on soil dehydrogenase activity. After the addition of chromium, a rapid and significant decrease in enzymatic activities was observed.

  18. Microbial metabolic activity in soil as measured by dehydrogenase determinations

    Casida, L. E., Jr.

    1977-01-01

    The dehydrogenase technique for measuring the metabolic activity of microorganisms in soil was modified to use a 6-h, 37 C incubation with either glucose or yeast extract as the electron-donating substrate. The rate of formazan production remained constant during this time interval, and cellular multiplication apparently did not occur. The technique was used to follow changes in the overall metabolic activities of microorganisms in soil undergoing incubation with a limiting concentration of added nutrient. The sequence of events was similar to that obtained by using the Warburg respirometer to measure O2 consumption. However, the major peaks of activity occurred earlier with the respirometer. This possibly is due to the lack of atmospheric CO2 during the O2 consumption measurements.

  19. Evolutionary origins of retinoid active short-chain dehydrogenases/reductases of SDR16C family.

    Belyaeva, Olga V; Chang, Chenbei; Berlett, Michael C; Kedishvili, Natalia Y

    2015-06-01

    Vertebrate enzymes that belong to the 16C family of short-chain dehydrogenases/reductases (SDR16C) were shown to play an essential role in the control of retinoic acid (RA) levels during development. To trace the evolution of enzymatic function of SDR16C family, and to examine the origins of the pathway for RA biosynthesis from vitamin A, we identified putative SDR16C enzymes through the extensive search of available genome sequencing data in a subset of species representing major metazoan phyla. The phylogenetic analysis revealed that enzymes from protostome, non-chordate deuterostome and invertebrate chordate species are found in three clades of SDR16C family containing retinoid active enzymes, which are retinol dehydrogenase 10 (RDH10), retinol dehydrogenases E2 (RDHE2) and RDHE2-similar, and dehydrogenase reductase (SDR family) member 3 (DHRS3). For the initial functional analysis, we cloned RDH10- and RDHE2-related enzymes from the early developmental stages of a non-chordate deuterostome, green sea urchin Lytechinus variegatus, and an invertebrate chordate, sea squirt Ciona intestinalis. In situ hybridization revealed that these proteins are expressed in a pattern relevant to development, while assays performed on proteins expressed in mammalian cell culture showed that they possess retinol-oxidizing activity as their vertebrate homologs. The existence of invertebrate homologs of DHRS3 was inferred from the analysis of phylogeny and cofactor-binding residues characteristic of preference for NADP(H). The presence of invertebrate homologs in the DHRS3 group of SDR16C is interesting in light of the complex mutually activating interaction, which we have recently described for human RDH10 and DHRS3 enzymes. Further functional analysis of these homologs will establish whether this interaction evolved to control retinoid homeostasis only in vertebrates, or is also conserved in pre-vertebrates. PMID:25451586

  20. Functional characterization of cinnamyl alcohol dehydrogenase and caffeic acid O-methyltransferase in Brachypodium distachyon.

    Lignin is a significant recalcitrant in the conversion of plant biomass to bioethanol. Cinnamyl alcohol dehydrogenase (CAD) and caffeic acid O-methyltransferase (COMT) catalyze key steps in the pathway of lignin monomer biosynthesis. Brown midrib mutants in Zea mays and Sorghum bicolor with impaired...

  1. Immobilization of dehydrogenase onto epoxy-functionalized nanoparticles for synthesis of (R)-mandelic acid.

    Jiang, Xiao-Ping; Lu, Ting-Ting; Liu, Cai-Hong; Ling, Xiao-Ming; Zhuang, Meng-Yao; Zhang, Jiu-Xun; Zhang, Ye-Wang

    2016-07-01

    Epoxy functionalized magnetic Fe3O4@SiO2 nanoparticles were successfully prepared and characterized by Fourier-transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The prepared nanoparticles were used for immobilization of alcohol dehydrogenase (ADH) from Saccharomyces cerevisiae by covalent attachment. The optimal immobilization conditions were obtained as follows: enzyme/support 4.49mg/g, pH 8.0, buffer concentration 0.05M, time 12h and temperature 30°C. Under these conditions, a high immobilization yield and efficiency of above 92% were obtained after the optimization. Broad pH tolerance and high thermostability were achieved by the immobilization. The immobilized ADH retained about 84% initial activity after five cycles. Kinetic parameters Vmax and Km of free and immobilized ADH were determined as 56.72μM/min, 44.27μM/min and 11.54mM, 31.32mM, respectively. (R)-mandelic acid synthesis with the immobilized ADH was carried out, and the yield of (R)-mandelic acid was as high as 64%. These results indicate that the ADH immobilized onto epoxy-functionalized nanoparticles is an efficient and simple way for preparation of stable ADH, and the immobilized ADH has potential applications in the production of (R)-mandelic acid. PMID:26995611

  2. A Case of Hyperammonemia Associated with High Dihydropyrimidine Dehydrogenase Activity

    Nagaharu, Keiki; Ikemura, Kenji; Yamashita, Yoshiki; Oda, Hiroyasu; Ishihara, Mikiya; Sugawara, Yumiko; Tamaru, Satoshi; Mizuno, Toshiro; Katayama, Naoyuki

    2016-01-01

    Over the past decades, 5-Fluorouracil (5-FU) has been widely used to treat several types of carcinoma, including esophageal squamous cell carcinoma. In addition to its common side effects, including diarrhea, mucositis, neutropenia, and anemia, 5-FU treatment has also been reported to cause hyperammonemia. However, the exact mechanism responsible for 5-FU-induced hyperammonemia remains unknown. We encountered an esophageal carcinoma patient who developed hyperammonemia when receiving 5-FU-containing chemotherapy but did not exhibit any of the other common adverse effects of 5-FU treatment. At the onset of hyperammonemia, laboratory tests revealed high dihydropyrimidine dehydrogenase (DPD) activity and rapid 5-FU clearance. Our findings suggested that 5-FU hypermetabolism may be one of the key mechanisms responsible for hyperammonemia during 5-FU treatment. PMID:27195162

  3. 17 beta-hydroxysteroid dehydrogenase activity in canine pancreas

    The mitochondrial fraction of the dog pancreas showed NAD(H)-dependent enzyme activity of 17 beta-hydroxysteroid dehydrogenase. The enzyme catalyzes oxidoreduction between androstenedione and testosterone. The apparent Km value of the enzyme for androstenedione was 9.5 +/- 0.9 microM, the apparent Vmax was determined as 0.4 nmol mg-1 min-1, and the optimal pH was 6.5. In phosphate buffer, pH 7.0, maximal rate of androstenedione reduction was observed at 37 degrees C. The oxidation of testosterone by the enzyme proceeded at the same rate as the reduction of the androstenedione at a pH of 6.8-7.0. The apparent Km value and the optimal pH of the enzyme for testosterone were 3.5 +/- 0.5 microM and 7.5, respectively

  4. Evaluation of Serum Lactate Dehydrogenase Activity in a Virtual Environment

    V.M.T. Trindade

    2013-05-01

    Full Text Available Introduction: Lactate dehydrogenase is a citosolic enzyme involved in reversible transformation of pyruvate to lactate. It participates in anaerobic glycolysis of skeletal muscle and red blood cells, in liver gluconeogenesis and in aerobic metabolism of heart muscle. The determination of its activity helps in the diagnosis of various diseases, because it is increased in serum of patients suffering from myocardial infarction, acute hepatitis, muscular dystrophy and cancer. This paper presents a learning object, mediated by computer, which contains the simulation of the laboratory determination serum lactate dehydrogenase activity measured by the spectrophotometric method, based in the decrease of absorbance at 340 nm. Materials and Methods: Initially, pictures and videos were obtained recording the procedure of the methodology. The most representative images were selected, edited and inserted into an animation developed with the aid of the tool Adobe ® Flash ® CS3. The validation of the object was performed by the students of Biochemistry I (Pharmacy-UFRGS from the second semester of 2009 and both of 2010. Results and Discussion: The analysis of students' answers revealed that 80% attributed the excellence of the navigation program, the display format and to aid in learning. Conclusion: Therefore, this software can be considered an adequate teaching resource as well as an innovative support in the construction of theoretical and practical knowledge of Biochemistry. Available at: http://www6.ufrgs.br/gcoeb/LDH

  5. Sjögren-Larsson syndrome. Deficient activity of the fatty aldehyde dehydrogenase component of fatty alcohol:NAD+ oxidoreductase in cultured fibroblasts.

    Rizzo, W B; Craft, D A

    1991-01-01

    Sjögren-Larsson syndrome (SLS) is an inherited disorder associated with impaired fatty alcohol oxidation due to deficient activity of fatty alcohol:NAD+ oxidoreductase (FAO). FAO is a complex enzyme which consists of two separate proteins that sequentially catalyze the oxidation of fatty alcohol to fatty aldehyde and fatty acid. To determine which enzymatic component of FAO was deficient in SLS, we assayed fatty aldehyde dehydrogenase (FALDH) and fatty alcohol dehydrogenase in cultured fibrob...

  6. Furosemide and 11beta-hydroxysteroid dehydrogenase activity, in man.

    Palermo, M; Armanini, D; Shackleton, C H L; Sorba, G; Cossu, M; Roitman, E; Scaroni, C; Delitala, G

    2002-09-01

    Mineralocorticoid receptors possess the same affinity for aldosterone and for cortisol and preferential binding of aldosterone is modulated by the 11 beta-hydroxysteroid dehydrogenase (11 beta-OHSD) enzyme, which converts cortisol to its inactive metabolite cortisone. Several endogenous or exogenous compounds able to inhibit the enzyme have been described and, as a consequence, produce the syndrome of apparent mineralocorticoid excess (AME) characterized by hypertension, hypokalemia, volume repletion and suppression of the renin-angiotensin-aldosterone system. High doses of furosemide, a diuretic that works in the luminal surface of the thick ascending limb of Henle's loop, have been reported to inhibit 11 beta-OHSD activity to the same extent as licorice in vivo and in vitro, in rat. The aim of our study was to verify the effect of the drug on 11 beta-OHSD activity in man at the doses currently used in clinical practice. We tested the activity of 11 beta-OHSD following both acute and protracted administration of furosemide. In the acute study, the drug was administered at low (40 mg i.v. in bolo) and high doses (infusion of 10 mg/kg bw i.v for six hours); the protracted furosemide administration consisted in 50 mg/day for 20 days, by mouth. The ratios between the cortisol metabolites tetrahydrocortisol plus allo-tetrahydrocortisol to tetra-hydrocortisone and urinary free cortisol to urinary free cortisone were used to measure the activity of 11 beta-OHSD. Urinary cortisol, cortisone and their metabolites were tested by a gas-chromatographic/mass spectrometric method. Neither acute nor prolonged administration of furosemide did affect the activity of 11 beta-OHSD although the drug was able to modify plasma aldosterone and PRA secretion and to determine hypokalemia. Our results suggest that furosemide does not play a significant role in 11 beta-OHSD modulation in humans, at least at the dosage used in clinical practice. PMID:12373630

  7. 11 beta-Hydroxysteroid dehydrogenase activity in hypothalamic obesity.

    Tiosano, Dov; Eisentein, Israel; Militianu, Daniela; Chrousos, George P; Hochberg, Ze'ev

    2003-01-01

    After extensive suprasellar operations for hypothalamic tumor removal, some patients develop Cushing-like morbid obesity while they receive replacement doses of glucocorticoids. In this study, we examined the hypothesis that target tissue conversion of inactive 11-ketosteroids to active 11 beta-OH glucocorticoids might explain the obesity of some patients with hypothalamic lesions. Toward this aim, we studied 10 patients with hypothalamic obesity and secondary adrenal insufficiency and 6 control Addisonian patients while they were on glucocorticoid replacement therapy. Pituitary hormone deficiencies were replaced when medically indicated. Twenty-four-hour urine was collected after a single oral dose of 12 mg/m(2) hydrocortisone acetate. The ratios of free and conjugated cortisol (F) to cortisone (E) and their metabolites, [tetrahydrocortisol (THF)+5 alpha THF]/tetrahyrdocortisone (THE), dihydrocortisols/dihydrocortisones, cortols/cortolones, and (F+E)/(THF+THE+5 alpha THF), were considered to represent 11 beta-hydroxysteroid dehydrogenase (HSD) activity. The 11-OH/11-oxo ratios were significantly higher in the urine of patients with hypothalamic obesity. The 11-OH/11-oxo ratios, however, did not correlate with the degree of obesity, yet a significant correlation was found between conjugated F/E and the ratio of visceral fat to sc fat measured by computerized tomography at the umbilical level. The consequence of increased 11 beta-HSD1 activity and the shift of the interconversion toward cortisol may contribute to the effects of the latter in adipose tissue. We propose that deficiency of hypothalamic messengers after surgical injury induces a paracrine/autocrine effect of enhanced glucocorticoid activity due to up-regulated 11 beta-HSD1 activity. PMID:12519880

  8. The Function of Retinol Dehydrogenase 1 in Retinoic Acid Synthesis and Metabolic Regulation

    Krois, Charles Robert

    2011-01-01

    Retinol dehydrogenases (RDH) convert retinol into retinal, the intermediate in the biosynthesis of retinoic acid. All-trans-retinoic acid (atRA) regulates gene transcription and/or translation through retinoic acid receptors (RARs) and PPARδ (1). To test function of Rdh1, an efficient (Vmax/Km) and widely distributed RDH (2), our lab created Rdh1 knockout (KO) mice (3). Initial study of Rdh1-KO mice determined that when fed a low or vitamin A-deficient (VAD) diet, Rdh1-KO mice gain 33% ...

  9. [Possible ways of regulating detoxifying processes in the alcohol dehydrogenase reaction with pantothenic acid derivatives].

    Chernikevich, I P; Dorofeev, B F; Moĭseenok, A G

    1993-01-01

    Oxidation of derivatives and precursors of pantothenic acid was studied in alcohol dehydrogenase reactions. Despite the presence of free hydroxymethyl groups in a number of pantothenic acid derivatives only panthenol with Km = 8 x 10(-3) M was shown to serve as a substrate for alcohol dehydrogenase from horse liver tissue (EC 1.1.1.1) Pantethine, sodium phosphopantothenate, CoA and acetyl-CoA decreased the rate of ethanol oxidation, where pantethine and sodium phosphopantothenate were competitive inhibitors, while CoA and acetyl-CoA inhibited the enzyme noncompetitively Ki = 1.2 x 10(-2) M, 2.1 x 10(-2) M, 4.4 x 10(-4) M and 5.1 x 10(-4) M, respectively. Metabolic precursors, which were different from pantothenic acid in their structure, were not involved in the alcohol dehydrogenase reaction. Possible regulation of alcohol intoxication using derivatives and precursors of vitamin B3 is discussed. PMID:8511887

  10. Two shikimate dehydrogenases, VvSDH3 and VvSDH4, are involved in gallic acid biosynthesis in grapevine.

    Bontpart, Thibaut; Marlin, Thérèse; Vialet, Sandrine; Guiraud, Jean-Luc; Pinasseau, Lucie; Meudec, Emmanuelle; Sommerer, Nicolas; Cheynier, Véronique; Terrier, Nancy

    2016-05-01

    In plants, the shikimate pathway provides aromatic amino acids that are used to generate numerous secondary metabolites, including phenolic compounds. In this pathway, shikimate dehydrogenases (SDH) 'classically' catalyse the reversible dehydrogenation of 3-dehydroshikimate to shikimate. The capacity of SDH to produce gallic acid from shikimate pathway metabolites has not been studied in depth. In grapevine berries, gallic acid mainly accumulates as galloylated flavan-3-ols. The four grapevine SDH proteins have been produced in Escherichia coli In vitro, VvSDH1 exhibited the highest 'classical' SDH activity. Two genes, VvSDH3 and VvSDH4, mainly expressed in immature berry tissues in which galloylated flavan-3-ols are accumulated, encoded enzymes with lower 'classical' activity but were able to produce gallic acid in vitro The over-expression of VvSDH3 in hairy-roots increased the content of aromatic amino acids and hydroxycinnamates, but had little or no effect on molecules more distant from the shikimate pathway (stilbenoids and flavan-3-ols). In parallel, the contents of gallic acid, β-glucogallin, and galloylated flavan-3-ols were increased, attesting to the influence of this gene on gallic acid metabolism. Phylogenetic analysis from dicotyledon SDHs opens the way for the examination of genes from other plants which accumulate gallic acid-based metabolites. PMID:27241494

  11. Characterization of the major dehydrogenase related to d-lactic acid synthesis in Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293.

    Li, Ling; Eom, Hyun-Ju; Park, Jung-Mi; Seo, Eunyoung; Ahn, Ji Eun; Kim, Tae-Jip; Kim, Jeong Hwan; Han, Nam Soo

    2012-10-10

    Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293 is a lactic acid bacterium that converts pyruvate mainly to d-(-)-lactic acid by using d-(-)-lactate dehydrogenase (ldhD). The aim of this study was to identify the gene responsible for d-lactic acid formation in this organism and to characterize the enzyme to facilitate the production of optically pure d-lactic acid. A genomic analysis of L. mesenteroides ATCC 8293 revealed that 7 genes encode lactate-related dehydrogenase. According to transcriptomic, proteomic, and phylogenetic analyses, LEUM_1756 was the major gene responsible for the production of d-lactic acid. The LEUM_1756 gene, of 996bp and encoding 332 amino acids (36.5kDa), was cloned and overexpressed in Escherichia coli BL21(DE3) Star from an inducible pET-21a(+) vector. The enzyme was purified by Ni-NTA column chromatography and showed a specific activity of 4450U/mg, significantly higher than those of other previously reported ldhDs. The gel permeation chromatography analysis showed that the purified enzyme exists as tetramers in solution and this was the first report among lactic acid bacteria. The pH and temperature optima were pH 8.0 and 30°C, respectively, for the pyruvate reduction reaction, and pH 11.0 and 20°C, respectively, for the lactate oxidation reaction. The K(m) kinetic parameters for pyruvate and lactate were 0.58mM and 260mM, respectively. In addition, the k(cat) values for pyruvate and lactate were 2900s(-1) and 2280s(-1), respectively. The enzyme was not inhibited by Ca(2+), Co(2+), Cu(2+), Mg(2+), Mn(2+), Na(+), or urea, but was inhibited by 1mM Zn(2+) and 1mM SDS. PMID:22975125

  12. INFLUENCE OF LIMING AND WASTE ORGANIC MATERIALS ON THE ACTIVITY OF UREASE AND DEHYDROGENASE IN SOIL CONTAMINATED WITH NICKEL

    Dorota Kalembasa

    2014-10-01

    Full Text Available In soil sampled after a two-year pot experiment, the activity of urease and dehydrogenase and content of nitrogen have been determined. The experiment included three factors: 1. the amount of nickel added to the soil (0, 75, 150 and 225 mg · kg-1 of soil, 2. liming (0 and Ca according to 1 Hh hydrolytic acidity, 3. organic materials (straw of rye and brown coal. Test plant was cocksfoot, which four cuts were collected in each growing season. It was found that nickel added to the soli in dose of 75 mg · kg-1 activates enzymes studied, whereas higher doses cause them explicit deactivation. Both liming and waste organic materials limited the negative effect of higher doses of nickel on the activity of dehydrogenase and urease. Simultaneously, both straw and brown coal caused a slight increase in the amount of nitrogen in the soil.

  13. Lack of Skeletal Muscle IL-6 Affects Pyruvate Dehydrogenase Activity at Rest and during Prolonged Exercise

    Gudiksen, Anders; Schwartz, Camilla Lindgren; Bertholdt, Lærke; Joensen, Ella; Knudsen, Jakob G.; Pilegaard, Henriette

    2016-01-01

    Pyruvate dehydrogenase (PDH) plays a key role in the regulation of skeletal muscle substrate utilization. IL-6 is produced in skeletal muscle during exercise in a duration dependent manner and has been reported to increase whole body fatty acid oxidation, muscle glucose uptake and decrease PDHa activity in skeletal muscle of fed mice. The aim of the present study was to examine whether muscle IL-6 contributes to exercise-induced PDH regulation in skeletal muscle. Skeletal muscle-specific IL-6 knockout (IL-6 MKO) mice and floxed littermate controls (control) completed a single bout of treadmill exercise for 10, 60 or 120 min, with rested mice of each genotype serving as basal controls. The respiratory exchange ratio (RER) was overall higher (Putilization during prolonged exercise via effects on PDH. PMID:27327080

  14. The oxyanion hole of Pseudomonas fluorescens mannitol 2-dehydrogenase: a novel structural motif for electrostatic stabilisation in alcohol dehydrogenase active sites

    Klimacek, Mario; Nidetzky, B

    2009-01-01

    Abstract The side chains of Asn-191 and Asn-300 constitute a characteristic structural motif of the active site of Pseudomonas fluorescens mannitol 2-dehydrogenase that lacks precedent in known alcohol dehydrogenases and resembles the canonical oxyanion binding pocket of serine proteases. We have used steady-state and transient kinetic studies of the effects of varied pH and deuterium isotopic substitutions in substrates and solvent on the enzymatic rates to delineate catalytic con...

  15. Ethylmalonic aciduria is associated with an amino acid variant of short chain acyl-coenzyme A dehydrogenase

    Corydon, M J; Gregersen, N; Lehnert, W; Ribes, A; Rinaldo, P; Kmoch, S; Christensen, E; Kristensen, T J; Andresen, B S; Bross, P; Winter, V; Martinez, G; Neve, S; Jensen, T G; Bolund, L; Kølvraa, S

    1996-01-01

    Ethylmalonic aciduria is a common biochemical finding in patients with inborn errors of short chain fatty acid beta-oxidation. The urinary excretion of ethylmalonic acid (EMA) may stem from decreased oxidation by short chain acyl-CoA dehydrogenase (SCAD) of butyryl-CoA, which is alternatively met...

  16. L-lactic acid production from D-xylose with Candida sonorensis expressing a heterologous lactate dehydrogenase encoding gene

    Koivuranta, Kari T; Ilmén, Marja; Wiebe, Marilyn G.; Ruohonen, Laura; Suominen, Pirkko; Penttilä, Merja

    2014-01-01

    Background Bioplastics, like polylactic acid (PLA), are renewable alternatives for petroleum-based plastics. Lactic acid, the monomer of PLA, has traditionally been produced biotechnologically with bacteria. With genetic engineering, yeast have the potential to replace bacteria in biotechnological lactic acid production, with the benefits of being acid tolerant and having simple nutritional requirements. Lactate dehydrogenase genes have been introduced to various yeast to demonstrate this pot...

  17. Expression of a Heterologous Glutamate Dehydrogenase Gene in Lactococcus lactis Highly Improves the Conversion of Amino Acids to Aroma Compounds

    Rijnen, Liesbeth; Courtin, Pascal; Gripon, Jean-Claude; Yvon, Mireille

    2000-01-01

    The first step of amino acid degradation in lactococci is a transamination, which requires an α-keto acid as the amino group acceptor. We have previously shown that the level of available α-keto acid in semihard cheese is the first limiting factor for conversion of amino acids to aroma compounds, since aroma formation is greatly enhanced by adding α-ketoglutarate to cheese curd. In this study we introduced a heterologous catabolic glutamate dehydrogenase (GDH) gene into Lactococcus lactis so ...

  18. Lipid-mediated unfolding of 3β-hydroxysteroid dehydrogenase 2 is essential for steroidogenic activity.

    Rajapaksha, Maheshinie; Thomas, James L; Streeter, Michael; Prasad, Manoj; Whittal, Randy M; Bell, John D; Bose, Himangshu S

    2011-12-27

    For inner mitochondrial membrane (IMM) proteins that do not undergo N-terminal cleavage, the activity may occur in the absence of a receptor present in the mitochondrial membrane. One such protein is human 3β-hydroxysteroid dehydrogenase 2 (3βHSD2), the IMM resident protein responsible for catalyzing two key steps in steroid metabolism: the conversion of pregnenolone to progesterone and dehydroepiandrosterone to androstenedione. Conversion requires that 3βHSD2 serve as both a dehydrogenase and an isomerase. The dual functionality of 3βHSD2 results from a conformational change, but the trigger for this change remains unknown. Using fluorescence resonance energy transfer, we found that 3βHSD2 interacted strongly with a mixture of dipalmitoylphosphatidylglycerol (DPPG) and dipalmitoylphosphatidylcholine (DPPC). 3βHSD2 became less stable when incubated with the individual lipids, as indicated by the decrease in thermal denaturation (T(m)) from 42 to 37 °C. DPPG, alone or in combination with DPPC, led to a decrease in α-helical content without an effect on the β-sheet conformation. With the exception of the 20 N-terminal amino acids, mixed vesicles protected 3βHSD2 from trypsin digestion. However, protein incubated with DPPC was only partially protected. The lipid-mediated unfolding completely supports the model in which a cavity forms between the α-helix and β-sheet. As 3βHSD2 lacks a receptor, opening the conformation may activate the protein. PMID:22106846

  19. Simulated ischaemia-reperfusion conditions increase xanthine dehydrogenase and oxidase activities in rat brain slices.

    Battelli, M G; Buonamici, L; Virgili, M; Abbondanza, A; Contestabile, A

    1998-01-01

    Xanthine dehydrogenase and oxidase activities increased by 87% in rat brain slices after 30 min in vitro ischaemia. A further 41% increase was induced by 30 min simulated reperfusion of ischaemic slices. No conversion from the dehydrogenase to the oxidase activity was observed. The increment of enzyme activity was not due to neosynthesis of the enzyme, since it was not affected by the addition of cycloheximide during the ischaemic incubation. The increased oxygen-dependent form of the enzyme could aggravate the ischaemic brain injury by free radicals production, in particular after reperfusion. PMID:9460697

  20. Growth hormone-induced insulin resistance in human subjects involves reduced pyruvate dehydrogenase activity

    Nellemann, Birgitte; Vendelbo, Mikkel H; Nielsen, Thomas S;

    2014-01-01

    Insulin resistance induced by growth hormone (GH) is linked to promotion of lipolysis by unknown mechanisms. We hypothesized that suppression of the activity of pyruvate dehydrogenase in the active form (PDHa) underlies GH-induced insulin resistance similar to what is observed during fasting....

  1. Oxidation of fatty aldehydes to fatty acids by Escherichia coli cells expressing the Vibrio harveyi fatty aldehyde dehydrogenase (FALDH).

    Buchhaupt, Markus; Guder, Jan; Sporleder, Fenja; Paetzold, Melanie; Schrader, Jens

    2013-03-01

    Fatty acids represent an important renewable feedstock for the chemical industry. To enable biotechnological one carbon truncations of fatty acids, the enzymes α-dioxygenase and fatty aldehyde dehydrogenase (FALDH) have to be combined in a two-step process. We expressed an FALDH from V. harveyi in E. coli and characterized its substrate spectrum with a focus on the number and position of double bonds in the fatty aldehyde molecules. Synthesis of the expected fatty acid products was proven by analysis of whole cell biotransformation products. Coexpression of a H(2)O-forming NADPH oxidase (NOX) from Lactobacillus sanfranciscensis led to the implementation of a cofactor regeneration cycle in in vitro oxidation experiments. The presence of NOX in whole cell biotransformations improved reaction velocity but did not result in higher product yields. We could further demonstrate that at least part of the endogenous NAD(P)(+) regeneration capacity in the resting cells results from the respiratory chain. The whole cell catalyst with the high broad range FALDH activity described here is an important biotechnological module for lipid biotransformation processes, especially the shortening of fatty acids. PMID:23180547

  2. Direct evidence for the inactivation of branched-chain oxo-acid dehydrogenase by enzyme phosphorylation

    The branched-chain 2-oxo-acid dehydrogenase (BCOAD) from mitochondria of several different rat tissues is inactivated by ATP and can be reactivated by incubation in Mg2+-containing buffers. Work carried out on the system from skeletal muscle mitochondria has shown that inactivation requires the cleavage of the γ-phosphate group of ATP and that modification is covalent. The non-metabolized ATP analog, p[NH]ppA, can block the inhibitory effect of ATP when added prior to ATP addition, but cannot reverse the inhibition of the inactivated dehydrogenase. These and other data raise the possibility that BCOAD may be regulated by enzyme phosphorylation. This hypothesis is supported by the finding that various procedures which separate the enzyme from its mitochondrial environment (e.g. detergent treatment, ammonium sulfate precipitation and freeze-thawing) do not alter the degree of inhibition induced by ATP in the mitochondrial preincubation. These experiments suggested the feasibility of labelling the enzyme with 32P and purifying it. (Auth.)

  3. Production of l-lactic acid by the yeast Candida sonorensis expressing heterologous bacterial and fungal lactate dehydrogenases

    Ilmén, Marja; Koivuranta, Kari; Ruohonen, Laura; Rajgarhia, Vineet; Suominen, Pirkko; Penttilä, Merja

    2013-01-01

    Background Polylactic acid is a renewable raw material that is increasingly used in the manufacture of bioplastics, which offers a more sustainable alternative to materials derived from fossil resources. Both lactic acid bacteria and genetically engineered yeast have been implemented in commercial scale in biotechnological production of lactic acid. In the present work, genes encoding l-lactate dehydrogenase (LDH) of Lactobacillus helveticus, Bacillus megaterium and Rhizopus oryzae were expre...

  4. Asp295 Stabilizes the Active-Site Loop Structure of Pyruvate Dehydrogenase, Facilitating Phosphorylation of Ser292 by Pyruvate Dehydrogenase-Kinase

    Hirani, Tripty A.; Alejandro Tovar-Méndez; Miernyk, Ján A.; Randall, Douglas D.

    2011-01-01

    We have developed an in vitro system for detailed analysis of reversible phosphorylation of the plant mitochondrial pyruvate dehydrogenase complex, comprising recombinant Arabidopsis thalianaα2β2-heterotetrameric pyruvate dehydrogenase (E1) plus A. thaliana E1-kinase (AtPDK). Upon addition of MgATP, Ser292, which is located within the active-site loop structure of E1α, is phosphorylated. In addition to Ser292, Asp295 and Gly297 are highly conserved in the E1α active-site loop sequences. Mutat...

  5. [Aldehyde dehydrogenase activity and level of dopamine in certain sections of the brain of rats preferring and refusing ethanol].

    Kharchenko, N K

    2000-01-01

    Aldehyde dehydrogenase activity (KF 1.2.1.3) of cytosol fractions of brain structures (hypothalamus, midbrain and new cortex) as well as dophamine content in these structures were studied in comparative aspect in rats preferring and rejection ethanol. It has been shown that there were two isoforms of aldehyde dehydrogenases (aldehyde dehydrogenase 1 and aldehyde dehydrogenase 2) in cytosol fractions of all investigated brain structures of animals preferring ethanol while only aldehyde dehydrogenase 2 has been found in the new cotex of rats rejecting ethanol. Thus, aldehyde-dehydrogenase activity is higher in the animals preferring ethanol than in those ones rejecting ethanol. Content of dophamine in the rats preferring ethanol is higher than in those ones rejecting ethanol both in the hypothalamus and new cortex. Differences between the studied groups of animals can underlie the pathologic attraction to alcohol. PMID:10979563

  6. Regulation of carbon monoxide dehydrogenase and hydrogenase in Rhodospirillum rubrum: effects of CO and oxygen on synthesis and activity.

    Bonam, D; Lehman, L.; Roberts, G P; Ludden, P W

    1989-01-01

    Exposure of the photosynthetic bacterium Rhodospirillum rubrum to carbon monoxide led to increased carbon monoxide dehydrogenase and hydrogenase activities due to de novo protein synthesis of both enzymes. Two-dimensional gels of [35S]methionine-pulse-labeled cells showed that induction of CO dehydrogenase synthesis was rapidly initiated (less than 5 min upon exposure to CO) and was inhibited by oxygen. Both CO dehydrogenase and the CO-induced hydrogenase were inactivated by oxygen in vivo an...

  7. Inhibition of dehydrogenase activity in petroleum refinery wastewater bacteria by phenolic compounds

    Gideon C. Okpokwasili

    2010-04-01

    Full Text Available The toxicity of phenol, 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 2-chlorophenol, 4-chlorophenol, 4-bromophenol and 3,5-dimethylphenol on Pseudomonas, Bacillus and Escherichia species isolated from petroleum refinery wastewater was assessed via inhibition of dehydrogenase enzyme activity. At low concentrations, 2-nitrophenol, 2-chlorophenol, 4-chlorophenol, 4-bromophenol and 3,5-dimethylphenol stimulated dehydrogenase activity and at sufficient concentrations, phenolic compounds inhibited dehydrogenase activities. Generally, phenol is less toxic than substituted phenols. Estimations of the degree of inhibition/stimulation of dehydrogenase activities showed significant dose-dependent responses that are describable by logistic functions. The toxicity thresholds varied significantly (P < 0.05 among the bacterial strains and phenolic compounds. The median inhibitory concentrations (IC50s ranged from 4.118 ± 0.097 mg.L-1 for 4-nitrophenol against Pseudomonas sp. DAF1 to 1407.997 ± 7.091 mg.L-1 for phenol against Bacillus sp. DISK1. This study suggested that the organisms have moderate sensitivity to phenols and have the potential to be used as indicators for assessment of chemical toxicity. They could also be used as catalysts for degradation of phenols in effluents.

