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Sample records for catalyzed friedel-crafts acetylation

  1. The synthesis of mono- and diacetyl-9H-fluorenes. Reactivity and selectivity in the Lewis acid catalyzed Friedel-Crafts acetylation of 9H-fluorene

    DEFF Research Database (Denmark)

    Titinchi, Salam J.J.; Kamounah, Fadhil S.; Abbo, Hanna S.;

    2008-01-01

    Friedel-Crafts acetylation of 9H-fluorene is an effective route for the preparation of mono- and diacetyl-9H-fluorenes. Using acetylchloride as the reagent and aluminum chloride as the Lewis acid catalyst the effect of the solvent polarity, the temperature, the reaction time and the mode of addit......Friedel-Crafts acetylation of 9H-fluorene is an effective route for the preparation of mono- and diacetyl-9H-fluorenes. Using acetylchloride as the reagent and aluminum chloride as the Lewis acid catalyst the effect of the solvent polarity, the temperature, the reaction time and the mode...

  2. The synthesis of mono- and diacetyl-9H-fluorenes. Reactivity and selectivity in the Lewis acid catalyzed Friedel-Crafts acetylation of 9H-fluorene

    DEFF Research Database (Denmark)

    Titinchi, Salam J.J.; Kamounah, Fadhil S.; Abbo, Hanna S.;

    2008-01-01

    Friedel-Crafts acetylation of 9H-fluorene is an effective route for the preparation of mono- and diacetyl-9H-fluorenes. Using acetylchloride as the reagent and aluminum chloride as the Lewis acid catalyst the effect of the solvent polarity, the temperature, the reaction time and the mode of......-fluorene was obtained in 5-11 % yield when carbon disulfide was used as the solvent. Acetylation of 9H-fluorene in dichloroethane and carbon disulfide, using an excess of acetyl chloride and aluminum chloride at reflux temperature, gives 2,7-diacetyl-9H-fluorene exclusively in high yields (> 97%). Attempts to...

  3. Friedel-Crafts alkylation of indoles with nitroalkenes catalyzed by Cu(Ⅱ)-imine complex

    Institute of Scientific and Technical Information of China (English)

    Ning Ning Wan; Yong Lei Yang; Wen Ping Wang; Zheng Feng Xie; Ji De Wang

    2011-01-01

    A series of new ligands L1-L7 were readily prepared in one step. Friedel-Crafts alkylation of indoles with nitroalkenes catalyzed by a novel Cu(Ⅱ)-L complex has been developed. The remarkable advantages of this reaction are mild reaction conditions, simple workup procedure, high yields of products and the use of ethanol as a green solvent.

  4. Lewis Acid Catalyzed Friedel-Crafts Alkylation of Alkenes with Trifluoropyruvates.

    Science.gov (United States)

    Xiang, Bin; Xu, Teng-Fei; Wu, Liang; Liu, Ren-Rong; Gao, Jian-Rong; Jia, Yi-Xia

    2016-05-01

    A Friedel-Crafts alkylation reaction of styrenes with trifluoropyruvates has been developed, which delivered allylic alcohols in excellent yields (up to 98%) using the Ni(ClO4)2·6H2O/bipyridine complex as a catalyst. The asymmetric reaction was catalyzed by the chiral Cu(OTf)2/bisoxazoline complex to afford the corresponding chiral allylic alcohols bearing trifluoromethylated quaternary stereogenic centers in moderate enantioselectivities (up to 75% ee). PMID:27028539

  5. A reactivity-selectivity study of the Friedel-Crafts acetylation of 3,3′-dimethylbiphenyl and the oxidation of the acetyl derivatives

    DEFF Research Database (Denmark)

    Titinchi, Salam JJ; Kamounah, Fadhil S.; Abbo, Hanna S.;

    2012-01-01

    Background: Friedel-Crafts acetylation is an important route to aromatic ketones, in research laboratories and in industry. The acetyl derivatives of 3,3'-dimethylbiphenyl (3,3'-dmbp) have applications in the field of liquid crystals and polymers and may be oxidized to the dicarboxylic acids...... converted to the carboxylic acids by hypochlorite oxidation. The relative stabilities of the isomeric products and the corresponding s-complexes were studied by DFT calculations and the data indicated that mono-and diacetylation followed different mechanisms. Conclusions: Friedel-Crafts acetylation of 3...