  8. Communication between Thiamin Cofactors in the Escherichia coli Pyruvate Dehydrogenase Complex E1 Component Active Centers

    Nemeria, Natalia S.; Arjunan, Palaniappa; Chandrasekhar, Krishnamoorthy; Mossad, Madouna; Tittmann, Kai; Furey, William; Jordan, Frank

    2010-01-01

    Kinetic, spectroscopic, and structural analysis tested the hypothesis that a chain of residues connecting the 4′-aminopyrimidine N1′ atoms of thiamin diphosphates (ThDPs) in the two active centers of the Escherichia coli pyruvate dehydrogenase complex E1 component provides a signal transduction pathway. Substitution of the three acidic residues (Glu571, Glu235, and Glu237) and Arg606 resulted in impaired binding of the second ThDP, once the first active center was filled, suggesting a pathway for communication between the two ThDPs. 1) Steady-state kinetic and fluorescence quenching studies revealed that upon E571A, E235A, E237A, and R606A substitutions, ThDP binding in the second active center was affected. 2) Analysis of the kinetics of thiazolium C2 hydrogen/deuterium exchange of enzyme-bound ThDP suggests half-of-the-sites reactivity for the E1 component, with fast (activated site) and slow exchanging sites (dormant site). The E235A and E571A variants gave no evidence for the slow exchanging site, indicating that only one of two active sites is filled with ThDP. 3) Titration of the E235A and E237A variants with methyl acetylphosphonate monitored by circular dichroism suggested that only half of the active sites were filled with a covalent predecarboxylation intermediate analog. 4) Crystal structures of E235A and E571A in complex with ThDP revealed the structural basis for the spectroscopic and kinetic observations and showed that either substitution affects cofactor binding, despite the fact that Glu235 makes no direct contact with the cofactor. The role of the conserved Glu571 residue in both catalysis and cofactor orientation is revealed by the combined results for the first time. PMID:20106967

  9. Effects of synthetic detergents on in vivo activity of tissue phosphatases and succinic dehydrogenase from Mystus vittatus

    Mohan, D.; Verma, S.R.

    1981-05-01

    African catfish (Mystus vittatus) were exposed to three sub-lethal concentrations of Swascofix E45 (13.8, 9.2 and 4.6 mg/l) and Swascol 3L (69.3, 46.2 and 23.1 mg/l) for 15 and 30 days, and their effects on alkaline and acid phosphatase, and succinic dehydrogenase in liver, kidney and intestine were measured. The enzymes were found to be inhibited in all the tissues. Maximum inhibition (38.44%) was observed in liver alkaline phosphatase activity after 30 days with the highest concentration of Swascofix E45 and the lowest inhibition (0.118%) was found in kidney acid phosphatase activity with the lowest concentration of Swascol 3L after 15 days. Insignificant enzyme stimulation in some cases was also observed.

  10. Cloning and characterization of a gene (msdA) encoding methylmalonic acid semialdehyde dehydrogenase from Streptomyces coelicolor.

    Zhang, Y. X.; Tang, L.; Hutchinson, C R

    1996-01-01

    A homolog of the mmsA gene of Pseudomonas aeruginosa, which encodes methylmalonic acid semialdehyde dehydrogenase (MSDH) and is involved in valine catabolism in pseudomonads and mammals, was cloned and sequenced from Streptomyces coelicolor. Of the two open reading frames (ORFs) found, which are convergently transcribed and separated by a 62-nucleotide noncoding region, the deduced amino acid sequence of the msdA ORF (homologous to mmsA) is similar to a variety of prokaryotic and eukaryotic a...

  11. Nuclear Magnetic Resonance Approaches in the Study of 2-Oxo Acid Dehydrogenase Multienzyme Complexes—A Literature Review

    Mulchand S. Patel

    2013-09-01

    Full Text Available The 2-oxoacid dehydrogenase complexes (ODHc consist of multiple copies of three enzyme components: E1, a 2-oxoacid decarboxylase; E2, dihydrolipoyl acyl-transferase; and E3, dihydrolipoyl dehydrogenase, that together catalyze the oxidative decarboxylation of 2-oxoacids, in the presence of thiamin diphosphate (ThDP, coenzyme A (CoA, Mg2+ and NAD+, to generate CO2, NADH and the corresponding acyl-CoA. The structural scaffold of the complex is provided by E2, with E1 and E3 bound around the periphery. The three principal members of the family are pyruvate dehydrogenase (PDHc, 2-oxoglutarate dehydrogenase (OGDHc and branched-chain 2-oxo acid dehydrogenase (BCKDHc. In this review, we report application of NMR-based approaches to both mechanistic and structural issues concerning these complexes. These studies revealed the nature and reactivity of transient intermediates on the enzymatic pathway and provided site-specific information on the architecture and binding specificity of the domain interfaces using solubilized truncated domain constructs of the multi-domain E2 component in its interactions with the E1 and E3 components. Where studied, NMR has also provided information about mobile loops and the possible relationship of mobility and catalysis.

  12. NAD(P-DEPENDENT DEHYDROGENASE ACTIVITY IN PERIPHERAL BLOOD LYMPHOCYTES OF INFANTS WITH ENLARGEMENT OF PHARYNGEAL TONSILS

    L. M. Kurtasova

    2014-08-01

    Full Text Available We have observed and examined 57 children 1 to 3 years old diagnosed with enlargement of pharyngeal tonsils. A control group was presented by 35 healthy children. Bioluminescence technique was applied for studying NAD(P-dependent dehydrogenase activity in peripheral blood lymphocytes. Activation of aerobic respiration and increasing activity of pentose phosphate cycle-dependent plastic processes were registered in blood lymphocytes of children with hypertrophic pharyngeal tonsils; along with decreased function of malate-aspartate shunt in energy metabolism of the cells, diminished anaerobic reaction of NADHdependent LDH, lower interaction between Krebs cycle and reactions of amino acid metabolism, and reduced activity of glutathione reductase.

  13. A role for AMPK in the inhibition of glucose-6-phosphate dehydrogenase by polyunsaturated fatty acids

    Kohan, Alison B.; Talukdar, Indrani; Walsh, Callee M. [Department of Biochemistry, West Virginia University, Morgantown, WV (United States); Salati, Lisa M., E-mail: lsalati@hsc.wvu.edu [Department of Biochemistry, West Virginia University, Morgantown, WV (United States)

    2009-10-09

    Both polyunsaturated fatty acids and AMPK promote energy partitioning away from energy consuming processes, such as fatty acid synthesis, towards energy generating processes, such as {beta}-oxidation. In this report, we demonstrate that arachidonic acid activates AMPK in primary rat hepatocytes, and that this effect is p38 MAPK-dependent. Activation of AMPK mimics the inhibition by arachidonic acid of the insulin-mediated induction of G6PD. Similar to intracellular signaling by arachidonic acid, AMPK decreases insulin signal transduction, increasing Ser{sup 307} phosphorylation of IRS-1 and a subsequent decrease in AKT phosphorylation. Overexpression of dominant-negative AMPK abolishes the effect of arachidonic acid on G6PD expression. These data suggest a role for AMPK in the inhibition of G6PD by polyunsaturated fatty acids.

  14. Coordination environment of the active-site metal ion of liver alcohol dehydrogenase.

    Makinen, M W; Yim, M B

    1981-01-01

    The coordination environment of the catalytically active metal ion of horse liver alcohol dehydrogenase (alcohol:NAD+ oxidoreductase, EC 1.1.1.1) has been investigated by electron paramagnetic resonance (EPR) methods with use of the active-site-specific Co2+-reconstituted enzyme. The EPR absorption spectrum of the metal-substituted enzyme is characteristic of a rhombically distorted environment. The spectrum of the enzyme--NAD+ complex shows approximate axial symmetry of the metal ion site, i...

  15. High aldehyde dehydrogenase activity identifies cancer stem cells in human cervical cancer

    Liu, Shu-Yan; Zheng, Peng-Sheng

    2013-01-01

    High aldehyde dehydrogenase (ALDH) activity characterizes a subpopulation of cells with cancer stem cell (CSC) properties in several malignancies. To clarify whether ALDH can be used as a marker of cervical cancer stem cells (CCSCs), ALDHhigh and ALDHlow cells were sorted from 4 cervical cancer cell lines and 5 primary tumor xenografts and examined for CSC characteristics. Here, we demonstrate that cervical cancer cells with high ALDH activity fulfill the functional criteria for CSCs: (1) ALD...

  16. Certain enzymatic activities in brain and liver mitochondria of rats treated with pantothenic acid after irradiation

    Whole body caesium-137 gamma irradiation of rats with single dose of 5 Gy induced significant decrease in the activities of glutamate dehydrogenase, isocitrate dehydrogenase and succunate dehydrogenase in mitochondria of brain and liver. Intraperitoneal administration of pantothenic acid (20 mg/Kg body weight/day) for 5 consecutive days after irradiation resulted of detectable improvement in the radiation-induced decrease inactivities of mitochondrial enzymes. It is postulated that pantothenic acid administered to rats after irradiation might play a role in the regulation of certain mitochondrial enzymes activities

  17. Nicotinamide Cofactors Suppress Active-Site Labeling of Aldehyde Dehydrogenases.

    Stiti, Naim; Chandrasekar, Balakumaran; Strubl, Laura; Mohammed, Shabaz; Bartels, Dorothea; van der Hoorn, Renier A L

    2016-06-17

    Active site labeling by (re)activity-based probes is a powerful chemical proteomic tool to globally map active sites in native proteomes without using substrates. Active site labeling is usually taken as a readout for the active state of the enzyme because labeling reflects the availability and reactivity of active sites, which are hallmarks for enzyme activities. Here, we show that this relationship holds tightly, but we also reveal an important exception to this rule. Labeling of Arabidopsis ALDH3H1 with a chloroacetamide probe occurs at the catalytic Cys, and labeling is suppressed upon nitrosylation and oxidation, and upon treatment with other Cys modifiers. These experiments display a consistent and strong correlation between active site labeling and enzymatic activity. Surprisingly, however, labeling is suppressed by the cofactor NAD(+), and this property is shared with other members of the ALDH superfamily and also detected for unrelated GAPDH enzymes with an unrelated hydantoin-based probe in crude extracts of plant cell cultures. Suppression requires cofactor binding to its binding pocket. Labeling is also suppressed by ALDH modulators that bind at the substrate entrance tunnel, confirming that labeling occurs through the substrate-binding cavity. Our data indicate that cofactor binding adjusts the catalytic Cys into a conformation that reduces the reactivity toward chloroacetamide probes. PMID:26990764

  18. FERROFLUIDS INFLUENCE ON DEHYDROGENASES ACTIVITY IN CELLULOLYTIC FUNGUS CHAETOMIUM GLOBOSUM

    Alexandru Manoliu; Lacramioara Oprica; Zenovia Olteanu; Dorina Creanga

    2003-01-01

    he activity of dehy drogenases was studied after ferrofluids supply ing in the culture medium of Chaetomium globosum. Spectral measurements were carried out after 7 and, respectively , 11 day s of growth. Different results were noticed for different ferrofluids concentrations: 20, 40, 60, 80 and 100 μl/L. Inhibitory or stimulatory ferrofluids effect was obtained depending on the nature of the investigated enzyme.

  19. Differential pulse voltammetric studies on the effects of Al(Ⅲ) on the lactate dehydrogenase activity

    2007-01-01

    In this paper, differential pulse voltammetry (DPV) was applied to study the effects of aluminum Al(Ⅲ) on the lactate dehydrogenase (LDH) activity. Michaelis-Menten constant (KNADHm) and maximum velocity (vmax) in the enzyme promoting catalytic reaction of "pyruvate(Pyr) + NADH + H+ LDH(=) lactate + NAD+" under different conditions by monitoring DPV reduction current of NAD+ were reported.(C) 2007 Shu Ping Bi. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  20. Lactate Dehydrogenase and Citrate Synthase activity in cardiac and skeletal muscle of lowland and highland tinamous

    Aira, Naomi

    2013-01-01

    Tinamous (Tinamidae) have the smallest heart in relation to body mass compared to any other flying bird today (Bishop 1997). This means that heart size is likely to restrict aerobic metabolism. Tinamous inhabit areas from sea level to 4800 m a.s.l., which means that the high altitude living species, Nothoprocta ornata (NO), is exposed to hypoxia. In this study the activity of the two metabolic enzymes Lactate Dehydrogenase (LDH) and Citrate Synthase (CS) was measured and the ratio between the...

  1. Structure of d-lactate dehydrogenase from Aquifex aeolicus complexed with NAD+ and lactic acid (or pyruvate)

    Antonyuk, Svetlana V.; Strange, Richard W.; Ellis, Mark J.; Bessho, Yoshitaka; Kuramitsu, Seiki; Inoue, Yumiko; Yokoyama, Shigeyuki; Hasnain, S. Samar

    2009-01-01

    The structure of d-lactate dehydrogenase from Aquifex aeolicus has been determined with each subunit of the homodimer in a ‘closed’ conformation and with the NAD+ cofactor and lactate (or pyruvate) bound at the inter-domain active-site cleft.

  2. Disease-causing missense mutations affect enzymatic activity, stability and oligomerization of glutaryl-CoA dehydrogenase (GCDH)

    Keyser, B.; Muhlhausen, C.; Dickmanns, A.; Muschol, N.; Ullrich, K.; Braulke, T.; Christensen, Ernst

    2008-01-01

    Glutaric aciduria type 1 (GA1) is an autosomal recessive neurometabolic disorder caused by mutations in the glutaryl-CoA dehydrogenase gene (GCDH), leading to an accumulation and high excretion of glutaric acid and 3-hydroxyglutaric acid. Considerable variation in severity of the clinical phenotype...

  3. Alcohol and Aldehyde Dehydrogenases: Retinoid Metabolic Effects in Mouse Knockout Models

    Kumar, Sandeep; Sandell, Lisa L.; Trainor, Paul A; Koentgen, Frank; Duester, Gregg

    2011-01-01

    Retinoic acid (RA) is the active metabolite of vitamin A (retinol) that controls growth and development. The first step of RA synthesis is controlled by enzymes of the alcohol dehydrogenase (ADH) and retinol dehydrogenase (RDH) families that catalyze oxidation of retinol to retinaldehyde. The second step of RA synthesis is controlled by members of the aldehyde dehydrogenase (ALDH) family also known as retinaldehyde dehydrogenase (RALDH) that further oxidize retinaldehyde to produce RA. RA fun...

  4. New insights in dihydropyrimidine dehydrogenase deficiency: a pivotal role for beta-aminoisobutyric acid?

    Van Kuilenburg, André B P; Stroomer, Alida E M; Van Lenthe, Henk; Abeling, Nico G G M; Van Gennip, Albert H

    2004-04-01

    DPD (dihydropyrimidine dehydrogenase) constitutes the first step of the pyrimidine degradation pathway, in which the pyrimidine bases uracil and thymine are catabolized to beta-alanine and the R-enantiomer of beta-AIB (beta-aminoisobutyric acid) respectively. The S-enantiomer of beta-AIB is predominantly derived from the catabolism of valine. It has been suggested that an altered homoeostasis of beta-alanine underlies some of the clinical abnormalities encountered in patients with a DPD deficiency. In the present study, we demonstrated that only a slightly decreased concentration of beta-alanine was present in the urine and plasma, whereas normal levels of beta-alanine were present in the cerebrospinal fluid of patients with a DPD deficiency. Therefore the metabolism of beta-alanine-containing peptides, such as carnosine, may be an important factor involved in the homoeostasis of beta-alanine in patients with DPD deficiency. The mean concentration of beta-AIB was approx. 2-3-fold lower in cerebrospinal fluid and urine of patients with a DPD deficiency, when compared with controls. In contrast, strongly decreased levels (10-fold) of beta-AIB were present in the plasma of DPD patients. Our results demonstrate that, under pathological conditions, the catabolism of valine can result in the production of significant amounts of beta-AIB. Furthermore, the observation that the R-enantiomer of beta-AIB is abundantly present in the urine of DPD patients suggests that significant cross-over exists between the thymine and valine catabolic pathways. PMID:14705962

  5. Dehydrogenase activity of technogenic soils of former sulphur mines (Yavoriv and Nemyriv, Ukraine)

    T. Włodarczyk; M. Brzezińska; Maryskevych, O.; V. Levyk

    2007-01-01

    The dehydrogenase activity (an index of the total soil biological activity), sulphur content, pH and Corg were determined in technogenic soils of the former (1954-1994) sulphur mines in Ukraine (open pit and underground sulphur melting, Yavoriv and Nemyriv, respectively). The soils were neither managed nor reclaimed, and underwent natural self-restoration processes. Soils of former open pit sulphur mine showed Corg of 0.07-1.29%, pH of 7-7.9 and a high SO4-S content (1.7-14.7 g kg-1). Dehydro...

  6. In vitro and in situ activity of carboxymethyl cellulase and glutamate dehydrogenase according to supplementation with different nitrogenous compounds

    Isabela Pena Carvalho de Carvalho

    2012-03-01

    Full Text Available Two experiments were carried out to evaluate the effect of supplementation with different nitrogenous compounds on the activities of carboxymethil cellulase (CMCase and glutamate dehydrogenase (GDH. In the first experiment, four treatments were evaluated in vitro: cellulose, cellulose with casein, cellulose with urea, and cellulose with casamino acids. After 6, 12 and 24 hours of incubation, CMCase and GDH activity, pH, and concentrations of ammonia nitrogen (AN and microbial protein were measured. In the three incubation periods, the concentration of AN was higher when urea was used as a supplemental source of nitrogen. The activity of CMCase was higher with the addition of urea and casamino acids when compared with the control and the casein treatment. Supplementation with casamino acids provided higher GDH activity when compared with the control at 6 hours of incubation. At 12 hours of incubation, the GHD activity was also stimulated by casein. At 24 hours, there was no difference in GHD activity among treatments. In the second experiment, three rumen-fistulated bulls were used for in situ evaluation. Animals were fed Tifton hay (Cynodon sp. ad libitum. The treatments consisted of control (no supplementation, supplementation with non-protein nitrogenous compounds (urea and ammonium sulphate, 9:1 and supplementation with protein (albumin. In treatments with nitrogenous compound supplementation, 1 g of crude protein/kg of body weight was supplied. The experiment was conducted in a 3 × 3 Latin square design. The measurements were performed at 6, 12 and 24 hours after supplementation. No difference in GDH activity was observed among treatments. The control treatment showed higher CMCase activity when compared with the treatments containing supplemental sources of nitrogen. However, urea supplementation provided higher CMCase activity compared to albumin.

  7. Active oxygen species and a degree of UV-modification of structural and functional properties of lactate dehydrogenase

    The spectrophotometry and photofluorescence techniques were used in the studies on photochemical transformations of lactate dehydrogenase exposed to UV-irradiation with a dose of 2.25 kJ/m2, in the native state and in the presence of exogenous modifiers: sodium azide, β-carotene, histidine, D-mannitol, and tret-butanol. It was shown that UV-irradiation of the mixtures of lactate dehydrogenase with sodium azide, β-carotene and histidine results in restoration (by 99, 65 and 63 %, respectively) of the level of catalytic activity of the enzyme as compared to that observed after irradiating in the absence of the protectors. The protective effect provided by mannitol during UV-irradiation of the lactate dehydrogenase was 23 %. Thus, it was shown that active oxygen species - singlet molecular oxygen and hydroxyl radical - make significant contributions to photomodification of lactate dehydrogenase. (author)

  8. Novel biohybrids of layered double hydroxide and lactate dehydrogenase enzyme: Synthesis, characterization and catalytic activity studies

    Djebbi, Mohamed Amine; Braiek, Mohamed; Hidouri, Slah; Namour, Philippe; Jaffrezic-Renault, Nicole; Ben Haj Amara, Abdesslem

    2016-02-01

    The present work introduces new biohybrid materials involving layered double hydroxides (LDH) and biomolecule such as enzyme to produce bioinorganic system. Lactate dehydrogenase (Lac Deh) has been chosen as a model enzyme, being immobilized onto MgAl and ZnAl LDH materials via direct ion-exchange (adsorption) and co-precipitation methods. The immobilization efficiency was largely dependent upon the immobilization methods. A comparative study shows that the co-precipitation method favors the immobilization of great and tunable amount of enzyme. The structural behavior, chemical bonding composition and morphology of the resulting biohybrids were determined by X-ray diffraction (XRD) study, Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM), respectively. The free and immobilized enzyme activity and kinetic parameters were also reported using UV-Visible spectroscopy. However, the modified LDH materials showed a decrease in crystallinity as compared to the unmodified LDH. The change in activity of the immobilized lactate dehydrogenase was considered to be due, to the reduced accessibility of substrate molecules to the active sites of the enzyme and the partial conformational change of the Lac Deh molecules as a result of the immobilization way. Finally, it was proven that there is a correlation between structure/microstructure and enzyme activity dependent on the immobilization process.

  9. Radiation-induced alterations in succinate dehydrogenase activity in the muscle of pigeon

    The histochemical changes in succinate dehydrogenase were investigated in pectoralis major muscle of pigeon exposed to sub-lethal dose (400 rad) of γ-irradiation. Biochemical study was also carried out after 200, 300 and 400 rad of irradiation. In the present study the overall decrease in enzyme activity could be due to the structural and/or functional damage to mitochondria after treatment of pigeon to different sub-lethal doses of γ-irradiation. The significance of these results has been discussed with special reference to oxidative metabolism. (author)

  10. Regulation of carbon monoxide dehydrogenase and hydrogenase in Rhodospirillum rubrum: Effects of CO and oxygen on synthesis and activity

    Exposure of the photosynthetic bacterium Rhodospirillum rubrum to carbon monoxide led to increased carbon monoxide dehydrogenase and hydrogenase activities due to de novo protein synthesis of both enzymes. Two-dimensional gels of [35S]methionine-pulse-labeled cells showed that induction of CO dehydrogenase synthesis was rapidly initiated (less than 5 min upon exposure to CO) and was inhibited by oxygen. Both CO dehydrogenase and the CO-induced hydrogenase were inactivated by oxygen in vivo and in vitro. In contrast to CO dehydrogenase, the CO-induced hydrogenase was 95% inactivated by heating at 70 degrees C for 5 min. Unlike other hydrogenases, this CO-induced hydrogenase was inhibited only 60% by a 100% CO gas phase

  11. Scanning mutagenesis of the amino acid sequences flanking phosphorylation site 1 of the mitochondrial pyruvate dehydrogenase complex

    Nagib eAhsan

    2012-07-01

    Full Text Available The mitochondrial pyruvate dehydrogenase complex is regulated by reversible seryl-phosphorylation of the E1α subunit by a dedicated, intrinsic kinase. The phospho-complex is reactivated when dephosphorylated by an intrinsic PP2C-type protein phosphatase. Both the position of the phosphorylated Ser-residue and the sequences of the flanking amino acids are highly conserved. We have used the synthetic peptide-based kinase client assay plus recombinant pyruvate dehydrogenase E1α and E1α-kinase to perform scanning mutagenesis of the residues flanking the site of phosphorylation. Consistent with the results from phylogenetic analysis of the flanking sequences, the direct peptide-based kinase assays tolerated very few changes. Even conservative changes such as Leu, Ile, or Val for Met, or Glu for Asp, gave very marked reductions in phosphorylation. Overall the results indicate that regulation of the mitochondrial pyruvate dehydrogenase complex by reversible phosphorylation is an extreme example of multiple, interdependent instances of co-evolution.

  12. Inhibitory effects of ofloxacin and cefepime on enzyme activity of 6-phosphogluconate dehydrogenase from chicken liver.

    Erat, Mustafa; Sakiroğlu, Halis

    2007-01-01

    In this study, effects of some antibiotics, namely, ofloxacin, cefepime, cefazolin, and ampicillin on the in vitro enzyme activity of 6-phosphogluconate dehydrogenase have been investigated. For this purpose, 6-phosphogluconate dehydrogenase was purified from chicken liver 535-fold with a yield of 18% by using ammonium sulphate precipitation, 2',5'-ADP Sepharose 4B affinity chromatography, and Sephadex G-200 gel filtration chromatography. In order to check the purity of the enzyme, SDS polyacylamide gel electrophoresis (SDS-PAGE) was performed. This analysis revealed a highly pure enzyme band on the gel. Among the antibiotics, ofloxacin and cefepime exhibited inhibitory effects, but cefazolin and ampicillin showed neither important inhibitory nor activatory effects on the enzyme activity. The measured I(50) values by plotting activity percent vs. inhibitor concentration, [I(50)] were 0.1713 mM for ofloxacin and 6.0028 mM for cefepime. Inhibition constants, K(i), for ofloxacin and cefepime were also calculated as 0.2740 +/- 0.1080 mM and 12.869 +/- 16.6540 mM by means of Lineweaver-Burk graphs, and inhibition types of the antibiotics were found out to be non-competitive and competitive, respectively. It has been understood from the calculated inhibitory parameters that the purified chicken enzyme has been quite inhibited by these two antimicrobials. PMID:17305608

  13. Comparative study of the activity of lactate dehydrogenase (LDH) in different forms of disease

    The activity of lactate dehydrogenase (LDH) was determined in the fluid gingival crevicular (FGC) from different sites of the anterior sector of the oral cavity in a clinically healthy subjects, and other with moderate gingivitis and with chronic severe generalized periodontists. Patients were treated and followed for three months, after the which has proceeded to make measurements of activity in the same sites discussed above. The results have showed statistically significant differences when comparing the activity of LDH in healthy individuals, and in other patients, treated by the pathology that presenting. On the other hand, were found without statistically significant differences between patients treated with clinically healthy subjects. The conclusion has been that the activity of LDH could be a quantitative marker for assessing cellular damage and evolution of treatment. (author)

  14. Cryopreservation of glucose-6-phosphate dehydrogenase activity inside red blood cells: developing a specimen repository in support of development and evaluation of glucose-6-phosphate dehydrogenase deficiency tests

    Kahn, Maria; LaRue, Nicole; Bansil, Pooja; Kalnoky, Michael; McGray, Sarah; Domingo, Gonzalo J

    2013-01-01

    Background Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common human enzyme deficiency. It is characterized by abnormally low levels of G6PD activity. Individuals with G6PD deficiency are at risk of undergoing acute haemolysis when exposed to 8‒aminoquinoline-based drugs, such as primaquine. For this reason it is imperative to identify individuals with G6PD deficiency prior to administering these anti-malarial drugs. There is a need for the development and evaluation of point-of-c...

  15. Cytoplasm-to-myonucleus ratios and succinate dehydrogenase activities in adult rat slow and fast muscle fibers

    Tseng, B. S.; Kasper, C. E.; Edgerton, V. R.

    1994-01-01

    The relationship between myonuclear number, cellular size, succinate dehydrogenase activity, and myosin type was examined in single fiber segments (n = 54; 9 +/- 3 mm long) mechanically dissected from soleus and plantaris muscles of adult rats. One end of each fiber segment was stained for DNA before quantitative photometric analysis of succinate dehydrogenase activity; the other end was double immunolabeled with fast and slow myosin heavy chain monoclonal antibodies. Mean +/- S.D. cytoplasmic volume/myonucleus ratio was higher in fast and slow plantaris fibers (112 +/- 69 vs. 34 +/- 21 x 10(3) microns3) than fast and slow soleus fibers (40 +/- 20 vs. 30 +/- 14 x 10(3) microns3), respectively. Slow fibers always had small volumes/myonucleus, regardless of fiber diameter, succinate dehydrogenase activity, or muscle of origin. In contrast, smaller diameter (fibers with high succinate dehydrogenase activity appeared to have low volumes/myonucleus while larger diameter (> 70 microns) fast fibers with low succinate dehydrogenase activity always had large volume/myonucleus. Slow soleus fibers had significantly greater numbers of myonuclei/mm than did either fast soleus or fast plantaris fibers (116 +/- 51 vs. 55 +/- 22 and 44 +/- 23), respectively. These data suggest that the myonuclear domain is more limited in slow than fast fibers and in the fibers with a high, compared to a low, oxidative metabolic capability.

  16. Characterization and evolution of an activator-independent methanol dehydrogenase from Cupriavidus necator N-1.

    Wu, Tung-Yun; Chen, Chang-Ting; Liu, Jessica Tse-Jin; Bogorad, Igor W; Damoiseaux, Robert; Liao, James C

    2016-06-01

    Methanol utilization by methylotrophic or non-methylotrophic organisms is the first step toward methanol bioconversion to higher carbon-chain chemicals. Methanol oxidation using NAD-dependent methanol dehydrogenase (Mdh) is of particular interest because it uses NAD(+) as the electron carrier. To our knowledge, only a limited number of NAD-dependent Mdhs have been reported. The most studied is the Bacillus methanolicus Mdh, which exhibits low enzyme specificity to methanol and is dependent on an endogenous activator protein (ACT). In this work, we characterized and engineered a group III NAD-dependent alcohol dehydrogenase (Mdh2) from Cupriavidus necator N-1 (previously designated as Ralstonia eutropha). This enzyme is the first NAD-dependent Mdh characterized from a Gram-negative, mesophilic, non-methylotrophic organism with a significant activity towards methanol. Interestingly, unlike previously reported Mdhs, Mdh2 does not require activation by known activators such as B. methanolicus ACT and Escherichia coli Nudix hydrolase NudF, or putative native C. necator activators in the Nudix family under mesophilic conditions. This enzyme exhibited higher or comparable activity and affinity toward methanol relative to the B. methanolicus Mdh with or without ACT in a wide range of temperatures. Furthermore, using directed molecular evolution, we engineered a variant (CT4-1) of Mdh2 that showed a 6-fold higher K cat/K m for methanol and 10-fold lower K cat/K m for n-butanol. Thus, CT4-1 represents an NAD-dependent Mdh with much improved catalytic efficiency and specificity toward methanol compared with the existing NAD-dependent Mdhs with or without ACT activation. PMID:26846745

  17. Glutathione metabolism and glucose 6-phosphate dehydrogenase activity in experimental liver injury.

    Watanabe,Akiharu

    1983-12-01

    Full Text Available Increased activities of liver glucose-6-phosphate dehydrogenase (G6PD, EC 1.1.1.49 and 6-phosphogluconate dehydrogenase (6PGD, EC 1.1.1.44 in the pentose phosphate cycle were accompanied with a depletion of reduced glutathione (GSH following an intragastric administration of carbon tetrachloride (CCl4 to rats. Oxidized glutathione (GSSG also decreased remarkably, keeping the GSSG: GSH ratio constant. No significant alteration of glutathione reductase (EC 1.6.4.2., glutathione peroxidase (EC 1.11.1.9 and malic enzyme (EC 1.1.1.40 activities in the supernatant and gamma-glutamyl transpeptidase (gamma-GTP, EC 2.3.2.2 activity in the homogenate of the injured liver were observed. Furthermore, no marked difference in the GSH-synthesizing activity was found between control and CCl4-intoxicated liver. An intraperitoneal injection of GSH produced a significant increase in liver GSH content in control rats but not in CCl4-treated rats; G6PD activity was not affected. Intraperitoneal injections of diethylmaleate resulted in continuously diminished levels of liver GSH without any alteration of liver G6PD activity. In vitro disappearance of GSH added to the liver homogenate from CCl4-treated rats occurred enzymatically and could not be prevented by the addition of a NADPH-generating system. The results suggest that increased G6PD activity in CCl4-injured liver does not play an important role in the maintenance of glutathione in the reduced form and that the decreased GSH content in the injured liver might be caused by enhanced GSH catabolism not due to gamma-GTP.

  18. Designing a highly active soluble PQQ-glucose dehydrogenase for efficient glucose biosensors and biofuel cells

    Research highlights: → A new mutant of PQQ-GDH designed for glucose biosensors application. → First mutant of PQQ-GDH with higher activity for D-glucose than the Wild type. → Position N428 is a key point to increase the enzyme activity. → Molecular modeling shows that the N428 C mutant displays a better interaction for PQQ than the WT. -- Abstract: We report for the first time a soluble PQQ-glucose dehydrogenase that is twice more active than the wild type for glucose oxidation and was obtained by combining site directed mutagenesis, modelling and steady-state kinetics. The observed enhancement is attributed to a better interaction between the cofactor and the enzyme leading to a better electron transfer. Electrochemical experiments also demonstrate the superiority of the new mutant for glucose oxidation and make it a promising enzyme for the development of high-performance glucose biosensors and biofuel cells.

  19. Substitution of valine for histidine 265 in carbon monoxide dehydrogenase from Rhodospirillum rubrum affects activity and spectroscopic states.

    Spangler, N J; Meyers, M R; Gierke, K L; Kerby, R L; Roberts, G P; Ludden, P W

    1998-02-13

    In carbon monoxide dehydrogenase (CODH) from Rhodospirillum rubrum, histidine 265 was replaced with valine by site-directed mutagenesis of the cooS gene. The altered form of CODH (H265V) had a low nickel content and a dramatically reduced level of catalytic activity. Although treatment with NiCl2 and CoCl2 increased the activity of H265V CODH by severalfold, activity levels remained more than 1000-fold lower than that of wild-type CODH. Histidine 265 was not essential for the formation and stability of the Fe4S4 clusters. The Km and KD for CO as well as the KD for cyanide were relatively unchanged as a result of the amino acid substitution in CODH. The time-dependent reduction of the [Fe4S4]2+ clusters by CO occurred on a time scale of hours, suggesting that, as a consequence of the mutation, a rate-limiting step had been introduced prior to the transfer of electrons from CO to the cubanes in centers B and C. EPR spectra of H265V CODH lacked the gav = 1.86 and gav = 1.87 signals characteristic of reduced forms of the active site (center C) of wild-type CODH. This indicates that the electronic properties of center C have been modified possibly by the disruption or alteration of the ligand-mediated interaction between the nickel site and Fe4S4 chromophore. PMID:9461598

  20. Effect of ionizing radiation on the colour and activity of lactate dehydrogenase of pork

    The most significant sensory and quality characteristic of meat is colour. The effect of irradiation of pork was studied in relation to color changes. Samples of M. longissimus lumborum et thoracic were obtained from the pork carcasses 24 h post mortem. Samples were irradiated using a 60Co source, at dose of 2.5 and 5 kGy; dose rate of 2.86 kGy/h. Unirradiated controls were stored in the same condition as irradiated samples. Measurement of colour was realised with portable spectrophotometer Superchroma S-Spex in CIELAB system. The colour of a freshly cut interior surface of control and irradiated pork was measured before and after irradiation. L* and b* values of controls and irradiated pork did not change after irradiation. The a* values (red colour) of irradiated pork were significantly higher than unirradiated. The activity of lactate dehydrogenase of pork was measured after irradiation. The activity did not change after irradiation. (authors)

  1. Lactate dehydrogenase-elevating virus induces systemic lymphocyte activation via TLR7-dependent IFNalpha responses by plasmacytoid dendritic cells.

    Christoph G Ammann

    Full Text Available BACKGROUND: Lactate dehydrogenase-elevating virus (LDV is a natural infectious agent of mice. Like several other viruses, LDV causes widespread and very rapid but transient activation of both B cells and T cells in lymphoid tissues and the blood. The mechanism of this activation has not been fully described and is the focus of the current studies. PRINCIPAL FINDINGS: A known inducer of early lymphocyte activation is IFNalpha, a cytokine strongly induced by LDV infection. Neutralization of IFNalpha in the plasma from infected mice ablated its ability to activate lymphocytes in vitro. Since the primary source of virus-induced IFNalpha in vivo is often plasmacytoid dendritic cells (pDC's, we depleted these cells prior to LDV infection and tested for lymphocyte activation. Depletion of pDC's in vivo eradicated both the LDV-induced IFNalpha response and lymphocyte activation. A primary receptor in pDC's for single stranded RNA viruses such as LDV is the toll-like receptor 7 (TLR7 pattern recognition receptor. Infection of TLR7-knockout mice revealed that both the IFNalpha response and lymphocyte activation were dependent on TLR7 signaling in vivo. Interestingly, virus levels in both TLR7 knockout mice and pDC-depleted mice were indistinguishable from controls indicating that LDV is largely resistant to the systemic IFNalpha response. CONCLUSION: Results indicate that LDV-induced activation of lymphocytes is due to recognition of LDV nucleic acid by TLR7 pattern recognition receptors in pDC's that respond with a lymphocyte-inducing IFNalpha response.

  2. MFE1, a Member of the Peroxisomal Hydroxyacyl Coenzyme A Dehydrogenase Family, Affects Fatty Acid Metabolism Necessary for Morphogenesis in Dictyostelium spp.

    Matsuoka, Satomi; Saito, Tamao; Kuwayama, Hidekazu; Morita, Naoki; Ochiai, Hiroshi; Maeda, Mineko

    2003-01-01

    β-Oxidation of long-chain fatty acids and branched-chain fatty acids is carried out in mammalian peroxisomes by a multifunctional enzyme (MFE) or d-bifunctional protein, with separate domains for hydroxyacyl coenzyme A (CoA) dehydrogenase, enoyl-CoA hydratase, and steroid carrier protein SCP2. We have found that Dictyostelium has a gene, mfeA, encoding MFE1 with homology to the hydroxyacyl-CoA dehydrogenase and SCP2 domains. A separate gene, mfeB, encodes MFE2 with homology to the enoyl-CoA h...

  3. The effect of ionizing radiation on the colour and the activity of lactate dehydrogenase in pork

    The effect of the irradiation of pork was studied in relation to colour changes. Samples of m. longissimus lumborum et thoracis were obtained from pork carcasses 24 hours post mortem. Samples were irradiated using a 6OCo source, at a dose of 2.5 and 5 kGy; a dose rate of 2.86 kGy·h-1. Non-irradiated controls were stored in the same condition as irradiated samples. The colour of a freshly cut interior surface of control and irradiated pork was measured (portable spectrophotometer Superchroma S-Spex in CIELAB system) before and after irradiation. L* and b* values of controls and irradiated pork did not change after irradiation. The a* values (red colour) of irradiated pork were significantly higher than non-irradiated pork. The activity of lactate dehydrogenase of pork was measured and did not change after irradiation (authors)

  4. A new bianthron glycoside as inhibitor of Trypanosoma cruzi glyceraldehyde 3-phosphate dehydrogenase activity

    A phytochemical investigation of the ethanolic extract of stalks of Senna martiana Benth. (Leguminoseae), native specie of northeast Brazil, resulted in the isolation and spectroscopic characterization of a new bianthrone glycoside, martianine 1 (10,10'-il-chrysophanol-10-oxi- 10,10'-bi-glucosyl). Its identification was established by HRMS, IR and 2D NMR experiments. The evaluation of martianine trypanocidal activity was carried out against gliceraldehyde 3-phosphate dehydrogenase enzyme from Trypanosoma cruzi. Its inhibitory constant (Ki) is in the low micromolar concentration and it was determined by isothermal titration calorimetry to be 27.3 +-2.47 μmol L-1. The non-competitive mechanism is asserted to be putative of the mode of action martianine displays against T. cruzi GAPDH. Results show that martianine has a great potential to become new lead molecule by inhibiting this key enzyme and for the development of new drugs against Chagas disease. (author)

  5. Effect of various chemicals on the aldehyde dehydrogenase activity of the rat liver cytosol.

    Marselos, M; Vasiliou, V

    1991-01-01

    The cytosolic activity of aldehyde dehydrogenase (ALDH) was studied in the rat liver, after acute administration of various carcinogenic and chemically related compounds. Male Wistar rats were treated with 27 different chemicals, including polycyclic aromatic hydrocarbons, aromatic amines, nitrosamines, azo dyes, as well as with some known direct-acting carcinogens. The cytosolic ALDH activity of the liver was determined either with propionaldehyde and NAD (P/NAD), or with benzaldehyde and NADP (B/NADP). The activity of ALDH remained unaffected after treatment with 1-naphthylamine, nitrosamines and also with the direct-acting chemical carcinogens tested. On the contrary, polycyclic aromatic hydrocarbons, polychlorinated biphenyls (Arochlor 1254) and 2-naphthylamine produced a remarkable increase of ALDH. In general, the response to the effectors was disproportionate between the two types of enzyme activity, being much in favour for the B/NADP activity. This fact resulted to an inversion of the ratio B/NADP vs. P/NAD, which under constitutive conditions is lower than 1. In this respect, the most potent compounds were found to be polychlorinated biphenyls, 3-methylcholanthrene, benzo(a)pyrene and 1,2,5,6-dibenzoanthracene. Our results suggest that the B/NADP activity of the soluble ALDH is greatly induced after treatment with compounds possessing aromatic ring(s) in their molecule. It is not known, if this response of the hepatocytes is related with the process of chemical carcinogenesis. PMID:2060039

  6. Vitality Improvement of the Mediterranean Fruit Fly, Ceratitis capitata Wied 1- Measured by using dehydrogenase Enzyme Activities

    The present study searches for the improvement vitality of the Mediterranean fruit fly, Ceratitis capitata Wied. Through the induction of a specific variance (mutation) in the genetic material. Several types of treatments that were thought to cause this mutation were used, as IGR's, temperature, formaldehyde, colchicine, alcohols, several types of larval rearing media and gamma-rays. Generally, the activities of the energy enzymes alpha-glycerophosphate dehydrogenase (alpha-GPDH) enzyme lactate dehydrogenase (LDH) enzyme and malate dehydrogenase (MDH) enzyme, when used as a direct measure for the fly vitality, increased due to treatments of the egg stage by the previously mentioned treatments specially by the usage of rice hulls in the larval rearing medium alone or followed by irradiation of the pupal stage with 90 Gy

  7. Influence of spaceflight on succinate dehydrogenase activity and soma size of rat ventral horn neurons

    Ishihara, A.; Ohira, Y.; Roy, R. R.; Nagaoka, S.; Sekiguchi, C.; Hinds, W. E.; Edgerton, V. R.

    1996-01-01

    Succinate dehydrogenase (SDH) activities and soma cross-sectional areas (CSA) of neurons in the dorsolateral region of the ventral horn at the L5 segmental level of the spinal cord in the rat were determined after 14 days of spaceflight and after 9 days of recovery on earth. The results were compared to those in age-matched ground-based control rats. Spinal cords were quick-frozen, and the SDH activity and CSA of a sample of neurons with a visible nucleus were determined using a digitizer and a computer-assisted image analysis system. An inverse relationship between CSA and SDH activity of neurons was observed in all groups of rats. No change in mean CSA or mean SDH activity or in the size distribution of neurons was observed following spaceflight or recovery. However, there was a selective decrease in the SDH activity of neurons with soma CSA between 500 and 800 microns2 in the flight rats, and this effect persisted for at least 9 days following return to 1 g. It remains to be determined whether the selected population of motoneurons or the specific motor pools affected by spaceflight may be restricted to specific muscles.

  8. In Vitro and In Vivo Effects and Safety Assessment of Corn Peptides on Alcohol Dehydrogenase Activities

    LI Hong-mei; WEN Lian-kui; LI Shi-jun; ZHANG Da-li; LIN Bai-song

    2011-01-01

    The in vitro and in vivo effects of corn peptides(CPs) prepared from corn gluten meal by proteolysis with an alkaline protease and fractions of CPs from Sephadex G-15 and G-10 columns on activities of alcohol dehydrogenase(ADH) were studied.The results show that CPs and fraction 3 of CPs from Sephadex G-10 column enhance in vitro ADH activity.Furthermore,the in vitro accelerating effect of the fraction 3 of CPs on ADH activity was superior to that of glutathione,which was also found even in the presence of ADH inhibitor,such as pyrazole.In the in vivo experiments,the animals were fed with different dosages of CPs and with a dose of Chinese distilled spirit orally,and sacrificed for the measurement of ADH activity.In vivo experimental results indicate that CPS enhanced hepatic ADH activities.To test the safety of CPs as health food,30 d feeding test was performed.No obvious toxic effects were detected in treated Wistar rats.

  9. Gastric alcohol dehydrogenase activity in man: influence of gender, age, alcohol consumption and smoking in a caucasian population

    Parlesak, Alexandr; Billinger, M. H.; Bode, C.;

    2002-01-01

    AIMS: The stomach is involved in first-pass metabolism of alcohol in humans. As conflicting data were published regarding the influence of age and gender on the activity of alcohol dehydrogenase (ADH) in human gastric mucosa, the present study aimed at the investigation of these and other potenti...

  10. Changes in microbial biomass and dehydrogenase activity following organic and inorganic tratments of a trace element contaminated in soil

    Pérez de Mora, Alfredo A; Cabrera, Francisco; Ortega Calvo, J. J.; Madejón, Engracia

    2003-01-01

    The aim of this research was to study the effect of different amendments and a plant cover on the remediation of a trace element contaminated soil through three microbiological paramaters: dehydrogenase activity (DH), microbial biomass carbon (MBC) and substrate induced respiration (SIR).

  11. Efficient synthesis of D-branched-chain amino acids and their labeled compounds with stable isotopes using D-amino acid dehydrogenase.

    Akita, Hironaga; Suzuki, Hirokazu; Doi, Katsumi; Ohshima, Toshihisa

    2014-02-01

    D-Branched-chain amino acids (D-BCAAs) such as D-leucine, D-isoleucine, and D-valine are known to be peptide antibiotic intermediates and to exhibit a variety of bioactivities. Consequently, much effort is going into achieving simple stereospecific synthesis of D-BCAAs, especially analogs labeled with stable isotopes. Up to now, however, no effective method has been reported. Here, we report the establishment of an efficient system for enantioselective synthesis of D-BCAAs and production of D-BCAAs labeled with stable isotopes. This system is based on two thermostable enzymes: D-amino acid dehydrogenase, catalyzing NADPH-dependent enantioselective amination of 2-oxo acids to produce the corresponding D-amino acids, and glucose dehydrogenase, catalyzing NADPH regeneration from NADP(+) and D-glucose. After incubation with the enzymes for 2 h at 65°C and pH 10.5, 2-oxo-4-methylvaleric acid was converted to D-leucine with an excellent yield (>99 %) and optical purity (>99 %). Using this system, we produced five different D-BCAAs labeled with stable isotopes: D-[1-(13)C,(15)N]leucine, D-[1-(13)C]leucine, D-[(15)N]leucine, D-[(15)N]isoleucine, and D-[(15)N]valine. The structure of each labeled D-amino acid was confirmed using time-of-flight mass spectrometry and nuclear magnetic resonance analysis. These analyses confirmed that the developed system was highly useful for production of D-BCAAs labeled with stable isotopes, making this the first reported enzymatic production of D-BCAAs labeled with stable isotopes. Our findings facilitate tracer studies investigating D-BCAAs and their derivatives. PMID:23661083

  12. Periplasmic nitrate reductase and formate dehydrogenase: similar molecular architectures with very different enzymatic activities.

    Cerqueira, Nuno M F S A; Gonzalez, Pablo J; Fernandes, Pedro A; Moura, José J G; Ramos, Maria João

    2015-11-17

    It is remarkable how nature has been able to construct enzymes that, despite sharing many similarities, have simple but key differences that tune them for completely different functions in living cells. Periplasmic nitrate reductase (Nap) and formate dehydrogenase (Fdh) from the DMSOr family are representative examples of this. Both enzymes share almost identical three-dimensional protein foldings and active sites, in terms of coordination number, geometry and nature of the ligands. The substrates of both enzymes (nitrate and formate) are polyatomic anions that also share similar charge and stereochemistry. In terms of the catalytic mechanism, both enzymes have a common activation mechanism (the sulfur-shift mechanism) that ensures a constant coordination number around the metal ion during the catalytic cycle. In spite of these similarities, they catalyze very different reactions: Nap abstracts an oxygen atom from nitrate releasing nitrite, whereas FdH catalyzes a hydrogen atom transfer from formate and releases carbon dioxide. In this Account, a critical analysis of structure, function, and catalytic mechanism of the molybdenum enzymes periplasmic nitrate reductase (Nap) and formate dehydrogenase (Fdh) is presented. We conclude that the main structural driving force that dictates the type of reaction, catalyzed by each enzyme, is a key difference on one active site residue that is located in the top region of the active sites of both enzymes. In both enzymes, the active site is centered on the metal ion of the cofactor (Mo in Nap and Mo or W in Fdh) that is coordinated by four sulfur atoms from two pyranopterin guanosine dinucleotide (PGD) molecules and by a sulfido. However, while in Nap there is a Cys directly coordinated to the Mo ion, in FdH there is a SeCys instead. In Fdh there is also an important His that interacts very closely with the SeCys, whereas in Nap the same position is occupied by a Met. The role of Cys in Nap and SeCys in FdH is similar in both

  13. The Spatial Variability of Soil Dehydrogenase Activity: A Survey in Urban Soils

    Ridvan Kizilkaya

    2007-03-01

    Full Text Available Information on soil microorganisms and their activity used to determine microbiological characteristics are very important for soil quality and productivity. Studies of enzyme activities provide information on the biochemical processes occurring in soil. There is growing evidence that soil biological parameters may be potential and sensitive indicators of soil ecological conditions and soil management. Soil microbiological parameters may be evaluated statistically due to application of geostatistical methods to soil science. Measurement of soil dehydrogenase activity (DHA has been used to establish indices of soil microbiological activity. The objective of this study was to assess the spatial variability of the DHA using the geostatistics in the topsoils of an urban area. DHA along a transect in an urban area was determined using 39 soil samples from the upper 20 cm of soil varied from 10.7-258.4 μg TPF g-1 soil respectively. The spherical model fits the best semivariogram model for DHA and exhibited spatial dependence with range of influence of approximately 48.2 km.

  14. Adenine nucleotide-dependent and redox-independent control of mitochondrial malate dehydrogenase activity in Arabidopsis thaliana.

    Yoshida, Keisuke; Hisabori, Toru

    2016-06-01

    Mitochondrial metabolism is important for sustaining cellular growth and maintenance; however, the regulatory mechanisms underlying individual processes in plant mitochondria remain largely uncharacterized. Previous redox-proteomics studies have suggested that mitochondrial malate dehydrogenase (mMDH), a key enzyme in the tricarboxylic acid (TCA) cycle and redox shuttling, is under thiol-based redox regulation as a target candidate of thioredoxin (Trx). In addition, the adenine nucleotide status may be another factor controlling mitochondrial metabolism, as respiratory ATP production in mitochondria is believed to be influenced by several environmental stimuli. Using biochemical and reverse-genetic approaches, we addressed the redox- and adenine nucleotide-dependent regulation of mMDH in Arabidopsis thaliana. Recombinant mMDH protein formed intramolecular disulfide bonds under oxidative conditions, but these bonds did not have a considerable effect on mMDH activity. Mitochondria-localized o-type Trx (Trx-o) did not facilitate re-reduction of oxidized mMDH. Determination of the in vivo redox state revealed that mMDH was stably present in the reduced form even in Trx-o-deficient plants. Accordingly, we concluded that mMDH is not in the class of redox-regulated enzymes. By contrast, mMDH activity was lowered by adenine nucleotides (AMP, ADP, and ATP). Each adenine nucleotide suppressed mMDH activity with different potencies and ATP exerted the largest inhibitory effect with a significantly lower Ki. Correspondingly, mMDH activity was inhibited by the increase in ATP/ADP ratio within the physiological range. These results suggest that mMDH activity is finely controlled in response to variations in mitochondrial adenine nucleotide balance. PMID:26946085

  15. Green Tea Polyphenols Control Dysregulated Glutamate Dehydrogenase in Transgenic Mice by Hijacking the ADP Activation Site

    Li, Changhong; Li, Ming; Chen, Pan; Narayan, Srinivas; Matschinsky, Franz M.; Bennett, Michael J.; Stanley, Charles A.; Smith, Thomas J. (CH-PA); (UPENN); (Danforth)

    2012-05-09

    Glutamate dehydrogenase (GDH) catalyzes the oxidative deamination of L-glutamate and, in animals, is extensively regulated by a number of metabolites. Gain of function mutations in GDH that abrogate GTP inhibition cause the hyperinsulinism/hyperammonemia syndrome (HHS), resulting in increased pancreatic {beta}-cell responsiveness to leucine and susceptibility to hypoglycemia following high protein meals. We have previously shown that two of the polyphenols from green tea (epigallocatechin gallate (EGCG) and epicatechin gallate (ECG)) inhibit GDH in vitro and that EGCG blocks GDH-mediated insulin secretion in wild type rat islets. Using structural and site-directed mutagenesis studies, we demonstrate that ECG binds to the same site as the allosteric regulator, ADP. Perifusion assays using pancreatic islets from transgenic mice expressing a human HHS form of GDH demonstrate that the hyperresponse to glutamine caused by dysregulated GDH is blocked by the addition of EGCG. As observed in HHS patients, these transgenic mice are hypersensitive to amino acid feeding, and this is abrogated by oral administration of EGCG prior to challenge. Finally, the low basal blood glucose level in the HHS mouse model is improved upon chronic administration of EGCG. These results suggest that this common natural product or some derivative thereof may prove useful in controlling this genetic disorder. Of broader clinical implication is that other groups have shown that restriction of glutamine catabolism via these GDH inhibitors can be useful in treating various tumors. This HHS transgenic mouse model offers a highly useful means to test these agents in vivo.

  16. Alcohol dehydrogenase gene ADH3 activates glucose alcoholic fermentation in genetically engineered Dekkera bruxellensis yeast.

    Schifferdecker, Anna Judith; Siurkus, Juozas; Andersen, Mikael Rørdam; Joerck-Ramberg, Dorte; Ling, Zhihao; Zhou, Nerve; Blevins, James E; Sibirny, Andriy A; Piškur, Jure; Ishchuk, Olena P

    2016-04-01

    Dekkera bruxellensis is a non-conventional Crabtree-positive yeast with a good ethanol production capability. Compared to Saccharomyces cerevisiae, its tolerance to acidic pH and its utilization of alternative carbon sources make it a promising organism for producing biofuel. In this study, we developed an auxotrophic transformation system and an expression vector, which enabled the manipulation of D. bruxellensis, thereby improving its fermentative performance. Its gene ADH3, coding for alcohol dehydrogenase, was cloned and overexpressed under the control of the strong and constitutive promoter TEF1. Our recombinant D. bruxellensis strain displayed 1.4 and 1.7 times faster specific glucose consumption rate during aerobic and anaerobic glucose fermentations, respectively; it yielded 1.2 times and 1.5 times more ethanol than did the parental strain under aerobic and anaerobic conditions, respectively. The overexpression of ADH3 in D. bruxellensis also reduced the inhibition of fermentation by anaerobiosis, the "Custer effect". Thus, the fermentative capacity of D. bruxellensis could be further improved by metabolic engineering. PMID:26743658

  17. Novel Inhibitors of Plasmodium falciparum Dihydroorotate Dehydrogenase with Anti-malarial Activity in the Mouse Model

    Booker, Michael L.; Bastos, Cecilia M.; Kramer, Martin L.; Barker, Jr., Robert H.; Skerlj, Renato; Sidhu, Amar Bir; Deng, Xiaoyi; Celatka, Cassandra; Cortese, Joseph F.; Guerrero Bravo, Jose E.; Crespo Llado, Keila N.; Serrano, Adelfa E.; Angulo-Barturen, Iñigo; Jiménez-Díaz, María Belén; Viera, Sara; Garuti, Helen; Wittlin, Sergio; Papastogiannidis, Petros; Lin, Jing-wen; Janse, Chris J.; Khan, Shahid M.; Duraisingh, Manoj; Coleman, Bradley; Goldsmith, Elizabeth J.; Phillips, Margaret A.; Munoz, Benito; Wirth, Dyann F.; Klinger, Jeffrey D.; Wiegand, Roger; Sybertz, Edmund (Leiden-MC); (Puerto Rico); (STPHI); (Harvard); (GSK); (Genzyme); (UTSMC)

    2010-11-22

    Plasmodium falciparum, the causative agent of the most deadly form of human malaria, is unable to salvage pyrimidines and must rely on de novo biosynthesis for survival. Dihydroorotate dehydrogenase (DHODH) catalyzes the rate-limiting step in the pyrimidine biosynthetic pathway and represents a potential target for anti-malarial therapy. A high throughput screen and subsequent medicinal chemistry program identified a series of N-alkyl-5-(1H-benzimidazol-1-yl)thiophene-2-carboxamides with low nanomolar in vitro potency against DHODH from P. falciparum, P. vivax, and P. berghei. The compounds were selective for the parasite enzymes over human DHODH, and x-ray structural data on the analog Genz-667348, demonstrated that species selectivity could be attributed to amino acid differences in the inhibitor-binding site. Compounds from this series demonstrated in vitro potency against the 3D7 and Dd2 strains of P. falciparum, good tolerability and oral exposure in the mouse, and ED{sub 50} values in the 4-day murine P. berghei efficacy model of 13-21 mg/kg/day with oral twice-daily dosing. In particular, treatment with Genz-667348 at 100 mg/kg/day resulted in sterile cure. Two recent analogs of Genz-667348 are currently undergoing pilot toxicity testing to determine suitability as clinical development candidates.

  18. 2-ketogluconic acid secretion by incorporation of Pseudomonas putida KT 2440 gluconate dehydrogenase (gad) operon in Enterobacter asburiae PSI3 improves mineral phosphate solubilization.

    Kumar, Chanchal; Yadav, Kavita; Archana, G; Naresh Kumar, G

    2013-09-01

    Enterobacter asburiae PSI3 is known to efficiently solubilize rock phosphate by secretion of approximately 50 mM gluconic acid in Tris-buffered medium in the presence of 75 mM glucose and in a mixture of seven aldosugars each at 15 mM concentration, mimicking alkaline vertisol soils. Efficacy of this bacterium in the rhizosphere requires P release in the presence of low amount of sugars. To achieve this, E. asburiae PSI3 has been manipulated to express gluconate dehydrogenase (gad) operon of Pseudomonas putida KT 2440 to produce 2-ketogluconic acid. E. asburiae PSI3 harboring gad operon had 438 U of GAD activity, secreted 11.63 mM 2-ketogluconic and 21.65 mM gluconic acids in Tris-rock phosphate-buffered medium containing 45 mM glucose. E. asburiae PSI3 gad transformant solubilized 0.84 mM P from rock phosphate in TRP-buffered liquid medium. In the presence of a mixture of seven sugars each at 12 mM, the transformant brought about a drop in pH to 4.1 and released 0.53 mM P. PMID:23666029

  19. Myricetin is a novel inhibitor of human inosine 5'-monophosphate dehydrogenase with anti-leukemia activity.

    Pan, Huiling; Hu, Qian; Wang, Jingyuan; Liu, Zehui; Wu, Dang; Lu, Weiqiang; Huang, Jin

    2016-09-01

    Human inosine 5'-monophosphate dehydrogenase (hIMPDH) is a rate-limiting enzyme in the de novo biosynthetic pathway of purine nucleotides, playing crucial roles in cellular proliferation, differentiation, and transformation. Dysregulation of hIMPDH expression and activity have been found in a variety of human cancers including leukemia. In this study, we found that myricetin, a naturally occurring phytochemical existed in berries, wine and tea, was a novel inhibitor of human type 1 and type 2 IMPDH (hIMPDH1/2) with IC50 values of 6.98 ± 0.22 μM and 4.10 ± 0.14 μM, respectively. Enzyme kinetic analysis using Lineweaver-Burk plot revealed that myricetin is a mix-type inhibitor for hIMPDH1/2. Differential scanning fluorimetry and molecular docking simulation data demonstrate that myricetin is capable of binding with hIMPDH1/2. Myricetin treatment exerts potent anti-proliferative and pro-apoptotic effects on K562 human leukemia cells in a dose-dependent manner. Importantly, cytotoxicity of myricetin on K562 cells were markedly attenuated by exogenous addition of guanosine, a salvage pathway of maintaining intracellular pool of guanine nucleotides. Taking together, these results indicate that natural product myricetin exhibits potent anti-leukemia activity by interfering with purine nucleotides biosynthetic pathway through the suppression of hIMPDH1/2 catalytic activity. PMID:27378425

  20. Oligosaccharide-based Surfactant/Citric Acid Buffer System Stabilizes Lactate Dehydrogenase during Freeze-drying and Storage without the Addition of Natural Sugar.

    Ogawa, Shigesaburo; Kawai, Ryuichiro; Koga, Maito; Asakura, Kouichi; Takahashi, Isao; Osanai, Shuichi

    2016-06-01

    Experiments were conducted to assess the maintenance effects of oligosaccharide-based surfactants on the enzymatic activity of a model protein, lactate dehydrogenase (LDH), during freeze-drying and room temperature storage using the citric acid buffer system. Oligosaccharide-based surfactants, which exhibit a high glass transition temperature (Tg), promoted the eminent retention of enzymatic activity during these protocols, whereas monosaccharide-based surfactants with a low Tg displayed poor performance at high concentration, albeit much better than that of Tween 80 at middle concentration. The increase in the alkyl chain length did not exert positive effects as observed for the maintenance effect during freeze-thawing, but an amphiphilic nature and a glass forming ability were crucial for the effective stabilization at a low excipient concentration during freeze-drying. Even a low oligosaccharide-based surfactant content (0.1 mg mL(-1)) could maintain LDH activity during freeze-drying, but a high surfactant content (1.0 mg mL(-1)) was required to prevent buffer precipitation and retain high LDH activity on storage. Regarding storage, glass formation restricted molecular mobility in the lyophilized matrix, and LDH activity was effectively retained. The present results describe a strategy based on the glass-forming ability of surfactant-type excipients that affords a natural sugar-free formulation or an alternative use for polysorbate-type surfactants. PMID:27181251

  1. Characterization of 10-hydroxygeraniol dehydrogenase from Catharanthus roseus reveals cascaded enzymatic activity in iridoid biosynthesis.

    Krithika, Ramakrishnan; Srivastava, Prabhakar Lal; Rani, Bajaj; Kolet, Swati P; Chopade, Manojkumar; Soniya, Mantri; Thulasiram, Hirekodathakallu V

    2015-01-01

    Catharanthus roseus [L.] is a major source of the monoterpene indole alkaloids (MIAs), which are of significant interest due to their therapeutic value. These molecules are formed through an intermediate, cis-trans-nepetalactol, a cyclized product of 10-oxogeranial. One of the key enzymes involved in the biosynthesis of MIAs is an NAD(P)(+) dependent oxidoreductase system, 10-hydroxygeraniol dehydrogenase (Cr10HGO), which catalyses the formation of 10-oxogeranial from 10-hydroxygeraniol via 10-oxogeraniol or 10-hydroxygeranial. This work describes the cloning and functional characterization of Cr10HGO from C. roseus and its role in the iridoid biosynthesis. Substrate specificity studies indicated that, Cr10HGO has good activity on substrates such as 10-hydroxygeraniol, 10-oxogeraniol or 10-hydroxygeranial over monohydroxy linear terpene derivatives. Further it was observed that incubation of 10-hydroxygeraniol with Cr10HGO and iridoid synthase (CrIDS) in the presence of NADP(+) yielded a major metabolite, which was characterized as (1R, 4aS, 7S, 7aR)-nepetalactol by comparing its retention time, mass fragmentation pattern, and co-injection studies with that of the synthesized compound. These results indicate that there is concerted activity of Cr10HGO with iridoid synthase in the formation of (1R, 4aS, 7S, 7aR)-nepetalactol, an important intermediate in iridoid biosynthesis. PMID:25651761

  2. Ethanol production by anaerobic thermophilic bacteria: regulation of lactate dehydrogenase activity in Clostridium thermohydrosulfuricum

    Germain, P.; Toukourou, F.; Donaduzzi, L.

    1986-07-01

    The enzyme lactate dehydrogenase (LDH) in Clostridium thermohydrosulfuricum is controlled by the type and the concentration of the substrate. In batch fermentations an increase of the initial concentration of glucose leads to an increase in the activity of LDH. This increase in activity is related to the accumulation of fructose 1,6-diphosphate (F 1,6-DP), an intermediate of the Embden-Meyerhof-Parnas (EMP) pathway, which stimulates the enzyme by increasing its affinity for pyruvate and NADH. The Ksub(m) values of LDH for pyruvate and NADH, which are 2.5 x 10/sup -3/ M and 9.1 x 10/sup -5/ M respectively in absence of F 1,6-DP, fall considerably in the presence of this substrate. In presence of 0.2 mM of F 1,6-DP we observed a Ksub(m) of 3.3 x 10/sup -4/ M for pyruvate and 4.1 x 10/sup -5/ M for NADH.