  6. A reactivity-selectivity study of the Friedel-Crafts acetylation of 3,3'-dimethylbiphenyl and the oxidation of the acetyl derivatives

    DEFF Research Database (Denmark)

    Titinchi, Salam J.J.; Kamounah, Fadhil S.; Abbo, Hanna S.;

    2012-01-01

    Background: Friedel-Crafts acetylation is an important route to aromatic ketones, in research laboratories and in industry. The acetyl derivatives of 3,3'-dimethylbiphenyl (3,3'-dmbp) have applications in the field of liquid crystals and polymers and may be oxidized to the dicarboxylic acids and...... converted to the carboxylic acids by hypochlorite oxidation. The relative stabilities of the isomeric products and the corresponding s-complexes were studied by DFT calculations and the data indicated that mono-and diacetylation followed different mechanisms. Conclusions: Friedel-Crafts acetylation of 3...... derivatives that are of interest in cancer treatment. Findings: The effect of solvent and temperature on the selectivity of monoacetylation of 3,3'-dmbp by the Perrier addition procedure was studied using stoichiometric amounts of reagents. 4-Ac-3,3'-dmbp was formed almost quantitatively in boiling 1...

  7. A reactivity-selectivity study of the Friedel-Crafts acetylation of 3,3′-dimethylbiphenyl and the oxidation of the acetyl derivatives

    Directory of Open Access Journals (Sweden)

    Titinchi Salam JJ

    2012-06-01

    Full Text Available Abstract Background Friedel-Crafts acetylation is an important route to aromatic ketones, in research laboratories and in industry. The acetyl derivatives of 3,3′-dimethylbiphenyl (3,3′-dmbp have applications in the field of liquid crystals and polymers and may be oxidized to the dicarboxylic acids and derivatives that are of interest in cancer treatment. Findings The effect of solvent and temperature on the selectivity of monoacetylation of 3,3’-dmbp by the Perrier addition procedure was studied using stoichiometric amounts of reagents. 4-Ac-3,3′-dmbp was formed almost quantitatively in boiling 1,2-dichloroethane and this is almost twice the yield hitherto reported. Using instead a molar ratio of substrate:AcCl:AlCl3 equal to 1:4:4 or 1:6:6 in boiling 1,2-dichloroethane, acetylation afforded 4,4′- and 4,6′-diacetyl-3,3′-dmbp in a total yield close to 100%. The acetyl derivatives were subsequently converted to the carboxylic acids by hypochlorite oxidation. The relative stabilities of the isomeric products and the corresponding σ-complexes were studied by DFT calculations and the data indicated that mono- and diacetylation followed different mechanisms. Conclusions Friedel-Crafts acetylation of 3,3′-dmbp using the Perrier addition procedure in boiling 1,2-dichloroethane was found to be superior to other recipes. The discrimination against the 6-acetyl derivative during monoacetylation seems to reflect a mechanism including an AcCl:AlCl3 complex or larger agglomerates as the electrophile, whereas the less selective diacetylations of the deactivated 4-Ac-3,3′-dmbp are suggested to include the acetyl cation as the electrophile. The DFT data also showed that complexation of intermediates and products with AlCl3 does not seem to be important in determining the mechanism.

  8. Platinum-Catalyzed Friedel-Crafts-Type C-H Coupling-Allylic Amination Cascade to Synthesize 3,4-Fused Tricyclic Indoles.

    Science.gov (United States)

    Suzuki, Yuta; Tanaka, Yuito; Nakano, Shun-ichi; Dodo, Kosuke; Yoda, Natsumi; Shinohara, Ken-Ichi; Kita, Kazuko; Kaneda, Atsushi; Sodeoka, Mikiko; Hamada, Yasumasa; Nemoto, Tetsuhiro

    2016-03-18

    A novel platinum-catalyzed cascade cyclization reaction was developed by intramolecular Friedel-Crafts-type C-H coupling of aniline derivatives with a propargyl carbonate unit-allylic amination sequence. Treatment of various propargyl carbonates tethered to meta-aniline derivatives with a Pt(dba)3/DPEphos catalyst system afforded the corresponding 3,4-fused tricyclic 3-alkylidene indolines in 42-99% yield, which were transformed into 3,4-fused indole derivatives by reaction with trifluoroacetic acid. The reaction products exhibited antiproliferative activities against cancer cells, but not normal cells, revealing the potential usefulness of this reaction for medicinal chemistry. PMID:26833557

  9. Cu(I)-Catalyzed Enantioselective Friedel-Crafts Alkylation of Indoles with 2-Aryl-N-sulfonylaziridines as Alkylating Agents.

    Science.gov (United States)

    Ge, Chen; Liu, Ren-Rong; Gao, Jian-Rong; Jia, Yi-Xia

    2016-07-01

    A highly enantioselective Friedel-Crafts alkylation of indoles with N-sulfonylaziridines as alkylating agents has been developed by utilizing the complex of Cu(CH3CN)4BF4/(S)-Segphos as a catalyst. A range of optically active tryptamine derivatives are obtained in good to excellent yields and enantioselectivities (up to >99% ee) via a kinetic resolution process. PMID:27309541

  10. Facile synthesis of nonsymmetrical heteroaryl-substituted triarylmethanes via the FeCl3·6H2O-catalyzed two-step Friedel-Crafts-type reaction.