  3. Hypoxic repression of pyruvate dehydrogenase activity is necessary for metabolic reprogramming and growth of model tumours

    Golias, Tereza; Papandreou, Ioanna; Sun, Ramon; Kumar, Bhavna; Brown, Nicole V.; Swanson, Benjamin J.; Pai, Reetesh; Jaitin, Diego; Le, Quynh-Thu; Teknos, Theodoros N.; Denko, Nicholas C.

    2016-01-01

    Tumour cells fulfil the bioenergetic and biosynthetic needs of proliferation using the available environmental metabolites. Metabolic adaptation to hypoxia causes decreased mitochondrial function and increased lactate production. This work examines the biological importance of the hypoxia-inducible inhibitory phosphorylations on the pyruvate dehydrogenase E1α subunit. Pancreatic cancer cell lines were genetically manipulated to alter the net phosphorylation of PDH E1α through reduced kinase expression or enhanced phosphatase expression. The modified cells were tested for hypoxic changes in phosphorylated E1α, mitochondrial metabolism and growth as xenografted tumours. Even though there are four PDHK genes, PDHK1 is essential for inhibitory PDH phosphorylation of E1α at serine 232, is partially responsible for modification of serines 293 and 300, and these phosphorylations are necessary for model tumour growth. In order to determine the clinical relevance, a cohort of head and neck cancer patient biopsies was examined for phosphorylated E1α and expression of PDHK1. Patients with detectable 232 phosphorylation or expression of PDHK1 tend to have worse clinical outcome. These data show that PDHK1 activity is unique and non-redundant in the family of PHDK enzymes and a PDHK1 specific inhibitor would therefore have anti-cancer activity with reduced chance of side effects from inhibition of other PDHKs. PMID:27498883

  4. Expression of Mitochondrial Branched-Chain Aminotransferase and α-Keto-Acid Dehydrogenase in Rat Brain: Implications for Neurotransmitter Metabolism

    Jeffrey Thomas Cole

    2012-05-01

    Full Text Available In the brain, metabolism of the essential branched chain amino acids (BCAAs leucine, isoleucine and valine, is regulated in part by protein synthesis requirements. Excess BCAAs are catabolized or excreted. The first step in BCAA catabolism is catalyzed by the branched chain aminotransferase (BCAT isozymes, mitochondrial BCATm and cytosolic BCATc. A product of this reaction, glutamate, is the major excitatory neurotransmitter and precursor of the major inhibitory neurotransmitter -aminobutyric acid (GABA. The BCATs are thought to participate in an α-keto-acid nitrogen shuttle that provides nitrogen for synthesis of glutamate from -ketoglutarate. The branched-chain α-keto acid dehydrogenase enzyme complex (BCKDC catalyzes the second and first irreversible step in BCAA metabolism, which is oxidative decarboxylation of the branched-chain α-keto acid (BCKA products of the BCAT reaction. Maple Syrup Urine Disease (MSUD results from genetic defects in BCKDC, which leads to accumulation of toxic levels of BCAAs and BCKAs that result in brain swelling. Immunolocalization of BCATm and BCKDC in rats revealed that BCATm is present in astrocytes in white matter and in neuropil, while BCKDC is expressed only in neurons. BCATm appears uniformly distributed in astrocyte cell bodies throughout the brain. The segregation of BCATm to astrocytes and BCKDC to neurons provides further support for the existence of a BCAA-dependent glial-neuronal nitrogen shuttle since the data show that BCKAs produced by glial BCATm must be exported to neurons. Additionally, the neuronal localization of BCKDC suggests that MSUD is a neuronal defect involving insufficient oxidation of BCKAs, with secondary effects extending beyond the neuron.

  5. Phosphorylation site on yeast pyruvate dehydrogenase complex

    The pyruvate dehydrogenase complex was purified to homogeneity from baker's yeast (Saccharomyces cerevisiae). Yeast cells were disrupted in a Manton-Gaulin laboratory homogenizer. The pyruvate dehydrogenase complex was purified by fractionation with polyethylene glycol, isoelectric precipitation, ultracentrifugation and chromatography on hydroxylapatite. Final purification of the yeast pyruvate dehydrogenase complex was achieved by cation-exchange high pressure liquid chromatography (HPLC). No endogenous pyruvate dehydrogenase kinase activity was detected during the purification. However, the yeast pyruvate dehydrogenase complex was phosphorylated and inactivated with purified pyruvate dehydrogenase kinase from bovine kidney. Tryptic digestion of the 32P-labeled complex yielded a single phosphopeptide which was purified to homogeniety. The tryptic digest was subjected to chromatography on a C-18 reverse phase HPLC column with a linear gradient of acetonitrile. Radioactive fractions were pooled, concentrated, and subjected to anion-exchange HPLC. The column was developed with a linear gradient of ammonium acetate. Final purification of the phosphopeptide was achieved by chromatography on a C-18 reverse phase HPLC column developed with a linear gradient of acetonitrile. The amino acid sequence of the homogeneous peptide was determined by manual modified Edman degradation

  6. Reduced mitochondrial malate dehydrogenase activity has a strong effect on photorespiratory metabolism as revealed by 13C labelling.

    Lindén, Pernilla; Keech, Olivier; Stenlund, Hans; Gardeström, Per; Moritz, Thomas

    2016-05-01

    Mitochondrial malate dehydrogenase (mMDH) catalyses the interconversion of malate and oxaloacetate (OAA) in the tricarboxylic acid (TCA) cycle. Its activity is important for redox control of the mitochondrial matrix, through which it may participate in regulation of TCA cycle turnover. In Arabidopsis, there are two isoforms of mMDH. Here, we investigated to which extent the lack of the major isoform, mMDH1 accounting for about 60% of the activity, affected leaf metabolism. In air, rosettes of mmdh1 plants were only slightly smaller than wild type plants although the fresh weight was decreased by about 50%. In low CO2 the difference was much bigger, with mutant plants accumulating only 14% of fresh weight as compared to wild type. To investigate the metabolic background to the differences in growth, we developed a (13)CO2 labelling method, using a custom-built chamber that enabled simultaneous treatment of sets of plants under controlled conditions. The metabolic profiles were analysed by gas- and liquid- chromatography coupled to mass spectrometry to investigate the metabolic adjustments between wild type and mmdh1 The genotypes responded similarly to high CO2 treatment both with respect to metabolite pools and (13)C incorporation during a 2-h treatment. However, under low CO2 several metabolites differed between the two genotypes and, interestingly most of these were closely associated with photorespiration. We found that while the glycine/serine ratio increased, a concomitant altered glutamine/glutamate/α-ketoglutarate relation occurred. Taken together, our results indicate that adequate mMDH activity is essential to shuttle reductants out from the mitochondria to support the photorespiratory flux, and strengthen the idea that photorespiration is tightly intertwined with peripheral metabolic reactions. PMID:26889011

  7. The Molybdenum Active Site of Formate Dehydrogenase Is Capable of Catalyzing C-H Bond Cleavage and Oxygen Atom Transfer Reactions.

    Hartmann, Tobias; Schrapers, Peer; Utesch, Tillmann; Nimtz, Manfred; Rippers, Yvonne; Dau, Holger; Mroginski, Maria Andrea; Haumann, Michael; Leimkühler, Silke

    2016-04-26

    Formate dehydrogenases (FDHs) are capable of performing the reversible oxidation of formate and are enzymes of great interest for fuel cell applications and for the production of reduced carbon compounds as energy sources from CO2. Metal-containing FDHs in general contain a highly conserved active site, comprising a molybdenum (or tungsten) center coordinated by two molybdopterin guanine dinucleotide molecules, a sulfido and a (seleno-)cysteine ligand, in addition to a histidine and arginine residue in the second coordination sphere. So far, the role of these amino acids in catalysis has not been studied in detail, because of the lack of suitable expression systems and the lability or oxygen sensitivity of the enzymes. Here, the roles of these active site residues is revealed using the Mo-containing FDH from Rhodobacter capsulatus. Our results show that the cysteine ligand at the Mo ion is displaced by the formate substrate during the reaction, the arginine has a direct role in substrate binding and stabilization, and the histidine elevates the pKa of the active site cysteine. We further found that in addition to reversible formate oxidation, the enzyme is further capable of reducing nitrate to nitrite. We propose a mechanistic scheme that combines both functionalities and provides important insights into the distinct mechanisms of C-H bond cleavage and oxygen atom transfer catalyzed by formate dehydrogenase. PMID:27054466

  8. Hypoxia and anoxia effects on alcohol dehydrogenase activity and hemoglobin content in Chironomus riparius Meigen, 1804

    Valentina Grazioli

    2016-02-01

    Full Text Available The metabolic effects of low oxygen content on alcohol-dehydrogenase (ADH activity and hemoglobin (Hb concentration were investigated in IV-instar larvae of Chironomus riparius (Diptera: Chironomidae from an Italian stream. Two series of short-term (48 h experiments were carried out: exposure to (1 progressive hypoxia (95 to 5% of oxygen saturation and (2 anoxia (at <5% of oxygen saturation. In (1, Hb amount increased with increasing oxygen depletion up to a critical value of oxygenation (about 70% of oxygen saturation. Below this percentage, the Hb amount declined to values comparable with those present in the control. The respiration rate (R remained almost constant at oxygen saturation >50% and decreased significantly only after 48 h of treatment (= <5% of oxygen saturation reaching values <100 mmolO2 gAFDW-1 h-1. ADH activity showed two phases of growth, within the first 14 h and over 18 h of exposure. Overall, we inferred that i Hb might function as short-term oxygen storage, enabling animals to delay the on-set of anaerobiosis; and ii alcoholic fermentation co-occurs for a short time with aerobic respiration, becoming the prevalent metabolic pathway below 5% of oxygen saturation (<1 mg L-1. These considerations were supported also by results from anoxia exposure (2. In such condition, larvae were visibly stressed, becoming immobile after few minutes of incubation, and ADH reached higher values than in the hypoxia treatment (2.03±0.15 UADH mg prot-1. Overall, this study showed a shift from aerobic to anaerobic activity in C. riparius larvae exposed to poorly oxygenated water with an associated alteration of ADH activity and the Hb amount. Such metabolites might be valid candidate biomarkers for the environmental monitoring of running waters.

  9. Estimating the number of viable animal cells in multi-well cultures based on their lactate dehydrogenase activities.

    Haslam, G; Wyatt, D; Kitos, P A

    2000-01-01

    A method is described for estimating the numbers ofanimal cells in multi-well culture by simultaneouslymeasuring the lactate dehydrogenase activity of thetotal culture and the medium. The difference betweenthe two reflects the dehydrogenase content of thecells and correlates with cell number. This LDH/INTmethod was tested using several lines of normal andtransformed suspension and adherent cells. Thelactate dehydrogenase activities of duplicate cultureswere determined colourimetrically using reactioncocktails containing lactate, NAD(+), diaphorase,and p-iodonitrotetrazolium violet, with and withoutTriton X-100. The difference in absorbance at 490 nm(DeltaA(490) = A(490, test) - A(490, control)) was used to calculate the lactatedehydrogenase activity of the total culture (+ Triton)and the medium (- Triton). The cellular lactatedehydrogenase activity (difference between totaland medium dehydrogenaseactivities) was proportional to viable cell number. The effects on cell growth of four metabolicinhibitors, sodium azide, actinomycin D,cycloheximide, and taxol, were determined using theLDH/INT assay and direct cell counting. The inhibitorconcentrations that caused decreases in the LDHactivity and cell number by 50% were similar. TheLDH/INT assay is quick and sensitive, works equallywell for adherent and suspension cells, and providesinformation about LDH activities of both the mediumand cells. It is particularly useful for screeningpotential cell-growth inhibitors. PMID:19002967

  10. Effects of silver nanoparticle on lactate dehydrogenase activity and histological changes of heart tissue in male wistar rats

    Noushin Naghsh

    2013-03-01

    Full Text Available Background & Objective: The silver nanoparticles are important in many applications of nanoparticles on human health . The toxicity of silver nanoparticles are not well documented yet. The aim of this study was to investigate the effect of silver nanoparticles on lactate dehydrogenase activity and histological changes in heart tissue.   Materials &Methods: In this study, 40 adult male wistar rats of 220±20gr were divided in to five groups including control and four experimental groups. The latter groups were injected intraperitoneally spherical nano silver particles of 50, 100, 200 and 400 ppm respectively for five consecutive days. Then three, eight and twelve days after the last injection, blood samples were collected and lactate dehydrogenase (LDH activity was assayed . Also, tissue samples from the heart muscle were prepared and studied after staining with Hematoxiline-Eosine. Data of LDH activity was analyzed by One way- ANOVA- test and P-value of ≤ 0.05 were considered as significant.   Results : The result showed that different concentrations of silver nanoparticles have no significant effect on the lactate dehydrogenase (p=0.192 . T he histological study of the tissue after exposure to 400 ppm concentration of silver nanoparticles showed the start of primary apoptosis in heart tissue.   Conclusion: The LDH activity was not changed significantly after exposure to different concentration of silver nanoparticles, which shows the safety of these particles on LDH activity.

  11. Age-related responses of right ventricle in swim-trained rats: changes in lactate and pyruvate contents and lactate dehydrogenase activity.

    Anitha, V; Asha Devi, S

    1996-09-18

    Age related changes in carbohydrate substrates such as, glucose, glycogen, pyruvic acid and lactic acid and the activity of lactate dehydrogenase (LDH) and LDH isoenzyme profile were evaluated in the right ventricle (RV) of swim-trained rats of 6- (adult), 12- (middle-aged) and 18- (old) months-of-age. Moderate hypertrophy was seen in the heart and RV in response to training in all age groups with the 12 months exhibiting a significant increase. While resting levels of pyruvate and glucose in the RV showed small elevations in adult and middle-aged rats, lactic acid showed reductions in all ages. Glycogen supercompensation was seen in the RV of trained animals. These age-related alterations in RV were associated with decreases in blood lactic acid and glucose in the trained rats belonging to all ages. Total protein of the RV decreased with age and exercise increased the content. Total LDH and M4-LDH activities decreased with age. However, training increased their activities in all ages. These changes in the RV suggests that swimming activity produces adaptations (e.g. increased LDH and M4) in all age groups. Considering the degree of adaptations, it can be suggested that adult and middle-aged are suitable for initiating swim-training programs, but not in old age. PMID:8869911

  12. A new bianthron glycoside as inhibitor of Trypanosoma cruzi glyceraldehyde 3-phosphate dehydrogenase activity

    Macedo, Edangelo M.S. de; Silva, Maria G.V. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Quimica Analitica e Fisico-Quimica; Wiggers, Helton J.; Montanari, Carlos A. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Quimica; Braz-Filho, Raimundo [Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, (Brazil). Setor de Quimica de Produtos Naturais; Andricopulo, Adriano D. [Universidade de Sao Paulo (USP), Sao Carlos SP (Brazil). Inst. de Fisica

    2009-07-01

    A phytochemical investigation of the ethanolic extract of stalks of Senna martiana Benth. (Leguminoseae), native specie of northeast Brazil, resulted in the isolation and spectroscopic characterization of a new bianthrone glycoside, martianine 1 (10,10'-il-chrysophanol-10-oxi- 10,10'-bi-glucosyl). Its identification was established by HRMS, IR and 2D NMR experiments. The evaluation of martianine trypanocidal activity was carried out against gliceraldehyde 3-phosphate dehydrogenase enzyme from Trypanosoma cruzi. Its inhibitory constant (K{sub i}) is in the low micromolar concentration and it was determined by isothermal titration calorimetry to be 27.3 +-2.47 {mu}mol L{sup -1}. The non-competitive mechanism is asserted to be putative of the mode of action martianine displays against T. cruzi GAPDH. Results show that martianine has a great potential to become new lead molecule by inhibiting this key enzyme and for the development of new drugs against Chagas disease. (author)

  13. Cytotoxicity and characterization of an active metabolite of benzamide riboside, a novel inhibitor of IMP dehydrogenase.

    Gharehbaghi, K; Paull, K D; Kelley, J A; Barchi, J J; Marquez, V E; Cooney, D A; Monks, A; Scudiero, D; Krohn, K; Jayaram, H N

    1994-03-15

    Benzamide riboside exhibits significant cytotoxicity against a variety of human tumor cells in culture. On the basis of metabolic studies, the primary target of this drug's action appears to be IMP dehydrogenase (IMPDH). Incubation of human myelogenous leukemia K562 cells with an IC50 concentration of benzamide riboside resulted in an expansion of IMP pools (5.9-fold), with a parallel reduction in the concentration of GMP (90%), GDP (63%), GTP (55%) and dGTP (40%). On kinetic grounds, it was deduced that benzamide riboside (whose Ki versus IMPDH is 6.4 mM, while that of its 5'-monophosphate is 3.9 mM) or its 5'-monophosphate were unlikely to be responsible for inhibition of this target enzyme, IMPDH, since only micromolar concentrations of benzamide riboside were needed to exert potent inhibition of tumor-cell growth. Studies on the metabolism of this C-nucleoside have revealed the presence of a new peak eluting in the nucleoside diphosphate area on HPLC. Treatment of this peak with venom phosphodiesterase degraded it and concurrently nullified its inhibitory activity versus IMPDH; alkaline phosphatase, on the other hand, totally failed to digest the anabolite. These results suggest that the metabolite in question is the phosphodiester, benzamide adenine dinucleotide (BAD). Evidence that the inhibitor was an analog of NAD, wherein the nicotinamide moiety has been replaced by benzamide, was provided by both NMR and mass spectrometric analysis and confirmed by enzymatic synthesis. Further insight into the nature of the active principle was obtained from kinetic studies, which established that BAD competitively inhibited NAD utilization by partially purified IMPDH from K562 cells with a Ki of 0.118 microM. In concert, these studies establish that benzamide riboside exhibits potent antiproliferative activity by inhibiting IMPDH through BAD. PMID:7907081

  14. Aldehyde dehydrogenase activity selects for the holoclone phenotype in prostate cancer cells

    Highlights: ► Isolated ALDHHi PC3 cells preferentially form primitive holoclone-type colonies. ► Primitive holoclone colonies are predominantly ALDHLo but contain rare ALDHHi cells. ► Holoclone-forming cells are not restricted to the ALDHHi population. ► ALDH phenotypic plasticity occurs in PC3 cells (ALDHLo to ALDHHi and vice versa). ► ALDHHi cells are observed but very rare in PC3 spheroids grown in stem cell medium. -- Abstract: Aldehyde dehydrogenase 1 (ALDH) activity is considered to be a marker of cancer stem cells (CSCs) in many tumour models, since these cells are more proliferative and tumourigenic than ALDHLo cells in experimental models. However it is unclear whether all CSC-like cells are within the ALDHHi population, or whether all ALDHHi cells are highly proliferative and tumourigenic. The ability to establish a stem cell hierarchy in vitro, whereby sub-populations of cells have differing proliferative and differentiation capacities, is an alternate indication of the presence of stem cell-like populations within cell lines. In this study, we have examined the interaction between ALDH status and the ability to establish a stem cell hierarchy in PC3 prostate cancer cells. We demonstrate that PC3 cells contain a stem cell hierarchy, and isolation of ALDHHi cells enriches for the most primitive holoclone population, however holoclone formation is not restricted to ALDHHi cells. In addition, we show that ALDH activity undergoes phenotypic plasticity, since the ALDHLo population can develop ALDHHi populations comparable to parental cells within 2 weeks in culture. Furthermore, we show that the majority of ALDHHi cells are found within the least primitive paraclone population, which is circumvented by culturing PC3 cells as spheroids in defined medium favouring stem cell characteristics. Although ALDHHi status enriches for holoclone formation, this activity may be mediated by a minority of ALDHHi cells.

  15. Death mode-dependent reduction in succinate dehydrogenase activity in hair cells of aging rat cochleae

    YANG Wei-ping; HU Bo-hua; SUN Jian-he; ZHAI Suo-qiang; Donald Henderson

    2010-01-01

    Background Our previous studies have shown that both apoptosis and necrosis are involved in hair cell (HC) pathogenesis in aging cochleae. To better understand the biological mechanisms responsible for the regulation of HC death, we examined the activity of succinate dehydrogenase (SDH), a mitochondrial bioenergetic enzyme, in the HCs of aging cochleae.Methods The auditory brainstem response thresholds elicited by tone bursts at 4, 10 and 20 kHz were measured in both young (2-3 months) and aging (22-23 months) Wistar rats. SDH activity was evaluated with a colorimetric assay using nitroblue tetrazolium monosodium salt. The SDH-labeled organs of Corti were double stained with propidium iodide, a DNA intercalating fluorescent probe for illustration of HC nuclei. All the specimens were examined with fluorescence microscopy and confocal microscopy.Results Aging rats exhibited a significant elevation of ABR thresholds with threshold shifts being 34 dB at 20 kHz, 28 dB at 10 kHz, and 25 dB at 4 kHz. Consistent with the reduction in the cochlear function, aging cochleae exhibited the reduction of SDH staining intensity in the apical and the basal ends of the cochleae, where a large number of apoptotic, necrotic, and missing HCs were evident. The reduction in SDH staining appeared in a cell-death-mode dependent fashion. Specifically, SDH labeling remained in apoptotic HCs. In contrast, SDH staining was markedly reduced or absent in necrotic HCs.Conclusions In the aging cochlea, SDH activity is preserved in HCs undergoing apoptosis, but is substantially reduced in necrosis. These results suggest that mitochondrial energetic function is involved in the regulation of cell death pathways in the pathogenesis of aging cochleae.

  16. Local Glucocorticoid Activation by 11β-Hydroxysteroid Dehydrogenase 1 in Keratinocytes: The Role in Hapten-Induced Dermatitis.

    Terao, Mika; Itoi, Saori; Matsumura, Sayaka; Yang, Lingli; Murota, Hiroyuki; Katayama, Ichiro

    2016-06-01

    Over the past decade, extra-adrenal cortisol production was reported in various tissues. The enzyme that catalyzes the conversion of hormonally inactive cortisone into active cortisol in cells is 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1). We recently reported that 11β-HSD1 is also expressed in keratinocytes and regulates inflammation and keratinocyte proliferation. To investigate the function of 11β-HSD1 in keratinocytes during inflammation in vivo, we created keratinocyte-specific 11β-HSD1 knockout (K5-Hsd11b1-KO) mice and analyzed the inflammatory response in models of hapten-induced contact irritant dermatitis. K5-Hsd11b1-KO mice showed enhanced ear swelling in low-dose oxazolone-, 2,4,6-trinitro-1-chlorobenzene (TNCB)-, and 2,4-dinitrofluorobenzene-induced irritant dermatitis associated with increased inflammatory cell infiltration. Topical application of corticosterone dose dependently suppressed TNCB-induced ear swelling and cytokine expression. Similarly in mouse keratinocytes in vitro, corticosterone dose dependently suppressed 2,4,6-trinitrobenzenesulfonic acid-induced IL-1α and IL-1β expression. The effect of 11-dehydrocorticosterone was attenuated in TNCB-induced irritant dermatitis in K5-Hsd11b1-KO mice compared with wild-type mice. In human samples, 11β-HSD1 expression was decreased in epidermis of psoriasis vulgaris compared with healthy skin. Taken together, these data suggest that corticosterone activation by 11β-HSD1 in keratinocytes suppresses hapten-induced irritant dermatitis through suppression of expression of cytokines, such as IL-1α and IL-1β, in keratinocytes. PMID:27070821

  17. Enhancement of L-3-hydroxybutyryl-CoA dehydrogenase activity and circulating ketone body levels by pantethine. Relevance to dopaminergic injury

    de Reggi Max

    2010-04-01

    Full Text Available Abstract Background The administration of the ketone bodies hydroxybutyrate and acetoacetate is known to exert a protective effect against metabolic disorders associated with cerebral pathologies. This suggests that the enhancement of their endogenous production might be a rational therapeutic approach. Ketone bodies are generated by fatty acid beta-oxidation, a process involving a mitochondrial oxido-reductase superfamily, with fatty acid-CoA thioesters as substrates. In this report, emphasis is on the penultimate step of the process, i.e. L-3-hydroxybutyryl-CoA dehydrogenase activity. We determined changes in enzyme activity and in circulating ketone body levels in the MPTP mouse model of Parkinson's disease. Since the active moiety of CoA is pantetheine, mice were treated with pantethine, its naturally-occurring form. Pantethine has the advantage of being known as an anti-inflammatory and hypolipidemic agent with very few side effects. Results We found that dehydrogenase activity and circulating ketone body levels were drastically reduced by the neurotoxin MPTP, whereas treatment with pantethine overcame these adverse effects. Pantethine prevented dopaminergic neuron loss and motility disorders. In vivo and in vitro experiments showed that the protection was associated with enhancement of glutathione (GSH production as well as restoration of respiratory chain complex I activity and mitochondrial ATP levels. Remarkably, pantethine treatment boosted the circulating ketone body levels in MPTP-intoxicated mice, but not in normal animals. Conclusions These finding demonstrate the feasibility of the enhancement of endogenous ketone body production and provide a promising therapeutic approach to Parkinson's disease as well as, conceivably, to other neurodegenerative disorders.

  18. Effect of Follicular Fluid and Platelet-Activating Factor on Lactate Dehydrogenase C Expression in Human Asthenozoospermic Samples

    Tahereh Esmaeilpour; Mohmmad-Reza Zarei; Soghra Bahmanpour; Elham Aliabadi; Ahmad Hosseini; Mansooreh Jaberipour

    2014-01-01

    Background: Application of follicular fluid (FF) and platelet-activating factor (PAF) in artificial insemination improves sperm motility. Lactate dehydrogenase C (LDH-C) is a key enzyme for sperm motility. In this study, the effects of FF and PAF on the sperm motility index and LDH-C expression were investigated. Moreover, LDH-C expression was compared between asthenozoospermic and normozoospermic samples. Methods: The expression of LDH-C was examined by quantitative real-time polymerase ...

  19. Effect of organic solvents on the activity and stability of halophilic alcohol dehydrogenase (ADH2) from Haloferax volcanii

    Alsafadi, Diya; Paradisi, Francesca

    2013-01-01

    The effect of various organic solvents on the catalytic activity, stability and substrate specificity of alchohol dehydrogenase from Haloferax volcanii (HvADH2) was evaluated. The HvADH2 showed remarkable stability and catalysed the reaction in aqueous–organic medium containing dimethyl sulfoxide (DMSO) and methanol (MeOH). Tetrahydrofuran and acetonitrile were also investigated and adversely affected the stability of the enzyme. High concentration of salt, essential to maintain the enzymatic...

  20. Serial lumbar and ventricle cerebrospinal fluid lactate dehydrogenase activities in patients with leptomeningeal metastases from solid and haematological tumours.

    Twijnstra, A; van Zanten, A. P.; Hart, A A; Ongerboer De Visser, B W

    1987-01-01

    Lactate dehydrogenase (LDH) activities were measured in cerebrospinal fluid in 350 patients with various neurological diseases to establish the sensitivity and specificity of the CSF LDH as a marker for the diagnosis of leptomeningeal metastases. Slight elevations of CSF LDH were observed in nonmalignant diseases, while marked elevations were observed in a considerable number of patients with bacterial meningitis. A sensitivity of 79% and a specificity of 83% were calculated. In the 34 patien...

  1. Effects of silver nanoparticle on lactate dehydrogenase activity and histological changes of heart tissue in male wistar rats

    Noushin Naghsh; Amir Masoud Mashayekh; Samaneh Khodadadi

    2013-01-01

    Background & Objective: The silver nanoparticles are important in many applications of nanoparticles on human health . The toxicity of silver nanoparticles are not well documented yet. The aim of this study was to investigate the effect of silver nanoparticles on lactate dehydrogenase activity and histological changes in heart tissue.   Materials &Methods: In this study, 40 adult male wistar rats of 220±20gr were divided in to five groups including control and four experimental groups. The la...

  2. Bioinformatics based structural characterization of glucose dehydrogenase (gdh) gene and growth promoting activity of Leclercia sp. QAU-66

    Muhammad Naveed; Iftikhar Ahmed; Nauman Khalid; Abdul Samad Mumtaz

    2014-01-01

    Glucose dehydrogenase (GDH; EC 1.1. 5.2) is the member of quinoproteins group that use the redox cofactor pyrroloquinoline quinoine, calcium ions and glucose as substrate for its activity. In present study, Leclercia sp. QAU-66, isolated from rhizosphere of Vigna mungo, was characterized for phosphate solubilization and the role of GDH in plant growth promotion of Phaseolus vulgaris. The strain QAU-66 had ability to solubilize phosphorus and significantly (p ≤ 0.05) promoted the shoot and roo...

  3. PHARMACOLOGICAL ACTIVITIES OF PROTOCATECHUIC ACID.

    Khan, Abida Kalsoom; Rashid, Rehana; Fatima, Nighat; Mahmood, Sadaf; Mir, Sadullah; Khan, Sara; Jabeen, Nyla; Murtaza, Ghulam

    2015-01-01

    Protocatechuic acid (3,4-dihydroxybenzoic acid, PCA) is a simple phenolic acid. It is found in a large variety of edible plants and possesses various pharmacological activities. This article aims to review the modern trends in phytochemical isolation and extraction of PCA from plants and other natural resources. Moreover, this article also encompasses pharmacological and biological activities of PCA. It is well known to have anti-inflammatory, antioxidant, anti-hyperglycemia, antibacterial, anticancer, anti-ageing, anti-athro- genic, anti-tumoral, anti-asthma, antiulcer, antispasmodic and neurological properties. PMID:26647619

  4. Luteal 3beta-hydroxysteroid dehydrogenase and 20alpha-hydroxysteroid dehydrogenase activities in the rat corpus luteum of pseudopregnancy: Effect of the deciduoma reaction

    Telleria Carlos M

    2004-05-01

    Full Text Available Abstract Background In the rat, the maintenance of gestation is dependent on progesterone production from the corpora lutea (CL, which are under the control of pituitary, decidual and placental hormones. The luteal metabolism of progesterone during gestation has been amply studied. However, the regulation of progesterone synthesis and degradation during pseudopregnancy (PSP, in which the CL are mainly under the control of pituitary prolactin (PRL, is not well known. The objectives of this investigation were: i to study the luteal metabolism of progesterone during PSP by measuring the activities of the enzymes 3beta-hydroxysteroid dehydrogenase (3betaHSD, involved in progesterone biosynthesis, and that of 20alpha-hydroxysteroid dehydrogenase (20alphaHSD, involved in progesterone catabolism; and ii to determine the role of decidualization on progesterone metabolism in PSP. Methods PSP was induced mechanically at 10:00 h on the estrus of 4-day cycling Wistar rats, and the stimulus for decidualization was provided by scratching the uterus on day 4 of PSP. 3betaHSD and 20alphaHSD activities were measured in the CL isolated from ovaries of PSP rats using a spectrophotometric method. Serum concentrations of progesterone, PRL, androstenedione, and estradiol were measured by radioimmunoassay (RIA. Results The PSP stage induced mechanically in cycling rats lasted 11.3 ± 0.09 days (n = 14. Serum progesterone concentration was high until day 10 of PSP, and declined thereafter. Serum PRL concentration was high on the first days of PSP but decreased significantly from days 6 to 9, having minimal values on days 10 and 11. Luteal 3betaHSD activities were elevated until day 6 of PSP, after which they progressively declined, reaching minimal values at the end of PSP. Luteal 20alphaHSD activities were very low until day 9, but abruptly increased at the end of PSP. When the deciduoma was induced by scratching the uterus of pseudopregnant animals on day 4 (PSP

  5. Functional characterization of highly purified human hematopoietic repopulating cells isolated according to aldehyde dehydrogenase activity.

    Hess, David A; Meyerrose, Todd E; Wirthlin, Louisa; Craft, Timothy P; Herrbrich, Phillip E; Creer, Michael H; Nolta, Jan A

    2004-09-15

    Human hematopoietic stem cells (HSCs) are commonly purified by the expression of cell surface markers such as CD34. Because cell phenotype can be altered by cell cycle progression or ex vivo culture, purification on the basis of conserved stem cell function may represent a more reliable way to isolate various stem cell populations. We have purified primitive HSCs from human umbilical cord blood (UCB) by lineage depletion (Lin(-)) followed by selection of cells with high aldehyde dehydrogenase (ALDH) activity. ALDH(hi)Lin(-) cells contained 22.6% +/- 3.0% of the Lin(-) population and highly coexpressed primitive HSC phenotypes (CD34(+) CD38(-) and CD34(+)CD133(+)). In vitro hematopoietic progenitor function was enriched in the ALDH(hi)Lin(-) population, compared with ALDH(lo)Lin(-) cells. Multilineage human hematopoietic repopulation was observed exclusively after transplantation of ALDH(hi)Lin(-) cells. Direct comparison of repopulation with use of the nonobese diabetic/severe combined immunodeficient (NOD/SCID) and NOD/SCID beta2 microglobulin (beta2M) null models demonstrated that 10-fold greater numbers of ALDH(hi)-Lin(-) cells were needed to engraft the NOD/SCID mouse as compared with the more permissive NOD/SCID beta2M null mouse, suggesting that the ALDH(hi)Lin(-) population contained committed progenitors as well as primitive repopulating cells. Cell fractionation according to lineage depletion and ALDH activity provides a viable and prospective purification of HSCs on the basis of cell function rather than cell surface phenotype. PMID:15178579

  6. Lactate dehydrogenase activity of rat epididymis and spermatozoa: effect of constant light.

    Ponc, R H; Carriazo, C S; Vermouth, N T

    2001-01-01

    During its passage through the epididymis, the gamete undergoes a process of "maturation" leading to the acquisition of its fertilizing ability. The epididymis displays regional variations in the morphology and metabolic properties of its epithelium which are relevant for the progressive development of mature sperm characteristics. The epididymis has spontaneous peristaltic contractions and receives sympathetic innervation that is modulated by melatonin, a hormone synthesized and released by the pineal gland. Constant lighting disrupts melatonin synthesis and secretion. We have studied the effect of constant light on lactate dehydrogenase (LDH; EC 1.1.1.27) and its isozyme C4 activities and protein content in whole epididymis, epididymal tissue and in spermatozoa from caput and cauda segments. Animals were exposed from birth to an illumination schedule of 14 h light:10 h dark (group L:D). At 60 days of age one group of animals was submitted to constant light over 50 days (group L:L). In order to test the fertilizing ability, the rats of each group were mated with soliciting estrous females. The percentage of pregnancies in females mated with males maintained in L:L was remarkably lower than those in females mated with males maintained in the L:D photoperiod (44% and 88% respectively). Constant light increased protein concentration and LDH activity in caput as well as in cauda of total epididymis. On the contrary, in epididymal tissue, the protein content decreased in both epididymal sections compared with controls. When enzymatic activity was expressed in Units per spermatozoa, constant light induced a significant reduction of total LDH and LDHC4 in caput and cauda spermatozoa while LDH activity of epididymal tissue was not affected. In spite of the decrease in LDH per sperm cell when rats were exposed to constant light, in total epididymis (epididymis tissue plus sperm cells content) and in spermatozoa, values of enzyme activities expressed per weight unit were

  7. Lactate dehydrogenase activity of rat epididymis and spermatozoa: Effect of constant light

    RH Ponce

    2009-12-01

    Full Text Available During its passage through the epididymis, the gamete undergoes a process of “maturation” leading to the acquisition of its fertilizing ability. The epididymis displays regional variations in the morphology and metabolic properties of its epithelium which are relevant for the progressive development of mature sperm characteristics. The epididymis has spontaneous peristaltic contractions and receives sympathetic innervation that is modulated by melatonin, a hormone synthesized and released by the pineal gland. Constant lighting disrupts melatonin synthesis and secretion. We have studied the effect of constant light on lactate dehydrogenase (LDH; EC 1.1.1.27 and its isozyme C4 activities and protein content in whole epididymis, epididymal tissue and in spermatozoa from caput and cauda segments. Animals were exposed from birth to an illumination schedule of 14 h light: 10 h dark (group L:D. At 60 days of age one group of animals was submitted to constant light over 50 days (group L:L. In order to test the fertilizing ability, the rats of each group were mated with soliciting estrous females. The percentage of pregnancies in females mated with males maintained in L:L was remarkably lower than those in females mated with males maintained in the L:D photoperiod (44% and 88% respectively. Constant light increased protein concentration and LDH activity in caput as well as in cauda of total epididymis. On the contrary, in epididymal tissue, the protein content decreased in both epididymal sections compared with controls. When enzymatic activity was expressed in Units per spermatozoa, constant light induced a significant reduction of total LDH and LDHC4 in caput and cauda spermatozoa while LDH activity of epididymal tissue was not affected. In spite of the decrease in LDH per sperm cell when rats were exposed to constant light, in total epididymis (epididymis tissue plus sperm cells content and in spermatozoa, values of enzyme activities expressed per

  8. Electrochemical Studies of the Inhibition and Activation Effects of Al (III on the Activity of Bovine Liver Glutamate Dehydrogenase

    Shuping Bi

    2005-04-01

    Full Text Available Since the study of Al3+ ion on the enzyme activity by using of electrochemical techniques was rarely found in available literatures, the differential-pulse polarography (DPP technique was applied to study the effects of Al3+ ion on the glutamate dehydrogenase (GDH activity in the catalytical reaction of α-KG +NADH+NH4 + ⇔ L-Glu+NAD++H2O by monitoring the DPP reduction current of NAD+. At the plant and animal physiologically relevant pH values (pH=6.5 and 7.5, the GDH enzyme activities were strongly depended on the concentrations of the metal ion in the assay mixture solutions. In the lower Al (III concentration solutions (80μM, the inhibition effects of Al (III were shown again. The cyclic voltammetry of NAD+ and NAD+-GDH in the presence of Al (III can help to explain some biological phenomena. According to the differential-pulse polarography and cyclic voltammetry experiments, the present research confirmed that the electrochemical technique is a convenient and reliable sensor for accurate determination of enzyme activity in biological and environmental samples.

  9. Correlation of viral RNA biosynthesis with glucose-6-phosphate dehydrogenase activity and host resistance

    Šindelář, Luděk; Šindelářová, Milada

    2002-01-01

    Roč. 215, - (2002), s. 862-869. ISSN 0032-0935 R&D Projects: GA ČR GA522/99/1264 Institutional research plan: CEZ:AV0Z5038910 Keywords : Glucose 6 phosphate dehydrogenase * Nicotiana (viral infection) * Plant viruses Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.960, year: 2002

  10. 5´AMP activated protein kinase α2 controls substrate metabolism during post-exercise recovery via regulation of pyruvate dehydrogenase kinase 4

    Fritzen, Andreas Mæchel; Lundsgaard, Anne-Marie; Jeppesen, Jacob;

    2015-01-01

    It is well known that exercise has a major impact on substrate metabolism for many hours after exercise. However, the regulatory mechanisms increasing lipid oxidation and facilitating glycogen resynthesis in the post-exercise period are unknown. To address this, substrate oxidation was measured...... in muscle pyruvate dehydrogenase kinase 4 (PDK4) mRNA expression in WT and AMPKα2 KO was observed following exercise, which is consistent with AMPKα2 -deficiency not affecting the exercise-induced activation of the PDK4 transcriptional regulators, HDAC4 and SIRT1. Interestingly, PDK4 protein content...... regulates muscle metabolism post-exercise through inhibition of the PDH complex and hence glucose oxidation, subsequently creating conditions for increased fatty acid oxidation. This article is protected by copyright. All rights reserved....

  11. Structural and Functional Studies of WlbA: A Dehydrogenase Involved in the Biosynthesis of 2,3-Diacetamido-2,3-dideoxy-d-mannuronic Acid

    Thoden, James B.; Holden, Hazel M. (UW)

    2010-09-08

    2,3-Diacetamido-2,3-dideoxy-D-mannuronic acid (ManNAc3NAcA) is an unusual dideoxy sugar first identified nearly 30 years ago in the lipopolysaccharide of Pseudomonas aeruginosa O:3a,d. It has since been observed in other organisms, including Bordetella pertussis, the causative agent of whooping cough. Five enzymes are required for the biosynthesis of UDP-ManNAc3NAcA starting from UDP-N-acetyl-D-glucosamine. Here we describe a structural study of WlbA, the NAD-dependent dehydrogenase that catalyzes the second step in the pathway, namely, the oxidation of the C-3{prime} hydroxyl group on the UDP-linked sugar to a keto moiety and the reduction of NAD{sup +} to NADH. This enzyme has been shown to use {alpha}-ketoglutarate as an oxidant to regenerate the oxidized dinucleotide. For this investigation, three different crystal structures were determined: the enzyme with bound NAD(H), the enzyme in a complex with NAD(H) and {alpha}-ketoglutarate, and the enzyme in a complex with NAD(H) and its substrate (UDP-N-acetyl-D-glucosaminuronic acid). The tetrameric enzyme assumes an unusual quaternary structure with the dinucleotides positioned quite closely to one another. Both {alpha}-ketoglutarate and the UDP-linked sugar bind in the WlbA active site with their carbon atoms (C-2 and C-3{prime}, respectively) abutting the re face of the cofactor. They are positioned {approx}3 {angstrom} from the nicotinamide C-4. The UDP-linked sugar substrate adopts a highly unusual curved conformation when bound in the WlbA active site cleft. Lys 101 and His 185 most likely play key roles in catalysis.

  12. Examining the anti-candidal activity of 10 selected Indian herbs and investigating the effect of Lawsonia inermis extract on germ tube formation, protease, phospholipase, and aspartate dehydrogenase enzyme activity in Candida albicans

    Ravichandran, Sripathy; Muthuraman, Sundararaman

    2016-01-01

    Objective: The objective of the study is to identify potential anti-candidal agents from natural resources and elucidate the effect of Lawsonia inermis extract on major virulent factors of Candida albicans. Materials and Methods: Plants, the most abundant and readily available resource of diverse bioactives, were chosen for the anti-candidal screening study. Ten different plants that were proven to have antimicrobial activity but not explored much for anti-candidal activity were chosen for this study. Ethyl acetate extract of these plant leaves were tested for the anti-candidal activity. Extracts with good anti-candidal activity were further screened for its effect in C. albicans germ tube formation and enzyme (protease, phospholipase, and aspartate dehydrogenase) activity. Results: Among 10 plants screened, L. inermis extract showed complete inhibition of C. albicans. On further evaluation, this extract completely inhibited C. albicans germ tube formation in serum until the end of incubation period (3 h). This extract also exhibited dose-dependent inhibitory activity against two major virulent enzymes of C. albicans, proteases (27–33%) and phospholipases (44.5%). In addition to it, this extract completely inhibited both the isoforms of constitutive candidal enzyme aspartate dehydrogenase, thereby affecting amino acid biosynthesis. Conclusion: Thus, this study confirms the anti-candidal potential of L. inermis and hence can be considered further for development of anti-candidal drug. PMID:26997722

  13. SIRT3 and SIRT5 regulate the enzyme activity and cardiolipin binding of very long-chain acyl-CoA dehydrogenase.

    Yuxun Zhang

    Full Text Available SIRT3 and SIRT5 have been shown to regulate mitochondrial fatty acid oxidation but the molecular mechanisms behind the regulation are lacking. Here, we demonstrate that SIRT3 and SIRT5 both target human very long-chain acyl-CoA dehydrogenase (VLCAD, a key fatty acid oxidation enzyme. SIRT3 deacetylates and SIRT5 desuccinylates K299 which serves to stabilize the essential FAD cofactor in the active site. Further, we show that VLCAD binds strongly to cardiolipin and isolated mitochondrial membranes via a domain near the C-terminus containing lysines K482, K492, and K507. Acetylation or succinylation of these residues eliminates binding of VLCAD to cardiolipin. SIRT3 deacetylates K507 while SIRT5 desuccinylates K482, K492, and K507. Sirtuin deacylation of recombinant VLCAD rescues membrane binding. Endogenous VLCAD from SIRT3 and SIRT5 knockout mouse liver shows reduced binding to cardiolipin. Thus, SIRT3 and SIRT5 promote fatty acid oxidation by converging upon VLCAD to promote its activity and membrane localization. Regulation of cardiolipin binding by reversible lysine acylation is a novel mechanism that is predicted to extrapolate to other metabolic proteins that localize to the inner mitochondrial membrane.

  14. Isoniazid acetylating phenotype in patients with paracoccidioidomycosis and its relationship with serum sulfadoxin levels, glucose-6-phosphate dehydrogenase and glutathione reductase activities

    Benedito Barraviera; Paulo Câmara Marques Pereira; Jussara Marcondes Machado; Maria Julia de Souza; Carlos Roberto G. Lima; Paulo Roberto Curi; Rinaldo Poncio Mendes; Domingos Alves Meira

    1991-01-01

    The authors evaluated the isoniazid acetylating phenotype and measured hematocrit, hemoglobin, glucose-6-phosphate dehydrogenase and glutathione reductase activities plus serum sulfadoxin levels in 39 patients with paracoccidioidomycosis (33 males and 6 females) aged 17 to 58 years. Twenty one (53.84%) of the patients presented a slow acetylatingphenotype and 18(46.16%) a fast acetylating phenotype. Glucose-6-phosphate- dehydrogenase (G6PD) acti vity was decreased in 5(23.80%) slow acetylator...

  15. Coimmobilization of L-asparaginase and glutamate dehydrogenase onto highly activated supports

    Balcão, Victor M.; Mateo, Cesar; Fernández-Lafuente, R.; Malcata, F. Xavier; Guisán, José M.

    2001-01-01

    In the present research work, production of coimmobilized derivatives of L-asparaginase and glutamate dehydrogenase was attempted. Comparison of immobilization of each enzyme independently with coimmobilization of the two enzymes unfolded important advantages of the latter, namely a decrease in the induction period (time before the maximum reaction rate is virtually achieved) and an increase in the maximum reaction rate. The effectiveness of the independent enzyme derivatives was low; however...

  16. Characterization of 10-Hydroxygeraniol Dehydrogenase from Catharanthus roseus Reveals Cascaded Enzymatic Activity in Iridoid Biosynthesis

    Ramakrishnan Krithika; Prabhakar Lal Srivastava; Bajaj Rani; Kolet, Swati P.; Manojkumar Chopade; Mantri Soniya; Hirekodathakallu V. Thulasiram

    2015-01-01

    Catharanthus roseus [L.] is a major source of the monoterpene indole alkaloids (MIAs), which are of significant interest due to their therapeutic value. These molecules are formed through an intermediate, cis-trans-nepetalactol, a cyclized product of 10-oxogeranial. One of the key enzymes involved in the biosynthesis of MIAs is an NAD(P)+ dependent oxidoreductase system, 10-hydroxygeraniol dehydrogenase (Cr10HGO), which catalyses the formation of 10-oxogeranial from 10-hydroxygeraniol via 10-...

  17. Novel Inhibitors of Plasmodium falciparum Dihydroorotate Dehydrogenase with Anti-malarial Activity in the Mouse Model*

    Booker, Michael L.; Bastos, Cecilia M.; Kramer, Martin L.; Barker, Robert H.; Skerlj, Renato; Sidhu, Amar Bir; Deng, Xiaoyi; Celatka, Cassandra; Cortese, Joseph F.; Guerrero Bravo, Jose E.; Crespo Llado, Keila N.; Serrano, Adelfa E.; Angulo-Barturen, Iñigo; Jiménez-Díaz, María Belén; Viera, Sara

    2010-01-01

    Plasmodium falciparum, the causative agent of the most deadly form of human malaria, is unable to salvage pyrimidines and must rely on de novo biosynthesis for survival. Dihydroorotate dehydrogenase (DHODH) catalyzes the rate-limiting step in the pyrimidine biosynthetic pathway and represents a potential target for anti-malarial therapy. A high throughput screen and subsequent medicinal chemistry program identified a series of N-alkyl-5-(1H-benzimidazol-1-yl)thiophene-2-carboxamides with low ...

  18. Molecular, biochemical, and functional characterization of a nudix hydrolase protein that stimulates the activity of a nicotinoprotein alcohol dehydrogenase

    Kloosterman, H; Vrijbloed, JW; Dijkhuizen, L.

    2002-01-01

    The cytoplasmic coenzyme NAD(+)-dependent alcohol (methanol) dehydrogenase (MDH) employed by Bacillus methanolicus during growth on C-1-C-4 primary alcohols is a decameric protein with 1 Zn2+-ion and 1-2 Mg2+-ions plus a tightly bound NAD(H) cofactor per subunit (a nicotinoprotein). Mg2+-ions are essential for binding of NAD(H) cofactor in MDH protein expressed in Escherichia coli. The low coenzyme NAD(+)-dependent activity of MDH with C-1-C-4 primary alcohols is strongly stimulated by a seco...

  19. Incorporation of 14C glucose into glycogen and glucose-6-phosphate dehydrogenase activity in rat brain following carbon monoxide intoxication

    Incorporation of 14C glucose into glycogen and glucose-6-phosphate dehydrogenase activity in rat brain following carbon monoxide intoxication was studied. In brains of rats tested on the 20, 30 and 60th minute of exposure to CO and immediately after removal from the chamber the enzyme activity showed no essential deviation from the control level. In the group of rats tested 1 hour after taking them out from the chamber increase of the enzyme activity was noticed, amounting to about 33% of the control value. The brains tested 24 hours after exposure showed the largest increase of the enzyme activity by about 94%. In the next time periods, 48 and 72 hours after intoxication, the enzyme activity was decreasing. The glycogen content in brains of control animals increased 3 hours after CO intoxication by about 69%. The increase of glycogen synthesis was expressed by increase of the total radioactivity, which amounted to 160% of the control value. (Z.M.)

  20. Effect of thoracic x-irradiation on glucose-6-phosphate dehydrogenase activity of the pectoral muscle of guinea pig

    The histochemical distribution of glucose-6-phosphate dehydrogenase (G6PD) was observed in the major pectoral muscle of a guinea pig that had received 240 R thoracic X-irradiation. The irradiation effects were studied at 24, 48 and 72 hrs after X-irradiation. Type I fibres of the pectoral muscle were deeply stained showing high activity whereas type II fibres demonstrated minimum enzyme activity. The intermediate fibres had medium levels of G6PD activity. Type II fibres showed more staining at 24 and 48 hrs as compared with control muscle. However, at 72 hrs all three fibre types showed a marked inhibition of G6PD activity. The significance of these changes suggests that muscle G6PD metabolism generally altered after irradiation, but the specific nature of these changes and their causes still remain unclear. (author)

  1. Communication between Thiamin Cofactors in the Escherichia coli Pyruvate Dehydrogenase Complex E1 Component Active Centers: EVIDENCE FOR A “DIRECT PATHWAY” BETWEEN THE 4′-AMINOPYRIMIDINE N1′ ATOMS*

    Nemeria, Natalia S.; Arjunan, Palaniappa; Chandrasekhar, Krishnamoorthy; Mossad, Madouna; Tittmann, Kai; Furey, William; Jordan, Frank

    2010-01-01

    Kinetic, spectroscopic, and structural analysis tested the hypothesis that a chain of residues connecting the 4′-aminopyrimidine N1′ atoms of thiamin diphosphates (ThDPs) in the two active centers of the Escherichia coli pyruvate dehydrogenase complex E1 component provides a signal transduction pathway. Substitution of the three acidic residues (Glu571, Glu235, and Glu237) and Arg606 resulted in impaired binding of the second ThDP, once the first active center was filled, suggesting a pathway...

  2. Radioprotective activity of folic acid

    The radioprotective activity of folic acid has been studied using rat liver mitochondria membrane, protein and superoxide dismutase (SOD) as well as pBR 322 plasmid DNA as the model in vitro systems. The vitamin could effectively prevent the γ-ray induced lipid peroxidation as assessed by measuring thiobarbituric acid reactive substrates and protein carbonyl formation effectively. It also could also prevent radiation-induced damage of mitochondrial SOD and restore its level to normalcy Likewise; it prevented radiation-induced DNA strand breaks in a concentration dependent manner. The radioprotective activity could be attributed to its ability to scavenge the hydroxyl and superoxide radicals wherein its pseudo-phenolic moiety and C-9 methylene group play the key role. Radioprotective activity of a polysaccharide preparation from the Indian medicinal plant, Tinospora cordifolia Miers has been established using Saccharomyces cerevisiae X2180 strain as the in vivo test model. The entire activity could be attributed to the radical scavenging capacity of the preparation, as it did not enhance the expression of the protective enzymes, catalase and superoxide dismutase in the yeast cells. (author)

  3. Identification of D-amino acid dehydrogenase as an upstream regulator of the autoinduction of a putative acyltransferase in Corynebacterium glutamicum.

    Lee, Jung-Hoon; Kim, Yong-Jae; Shin, Hee-Sung; Lee, Heung-Shick; Jin, Shouguang; Ha, Un-Hwan

    2016-06-01

    Expression of a putative acyltransferase encoded by NCgl- 0350 of Corynebacterium glutamicum is induced by cell-free culture fluids obtained from stationary-phase growth of both C. glutamicum and Pseudomonas aeruginosa, providing evidence for interspecies communication. Here, we further confirmed that such communication occurs by showing that acyltransferase expression is induced by culture fluid obtained from diverse Gram-negative and -positive bacterial strains, including Escherichia coli, Salmonella Typhimurium, Bacillus subtilis, Staphylococcus aureus, Mycobacterium sp. strain JC1, and Mycobacterium smegmatis. A homologous acyltransferase encoded by PA5238 of P. aeruginosa was also induced by fluids obtained from P. aeruginosa as well as other bacterial strains, as observed for NCgl0350 of C. glutamicum. Because C. glutamicum is difficult to study using molecular approaches, the homologous gene PA5238 of P. aeruginosa was used to identify PA5309 as an upstream regulator of expression. A homologous D-amino acid dehydrogenase encoded by NCgl- 2909 of C. glutamicum was cloned based on amino acid similarity to PA5309, and its role in the regulation of NCgl0350 expression was confirmed. Moreover, NCgl2909 played positive roles in growth of C. glutamicum. Thus, we identified a D-amino acid dehydrogenase as an upstream regulator of the autoinduction of a putative acyltransferase in C. glutamicum. PMID:27225460

  4. Alcohol dehydrogenase gene ADH3 activates glucose alcoholic fermentation in genetically engineered Dekkera bruxellensis yeast

    Schifferdecker, Anna Judith; Siurkus, Juozas; Andersen, Mikael Rørdam;

    2016-01-01

    developed an auxotrophic transformation system and an expression vector, which enabled the manipulation of D. bruxellensis, thereby improving its fermentative performance. Its gene ADH3, coding for alcohol dehydrogenase, was cloned and overexpressed under the control of the strong and constitutive promoter...... TEF1. Our recombinant D. bruxellensis strain displayed 1.4 and 1.7 times faster specific glucose consumption rate during aerobic and anaerobic glucose fermentations, respectively; it yielded 1.2 times and 1.5 times more ethanol than did the parental strain under aerobic and anaerobic conditions......, respectively. The overexpression of ADH3 in D. bruxellensis also reduced the inhibition of fermentation by anaerobiosis, the "Custer effect". Thus, the fermentative capacity of D. bruxellensis could be further improved by metabolic engineering....

  5. The effect of fullerenol C60(OH)∼30 on the alcohol dehydrogenase activity irradiated with X-rays

    In the present study the effect of X-irradiation on the alcohol dehydrogenase (ADH) activity in the presence of nanoparticles of fullerenol C60(OH)∼30 under aerobic conditions was investigated in order to assess the potential radioprotective properties of fullerenol. Fullerenol at 75 mg/mL decreased the radiation yield of inactivation of ADH irradiated with fullerenol by 20% comparing to ADH irradiated without fullerenol. Under conditions used during irradiation, 50% of ·OH radicals could react with fullerenol and 50% could react with ADH. Thus, it can be assumed that protective effect of fullerenol on the radiation inactivation of ADH was mostly due to scavenging ·OH radicals by fullerenol. Moreover, fullerenol did not protect against post-irradiation damage as the Ginact for ADH irradiated with fullerenol was still 20% lower than for ADH irradiated without fullerenol after 24 h from irradiation. Additionally, fullerenol at 75 mg/L had no influence on the activity of unirradiated ADH up to 24 h. We concluded that fullerenol C60(OH)∼30 protected ADH against radiation inactivation due to simple competition for the ·OH radicals and did not modify its activity by association with the protein as it was proved in our previous papers for erythrocyte membrane proteins. - Highlights: • Fullerenol C60(OH)∼30 itself do not modify the activity of alcohol dehydrogenase (ADH). • Fullerenol protects ADH against radiation inactivation due to simple competition for the ·OH radicals. • Fullerenol has the reduced ability to prevent the formation of protein peroxides. • Since the main role in radiosensitivity of ADH is played by –SH groups, fullerenol could prevent oxidation of –SH groups by electrostatic interactions

  6. Amino Acid Decarboxylase Activity of Some Lactic Acid Bacteria

    Pelin ERTÜRKMEN; Turhan, İlkay; Öner, Zübeyde

    2015-01-01

    Microorganisms which have decarboxylase activity can form biogenic amine by enzymatic decarboxylation of amino acids in foods. Histamine poisoning results from consumption of foods typically certain types of fish and cheeses that contain unusually high levels of histamine. Therefore, decarboxylase activity is an important problem at the selection of lactic acid bacteria as a starter culture in fermented products. In this study, decarboxylase activities of 161 lactic acid bacteria (LAB) strain...

  7. Sorbitol dehydrogenase is a zinc enzyme.

    Jeffery, J; Chesters, J; C. Mills; P.J. Sadler; Jörnvall, H

    1984-01-01

    Evidence is given that tetrameric sorbitol dehydrogenase from sheep liver contains one zinc atom per subunit, most probably located at the active site, and no other specifically bound zinc or iron atom. In alcohol dehydrogenases that are structurally related to sorbitol dehydrogenase, more than one zinc atom per subunit can complicate investigations of zinc atom function. Therefore, sorbitol dehydrogenase will be particularly valuable for defining the precise roles of zinc in alcohol and poly...

  8. Amino acid residues involved in the catalytic mechanism of NAD-dependent glutamate dehydrogenase from Halobacterium salinarum.

    Pérez-Pomares, F; Ferrer, J; Camacho, M; Pire, C; LLorca, F; Bonete, M J

    1999-02-01

    The pH dependence of kinetic parameters for a competitive inhibitor (glutarate) was determined in order to obtain information on the chemical mechanism for NAD-dependent glutamate dehydrogenase from Halobacterium salinarum. The maximum velocity is pH dependent, decreasing at low pHs giving a pK value of 7.19+/-0.13, while the V/K for l-glutamate at 30 degrees C decreases at low and high pHs, yielding pK values of 7.9+/-0.2 and 9.8+/-0.2, respectively. The glutarate pKis profile decreases at high pHs, yielding a pK of 9. 59+/-0.09 at 30 degrees C. The values of ionization heat calculated from the change in pK with temperature are: 1.19 x 10(4), 5.7 x 10(3), 7 x 10(3), 6.6 x 10(3) cal mol-1, for the residues involved. All these data suggest that the groups required for catalysis and/or binding are lysine, histidine and tyrosine. The enzyme shows a time-dependent loss in glutamate oxidation activity when incubated with diethyl pyrocarbonate (DEPC). Inactivation follows pseudo-first-order kinetics with a second-order rate constant of 53 M-1min-1. The pKa of the titratable group was pK1=6.6+/-0.6. Inactivation with ethyl acetimidate also shows pseudo-first-order kinetics as well as inactivation with TNM yielding second-order constants of 1.2 M-1min-1 and 2.8 M-1min-1, and pKas of 8.36 and 9.0, respectively. The proposed mechanism involves hydrogen binding of each of the two carboxylic groups to tyrosyl residues; histidine interacts with one of the N-hydrogens of the l-glutamate amino group. We also corroborate the presence of a conservative lysine that has a remarkable ability to coordinate a water molecule that would act as general base. PMID:10076069

  9. STUDIES ON THE DYNAMICS OF DEHYDROGENASES KREBS CYCLE ACTIVITY AT MONILINIA LAXA (ADERH. & RUHL. HONEY FUNGUS GROWN ON MEDIA WITH DIFFERENT CARBOHYDRATES

    Elena Ciornea

    2010-09-01

    Full Text Available As ubiquitous organisms, fungi grow on a large number of organic substrate, alive or dead, confronting therefore with a wide variety of carbohydrates and various physical factors, and their versatility to adapt and be able to use a large number of these compounds could provide them the chance to survive. Given that, these fungi have a rich enzyme equipment that allows them to operate on different metabolic pathways, this study aims to monitor the dynamics activity of some Krebs cycle dehydrogenases in Monilinia laxa (Aderh & Ruhl. Honey species parasitic on various species of plum trees. To this end, the fungus was cultivated in vitro on media enriched with different carbohydrates and the isocitrate dehydrogenase, �-cetoglutarate dehydrogenase, succinate dehydrogenase and malate dehydrogenase activity in the fungus mycelium was followed, at 7, respectively, 14 days after the inoculation of the culture medium and determined using the spectrophotometric Sîsoev and Krasna method (Cojocaru, D.C., 2009. Data revealed obvious differences depending on the type of carbohydrate introduced into the medium and the age of the culture mycelia.

  10. The level of glucose-6-phosphate dehydrogenase activity strongly influences xylose fermentation and inhibitor sensitivity in recombinant Saccharomyces cerevisiae strains

    Jeppsson, M.; Johansson, B.; Jensen, Peter Ruhdal;

    2003-01-01

    Disruption of the ZWF1 gene encoding glucose-6-phosphate dehydrogenase (G6PDH) has been shown to reduce the xylitol yield and the xylose consumption in the xylose-utilizing recombinant Saccharomyces cerevisiae strain TMB3255. In the present investigation we have studied the influence of different...... consumption, respectively, compared with the ZWF1-disrupted strain. Both strains exhibited decreased xylitol yields (0.13 and 0.19 g/g xylose) and enhanced ethanol yields (0.36 and 0.34 g/g xylose) compared with the control strain TMB3001 (0.29 g xylitol/g xylose, 0.31 g ethanol/g xylose). Cytoplasmic...... transhydrogenase (TH) from Azotobacter vinelandii has previously been shown to transfer NADPH and NAD(+) into NADP(+) and NADH, and TH-overproduction resulted in lower xylitol yield and enhanced glycerol yield during xylose utilization. Strains with low G6PDH-activity grew slower in a lignocellulose hydrolysate...

  11. Succinate-dependent energy generation and pyruvate dehydrogenase complex activity in isolated Ascaris suum mitochondria

    Body wall muscle from the parasitic nematode, Ascaris suum, contain unique anaerobic mitochondria that preferentially utilize fumarate and branched-chain enoyl CoA's as terminal electron acceptors instead of oxygen. While electron transport in these organelles is well characterized, the role of oxygen in succinate-dependent phosphorylation is still not clearly defined. Therefore, the present study was designed to more fully characterize succinate metabolism in these organelles as well as the in vitro regulation of a key mitochondrial enzyme, the pyruvate dehydrogenase complex (PDC). In the absence of added adenine nucleotides, incubations in succinate resulted in substantial elevations in intramitochrondrial ATP levels, but ATP/ADP ratios were considerably higher in incubations with malate. The stimulation of phosphorylation in aerobic incubations with succinate was rotenone sensitive and appears to be Site I dependent. Increase substrate level phosphorylation, coupled to propionate formation, or additional sites of electron-transport associated ATP synthesis were not significant. Under aerobic conditions, 14CO2 evolution from 1,4-[14C]succinate was stimulated and NADH/NAD+ ratios were elevated, but the formation of 14C propionate was unchanged

  12. Succinate-dependent energy generation and pyruvate dehydrogenase complex activity in isolated Ascaris suum mitochondria

    Campbell, T.A.

    1988-01-01

    Body wall muscle from the parasitic nematode, Ascaris suum, contain unique anaerobic mitochondria that preferentially utilize fumarate and branched-chain enoyl CoA's as terminal electron acceptors instead of oxygen. While electron transport in these organelles is well characterized, the role of oxygen in succinate-dependent phosphorylation is still not clearly defined. Therefore, the present study was designed to more fully characterize succinate metabolism in these organelles as well as the in vitro regulation of a key mitochondrial enzyme, the pyruvate dehydrogenase complex (PDC). In the absence of added adenine nucleotides, incubations in succinate resulted in substantial elevations in intramitochrondrial ATP levels, but ATP/ADP ratios were considerably higher in incubations with malate. The stimulation of phosphorylation in aerobic incubations with succinate was rotenone sensitive and appears to be Site I dependent. Increase substrate level phosphorylation, coupled to propionate formation, or additional sites of electron-transport associated ATP synthesis were not significant. Under aerobic conditions, {sup 14}CO{sub 2} evolution from 1,4-({sup 14}C)succinate was stimulated and NADH/NAD{sup +} ratios were elevated, but the formation of {sup 14}C propionate was unchanged.