    Science.gov (United States)

    Ruengsangtongkul, S; Taprasert, P; Sirion, U; Jaratjaroonphong, J

    2016-09-28

    The FeCl3·6H2O-catalyzed three-component aza-Friedel-Crafts reaction of aromatic/heteroaromatic compounds, aromatic aldehydes and tert-butyl carbamate was reported. The subsequent Friedel-Crafts-type alkylation of the resulting tert-butyl diarylmethyl carbamate with heteroaromatic compounds under "open-flask" at room temperature was also performed. The two-step reaction was especially useful for the synthesis of functionalized nonsymmetrical heteroaryl-substituted triarylmethanes in good yields under an air atmosphere at room temperature. PMID:27541849

  11. Catalytic Friedel-Crafts reaction of aminocyclopropanes.

    Science.gov (United States)

    de Nanteuil, Florian; Loup, Joachim; Waser, Jérôme

    2013-07-19

    A Lewis acid catalyzed Friedel-Crafts reaction between donor-acceptor aminocyclopropanes and indoles and other electron-rich aromatic compounds is reported. Indole alkylation at the C3 position was generally obtained for a broad range of functional groups and substitution patterns. In the case of C3-substituted indoles, C2 alkylation was observed. The reaction gives a rapid access to gamma amino acid derivatives present in numerous bioactive molecules. PMID:23815365

  12. Temperature Dual Enantioselective Control in a Rhodium-Catalyzed Michael-Type Friedel-Crafts Reaction: A Mechanistic Explanation.

    Science.gov (United States)

    Méndez, Isabel; Rodríguez, Ricardo; Polo, Víctor; Passarelli, Vincenzo; Lahoz, Fernando J; García-Orduña, Pilar; Carmona, Daniel

    2016-07-25

    By changing the temperature from 283 to 233 K, the S (99 % ee) or R (96 % ee) enantiomer of the Friedel-Crafts (FC) adduct of the reaction between N-methyl-2-methylindole and trans-β-nitrostyrene can be obtained by using (SRh ,RC )-[(η(5) -C5 Me5 )Rh{(R)-Prophos}(H2 O)][SbF6 ]2 as the catalyst precursor. This catalytic system presents two other uncommon features: 1) The ee changes with reaction time showing trends that depend on the reaction temperature and 2) an increase in the catalyst loading results in a decrease in the ee of the S enantiomer. Detection and characterization of the intermediate metal-nitroalkene and metal-aci-nitro complexes, the free aci-nitro compound, and the FC adduct-complex, together with solution NMR measurements, theoretical calculations, and kinetic studies have allowed us to propose two plausible alternative catalytic cycles. On the basis of these cycles, all the above-mentioned observations can be rationalized. In particular, the reversibility of one of the cycles together with the kinetic resolution of the intermediate aci-nitro complexes account for the high ee values achieved in both antipodes. On the other hand, the results of kinetic measurements explain the unusual effect of the increment in catalyst loading. PMID:27345293

  13. A Quinine-Squaramide Catalyzed Enantioselective Aza-Friedel-Crafts Reaction of Cyclic Trifluoromethyl Ketimines with Naphthols and Electron-Rich Phenols.

    Science.gov (United States)

    Zhou, Ding; Huang, Zheng; Yu, Xueting; Wang, Youxin; Li, Jian; Wang, Wei; Xie, Hexin

    2015-11-20

    A highly enantioselective aza-Friedel-Crafts (aza-F-C) reaction of cyclic trifluoromethyl ketimines and naphthols/phenols was developed with fluorenyl-substituted quinine-squaramide as the catalyst. This protocol enables direct access to biologically important chiral trifluoromethyl dihydroquinazolinones with up to 99% yields and up to 99% ee's.

  14. Organocatalytic Enantioselective Aza-Friedel-Crafts Reaction of Cyclic Ketimines with Pyrroles using Imidazolinephosphoric Acid Catalysts.

    Science.gov (United States)

    Nakamura, Shuichi; Matsuda, Nazumi; Ohara, Mutsuyo

    2016-07-01

    Organocatalytic enantioselective aza-Friedel-Crafts reactions of cyclic ketimines with pyrroles or indoles were catalyzed by imidazoline/phosphoric acid catalysts. The reaction was applied to various 3H-indol-3-ones to afford products in excellent yields and enantioselectivities. The chiral catalysts can be recovered by a single separation step using column chromatography and are reusable without further purification. Based on the experimental investigations, a possible transition state has been proposed to explain the origin of the asymmetric induction. PMID:27124556

  15. Enantioselective Organocatalytic Construction of Spiroindane Derivatives by Intramolecular Friedel-Crafts-Type 1,4-Addition.