  13. In Silico Identification and in Vitro Activity of Novel Natural Inhibitors of Trypanosoma brucei Glyceraldehyde-3-phosphate-dehydrogenase

    Fabian C. Herrmann

    2015-09-01

    Full Text Available As part of our ongoing efforts to identify natural products with activity against pathogens causing neglected tropical diseases, we are currently performing an extensive screening of natural product (NP databases against a multitude of protozoan parasite proteins. Within this project, we screened a database of NPs from a commercial supplier, AnalytiCon Discovery (Potsdam, Germany, against Trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase (TbGAPDH, a glycolytic enzyme whose inhibition deprives the parasite of energy supply. NPs acting as potential inhibitors of the mentioned enzyme were identified using a pharmacophore-based virtual screening and subsequent docking of the identified hits into the active site of interest. In a set of 700 structures chosen for the screening, 13 (1.9% were predicted to possess significant affinity towards the enzyme and were therefore tested in an in vitro enzyme assay using recombinant TbGAPDH. Nine of these in silico hits (69% showed significant inhibitory activity at 50 µM, of which two geranylated benzophenone derivatives proved to be particularly active with IC50 values below 10 µM. These compounds also showed moderate in vitro activity against T. brucei rhodesiense and may thus represent interesting starting points for further optimization.

  14. The Arabidopsis KS-type dehydrin recovers lactate dehydrogenase activity inhibited by copper with the contribution of His residues.

    Hara, Masakazu; Monna, Shuhei; Murata, Takae; Nakano, Taiyo; Amano, Shono; Nachbar, Markus; Wätzig, Hermann

    2016-04-01

    Dehydrin, which is one of the late embryogenesis abundant (LEA) proteins, is involved in the ability of plants to tolerate the lack of water. Although many reports have indicated that dehydrins bind heavy metals, the physiological role of this metal binding has not been well understood. Here, we report that the Arabidopsis KS-type dehydrin (AtHIRD11) recovered the lactate dehydrogenase (LDH) activity denatured by Cu(2+). The LDH activity was partially inhibited by 0.93 μM Cu(2+) but totally inactivated by 9.3 μM Cu(2+). AtHIRD11 recovered the activity of LDH treated with 9.3 μM Cu(2+) in a dose-dependent manner. The recovery activity of AtHIRD11 was significantly higher than those of serum albumin and lysozyme. The conversion of His residues to Ala in AtHIRD11 resulted in the loss of the Cu(2+) binding of the protein as well as the disappearance of the conformational change induced by Cu(2+) that is observed by circular dichroism spectroscopy. The mutant protein showed lower recovery activity than the original AtHIRD11. These results indicate that AtHIRD11 can reactivate LDH inhibited by Cu(2+) via the His residues. This function may prevent physiological damage to plants due to heavy-metal stress. PMID:26940498

  15. Effects of 14 days of spaceflight and nine days of recovery on cell body size and succinate dehydrogenase activity of rat dorsal root ganglion neurons

    Ishihara, A.; Ohira, Y.; Roy, R. R.; Nagaoka, S.; Sekiguchi, C.; Hinds, W. E.; Edgerton, V. R.

    1997-01-01

    The cross-sectional areas and succinate dehydrogenase activities of L5 dorsal root ganglion neurons in rats were determined after 14 days of spaceflight and after nine days of recovery. The mean and distribution of the cross-sectional areas were similar to age-matched, ground-based controls for both the spaceflight and for the spaceflight plus recovery groups. The mean succinate dehydrogenase activity was significantly lower in spaceflight compared to aged-matched control rats, whereas the mean succinate dehydrogenase activity was similar in age-matched control and spaceflight plus recovery rats. The mean succinate dehydrogenase activity of neurons with cross-sectional areas between 1000 and 2000 microns2 was lower (between 7 and 10%) in both the spaceflight and the spaceflight plus recovery groups compared to the appropriate control groups. The reduction in the oxidative capacity of a subpopulation of sensory neurons having relatively large cross-sectional areas immediately following spaceflight and the sustained depression for nine days after returning to 1 g suggest that the 0 g environment induced significant alterations in proprioceptive function.

  16. Aldehyde Dehydrogenase Type 2 Activation by Adenosine and Histamine Inhibits Ischemic Norepinephrine Release in Cardiac Sympathetic Neurons: Mediation by Protein Kinase Cε

    Robador, Pablo A.; Seyedi, Nahid; Chan, Noel Yan-Ki; Koda, Kenichiro; Levi, Roberto

    2012-01-01

    During myocardial ischemia/reperfusion, lipid peroxidation leads to the formation of toxic aldehydes that contribute to ischemic dysfunction. Mitochondrial aldehyde dehydrogenase type 2 (ALDH2) alleviates ischemic heart damage and reperfusion arrhythmias via aldehyde detoxification. Because excessive norepinephrine release in the heart is a pivotal arrhythmogenic mechanism, we hypothesized that neuronal ALDH2 activation might diminish ischemic norepinephrine release. Incubation of cardiac sym...

  17. Burst of succinate dehydrogenase and α-ketoglutarate dehydrogenase activity in concert with the expression of genes coding for respiratory chain proteins underlies short-term beneficial physiological stress in mitochondria.

    Zakharchenko, Marina V; Zakharchenko, A V; Khunderyakova, N V; Tutukina, M N; Simonova, M A; Vasilieva, A A; Romanova, O I; Fedotcheva, N I; Litvinova, E G; Maevsky, E I; Zinchenko, V P; Berezhnov, A V; Morgunov, I G; Gulayev, A A; Kondrashova, M N

    2013-01-01

    Conditions for the realization in rats of moderate physiological stress (PHS) (30-120 min) were selected, which preferentially increase adaptive restorative processes without adverse responses typical of harmful stress (HST). The succinate dehydrogenase (SDH) and α-ketoglutarate dehydrogenase (KDH) activity and the formation of reactive oxygen species (ROS) in mitochondria were measured in lymphocytes by the cytobiochemical method, which detects the regulation of mitochondria in the organism with high sensitivity. These mitochondrial markers undergo an initial 10-20-fold burst of activity followed by a decrease to a level exceeding the quiescent state 2-3-fold by 120 min of PHS. By 30-60 min, the rise in SDH activity was greater than in KDH activity, while the activity of KDH prevailed over that of SDH by 120 min. The attenuation of SDH hyperactivity during PHS occurs by a mechanism other than oxaloacetate inhibition developed under HST. The dynamics of SDH and KDH activity corresponds to the known physiological replacement of adrenergic regulation by cholinergic during PHS, which is confirmed here by mitochondrial markers because their activity reflects these two types of nerve regulation, respectively. The domination of cholinergic regulation provides the overrestoration of expenditures for activity. In essence, this phenomenon corresponds to the training of the organism. It was first revealed in mitochondria after a single short-time stress episode. The burst of ROS formation was congruous with changes in SDH and KDH activity, as well as in ucp2 and cox3 expression, while the activity of SDH was inversely dependent on the expression of the gene of its catalytic subunit in the spleen. As the SDH activity enhanced, the expression of the succinate receptor decreased with subsequent dramatic rise when the activity was becoming lower. This article is part of a Directed Issue entitled: Bioenergetic dysfunction, adaption and therapy. PMID:22814171

  18. Communication between thiamin cofactors in the Escherichia coli pyruvate dehydrogenase complex E1 component active centers: evidence for a "direct pathway" between the 4'-aminopyrimidine N1' atoms.

    Nemeria, Natalia S; Arjunan, Palaniappa; Chandrasekhar, Krishnamoorthy; Mossad, Madouna; Tittmann, Kai; Furey, William; Jordan, Frank

    2010-04-01

    Kinetic, spectroscopic, and structural analysis tested the hypothesis that a chain of residues connecting the 4'-aminopyrimidine N1' atoms of thiamin diphosphates (ThDPs) in the two active centers of the Escherichia coli pyruvate dehydrogenase complex E1 component provides a signal transduction pathway. Substitution of the three acidic residues (Glu(571), Glu(235), and Glu(237)) and Arg(606) resulted in impaired binding of the second ThDP, once the first active center was filled, suggesting a pathway for communication between the two ThDPs. 1) Steady-state kinetic and fluorescence quenching studies revealed that upon E571A, E235A, E237A, and R606A substitutions, ThDP binding in the second active center was affected. 2) Analysis of the kinetics of thiazolium C2 hydrogen/deuterium exchange of enzyme-bound ThDP suggests half-of-the-sites reactivity for the E1 component, with fast (activated site) and slow exchanging sites (dormant site). The E235A and E571A variants gave no evidence for the slow exchanging site, indicating that only one of two active sites is filled with ThDP. 3) Titration of the E235A and E237A variants with methyl acetylphosphonate monitored by circular dichroism suggested that only half of the active sites were filled with a covalent predecarboxylation intermediate analog. 4) Crystal structures of E235A and E571A in complex with ThDP revealed the structural basis for the spectroscopic and kinetic observations and showed that either substitution affects cofactor binding, despite the fact that Glu(235) makes no direct contact with the cofactor. The role of the conserved Glu(571) residue in both catalysis and cofactor orientation is revealed by the combined results for the first time. PMID:20106967

  19. Conversion of inactive (phosphorylated) pyruvate dehydrogenase complex into active complex by the phosphate reaction in heart mitochondria is inhibited by alloxan-diabetes or starvation in the rat.

    Hutson, N J; Kerbey, A L; Randle, P J; Sugden, P H

    1978-08-01

    1. The conversion of inactive (phosphorylated) pyruvate dehydrogenase complex into active (dephosphorylated) complex by pyruvate dehydrogenase phosphate phosphatase is inhibited in heart mitochondria prepared from alloxan-diabetic or 48h-starved rats, in mitochondria prepared from acetate-perfused rat hearts and in mitochondria prepared from normal rat hearts incubated with respiratory substrates for 6 min (as compared with 1 min). 2. This conclusion is based on experiments with isolated intact mitochondria in which the pyruvate dehydrogenase kinase reaction was inhibited by pyruvate or ATP depletion (by using oligomycin and carbonyl cyanide m-chlorophenylhydrazone), and in experiments in which the rate of conversion of inactive complex into active complex by the phosphatase was measured in extracts of mitochondria. The inhibition of the phosphatase reaction was seen with constant concentrations of Ca2+ and Mg2+ (activators of the phosphatase). The phosphatase reaction in these mitochondrial extracts was not inhibited when an excess of exogenous pig heart pyruvate dehydrogenase phosphate was used as substrate. It is concluded that this inhibition is due to some factor(s) associated with the substrate (pyruvate dehydrogenase phosphate complex) and not to inhibition of the phosphatase as such. 3. This conclusion was verified by isolating pyruvate dehydrogenase phosphate complex, free of phosphatase, from hearts of control and diabetic rats an from heart mitochondria incubed for 1min (control) or 6min with respiratory substrates. The rates of re-activation of the inactive complexes were then measured with preparations of ox heart or rat heart phosphatase. The rates were lower (relative to controls) with inactive complex from hearts of diabetic rats or from heart mitochondria incubated for 6min with respiratory substrates. 4. The incorporation of 32Pi into inactive complex took 6min to complete in rat heart mitocondria. The extent of incorporation was consistent with

  20. Acid Rain: Activities for Science Teachers.

    Johnson, Eric; And Others

    1983-01-01

    Seven complete secondary/college level acid rain activities are provided. Activities include overview; background information and societal implications; major concepts; student objectives; vocabulary/material lists; procedures; instructional strategies; and questions/discussion and extension suggestions. Activities consider effects of acid rain on…

  1. Preparation of 15N-labeled L-alanine by coupling the alanine dehydrogenase and alcohol dehydrogenase reactions

    A simple enzymatic procedure for the preparation of L-[15N]alanine, one of the metabolically most active amino acids in all types of cells, is reported. The procedure is based on the coupling of two reactions, one catalyzed by bacterial alanine dehydrogenase, the second catalyzed by yeast alcohol dehydrogenase. An impediment in the use of this procedure could be the high cost of commercial AlaDH. However, the enzyme is widespread in the Bacillus species and partially purified samples, adequate preparative purposes, could be obtained relatively easily by chromatography on blue-Sepharose. (Auth.)

  2. Assessment of lactate dehydrogenase, alkaline phosphatase and aspartate aminotransferase activities in cow's milk as an indicator of subclinical mastitis.

    Babaei, H; Mansouri-Najand, L; Molaei, M M; Kheradmand, A; Sharifan, M

    2007-05-01

    This study examined the activities of lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) in the milk of lactating Holstein cows in association with subclinical mastitis (SCM). A total of 94 milk samples were collected from 58 lactating dairy cows representing stages of lactation from the second to the tenth week after calving. Those which were classified as positive by California mastitis test (CMT) were deemed to have subclinical mastitis. All the milk samples were skimmed by centrifugation at 10 000g at 0 degrees C and were used for enzyme activities estimations. The mean activities of LDH and ALP were higher in the milk from udders with SCM than in the milk from healthy udders (p CMT results and LDH and ALP values were seen at thresholds of > 180 IU/L and > 40 IU/L respectively (kappa values 0.65 and 0.79, respectively). However, the sensitivity of the tests for identifying SCM at these thresholds was higher for ALP (96.4%) than for LDH (68.5%). In this study, LDH and ALP tests were standardized for cow's milk and results showed that only the ALP test was reliable in the early diagnosis of subclinical mastitis. PMID:17268916

  3. Effect of organic solvents on the activity and stability of halophilic alcohol dehydrogenase (ADH2) from Haloferax volcanii.

    Alsafadi, Diya; Paradisi, Francesca

    2013-01-01

    The effect of various organic solvents on the catalytic activity, stability and substrate specificity of alchohol dehydrogenase from Haloferax volcanii (HvADH2) was evaluated. The HvADH2 showed remarkable stability and catalysed the reaction in aqueous-organic medium containing dimethyl sulfoxide (DMSO) and methanol (MeOH). Tetrahydrofuran and acetonitrile were also investigated and adversely affected the stability of the enzyme. High concentration of salt, essential to maintain the enzymatic activity and structural integrity of the halophilic enzyme under standard conditions may be partially replaced by DMSO and MeOH. The presence of organic solvents did not induce gross changes in substrate specificity. DMSO offered a protective effect for the stability of the enzyme at nonoptimal pHs such as 6 and 10. Salt and solvent effects on the HvADH2 conformation and folding were examined through fluorescence spectroscopy. The fluorescence findings were consistent with the activity and stability results and corroborated the denaturing properties of some solvents. The intrinsic tolerance of this enzyme to organic solvent makes it highly attractive to industry. PMID:23179592

  4. Activity and electrophoretic profiles of liver aldehyde dehydrogenases from mice of inbred strains with different alcohol preference.

    Yamazaki, H; Nishiguchi, K; Miyamoto, R; Ogita, Z I; Nakanishi, S

    1983-01-01

    1. The activity of low Km-aldehyde dehydrogenase (ALDH) in the liver mitochondrial fraction (MT-fraction) from male C57BL/6J strain mice (alcohol preferring) was significantly higher than that from DBA/2 mice (alcohol avoiding). The F1 hybrids (C57BL/6J X DBA/2) did not exhibit the intermediate activity to these two strains. 2. Strain differences in liver mitochondrial ALDH isozymes were observed by isoelectric focusing. C57BL/6J strain had two isozymes at pH 7.1 while DBA/2 had no band at this pH. F1 hybrid mice had similar two bands with lower density to those of C57BL/6J at pH 7.1. There was no difference in zymograms of the soluble fraction between C57BL/6J and DBA/2 strains. 3. The present results suggest that the difference in alcohol preference of mice may depend on some restricted ALDH isozymes with different pl or electric mobility rather than the enzymatic activity in the liver MT-fraction. PMID:6822317

  5. Biological activities of substituted trichostatic acid derivatives

    Cédric Charrier; Joëlle Roche; Jean-Pierre Gesson; Philippe Bertrand

    2009-07-01

    New substituted trichostatic acid derivatives have been synthesized and evaluated for their biological activities towards the H661 non-small lung cancer cell line. These syntheses were achieved by alkylation of propiophenones to introduce the side chain with a terminal precursor of hydroxamic acid and aminobenzamide derivatives. The first fluorinated derivatives of trichostatic acid are described, such as 6-fluoro trichostatin A, with antiproliferative activities in the micromolar range and with histone deacetylase inhibitory activity.

  6. ANTIMICROBIAL ACTIVITY OF LACTIC ACID BACTERIAL ISOLATES

    Utkarsha S. Shivsharan

    2013-08-01

    Full Text Available Micro-organisms have tendency to produce antimicrobial substances which show biological activity against other kind of micro-organisms. This phenomenon of bacterial antagonism is observed in lactic acid bacteria with competitive advantages. The lactic acid bacteria are commonly present in many fermented products, fruits and milk products. The variety of antimicrobial substances produced by lactic acid bacteria showing good inhibition capacity include production of lactic acid, acetic acid, hydrogen peroxide, carbon dioxide, diacetyl and bacteriocin. Bacteriocins produced by lactic acid bacteria are the subject of intense research because of their antimicrobial activity against food born bacteria such as Listeria monocytogenes, staphylococcus aureus, Bacillus cereus, Clostridium botulinum and several others .Bacteriocins may be bacteriostatic or bactericidal with narrow or broad range of activity. The main of the study was to study the antimicrobial activity of such lactic acid bacterial isolates.

  7. Comparison of Activity of Four Dehydrogenases in Ginseng from Different Origins%不同产地人参中4种脱氢酶活力比较

    杨菲; 赵雨; 王思明; 刘美辰; 李晓华

    2012-01-01

    The aim was to provide theoretical basis for the cultivation and optimization of ginseng.Adopt neutral buffer solution to extract the enzyme solution of Radix Ginseng.The activities of malate dehydrogenase (MDH), lactate dehydrogenase (LDH), alcohol dehydrogenase (ADH) and glucose-6-phosphate dehydrogenase (G6PDH) were detected by spectrophotometry, and compared.The clustering analysis was performed using the software SPSS 13.0 to system for 15 batch sample.There were obvious differences of the activities dehydrogenase of ginseng from different origin.The activities of four dehydrogenases from the same origin were basically same.In Antu County Wanbao Town, MDH, LDH and G6PDH had the highest activities, 124.58 LV(g·FW), 129.88 U/(g·FW) and 109.84 U/(g·FW) respectively.The four kinds of enzymes activity of two origins in Heilongjiang Province were generally low.The sample was divided into four categories.The activities of MDH, LDH, ADH and G6PDH could provide theoretical basis for the cultivation and optimization of ginseng.%为了给人参的培育和优选提供理论依据,采用中性缓冲液提取粗酶液,应用分光光度法对15个不同产地的人参中苹果酸脱氢酶(malate dehydrogenase,MDH)、乳酸脱氢酶(lactate dehydrogenase,LDH)、乙醇脱氢酶(alcohol dehydrogenase,ADH)、葡萄糖-6-磷酸脱氢酶(glucose-6-phosphate dehydrogenase,G6PDH)4种脱氢酶活力进行比较.运用SPSS 13.0软件对15批样品进行系统聚类分析.结果表明不同产地人参脱氢酶活力差别明显,同一产地4种脱氢酶活力趋势基本相同.其中安图县万宝镇的人参样品的MDH、LDH、G6PDH 3种酶活力均是最高值,分别为124.58 U/(g· FW)、129.88 U/(g·FW)、109.84U/(g·FW);黑龙江2个产地的4种酶活力普遍比较低.聚类分析的结果将样品分为4类.MDH、LDH、ADH、G6PDH的活力可以作为人参培育和优选提供理论依据.

  8. Glycyrrhetinic acid, the active principle of licorice, can reduce the thickness of subcutaneous thigh fat through topical application.

    Armanini, Decio; Nacamulli, Davide; Francini-Pesenti, Francesco; Battagin, Giuliana; Ragazzi, Eugenio; Fiore, Cristina

    2005-07-01

    Cortisol is involved in the distribution and deposition of fat, and its action is regulated by the activity of 11beta-hydroxysteroid dehydrogenase. Glycyrrhetinic acid, the active principle of licorice root, blocks 11beta-hydroxysteroid dehydrogenase type 1, thus reducing the availability of cortisol at the level of adipocytes. We evaluated the effect of topical application of a cream containing glycyrrhetinic acid in the thickness of fat at the level of the thigh. Eighteen healthy women (age range 20-33 years) with normal BMI were randomly allocated to treatment, at the level of the dominant thigh, with a cream containing 2.5% glycyrrhetinic acid (n=9) or with a placebo cream containing the excipients alone (n=9). Before and after 1 month of treatment both the circumference and the thickness of the superficial fat layer of the thighs (by ultrasound analysis) were measured. The circumference and the thickness of the superficial fat layer were significantly reduced in comparison to the controlateral untreated thigh and to control subjects treated with the placebo cream. No changes were observed in blood pressure, plasma renin activity, plasma aldosterone or cortisol. The effect of glycyrrhetinic acid on the thickness of subcutaneous fat was likely related to a block of 11beta-hydroxysteroid dehydrogenase type 1 at the level of fat cells; therefore, glycyrrhetinic acid could be effectively used in the reduction of unwanted local fat accumulation. PMID:15894038

  9. Production of lactose-free galacto-oligosaccharide mixtures: comparison of two cellobiose dehydrogenases for the selective oxidation of lactose to lactobionic acid.

    Maischberger, Thomas; Nguyen, Thu-Ha; Sukyai, Prakit; Kittl, Roman; Riva, Sergio; Ludwig, Roland; Haltrich, Dietmar

    2008-08-11

    Galacto-oligosaccharides, complex mixtures of various sugars, are produced by transgalactosylation from lactose using beta-galactosidase and are of great interest for food and feed applications because of their prebiotic properties. Most galacto-oligosaccharide preparations currently available in the market contain a significant amount of monosaccharides and lactose. The mixture of galacto-oligosaccharides (GalOS) in this study produced from lactose using recombinant beta-galactosidase from Lactobacillus reuteri contains 48% monosaccharides, 26.5% lactose and 25.5% GalOS. To remove efficiently both monosaccharides and lactose from this GalOS mixture containing significant amounts of prebiotic non-lactose disaccharides, a biocatalytic approach coupled with subsequent chromatographic steps was used. Lactose was first oxidised to lactobionic acid using fungal cellobiose dehydrogenases, and then lactobionic acid and monosaccharides were removed by ion-exchange and size-exclusion chromatography. Two different cellobiose dehydrogenases (CDH), originating from Sclerotium rolfsii and Myriococcum thermophilum, were compared with respect to their applicability for this process. CDH from S. rolfsii showed higher specificity for the substrate lactose, and only few other components of the GalOS mixture were oxidised during prolonged incubation. Since these sugars were only converted once lactose oxidation was almost complete, careful control of the CDH-catalysed reaction will significantly reduce the undesired oxidation, and hence subsequent removal, of any GalOS components. Removal of ions and monosaccharides by the chromatographic steps gave an essentially pure GalOS product, containing less than 0.3% lactose and monosaccharides, in a yield of 60.3%. PMID:18353295

  10. Alcohol dehydrogenase gene ADH3 activates glucose alcoholic fermentation in genetically engineered Dekkera bruxellensis yeast

    Schifferdecker, Anna Judith; Siurkus, Juozas; Andersen, Mikael Rørdam; Jørck-Ramberg, Dorte; Ling, Zhihao; Zhou, Nerve; Blevins, James E.; Sibirny, Andriy A.; Piškur, Jure; Ishchuk, Olena P

    2016-01-01

    Dekkera bruxellensis is a non-conventional Crabtree-positive yeast with a good ethanol production capability. Compared to Saccharomyces cerevisiae, its tolerance to acidic pH and its utilization of alternative carbon sources make it a promising organism for producing biofuel. In this study, we developed an auxotrophic transformation system and an expression vector, which enabled the manipulation of D. bruxellensis, thereby improving its fermentative performance. Its gene ADH3, coding for alco...

  11. Mixed disulfide formation at Cys141 leads to apparent unidirectional attenuation of Aspergillus niger NADP-glutamate dehydrogenase activity.

    Adhish S Walvekar

    Full Text Available NADP-Glutamate dehydrogenase from Aspergillus niger (AnGDH exhibits sigmoid 2-oxoglutarate saturation. Incubation with 2-hydroxyethyl disulfide (2-HED, the disulfide of 2-mercaptoethanol resulted in preferential attenuation of AnGDH reductive amination (forward activity but with a negligible effect on oxidative deamination (reverse activity, when monitored in the described standard assay. Such a disulfide modified AnGDH displaying less than 1.0% forward reaction rate could be isolated after 2-HED treatment. This unique forward inhibited GDH form (FIGDH, resembling a hypothetical 'one-way' active enzyme, was characterized. Kinetics of 2-HED mediated inhibition and protein thiol titrations suggested that a single thiol group is modified in FIGDH. Two site-directed cysteine mutants, C141S and C415S, were constructed to identify the relevant thiol in FIGDH. The forward activity of C141S alone was insensitive to 2-HED, implicating Cys141 in FIGDH formation. It was observed that FIGDH displayed maximal reaction rate only after a pre-incubation with 2-oxoglutarate and NADPH. In addition, compared to the native enzyme, FIGDH showed a four fold increase in K0.5 for 2-oxoglutarate and a two fold increase in the Michaelis constants for ammonium and NADPH. With no change in the GDH reaction equilibrium constant, the FIGDH catalyzed rate of approach to equilibrium from reductive amination side was sluggish. Altered kinetic properties of FIGDH at least partly account for the observed apparent loss of forward activity when monitored under defined assay conditions. In sum, although Cys141 is catalytically not essential, its covalent modification provides a striking example of converting the biosynthetic AnGDH into a catabolic enzyme.

  12. Constitutive NADPH-Dependent Electron Transferase Activity of the Nox4 Dehydrogenase Domain†

    Nisimoto, Yukio; Jackson, Heather M.; Ogawa, Hisamitsu; Kawahara, Tsukasa; Lambeth, J. David

    2010-01-01

    NADPH oxidase 4 (Nox4) is constitutively active, while Nox2 requires the cytosolic regulatory subunits p47 phox and p67 phox and activated Rac with activation by phorbol 12-myristate 13-acetate (PMA). This study was undertaken to identify the domain on Nox4 that confers constitutive activity. Lysates from Nox4-expressing cells exhibited constitutive NADPH- but not NADH-dependent hydrogen peroxide production with a K m for NADPH of 55 ± 10 μM. The concentration of Nox4 in cell lysates was esti...

  13. Affinity alkylators, 11α-bromoacetoxyprogesterone and estrone 3-bromoacetate, modify a common active site-histidine in human placental 17β,20-α-hydroxysteroid dehydrogenase

    Purified human placental 17β,20α-hydroxysteroid dehydrogenase (17,20-HSD), after complete inactivation by estrone 3-bromoacetate (3-BAE) in the presence of NADPH, was reactivated to 100% activity by base-catalyzed hydrolysis of the steroidal ester-enzyme conjugate and then repurified. Computer modeling predicted that 3-BAE and 11α-bromoacetoxyprogesterone (11-BAP) alkylate a common region of the enzyme active site. Kinetic studies argued that reactivated enzyme (RE) and native enzyme (NE) bind 11-BAP in the same orientation. 11-14C-BAP produced 5-fold less radiolabeled 3-(carboxymethyl)histidine (3-CM-His) in RE than in NE. Despite having the same affinity for RE and NE, 11-BAP re-inactivated RE5-fold slower than NE. These results demonstrate that the nonradiolabeled 3-CM-His originally produced by 3-BAE in the enzyme active site hindered radioalkylation of this histidyl reside in RE by 11-14C-BAP. Thus, 11-BAP and 3-BAE modify a common histidine in the enzyme active site, and this is direct evidence that the estradiol 17β-dehydrogenase and 20α-hydroxysteroid dehydrogenase activities of 17,20-HSD reside at a single locus on one protein

  14. Lipoxygenase inhibitory activity of anacardic acids.

    Ha, Tae Joung; Kubo, Isao

    2005-06-01

    6[8'(Z)-pentadecenyl]salicylic acid, otherwise known as anacardic acid (C15:1), inhibited the linoleic acid peroxidation catalyzed by soybean lipoxygenase-1 (EC 1.13.11.12, type 1) with an IC50 of 6.8 microM. The inhibition of the enzyme by anacardic acid (C15:1) is a slow and reversible reaction without residual activity. The inhibition kinetics analyzed by Dixon plots indicates that anacardic acid (C15:1) is a competitive inhibitor and the inhibition constant, KI, was obtained as 2.8 microM. Although anacardic acid (C15:1) inhibited the linoleic acid peroxidation without being oxidized, 6[8'(Z),11'(Z)-pentadecadienyl]salicylic acid, otherwise known as anacardic acid (C15:2), was dioxygenated at low concentrations as a substrate. In addition, anacardic acid (C15:2) was also found to exhibit time-dependent inhibition of lipoxygenase-1. The alk(en)yl side chain of anacardic acids is essential to elicit the inhibitory activity. However, the hydrophobic interaction alone is not enough because cardanol (C15:1), which possesses the same side chain as anacardic acid (C15:1), acted neither as a substrate nor as an inhibitor. PMID:15913294

  15. EFFECT OF TRIGONELLA FOENUM GRAECUM ON LACTATE DEHYDROGENASE (LDH ACTIVITY OF BLOOD, LIVER AND PANCREAS IN NORMAL AND ALLOXAN- INDUCED DIABETIC MICE

    Sekaran Sridhar et al.

    2012-02-01

    Full Text Available The effect of aqueous seeds extract of Trigonella foenum graecum Linn was studied on Lactate dehydrogenase (LDH activity of blood, liver and pancreas in normal and alloxan- induced diabetic mice. Our study showed that aqueous seeds extract, Oral administration of 50 mg/animal (0.5 ml of extract in alternative days up to 7 days (1st, 3rd, 5th & 7th day. In alloxan induced diabetic mice, there was a significant increase in LDH activity of all the three tissues. The enzyme Lactate dehydrogenase showed significant decrease in the diabetic group treated with aqueous extract of tested plant when compared with the diabetic group. It is clear from the current data in this study that ginseng aqueous extract was the most efficient of the tested plant.

  16. Effects of L-carnitine and Pentoxifylline on the Activity of Lactate Dehydrogenase C4 isozyme and Motility of Testicular Spermatozoa in Mice

    Aliabadi, Elham; Karimi, Fatemeh; Rasti, Mozhgan; Akmali, Masoumeh; Esmaeilpour, Tahereh

    2013-01-01

    Background Extracted sperm from the testis have poor motility. Moreover, their motility changes during their journey through epidydimis. Meanwhile, they face high concentration of L-carnitin. In addition, lactate dehydrogenase C4 (LDH-C4) gene disorders has been shown to cause impaired sperm motility, leading to infertility in male mice. The aim of this study was to evaluate sperm motility and LDH-C4 enzyme activity upon L-carnitine (LC) and Pentoxifylline (PTX) administrations in mice. Metho...

  17. Evaluation of Milk Trace Elements, Lactate Dehydrogenase, Alkaline Phosphatase and Aspartate Aminotransferase Activity of Subclinical Mastitis as and Indicator of Subclinical Mastitis in Riverine Buffalo (Bubalus bubalis)

    Guha, Anirban; Gera, Sandeep; Sharma, Anshu

    2012-01-01

    Mastitis is a highly morbid disease that requires detection at the subclinical stage. Tropical countries like India mainly depend on milch buffaloes for milk. The present study was conducted to investigate whether the trace minerals viz. copper (Cu), iron (Fe), zinc (Zn), cobalt (Co) and manganese (Mn) and enzyme activity of lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) in riverine buffalo milk can be used as an indicator of subclinical mastitis ...

  18. Molybdenum center of xanthine dehydrogenase

    Cyanolysis of native, oxidized xanthine dehydrogenase is known to inactivate the enzyme by removing a unique sulfur as thiocyanate. Chemical, genetic, and spectroscopic evidence indicates that this sulfur is a terminal ligand of Mo and is present in native xanthine dehydrogenase, but not in cyanolyzed xanthine dehydrogenase or native sulfite oxidase. A procedure for rapid, reproducible, and quantitative reconstitution of desulfo Mo hydroxylases with sulfide was developed. The cyanolyzable sulfur of xanthine dehydrogenase was specifically radiolabeled with 35sulfide using this procedure. Various chemical properties of the cyanolyzable sulfur could be determined with the radiolabelled enzyme. The data support the conclusion that the cyanolyzable sulfur is a terminal sulfur ligand of the Mo atoms, and is not part of an organic moiety. Application of the resulfuration procedure to crude extracts of Drosophila melanogaster ma-1 flies, which are pleiotropically deficient in xanthine dehydrogenase and aldehyde oxidase, led to the emergence of these enzyme activities. Evidence for the identity of in vitro reconstituted xanthine dehydrogenase from ma-1 mutants with wild type enzyme is presented. A system for efficient reconstitution of the apo-subunits of the molybdoenzyme nitrate reductase from the Neurospora crassa mutant nit-1 with molybdenum cofactor from denatured purified molybdoenzymes in the absence of exogenous molybdate was developed

  19. Effects of the cofactor binding sites on the activities of secondary alcohol dehydrogenase (SADH).

    Wang, Tao; Chen, Xiangjun; Han, Jun; Ma, Sichun; Wang, Jianmei; Li, Xufeng; Zhang, Hui; Liu, Zhibin; Yang, Yi

    2016-07-01

    SADHs from Thermoanaerobacter ethanolicus are enzymes that, together with various cofactors, catalyze the reversible reduction of carbonyl compounds to their corresponding alcohols. To explore how cofactors bind to SADH, TeSADH was cloned in this study, and Ser(199) and Arg(200) were replaced by Tyr and Asp, respectively. Both sites were expected to be inside or adjacent to the cofactor-binding domain according to computational a prediction. Analysis of TeSADH activities revealed that the enzymatic efficiency (kcat/Km) of the S199Y mutant was noticeably enhanced using by NADH, NADPH as cofactors, and similar with that of wild-type using by NADP(+), NAD(+). Conversely, the activity of the R200D mutant significantly decreased with all cofactors. Furthermore, in yeast, the S199Y mutant substantially elevated the ethanol concentration compared with the wild type. Molecular dynamics simulation results indicated the H-bonding network between TeSADH and the cofactors was stronger for the S199Y mutant and the binding energy was simultaneously increased. Moreover, the fluorescence results indicated the S199Y mutant exhibited an increased preference for NAD(P)H, binding with NAD(P)H more compactly compared with wild type. PMID:27016086

  20. NAD- and NADP-dependent 7alpha-hydroxysteroid dehydrogenases from bacteroides fragilis.

    Macdonald, I A; Williams, C N; Mahony, D E; Christie, W M

    1975-03-28

    Twenty strains of Bacteroides fragilis were screened for hydroxysteroid oxidoreductase activity in cell-free preparations. Eighteen strains were shown to contain NAD-dependent 7alpha-hydroxysteroid dehydrogenase. Sixteen of the strains containing the NAD-dependent enzyme also contained NADP-depedent 7alpha-hydroxysteroid dehydrogenase, but invariably in lesser amounts. A strain particulary rich in both 7alpha-hydroxysteroid dehydrogenase activities was selected for further study. Measurement of activity as a function of pH revealed a fairly sharp optimal activity range of 9.5--10.0 for the NAD-dependent enzyme and a broad flat optimal range of 7.0--9.0 for the NADP-dependent enzyme. Michaelis constants for trihydroxy-bile acids for the NAD-dependent enzyme were in the range of 0.32--0.34 mM, whereas dihydroxy-bile acids gave a Km of 0.1 mM. Thin-layer chromatography studies on the oxidation product of 3alpha, 7alpha-dihydroxy-5beta-cholanoic acid (chenodeoxycholic acid) by the dehydrogenase revealed a band corresponding to that of synthetic 3alpha-hydroxy, 7-keto-5beta-cholanoic acid. Similarly the oxidation product of chenodeoxycholic acid by both 7alpha-hydroxysteroid dehydrogenase and commercially available 3alpha-hy-droxysteroid dehydrogenase revealed a band corresponding to that of synthetic 3,7-diketo-5beta-cholanoic acid. Neither of these two oxidation products could be distinguished from those by the Escherichia coli dehydrogenase oxidation previously reported. Disc-gel electrophoresis of a cell-free lyophilized preparation indicated one active band for NAD-dependent activity of mobility similar to that for the NADP-dependent E. coli enzyme. The NADP-dependent dehydrogenase was unstable and rapidly lost activity after polyacylamide disc-gel electrophoresis, ultracentrifugation, freezing on refrigeration at 4 degrees C. No 3 alpha- or 12alpha-oriented oxidoreductase activity was demonstrated in any of the strains examined. PMID:236764

  1. Enhanced enzymatic activity of glycerol-3-phosphate dehydrogenase from the cryophilic Saccharomyces kudriavzevii.

    Bruno M Oliveira

    Full Text Available During the evolution of the different species classified within the Saccharomyces genus, each one has adapted to live in different environments. One of the most important parameters that have influenced the evolution of Saccharomyces species is the temperature. Here we have focused on the study of the ability of certain species as Saccharomyces kudriavzevii to grow at low temperatures, in contrast to Saccharomyces cerevisiae. We observed that S. kudriavzevii strains isolated from several regions are able to synthesize higher amounts of glycerol, a molecule that has been shown to accumulate in response to freeze and cold stress. To explain this observation at the molecular level we studied the expression of glycerol biosynthetic pathway genes and we observed a higher expression of GPD1 gene in S. kudriavzevii compared to S. cerevisiae in micro-vinification conditions. We observed higher enzymatic activity of Gpd1p in S. kudriavzevii in response to osmotic and cold stress. Also, we determined that S. kudriavzevii Gpd1p enzyme presents increased catalytic properties that will contribute to increase glycerol production. Finally, we evaluated the glycerol production with S. cerevisiae, S. kudriavzevii or a recombinant Gpd1p variant in the same background and observed that the S. kudriavzevii enzyme produced increased glycerol levels at 12 or 28°C. This suggests that glycerol is increased in S. kudriavzevii mainly due to increased V max of the Gpd1p enzyme. All these differences indicate that S. kudriavzevii has changed the metabolism to promote the branch of the glycolytic pathway involved in glycerol production to adapt to low temperature environments and maintain the NAD(+/NADH ratio in alcoholic fermentations. This knowledge is industrially relevant due to the potential use, for example, of S. cerevisiae-S. kudriavzevii hybrids in the wine industry where glycerol content is an important quality parameter.

  2. Elevated lactate dehydrogenase activity and increased cardiovascular mortality in the arsenic-endemic areas of southwestern Taiwan

    Arsenic ingestion has been linked to increasing global prevalence of and mortality from cardiovascular disease (CVD); arsenic can be removed from drinking water to reduce related health effects. Lactate dehydrogenase (LDH) is used for the evaluation of acute arsenic toxicity in vivo and in vitro, but it is not validated for the evaluation of long-term, chronic arsenic exposure. The present study examined the long-term effect of chronic arsenic exposure on CVD and serum LDH levels, after consideration of arsenic metabolism capacity. A total of 380 subjects from an arseniasis-endemic area and 303 from a non-endemic area of southwestern Taiwan were recruited in 2002. Various urinary arsenic species were analyzed using high-performance liquid chromatography (HPLC) and hydride generation systems. Fasting serum was used for quantitative determination of the total LDH activity. A significant dose–response relationship was observed between arsenic exposure and LDH elevation, independent of urinary arsenic profiles (P < 0.001). Furthermore, abnormal LDH elevation was associated with CVD mortality after adjustment for Framingham risk scores for 10-year CVD and arsenic exposure (hazard ratio, 3.98; 95% confidence interval, 1.07–14.81). LDH was elevated in subjects with arsenic exposure in a dose-dependent manner. LDH is a marker of arsenic toxicity associated with CVD mortality. Results of this study have important implications for use in ascertaining long-term arsenic exposure risk of CVD. -- Highlights: ► We showed that arsenic exposure was correlated with LDH elevation. ► LDH elevation was related to arsenic methylation capacity. ► Abnormal LDH elevation can be a marker of susceptibility to CVD mortality.

  3. Effect of Follicular Fluid and Platelet-Activating Factor on Lactate Dehydrogenase C Expression in Human Asthenozoospermic Samples

    Tahereh Esmaeilpour

    2014-01-01

    Full Text Available Background: Application of follicular fluid (FF and platelet-activating factor (PAF in artificial insemination improves sperm motility. Lactate dehydrogenase C (LDH-C is a key enzyme for sperm motility. In this study, the effects of FF and PAF on the sperm motility index and LDH-C expression were investigated. Moreover, LDH-C expression was compared between asthenozoospermic and normozoospermic samples. Methods: The expression of LDH-C was examined by quantitative real-time polymerase chain reaction (q-RT PCR and western blotting after it was treated with optimized concentrations of FF and PAF in twenty asthenozoospermic samples. Also, LDH-C expression was evaluated in five normozoospermic samples. Results: Samples with 75% FF and 100 nM of PAF had an increase in their percentages of progressive and slowly motile sperms and a decrease in their percentages of non-progressive and non-motile sperms. Moreover, LDH-C mRNA transcripts were not changed following PAF and FF treatment, and LDH-C protein was detected in highly progressive motile specimens treated with FF in the asthenozoospermic samples. Furthermore, LDH-C expression was more detectable in the normal sperms. Conclusion: Our results indicated that PAF had more beneficial effects than FF on sperm motility in the asthenozoospermic samples (P=0.0001, although the LDH-C expressions of the sperms were not changed significantly in both groups. We found no association between LDH-C expression and sperm motility after FF and PAF actions. This finding, however, requires further investigation. The fact that LDH-C protein was detected in the normozoospermic, but not asthenozoospermic, samples could be cited as a reason for the infertility in these patients.

  4. Role of 11β-hydroxysteroid dehydrogenase 2 renal activity in potassium homeostasis in rats with chronic renal failure

    N.L. Yeyati

    2010-01-01

    Full Text Available Aldosterone concentrations vary in advanced chronic renal failure (CRF. The isozyme 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2, which confers aldosterone specificity for mineralocorticoid receptors in distal tubules and collecting ducts, has been reported to be decreased or normal in patients with renal diseases. Our objective was to determine the role of aldosterone and 11β-HSD2 renal microsome activity, normalized for glomerular filtration rate (GFR, in maintaining K+ homeostasis in 5/6 nephrectomized rats. Male Wistar rats weighing 180-220 g at the beginning of the study were used. Rats with experimental CRF obtained by 5/6 nephrectomy (N = 9 and sham rats (N = 10 were maintained for 4 months. Systolic blood pressure and plasma creatinine (Pcr concentration were measured at the end of the experiment. Sodium and potassium excretion and GFR were evaluated before and after spironolactone administration (10 mg·kg-1·day-1 for 7 days and 11β-HSD2 activity on renal microsomes was determined. Systolic blood pressure (means ± SEM; Sham = 105 ± 8 and CRF = 149 ± 10 mmHg and Pcr (Sham = 0.42 ± 0.03 and CRF = 2.53 ± 0.26 mg/dL were higher (P < 0.05 while GFR (Sham = 1.46 ± 0.26 and CRF = 0.61 ± 0.06 mL/min was lower (P < 0.05 in CRF, and plasma aldosterone (Pald was the same in the two groups. Urinary sodium and potassium excretion was similar in the two groups under basal conditions but, after spironolactone treatment, only potassium excretion was decreased in CRF rats (sham = 0.95 ± 0.090 (before vs 0.89 ± 0.09 µEq/min (after and CRF = 1.05 ± 0.05 (before vs 0.37 ± 0.07 µEq/min (after; P < 0.05. 11β-HSD2 activity on renal microsomes was lower in CRF rats (sham = 0.807 ± 0.09 and CRF = 0.217 ± 0.07 nmol·min-1·mg protein-1; P < 0.05, although when normalized for mL GFR it was similar in both groups. We conclude that K+ homeostasis is maintained during CRF development despite normal Pald levels. This adaptation may be mediated by

  5. The effects of chemical and radioactive properties of Tl-201 on human erythrocyte glucose 6-phosphate dehydrogenase activity

    Sahin, Ali [Faculty of Medicine, Department of Nuclear Medicine, Ataturk University, Erzurum 25240 (Turkey)], E-mail: alibabam2001@yahoo.com; Senturk, Murat [Science Faculty, Department of Chemistry, Ataturk University, Erzurum 25240 (Turkey); Ciftci, Mehmet [Science and Arts Faculty, Department of Chemistry, Agri Ibrahim Cecen University, 04100, Agri (Turkey); Varoglu, Erhan [Faculty of Medicine, Department of Nuclear Medicine, Ataturk University, Erzurum 25240 (Turkey); Kufrevioglu, Omer Irfan [Science and Arts Faculty, Department of Chemistry, Agri Ibrahim Cecen University, 04100, Agri (Turkey)

    2010-04-15

    Aim: The inhibitory effects of thallium-201 ({sup 201}Tl) solution on human erythrocyte glucose 6-phosphate dehydrogenase (G6PD) activity were investigated. Methods: For this purpose, erythrocyte G6PD was initially purified 835-fold at a yield of 41.7% using 2',5'-Adenosine diphosphate sepharose 4B affinity gel chromatography. The purification was monitored by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which showed a single band for the final enzyme preparation. The in vitro and in vivo effects of the {sup 201}Tl solution including Tl{sup +}, Fe{sup +3} and Cu{sup +2} metals and the in vitro effects of the radiation effect of the {sup 201}Tl solution and non-radioactive Tl{sup +}, Fe{sup +3} and Cu{sup +2} metals on human erythrocyte G6PD enzyme were studied. Enzyme activity was determined with the Beutler method at 340 nm using a spectrophotometer. All purification procedures were carried out at +4 deg. C. Results: {sup 201}Tl solution and radiation exposure had inhibitory effects on the enzyme activity. IC{sub 50} value of {sup 201}Tl solution was 36.86 {mu}l ([Tl{sup +}]: 0.0036 {mu}M, [Cu{sup +2}]: 0.0116 {mu}M, [Fe{sup +3}]: 0.0132 {mu}M), of human erythrocytes G6PD. Seven human patients were also used for in vivo studies of {sup 201}Tl solution. Furthermore, non-radioactive Tl{sup +}, Fe{sup +3} and Cu{sup +2} were found not to have influenced the enzyme in vitro. Conclusion: Human erythrocyte G6PD activity was inhibited by exposure for up to 10 minutes to 0.057 mCi/kg {sup 201}Tl solution. It was detected in in vitro and in vivo studies that the human erythrocyte G6PD enzyme is inhibited due to the radiation effect of {sup 201}Tl solution.

  6. Structural characterization of a β-hydroxyacid dehydrogenase from Geobacter sulfurreducens and Geobacter metallireducens with succinic semialdehyde reductase activity

    Zhang, Yanfeng; Zheng, Yi; Qin, Ling; Wang, Shihua; Buchko, Garry W.; Garavito, Michael R.

    2014-07-30

    Beta-hydroxyacid dehydrogenase (β-HAD) genes have been identified in all sequenced genomes of eukaryotes and prokaryotes. Their gene products catalyze the NAD+- or NADP+-dependent oxidation of various β-hydroxy acid substrates into their corresponding semialdehyde. In many fungal and bacterial genomes, multiple β-HAD genes are observed leading to the hypothesis that these gene products may have unique, uncharacterized metabolic roles specific to their species. The genomes of Geobacter sulfurreducens and Geobacter metallireducens each contain two potential β-HAD genes. The protein sequences of one pair of these genes, Gs-βHAD (Q74DE4) and Gm-βHAD (Q39R98), have 65% sequence identity and 77% sequence similarity with each other. Both proteins reduce succinic semialdehyde, a metabolite of the GABA shunt. To further explore the structural and functional characteristics of these two β-HADs with a potentially unique substrate specificity, crystal structures for Gs-βHAD and Gm-βHAD in complex with NADP+ were determined to a resolution of 1.89 Å and 2.07 Å, respectively. The structure of both proteins are similar, composed of 14 α-helices and nine β-strands organized into two domains. Domain One (1-165) adopts a typical Rossmann fold composed of two α/β units: a six-strand parallel β-sheet surrounded by six α-helices (α1 – α6) followed by a mixed three-strand β-sheet surrounded by two α-helices (α7 and α8). Domain Two (166-287) is composed of a bundle of seven α-helices (α9 – α14). Four functional regions conserved in all β-HADs are spatially located near each other at the interdomain cleft in both Gs-βHAD and Gm-βHAD with a buried molecule of NADP+. The structural features of Gs-βHAD and Gm-βHAD are described in relation to the four conserved consensus sequences characteristic of β-HADs and the potential biochemical importance of these enzymes as an alternative pathway for the degradation of succinic semialdehyde.

  7. Retinol dehydrogenase 10 is indispensible for spermatogenesis in juvenile males

    Tong, Ming-Han; Yang, Qi-En; Davis, Jeffrey C.; Griswold, Michael D.

    2012-01-01

    Retinoic acid (RA), an active vitamin A derivative, is essential for mammalian spermatogenesis. Genetic studies have revealed that oxidation of vitamin A to retinal by retinol dehydrogenase 10 (RDH10) is critical for embryonic RA biosynthesis. However, physiological roles of RDH10 in postnatal RA synthesis remain unclear, given that Rdh10 loss-of-function mutations lead to early embryonic lethality. We conducted in vivo genetic studies of Rdh10 in postnatal mouse testes and found that an RDH1...

  8. Atividade da 6-fosfogliconato desidrogenase em deficientes de glicose-6-fosfato desidrogenase Activity of 6-phosphogluconate dehydrogenase in glucose-6-phosphate dehydrogenase deficiency

    Daniela B. Nicolielo

    2006-06-01

    to know better the actuation of these enzymes. The goal of this study was to evaluate the 6PGD enzymatic activity on a population with G6PD deficiency, to verify if there is an elevation of the activity of this enzyme, and try to correlate to a possible increase on the number of reticulocytes or the presence of alterations on red series. The research with 2657 male individuals detected 97 deficient for G6PD, which determined a 3.65% prevalence for the Bauru (SP region, with mean enzymatic activity of 1.74 UI.g Hb-1. min-1 at 37ºC, 14,4% of the normal G6PD activity. Mean 6PGD enzymatic activity was 9.5 UI.g Hb-1. min-1 at 37ºC, and was elevated in 47.4% of the G6PD deficient individuals. The result obtained did not confirm the hypothesis that the elevation of the 6PGD enzymatic activity, in G6PD deficient individuals, was due to the presence of an increase of reticulocytes in blood stream, age or erythrocytometric alterations that could denote anemia. The most plausible theory is that the auto-limited hemolysis, imposed by oxidative processes, preserves young erythrocytes that have an elevated enzymatic activity, as naturally these enzymes lose activity with cellular aging.

  9. Regenerative Capacity of Cacti Schlumbergera and Rhipsalidopsis in Relation to Endogenous Phytohormones, Cytokinin Oxidase/Dehydrogenase, and Peroxidase Activities

    Sriskandarajah, S.; Prinsen, E.; Motyka, Václav; Dobrev, Petre; Serek, M.

    2006-01-01

    Roč. 25, č. 1 (2006), s. 79-88. ISSN 0721-7595 R&D Projects: GA ČR GA206/03/0313 Institutional research plan: CEZ:AV0Z50380511 Keywords : Cytokinin dehydrogenase * Cytokinin oxidase * Endogenous phytohormones * In vitro regeneration * Peroxidase * Rhipsalidopsis * Schlumbergera Subject RIV: EF - Botanics Impact factor: 2.107, year: 2006

  10. Characterization of 17α-hydroxysteroid dehydrogenase activity (17α-HSD and its involvement in the biosynthesis of epitestosterone

    Breton Rock

    2005-07-01

    Full Text Available Abstract Background Epi-testosterone (epiT is the 17α-epimer of testosterone. It has been found at similar level as testosterone in human biological fluids. This steroid has thus been used as a natural internal standard for assessing testosterone abuse in sports. EpiT has been also shown to accumulate in mammary cyst fluid and in human prostate. It was found to possess antiandrogenic activity as well as neuroprotective effects. So far, the exact pathway leading to the formation of epiT has not been elucidated. Results In this report, we describe the isolation and characterization of the enzyme 17α-hydroxysteroid dehydrogenase. The name is given according to its most potent activity. Using cells stably expressing the enzyme, we show that 17α-HSD catalyzes efficienty the transformation of 4-androstenedione (4-dione, dehydroepiandrosterone (DHEA, 5α-androstane-3,17-dione (5α-dione and androsterone (ADT into their corresponding 17α-hydroxy-steroids : epiT, 5-androstene-3β,17α-diol (epi5diol, 5α-androstane-17α-ol-3-one (epiDHT and 5α-androstane-3α,17α-diol (epi3α-diol, respectively. Similar to other members of the aldo-keto reductase family that possess the ability to reduce the keto-group into hydroxyl-group at different position on the steroid nucleus, 17α-HSD could also catalyze the transformation of DHT, 5α-dione, and 5α-pregnane-3,20-dione (DHP into 3α-diol, ADT and 5α-pregnane-3α-ol-20-one (allopregnanolone through its less potent 3α-HSD activity. We also have over-expressed the 17α-HSD in Escherichia coli and have purified it by affinity chromatography. The purified enzyme exhibits the same catalytic properties that have been observed with cultured HEK-293 stably transfected cells. Using quantitative Realtime-PCR to study tissue distribution of this enzyme in the mouse, we observed that it is expressed at very high levels in the kidney. Conclusion The present study permits to clarify the biosynthesis pathway of epiT. It

  11. Glucose-6-phosphate dehydrogenase and glutathione reductase activity in methemoglobin reduction by methylene blue and cyst amine: study on glucose-6-phosphate dehydrogenase-deficient individuals, on normal subjects and on riboflavin-treated subjects

    Benedito Barraviera

    1988-10-01

    Full Text Available The authors have standardized methods for evaluation of the activity of the glucose-6-phosphate dehydrogenase and of glutathione reductase. The general principle of the first method was based on methemoglobin formation by sodium nitrite followed by stimulation of the glucose-6-phosphate dehydrogenase with methylene blue. Forty six adults (23 males and 23 females were studied. Subjects were not G6PD deficient and were aged 20 to 30 years. The results showed that methemoglobin reduction by methylene blue was 154.40 and 139.90 mg/min (p<0.05 for males and females, respectively, in whole blood, and 221.10 and 207.85 mg/min (n.s., respectively, in washed red cells. These data showed that using washed red cells and 0.7g% sodium nitrite concentration produced no differences between sexes and also shortened reading time for the residual amount of methemoglobin to 90 minutes. Glutathione reductase activity was evaluated on the basis of the fact that cystamine (a thiol agent binds to the SH groups of hemoglobin, forming complexes. These complexes are reversed by the action of glutathione reductase, with methemoglobin reduction occurring simultaneously with this reaction. Thirty two adults (16 males and 16 females were studied. Subjects were not G6PD deficient and were aged 20 to 30 years. Methemoglobin reduction by cystamine was 81.27 and 91.13 mg/min (p<0.01 for males and females, respectively. These data showed that using washed red cells and 0.1 M cystamine concentration permits a reading of the residual amount of methemoglobin at 180 minutes of incubation. Glutathione reductase activity was evaluated by methemoglobin reduction by cystamine in 14 females before and after treatment with 10 mg riboflavin per day for 8 days. The results were 73.69 and 94.26 jug/min (p<0.01 before and after treatment, showing that riboflavin treatment increase glutathione reductase activity even in normal individuals. Three Black G6PD-deficient individuals (2 males and 1

  12. Influence of long-term hyper-gravity on the reactivity of succinic acid dehydrogenase and NADPH-diaphorase in the central nervous system of fish: a histochemical study

    Anken, R. H.; Rahmann, H.

    In the course of a densitometric evaluation, the histochemically demonstrated reactivity of succinic acid dehydrogenase (SDH) and of NADPH-diaphorase (NADPHD) was determined in different brain nuclei of two teleost fish (cichlid fish Oreochromis mossambicus, swordtail fish Xiphophorus helleri), which had been kept under 3g hyper-gravity for 8 days. SDH was chosen since it is a rate limiting enzyme of the Krebs cycle and therefore it is regarded as a marker for metabolic and neuronal activity. NADPHD reactivity reflects the activity of nitric oxide synthase. Nitric oxide (NO) is a gaseous intercellular messenger that has been suggested to play a major role in several different in vivo models of neuronal plasticity including learning. Within particular vestibulum-connected brain centers, significant effects of hyper-gravity were obtained, e.g., in the magnocellular nucleus, a primary vestibular relay ganglion of the brain stem octavolateralis area, in the superior rectus subdivision of the oculomotoric nucleus and within cerebellar eurydendroid cells, which in teleosts possibly resemble the deep cerebellar nucleus of higher vertebrates. Non-vestibulum related nuclei did not respond to hypergravity in a significant way. The effect of hyper-gravity found was much less distinct in adult animals as compared to the circumstances seen in larval fish (Anken et al., Adv. Space Res. 17, 1996), possibly due to a development correlated loss of neuronal plasticity.

  13. Glucose-6-phosphate dehydrogenase

    ... this page: //medlineplus.gov/ency/article/003671.htm Glucose-6-phosphate dehydrogenase test To use the sharing features on this page, please enable JavaScript. Glucose-6-phosphate dehydrogenase (G6PD) is a type of ...

  14. Efficient Production of Optically Pure d-Lactic Acid from Raw Corn Starch by Using a Genetically Modified l-Lactate Dehydrogenase Gene-Deficient and α-Amylase-Secreting Lactobacillus plantarum Strain▿

    Okano, Kenji; Zhang, Qiao; Shinkawa, Satoru; Yoshida, Shogo; Tanaka, Tsutomu; Fukuda, Hideki; Kondo, Akihiko

    2008-01-01

    In order to achieve direct and efficient fermentation of optically pure d-lactic acid from raw corn starch, we constructed l-lactate dehydrogenase gene (ldhL1)-deficient Lactobacillus plantarum and introduced a plasmid encoding Streptococcus bovis 148 α-amylase (AmyA). The resulting strain produced only d-lactic acid from glucose and successfully expressed amyA. With the aid of secreting AmyA, direct d-lactic acid fermentation from raw corn starch was accomplished. After 48 h of fermentation,...

  15. Diagnostic Value of Serum Lactate Dehydrogenase Isoenzyme and Amino Acid Patterns in Several Schistosomal and Non-Schistosomal Disorders as Compared to other Biochemical Parameters

    Samia A. Ahmed

    1996-01-01

    Full Text Available Serum lactate dehydrogenase (LDH isoenzyme and amino acid (a. a patterns were evaluated in comparison to several other biochemical parameters for liver and renal function with the objective of clarifying the differential diagnosis of hepatic disorders and predicting the outcome of schistosomal infection in Egyptian patients. Patients examined included those with complicated hepatic disorders and others with different stages of schistosomal infestation, hepatoma or bladder cancer, in addition to a normal control group. Several biochemical parameters appeared to be useful in establishing consistent differences or similarities between the studied groups. Examples are; elevated serum AST/ AL T ratio and methionine content in chronic schistosomiasis, elevated serum urea/creatinine ratio and leucine content in all schistosomal patients and extremely high levels of N-acetyl-β-D-glucosaminidase (NAG in the urine of non-schistosomal bladder cancer patients. In addition, characteristic LDH isoenzyme profiles distinguish between the studied groups, in particular separating chronic schistosomiasis from schistosomal bladder cancer and hepatoma from other hepatic disorders.

  16. Effect of repeated pesticide applications on soil properties in cotton fields: II. Insecticide residues and impact on dehydrogenase and arginine deaminase activities

    Insecticides were applied sequentially at recommended dosages post crop emergence in cotton fields and soil was sampled at regular intervals after each treatment. Soil was analysed for insecticide residues and activity of the enzymes dehydrogenase and arginine deaminase. Insecticide residues detected in the soil were in small quantities and they did not persist for long. Only endosulfan leached below 15 cm. Insecticides had only temporary effects on enzyme activities which disappeared either before the next insecticide treatment or by the end of the experimental period. (author)

  17. Cytokinin oxidase/dehydrogenase activity as a tool in gibberellic acid/cytokinin cross talk

    Todorova, D.; Vaseva, I.; Malbeck, Jiří; Trávníčková, Alena; Macháčková, Ivana; Karanov, E.

    2007-01-01

    Roč. 51, č. 3 (2007), s. 579-583. ISSN 0006-3134 Institutional research plan: CEZ:AV0Z50380511 Keywords : isopentenyladenine * pea * Pisum sativum * zeatin Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.259, year: 2007

  18. Crystal structure of homoisocitrate dehydrogenase from Schizosaccharomyces pombe

    Bulfer, Stacie L.; Hendershot, Jenna M.; Trievel, Raymond C. (Michigan); (UCSF)

    2013-09-18

    Lysine biosynthesis in fungi, euglena, and certain archaebacteria occurs through the {alpha}-aminoadipate pathway. Enzymes in the first steps of this pathway have been proposed as potential targets for the development of antifungal therapies, as they are absent in animals but are conserved in several pathogenic fungi species, including Candida, Cryptococcus, and Aspergillus. One potential antifungal target in the {alpha}-aminoadipate pathway is the third enzyme in the pathway, homoisocitrate dehydrogenase (HICDH), which catalyzes the divalent metal-dependent conversion of homoisocitrate to 2-oxoadipate (2-OA) using nicotinamide adenine dinucleotide (NAD{sup +}) as a cofactor. HICDH belogns to a family of {beta}-hydroxyacid oxidative decarboxylases that includes malate dehydrogenase, tartrate dehydrogenase, 6-phosphogluconate dehydrogenase, isocitrate dehydrogenase (ICDH), and 3-isopropylmalte dehydrogenase (IPMDH). ICDH and IPMDH are well-characterized enzymes that catalyze the decarboxylation of isocitrate to yield 2-oxoglutarate (2-OG) in the citric acid cycle and the conversion of 3-isopropylmalate to 2-oxoisovalerate in the leucine biosynthetic pathway, respectively. Recent structural and biochemical studies of HICDH reveal that this enzyme shares sequence, structural, and mechanistic homology with ICDH and IPMDH. To date, the only published structures of HICDH are from the archaebacteria Thermus thermophilus (TtHICDH). Fungal HICDHs diverge from TtHICDH in several aspects, including their thermal stability, oligomerization state, and substrate specificity, thus warranting further characterization. To gain insights into these differences, they determined crystal structures of a fungal Schizosaccharomyces pombe HICDH (SpHICDH) as an apoenzyme and as a binary complex with additive tripeptide glycyl-glycyl-glycine (GGG) to 1.55 {angstrom} and 1.85 {angstrom} resolution, respectively. Finally, a comparison of the SpHICDH and TtHICDH structures reveal differences in

  19. Platform Engineering of Corynebacterium glutamicum with Reduced Pyruvate Dehydrogenase Complex Activity for Improved Production of l-Lysine, l-Valine, and 2-Ketoisovalerate

    Buchholz, Jens; Schwentner, Andreas; Brunnenkan, Britta; Gabris, Christina; Grimm, Simon; Gerstmeir, Robert; Takors, Ralf; Eikmanns, Bernhard J.; Blombach, Bastian

    2013-01-01

    Exchange of the native Corynebacterium glutamicum promoter of the aceE gene, encoding the E1p subunit of the pyruvate dehydrogenase complex (PDHC), with mutated dapA promoter variants led to a series of C. glutamicum strains with gradually reduced growth rates and PDHC activities. Upon overexpression of the l-valine biosynthetic genes ilvBNCE, all strains produced l-valine. Among these strains, C. glutamicum aceE A16 (pJC4 ilvBNCE) showed the highest biomass and product yields, and thus it wa...

  20. Activation of AMP-activated protein kinase stimulates the nuclear localization of glyceraldehyde 3-phosphate dehydrogenase in human diploid fibroblasts

    Kwon, Hyun Jin; Rhim, Ji Heon; Jang, Ik-Soon; Kim, Go-Eun; Park, Sang Chul; Yeo, Eui-Ju

    2010-01-01

    In addition to its well-known glycolytic activity, GAPDH displays multiple functions, such as nuclear RNA export, DNA replication and repair, and apoptotic cell death. This functional diversity depends on its intracellular localization. In this study, we explored the signal transduction pathways involved in the nuclear translocation of GAPDH using confocal laser scanning microscopy of immunostained human diploid fibroblasts (HDFs). GAPDH was present mainly in the cytoplasm when cultured wi...

  1. Excitotoxic increase of xanthine dehydrogenase and xanthine oxidase in the rat olfactory cortex.

    Battelli, M G; Buonamici, L; Abbondanza, A; Virgili, M; Contestabile, A; Stirpe, F

    1995-05-26

    Excitotoxic lesions induced by systemic injection of kainic acid, resulted in 2-3-fold increase of xanthine dehydrogenase and xanthine oxidase activities in the rat olfactory cortex 48-72 h after drug administration. A significant increase of the xanthine oxidase/dehydrogenase ratio was also observed at 4 and 48 h post-injection. No similar changes were noticed in the hippocampus. The enhancement of enzyme activity seems to be primarily a consequence of the altered cell composition in damaged area. Free radicals produced by the increased oxygen-dependent form of the enzyme could in turn aggravate the excitotoxic brain injury. PMID:7656426

  2. Improvement of the fermentative activity of lactic acid bacteria starter culture by the addition of Mn²⁺.

    Cheng, Xin; Dong, Ying; Su, Ping; Xiao, Xiang

    2014-11-01

    Production of lactic acid bacteria (LAB) starter with raw material has received much scientific investigation, but little information is available on the influences of some trace elements on the growth and fermentative activity of LAB. Based on this fact, this paper aimed to investigate the effects of Mn(2+) on the performance of Lactobacillus plantarum CX-15 starter with Jerusalem artichoke (JA) as the main medium substrate. The results showed that Mn(2+) addition had a significant beneficial affect on the fermentative activity of L. plantarum CX-15 starter. In contrast, the lack of Mn(2+) would cause the subsequent fermentation significantly slower, whether the cell density in starter culture was higher or lower. The possible mechanism of these phenomenons was further elucidated by the time course analysis of the specific activities of metabolism key enzymes during the culture processes of L. plantarum CX-15 starter. Compared to the fermentation processes without Mn(2+) addition, it was found that Mn(2+) addition would enhance the lactate dehydrogenase (LDH) activity but reduce the activities of pyruvate dehydrogenase (PDH) and ATPase activity. Therefore, it could be concluded that the improvement of L. plantarum starter fermentative activity was probably a consequence of Mn(2+) acting as "metabolic switch," which regulated the metabolic flux from pyruvic acid to lactic acid and other metabolism pathway. PMID:25146195

  3. Amino acid substitutions in malate dehydrogenases of piezophilic bacteria isolated from intestinal contents of deep-sea fishes retrieved from the abyssal zone.

    Saito, Rie; Kato, Chiaki; Nakayama, Akihiko

    2006-02-01

    To examine the occurrence in other deep-sea bacteria of two amino acid substitutions (Ala-180 and His-229) in malate dehydrogenase (MDH) found previously in the deep-sea piezophilic Moritella sp. strain 2D2, we cloned and sequenced MDH genes of deep-sea piezophilic Moritella and Shewanella strains isolated from intestinal contents of deep-sea fishes, as well as other Moritella species from deep-sea water and sediments: M. marina, M. japonica, and M. yayanosii. The piezophilic Moritella strains had a Val residue or an Ala residue at position 180 and all the Moritella strains except for one had a His residue at position 229. However, four piezophilic-strain-specific substitutions at positions 103, 111, 229, and 283 were found to be completely conserved in the MDH of the intestinal Moritella strains of deep-sea fishes, indicating the substitutions may be habitat-specific. The piezophilic Shewanella strains had a Val residue and a Gln residue at positions 180 and 229, respectively. However, the MDHs of the Shewanella strains had five piezophilic-strain-specific substitutions at positions 61, 65, 107, 161, and 202. Therefore, the enzymatic strategies for responding to deep-sea high pressure environments of the MDHs between the genera Moritella and Shewanella are potentially different. Moreover, homology modeling shows these substitutions found in the MDHs of both genera except for position 229 in the subunit interface are located on the exposed region of the MDH molecules, indicating the substitutions may be related to the hydration state of the molecules. PMID:16598154

  4. Effect of noise exposure (85 dB ) on testicular adrenocortical steroidogenic key enzymes, acid and alkaline phosphatase activities of sex organs in mature albino rats

    2000-01-01

    Changes in the activities of △5-3β-hydroysteroid dehydrogenase (HSD) in testis and adrenal gland, 17β-hydroxysteroid dehydrogenase in testis, acid and alkaline phosphatase in testis, prostate and seminal vesicle were observed in noise exposed mature rats at the intensity of 85 dB for 8 h/day for 45 days. The results indicated that noise exposed group showed a significant diminution in the activities of androgenic key enzymes △5-3β and 17β-HSD, acid phosphatase in testis, prostate and seminal vesicle. There was a significant elevation in the activities of adrenal △5-3β-HSD, alkaline phosphatase in testis and other accessory sex organ in noise exposed group. Gonadosomatic, prostatosomatic and seminal vesiculo-somatic indexes were decreased significantly in noise exposed group. Therefore, it is evident that noise exposure at 85dB exerts a deleterious effect on testicular and adrenocortical activities.

  5. On the anticonvulsant activity of kaurenic acid.

    Daló, Nelson L; Sosa-Sequera, Miriam C; Usubillaga, Alfredo

    2007-09-01

    Kaurenic acid [(-)-kaur-16-en-19-oic acid] is a diterpene isolated from the aerial parts of Espeletia semiglobulata, one of 85 species of Espeletiinae found in Venezuela. Its anticonvulsive activity was studied using two different models of experimental seizures: spinal seizures induced by sudden cooling (SSSC) in amphibians and seizures induced by pentylenetetrazol (PTZ) in mice. In SSSC, kaurenic acid (KA) inhibited the tonic hind-limb extension with an ED50 of 2.5 mg/kg. It was 4-fold more potent than known anticonvulsant drugs such as carbamazepine and phenytoin and 100-fold more potent than valproic acid. However, KA as well as valproic acid were ineffective against the clonic phase of SSSC. In the PTZ-induced seizures, KA at doses of 0.625 and 1.25 mg/kg increased the latency of seizure onset and protected against generalized clonic-tonic seizures by 45% and 65%, respectively. The sedative effects of KA had an ED50 of 8.5 mg/kg in mice and 75 mg/kg in amphibians. This work provides experimental evidence supporting the potential value of kaurenic acid as an anticonvulsive drug. PMID:17853794

  6. Photoprotective Activity of Vulpinic and Gyrophoric Acids Toward Ultraviolet B-Induced Damage in Human Keratinocytes.

    Varol, Mehmet; Türk, Ayşen; Candan, Mehmet; Tay, Turgay; Koparal, Ayşe Tansu

    2016-01-01

    Vulpinic and gyrophoric acids are known as ultraviolet filters for natural lichen populations because of their chemical structures. However, to the best of our knowledge, there has been no reference to their cosmetic potential for skin protection against ultraviolet B (UVB)-induced damage and, consequently, we propose to highlight their photoprotective profiles in human keratinocytes (HaCaT). Therefore, vulpinic acid and gyrophoric acid were isolated from acetone extracts of Letharia vulpina and Xanthoparmelia pokornyi, respectively. Their photoprotective activities on irradiated HaCaT cells and destructive effects on non-irradiated HaCaT cells were compared through in vitro experimentation: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays, 4',6-diamino-2-phenylindole and tetramethylrhodamine B isothiocyanate-phalloidin staining protocols. Both of the lichen substances effectively prevented cytotoxic, apoptotic and cytoskeleton alterative activities of 2.5 J/cm(2) UVB in a dose-dependent manner. Moreover, vulpinic and gyrophoric acids showed no toxic, apoptotic or cytoskeleton alterative effects on non-irradiated HaCaT cells, except at high doses (≥400 μM) of gyrophoric acid. The findings suggest that vulpinic and gyrophoric acids can be promising cosmetic ingredients to photo-protect human skin cells and should therefore be further investigated by in vitro and in vivo multiple bioassays. PMID:26463741

  7. Safety, efficacy and physiological actions of a lysine-free, arginine-rich formula to treat glutaryl-CoA dehydrogenase deficiency: focus on cerebral amino acid influx.

    Strauss, Kevin A; Brumbaugh, Joan; Duffy, Alana; Wardley, Bridget; Robinson, Donna; Hendrickson, Christine; Tortorelli, Silvia; Moser, Ann B; Puffenberger, Erik G; Rider, Nicholas L; Morton, D Holmes

    2011-01-01

    Striatal degeneration from glutaryl-CoA dehydrogenase deficiency (glutaric aciduria type 1, GA1) is associated with cerebral formation and entrapment of glutaryl-CoA and its derivatives that depend on cerebral lysine influx. In 2006 we designed a lysine-free study formula enriched with arginine to selectively block lysine transport across cerebral endothelia and thereby limit glutaryl-CoA production by brain. Between 2006 and present, we treated twelve consecutive children with study formula (LYSx group) while holding all other treatment practices constant. Clinical and biochemical outcomes were compared to 25 GA1 patients (PROx group) treated between 1995 and 2005 with natural protein restriction (dietary lysine/arginine ratio of 1.7±0.3 mg:mg). We used published kinetic parameters of the y+and LAT1 blood-brain barrier transporters to model the influx of amino acids into the brain. Arginine fortification to achieve a mean dietary lysine/arginine ratio of 0.7±0.2 mg:mg was neuroprotective. All 12 LYSx patients are physically and neurologically healthy after 28 aggregate patient-years of follow up (current ages 28±21 months) and there were no adverse events related to formula use. This represents a 36% reduction of neurological risk (95% confidence interval 14-52%, p=0.018) that we can directly attribute to altered amino acid intake. During the first year of life, 20% lower lysine intake and two-fold higher arginine intake by LYSx patients were associated with 50% lower plasma lysine, 3-fold lower plasma lysine/arginine concentration ratio, 42% lower mean calculated cerebral lysine influx, 54% higher calculated cerebral arginine influx, 15-26% higher calculated cerebral influx of several anaplerotic precursors (isoleucine, threonine, methionine, and leucine), 50% less 3-hydroxyglutarate excretion, and a 3-fold lower hospitalization rate (0.8 versus 2.3 hospitalizations per patient per year). The relationship between arginine fortification and plasma lysine

  8. Combined Effect of L-Cysteine and Vitamin E Injected Pre-Irradiation on Glucose-6-Phosphate Dehydrogenase Activity and Certain products of Glycolysis in Blood of Female Rats

    The present work aims to evaluate the protective limits of L-cysteine and vitamin E combination against deleterious effects of gamma radiation on glucose-6-phosphate dehydrogenase activity, liver glycogen, blood glucose, pyruvic and lactic acids and their correlations in adult female rats. Mature female white rats were divided into four groups: 1- Control group. 2- Whole body gamma irradiated group at a dose level two Gy. 3-Group injected with 120 mg/100 g b.wt. L-cysteine+10 mg/100 g b.wt. vitamin E. 4- Group injected with cysteine+ vitamin E one hour before irradiation at 2 Gy dose level. Results revealed that combined administration of cysteine and vitamin E before gamma-irradiation have accelerated the radiation injury on liver glycogen, plasma glucose and G 6 Pd activity, while they showed a protective effect on lactic and pyruvic acids. This could be due to different mechanisms or a biphasic mechanism related to hormonal (like E2, T3 and insulin), enzymatic or metabolic (e.g. oxidation/reduction, catabolic, anabolic factors) control

  9. Yeast and horse liver alcohol dehydrogenases: potential problems in target size analysis and evidence for a monomer active unit

    Yeast and horse alcohol dehydrogenases are commonly used as standards for radiation inactivation analysis of proteins, usually assuming that the minimal functional unit corresponds to the physical size in solution, a tetramer (M/sub r/ = 148,000) and a dimer (M/sub r/ = 80,000), respectively. Results described in this paper demonstrate that molecular weight overestimates may be obtained for the yeast protein as a result of its unusual sensitivity to secondary radiation products. Irradiation in the presence of sulhydryl reagents results in a smaller functional size estimate (67,000 +/- 3000) than that obtained in their absence (128,000 +/- 5000), indicating that some sulfhydryl groups in the enzyme may be particularly susceptible to attack by radiolytic species. Analysis of the horse liver enzyme reveals that although it has structural and functional similarities to the yeast protein, it is not as prone to secondary radiation damage and gives a minimal functional size estimate (33,000 +/= 1000) that most closely corresponds to a monomer. Quantitation of disappearance of the protein from a sodium dodecyl sulfate gel as a function of radiation dose also gives a target size (48,000 +/- 3000) in reasonable agreement with the monomer molecular weight. These results indicate that the individual subunits of horse liver alcohol dehydrogenase have independent catalytic capacity and imply that the same may be true for the yeast enzyme

  10. Derivatives of (phenylsulfonamido-methyl)nicotine and (phenylsulfonamido-methyl)thiazole as novel 11β-hydroxysteroid dehydrogenase type 1 inhibitors: synthesis and biological activities in vitro

    Xu ZHANG; Yang ZHOU; Yu SHEN; Li-li DU; Jun-hua CHEN; Ying LENG; Jian-hua SHEN

    2009-01-01

    Aim: To design and synthese a novel class of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitors, featuring the (phenylsul-fonamido-methyl)pyridine and (phenyisulfonamido-methyl)thiazole framework. Methods: Our initial lead 4-(phenylsulfonamido-methyl)benzamides were modified. Inhibition of human and mouse 11β-HSD1 enzy-matic activities by the new compounds was determined by a scintillation proximity assay (SPA) using microsomes containing 11β-HSD1.Results: Sixteen new compounds (6a-6h, 7a-7h) were designed, synthesized and bioassayed. In dose-response studies, several com-pounds showed strong inhibitory activities with IC_(50) values at nanomolar or low nanomolar concentrations. Structure-activity relation-ships are also discussed with respect to molecular docking results. Conclusion: This study provides two promising new templates for 11β-HSD1 inhibitors.

  11. Pyruvate Dehydrogenase and Pyruvate Dehydrogenase Kinase Expression in Non Small Cell Lung Cancer and Tumor-Associated Stroma

    Michael I. Koukourakis

    2005-01-01

    Full Text Available Pyruvate dehydrogenase (PDH catalyzes the conversion of pyruvate to acetyl-coenzyme A, which enters into the Krebs cycle, providing adenosine triphosphate (ATP to the cell. PDH activity is under the control of pyruvate dehydrogenase kinases (PDKs. Under hypoxic conditions, conversion of pyruvate to lactate occurs, a reaction catalyzed by lactate dehydrogenase 5 (LDH5. In cancer cells, however, pyruvate is transformed to lactate occurs, regardless of the presence of oxygen (aerobic glycolysis/Warburg effect. Although hypoxic intratumoral conditions account for HIFia stabilization and induction of anaerobic metabolism, recent data suggest that high pyruvate concentrations also result in HIFia stabilization independently of hypoxia. In the present immunohistochemical study, we provide evidence that the PDH/PDK pathway is repressed in 73% of non small cell lung carcinomas, which may be a key reason for HIFia stabilization and “aerobic glycolysis.” However, about half of PDHdeficient carcinomas are not able to switch on the HIF pathway, and patients harboring these tumors have an excellent postoperative outcome. A small subgroup of clinically aggressive tumors maintains a coherent PDH and HIF/LDH5 expression. In contrast to cancer cells, fibroblasts in the tumor-supporting stroma exhibit an intense PDH but reduced PDK1 expression favoring maximum PDH activity. This means that stroma may use lactic acid produced by tumor cells, preventing the creation of an intolerable intratumoral acidic environment at the same time.

  12. Lithocholic acid and derivatives: Antibacterial activity.

    do Nascimento, Patrícia G G; Lemos, Telma L G; Almeida, Macia C S; de Souza, Juliana M O; Bizerra, Ayla M C; Santiago, Gilvandete M P; da Costa, José G M; Coutinho, Henrique D M

    2015-12-01

    In order to develop bioactive lithocholic acid derivatives, we prepared fifteen semi-synthetic compounds through modification at C-3 and/or C-24. The reactions showed yields ranging from 37% to 100%. The structures of all compounds obtained were identified on the basis of their spectral data (IR, MS, 1D- and 2D-NMR). The activity of lithocholic acid and derivatives was evaluated against the growth of Escherichia coli, Staphylococcus aureus, Bacillus cereus and Pseudomonas aeruginosa. The derivative 3α-formyloxy-5β-cholan-24-oic acid (LA-06) showed the best activity, with MIC values of 0.0790 mM against E. coli (Ec 27) and B. cereus in both cases, and 0.0395 mM against S. aureus (ATCC 12692). Lithocholic acid and the derivatives with MIC⩽1.2 mM were evaluated on the susceptibility of some bacterial pathogens to the aminoglycoside antibiotics neomycin, amikacin and gentamicin was evaluated. There are no previously reported studies about these compounds as modifiers of the action of antibiotics or any other drugs. PMID:26216208

  13. Screening of aspartate dehydrogenase of bacteria

    Fukuda, Shoko; Okamura, Tokumitsu; Yasumasa, Izumi; Takeno, Tomomi; Ohsugi, Masahiro

    2001-01-01

    Fifty-two strains of bacteria cultured under aerobic conditions and 12 strains of bacteria cultured under anaerobic conditions demonstrated high activity staining of aspartate dehydrogenase with NAD^+. Four strains of bacteria cultured under aerobic conditions and 7 strains of bacteria cultured under anaerobic conditions demonstrated high activity staining of aspartate dehydrogenase with NADP^+. Seven strains of bacteria cultured under aerobic conditions and 4 strains of bacteria cultured und...

  14. Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele;

    2003-01-01

    Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them...

  15. Maternal coordination of the daily rhythm of malate dehydrogenase activity in testes from young rats: effect of maternal sympathetic denervation of the pineal gland and administration of melatonin.

    Vermouth, N T; Carriazo, C S; Gallará, R V; Carpentieri, A R; Bellavía, S L

    1995-02-01

    Chronic sympathetic denervation of the pineal gland by bilateral removal of the superior cervical ganglia (SCG) was performed on female rats 30 days before impregnation. The offspring, maintained in the dark from birth, had disruption of the malate dehydrogenase circadian rhythm in the testes at 25 days of age. A daily injection of melatonin (1 mg/kg s.c. at 10:00 or 18:00 h) to denervated mothers from the 14th day of pregnancy up to the 10th day postpartum produced one daily phase in the enzyme activity of tests in the offspring. Entrainment of daily enzyme activity also was obtained when the hormone was administered orally to the pups during the postnatal period or when pups were reared by intact (not denervated) foster mothers. The results indicate the involvement of the maternal pineal gland in the maternal transfer of photoperiodic information necessary for the coordination of the circadian system in young rats. PMID:7750160

  16. Glucose-6-phosphate dehydrogenase (G6PD. Response of the human erythrocyte and another cells to the decrease in their activity.

    Javier Fernando Bonilla

    2009-11-01

    Full Text Available Glucose-6-phosphate dehydrogenase is the first enzyme in the pentose phosphate pathway and the main intracellular source of reduced nicotidamineadenine nucleotidephosphate (NADPH, involved in diverse physiological processes such as antioxidant defense, (for instance in the erythrocyte endothelial growth modulation, erithropoyesis, vascularization and phagocitosis. G6PDH deficiency is the most common X-chromosome-linked enzymopathy in human beings. Although it is present in any type cell, its absolute deficiency is incompatible with life. According to WHO, 400 million people are affected by G6PD deficiency in the world but in Colombia, the severe form prevalence is about 3% to 7%. There are no data related to slight and moderate alterations, that also have clinical effects. This paper reviews some G6PD biomolecular aspects, its classification according to activity and electrophoretic mobility, as well as some main clinical aspects related to its activity alteration.

  17. Enhanced acyl-CoA dehydrogenase activity is associated with improved mitochondrial and contractile function in heart failure

    Heart failure is associated with decreased myocardial fatty acid oxidation capacity and has been likened to energy starvation. Increased fatty acid availability results in an induction of genes promoting fatty acid oxidation. The aim of the present study was to investigate possible mechanisms by whi...

  18. The effects of inhaled formaldehyde on the activities of some metabolic enzymes in the liver of male rats: subchronic (13-weeks) effects

    Yılmaz, H.Ramazan; ÖZEN, O. Aslan; Özyurt, Hüseyin; Songur, Ahmet; Şahin, Şemsettin; Sarsılmaz, Mustafa

    2013-01-01

    Abstract. We aimed to investigate the effects of different formaldehyde (FA) concentrations on some enzyme activities that take part in metabolic pathways in the liver. The enzymes studied were hexokinase (HK), glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), lactate dehydrogenase (LDH), and malate dehydrogenase (MDH) which are included in the three main metabolic pathways; glycolysis, citric acid cycle, and pentose phosphate pathway. Thirty male Wistar albin...

  19. Clinical implications of thymidylate synthetase, dihydropyrimidine dehydrogenase and orotate phosphoribosyl transferase activity levels in colorectal carcinoma following radical resection and administration of adjuvant 5-FU chemotherapy

    A number of studies have investigated whether the activity levels of enzymes involved in 5-fluorouracil (5-FU) metabolism are prognostic factors for survival in patients with colorectal carcinoma. Most reports have examined thymidylate synthetase (TS) and dihydropyrimidine dehydrogenase (DPD) in unresectable or metastatic cases, therefore it is unclear whether the activity of these enzymes is of prognostic value in colorectal cancer patients treated with radical resection and adjuvant chemotherapy with 5-FU. This study examined fresh frozen specimens of colorectal carcinoma from 40 patients who had undergone curative operation and were orally administered adjuvant tegafur/uracil (UFT) chemotherapy. TS, DPD and orotate phosphoribosyl transferase (OPRT) activities were assayed in cancer tissue and adjacent normal tissue and their association with clinicopathological variables was investigated. In addition, the relationships between TS, DPD and OPRT activities and patient survival were examined to determine whether any of these enzymes could be useful prognostic factors. While there was no clear relationship between pathological findings and TS or DPD activity, OPRT activity was significantly lower in tumors with lymph node metastasis than in tumors lacking lymph node metastasis. Postoperative survival was significantly better in the groups with low TS activity and/or high OPRT activity. TS and OPRT activity levels in tumor tissue may be important prognostic factors for survival in Dukes' B and C colorectal carcinoma with radical resection and adjuvant chemotherapy with UFT

  20. New nalidixic acid resistance mutations related to deoxyribonucleic acid gyrase activity.

    Yamagishi, J; Furutani, Y; Inoue, S.; Ohue, T; Nakamura, S; Shimizu, M

    1981-01-01

    In Escherichia coli K-12 mutants which had a new nalidixic acid resistance mutation at about 82 min on the chromosome map, cell growth was resistant to or hypersusceptible to nalidixic acid, oxolinic acid, piromidic acid, pipemidic acid, and novobiocin. Deoxyribonucleic acid gyrase activity as tested by supercoiling of lambda phage deoxyribonucleic acid inside the mutants was similarly resistant or hypersusceptible to the compounds. The drug concentrations required for gyrase inhibition were ...

  1. HISTIDINE MUTAGENESIS OF ARABIDOPSIS THALIANA PYRUVATE DEHYDROGENASE KINASE

    Pyruvate dehydrogenase kinase (PDK) is the primary regulator of flux through the mitochondrial pyruvate dehydrogenase complex (PDC). Analysis of the primary amino acid sequences of PDK from various sources reveals that these enzymes include the five domains characteristic of prokaryotic two-compone...

  2. Real-time monitoring of glucose-6-phosphate dehydrogenase activity using liquid droplet arrays and its application to human plasma samples.

    Jung, Se-Hui; Ji, Su-Hyun; Han, Eun-Taek; Park, Won Sun; Hong, Seok-Ho; Kim, Young-Myeong; Ha, Kwon-Soo

    2016-05-15

    Glucose-6-phosphate dehydrogenase (G6PD) regulates nicotinamide adenine dinucleotide phosphate (NADPH) levels and is related to the pathogenesis of various diseases, including G6PD deficiency, type 2 diabetes, aldosterone-induced endothelial dysfunction, and cancer. Therefore, a highly sensitive array-based assay for determining quantitative G6PD activity is required. Here, we developed an on-chip G6PD activity assay using liquid droplet fluorescence arrays. Quantitative G6PD activity was determined by calculating reduced resorufin concentrations in liquid droplets. The limit of detection (LOD) of this assay was 0.162 mU/ml (2.89 pM), which is much more sensitive than previous assays. We used our activity assay to determine kinetic parameters, including Michaelis-Menten constants (Km) and maximum rates of enzymatic reaction (Vmax) for NADP(+) and G6P, and half-maximal inhibitory concentrations (IC50). We successfully applied this new assay to determine G6PD activity in human plasma from normal healthy individuals (n=30) and patients with inflammation (n=30). The inflammatory group showed much higher G6PD activities than did the normal group (pG6PD-associated diseases and utilizing kinetic studies. PMID:26802575

  3. Activation of the biochemical processes in an oil-contaminated soil using a light-correcting film and humic acids

    Filatov, D. A.; Ivanov, A. A.; Svarovskaya, L. I.; Yudina, N. V.

    2011-02-01

    It was shown that the use of a light-correcting film as a covering material for an oil-contaminated soil in combination with humic acids increased the number of the main physiological groups of the soil microorganisms responsible for the development of the soil's fertility (heterotrophic bacteria, actinomycetes, and micromycetes) by 60-100 times. The activity of the soil enzymes (catalase, dehydrogenase, polyphenoloxidase, peroxidase, and urease) increased by 3-6 times. The biochemical oxidation of oil hydrocarbons in the soil became significantly more intense.

  4. Combined influence of γ-irradiation and nitrocompounds on the activity of the main ferments of the glutamic acid metabolism

    Activity of aspartate aminotransferase, glutamate dehydrogenase in the liver of rats in 1, 7 and 15 days after γ-irradiation effect of the dose of 0.5 Gy on the background of consumption by animals of sodium nitrate, sodium nitrite and nitrosodiethylamine was studied. The combined influence of chemical agents and γ-irradiation modified the effects of nitrocompounds-xenobiotics on the processes of synthesis and dissociation of the glutamic acid as well as the intensity of transamination of reamination by aspartate aminotransferase

  5. Theoretical Calculations of the Catalytic Triad in Short-Chain Alcohol Dehydrogenases/Reductases

    Gani, Osman A B S M; Adekoya, Olayiwola A; Giurato, Laura; Spyrakis, Francesca; Cozzini, Pietro; Guccione, Salvatore; Winberg, Jan-Olof; Sylte, Ingebrigt

    2007-01-01

    Three highly conserved active site residues (Ser, Tyr, and Lys) of the family of short-chain alcohol dehydrogenases/reductases (SDRs) were demonstrated to be essential for catalytic activity and have been denoted the catalytic triad of SDRs. In this study computational methods were adopted to study the ionization properties of these amino acids in SDRs from Drosophila melanogaster and Drosophila lebanonensis. Three enzyme models, with different ionization scenarios of the catalytic triad that...

  6. Boswellic acids synergize antitumor activity and protect against the cardiotoxicity of doxorubicin in mice bearing Ehrlich's carcinoma.

    Ali, Shimaa A; Zaitone, Sawsan A; Moustafa, Yasser M

    2015-08-01

    This study aimed to test whether boswellic acids add to the antitumor effects of doxorubicin against solid tumors of Ehrlich's ascites carcinoma (EAC) grown in mice, and to investigate the protective effects of boswellic acids against doxorubicin-induced cardiotoxicity. Sixty-four female Swiss albino mice bearing EAC solid tumors were distributed among 8 groups as follows: group 1, EAC control group; group 2, doxorubicin treatment group [mice were injected with doxorubicin (6 mg·(kg body mass)(-1)·week(-1)) for 3 weeks]; groups 3-5, these mice were treated with boswellic acids (125, 250, or 500 mg·kg(-1)·day(-1)), respectively; groups 6-8, these mice were treated with a combination of doxorubicin and boswellic acids (125, 250, or 500 mg·kg(-1)·day(-1)), respectively, for 3 weeks. The results indicated that boswellic acids synergized the antitumor activity of doxorubicin. Doxorubicin-treated mice showed elevated serum activities of lactate dehydrogenase and creatine kinase isoenzyme MB as well as cardiac malondialdehyde. Further, decreases in cardiac levels of reduced glutathione, superoxide dismutase, and catalase activities were observed. These effects were accompanied by an increase in cardiac expression of caspase 3. Thus, treatment with boswellic acids attenuated doxorubicin-evoked disturbances in the above-mentioned parameters, highlighting antioxidant and antiapoptotic activities. Therefore, boswellic acids could be potential candidates for ameliorating the cardiotoxicity of doxorubicin. PMID:26230640

  7. Communication between Thiamin Cofactors in the Escherichia coli Pyruvate Dehydrogenase Complex E1 Component Active Centers EVIDENCE FOR A DIRECT PATHWAY BETWEEN THE 4′-AMINOPYRIMIDINE N1′ ATOMS

    Nemeria, Natalia S; Arjunan, Palaniappa; Chandrasekhar, Krishnamoorthy; Mossad, Madouna; Tittmann, Kai; Furey, William; Jordan, Frank [Pitt; (Goettingen); (VA); (Rutgers)

    2010-11-03

    Kinetic, spectroscopic, and structural analysis tested the hypothesis that a chain of residues connecting the 4{prime}-aminopyrimidine N1{prime} atoms of thiamin diphosphates (ThDPs) in the two active centers of the Escherichia coli pyruvate dehydrogenase complex E1 component provides a signal transduction pathway. Substitution of the three acidic residues (Glu{sup 571}, Glu{sup 235}, and Glu{sup 237}) and Arg{sup 606} resulted in impaired binding of the second ThDP, once the first active center was filled, suggesting a pathway for communication between the two ThDPs. (1) Steady-state kinetic and fluorescence quenching studies revealed that upon E571A, E235A, E237A, and R606A substitutions, ThDP binding in the second active center was affected. (2) Analysis of the kinetics of thiazolium C2 hydrogen/deuterium exchange of enzyme-bound ThDP suggests half-of-the-sites reactivity for the E1 component, with fast (activated site) and slow exchanging sites (dormant site). The E235A and E571A variants gave no evidence for the slow exchanging site, indicating that only one of two active sites is filled with ThDP. (3) Titration of the E235A and E237A variants with methyl acetylphosphonate monitored by circular dichroism suggested that only half of the active sites were filled with a covalent predecarboxylation intermediate analog. (4) Crystal structures of E235A and E571A in complex with ThDP revealed the structural basis for the spectroscopic and kinetic observations and showed that either substitution affects cofactor binding, despite the fact that Glu{sup 235} makes no direct contact with the cofactor. The role of the conserved Glu{sup 571} residue in both catalysis and cofactor orientation is revealed by the combined results for the first time.

  8. Mesenchymal Stem/Stromal Cells Derived From a Reproductive Tissue Niche Under Oxidative Stress Have High Aldehyde Dehydrogenase Activity.

    Kusuma, Gina D; Abumaree, Mohamed H; Pertile, Mark D; Perkins, Anthony V; Brennecke, Shaun P; Kalionis, Bill

    2016-06-01

    The use of mesenchymal stem/stromal cells (MSC) in regenerative medicine often requires MSC to function in environments of high oxidative stress. Human pregnancy is a condition where the mother's tissues, and in particular her circulatory system, are exposed to increased levels of oxidative stress. MSC in the maternal decidua basalis (DMSC) are in a vascular niche, and thus would be exposed to oxidative stress products in the maternal circulation. Aldehyde dehydrogenases (ALDH) are a large family of enzymes which detoxify aldehydes and thereby protect stem cells against oxidative damage. A subpopulation of MSC express high levels of ALDH (ALDH(br)) and these are more potent in repairing and regenerating tissues. DMSC was compared with chorionic villous MSC (CMSC) derived from the human placenta. CMSC reside in vascular niche and are exposed to the fetal circulation, which is in lower oxidative state. We screened an ALDH isozyme cDNA array and determined that relative to CMSC, DMSC expressed high levels of ALDH1 family members, predominantly ALDH1A1. Immunocytochemistry gave qualitative confirmation at the protein level. Immunofluorescence detected ALDH1 immunoreactivity in the DMSC and CMSC vascular niche. The percentage of ALDH(br) cells was calculated by Aldefluor assay and DMSC showed a significantly higher percentage of ALDH(br) cells than CMSC. Finally, flow sorted ALDH(br) cells were functionally potent in colony forming unit assays. DMSC, which are derived from pregnancy tissues that are naturally exposed to high levels of oxidative stress, may be better candidates for regenerative therapies where MSC must function in high oxidative stress environments. PMID:26880140

  9. Plant Formate Dehydrogenase

    John Markwell

    2005-01-10

    The research in this study identified formate dehydrogenase, an enzyme that plays a metabolic role on the periphery of one-carbon metabolism, has an unusual localization in Arabidopsis thaliana and that the enzyme has an unusual kinetic plasticity. These properties make it possible that this enzyme could be engineered to attempt to engineer plants with an improved photosynthetic efficiency. We have produced transgenic Arabidopsis and tobacco plants with increased expression of the formate dehydrogenase enzyme to initiate further studies.

  10. Studies on the acid activation of Brazilian smectitic clays

    Francisco R. Valenzuela Díaz; Pérsio de Souza Santos

    2001-01-01

    Fuller's earth and acid activated smectitic clays are largely used as bleaching earth for the industrial processing of vegetable, animal and mineral oils and waxes. The paper comments about the nomenclature used for these materials, the nature of the acid activation of smectitic clays (bentonites), activation laboratory procedures and presents a review of the acid activation of bentonites from 20 deposits from several regions of Brazil. The activated clays were tested and show good decolorizi...