    Science.gov (United States)

    Yoshida, Keisuke; Itatsu, Yukihiro; Fujino, Yuta; Inoue, Hiroki; Takao, Ken-Ichi

    2016-06-01

    The highly enantioselective organocatalytic construction of spiroindanes containing an all-carbon quaternary stereocenter by intramolecular Friedel-Crafts-type 1,4-addition is described. The reaction was catalyzed by a cinchonidine-based primary amine and accelerated by water and p-bromophenol. A variety of spiro compounds containing quaternary stereocenters were obtained with excellent enantioselectivity (up to 95 % ee). The reaction was applied to the asymmetric formal synthesis of the spirocyclic natural products (-)-cannabispirenones A and B. PMID:27111396

  16. A Research-Based Undergraduate Organic Laboratory Project: Investigation of a One-Pot, Multicomponent, Environmentally Friendly Prins-Friedel-Crafts-Type Reaction

    Science.gov (United States)

    Dintzner, Matthew R.; Maresh, Justin J.; Kinzie, Charles R.; Arena, Anthony F.; Speltz, Thomas

    2012-01-01

    Students in the undergraduate organic laboratory synthesize tetrahydro-2-(4-nitrophenyl)-4-phenyl-2"H"-pyran via the Montmorillonite K10 clay-catalyzed reaction of p-nitrobenzaldehye with methanol, 3-buten-1-ol, and benzene. The synthesis comprises an environmentally friendly tandem Prins-Friedel-Crafts-type multicomponent reaction (MCR) and sets…

  17. Polystyrene or Magnetic Nanoparticles as Support in Enantioselective Organocatalysis? A Case Study in Friedel-Crafts Chemistry.

    Science.gov (United States)

    Ranjbar, Sara; Riente, Paola; Rodríguez-Escrich, Carles; Yadav, Jagjit; Ramineni, Kishore; Pericàs, Miquel A

    2016-04-01

    Heterogenized versions of the second-generation MacMillan imidazolidin-4-one are described for the first time. This versatile organocatalyst has been supported on 1% DVB Merrifield resin and Fe3O4 magnetic nanoparticles through a copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction. The resulting catalytic materials have been successfully applied to the asymmetric Friedel-Crafts alkylation of indoles with α,β-unsaturated aldehydes. While both catalytic systems can be easily recovered and admit repeated recycling, the polystyrene-based catalyst shows higher stability and provides better stereoselectivities. PMID:27010999

  18. Friedel-Crafts Alkylation of Indoles with p-Quinols: The Role of Hydrogen Bonding of Water for the Desymmetrization of the Cyclohexadienone System.

    Science.gov (United States)

    García-García, Carolina; Ortiz-Rojano, Laura; Álvarez, Susana; Álvarez, Rosana; Ribagorda, María; Carreño, M Carmen

    2016-05-01

    Lewis acid catalyzed Friedel-Crafts alkylation of indoles has been achieved in high yields and selectivities using p-quinols as electrophiles. (S)-Binol-3,3'-(9-anthracenyl)-phosphoric acid was able to catalyze the enantioselective formation of 5-(3-indole)-2-cyclohexenone derivatives. Experimental results and theoretical calculations explained the enantioselectivity based on a transition state where two water molecules act as a tether joining the p-quinol with the phosphoric acid and the NH of indole, thus facilitating the desymmetrization of the prochiral cyclohexadienone framework. PMID:27088217

  19. Poly(vinyl chloride-grafted multi-walled carbon nanotubes via Friedel-Crafts alkylation

    Directory of Open Access Journals (Sweden)

    2010-11-01

    Full Text Available A novel approach was developed for the surface modification of the multi-walled carbon nanotubes (MWCNTs with high percentage of grafting (PG% by the grafting of polymer via the Friedel-Crafts alkylation. The graft reaction conditions, such as the amount of catalyst added, the reaction temperature, and the reaction time were optimized for the Friedel-Crafts alkylation of the MWCNTs with poly(vinyl chloride (PVC with anhydrous aluminum chloride (AlCl3 as catalyst in chloroform (CHCl3. The Fourier Transform Infrared (FT-IR, Raman, and thermogravimetric (TGA analysis showed that PVC had been successfully grafted onto MWCNTs both at the ends and on the sidewalls by the proposed Friedel-Crafts alkylation. The PVC grafted MWCNTs (PVC-MWCNTs could be dispersed well in organic solvent and the dispersion was more stable.

  20. Highly enantioselective synthesis of beta-heteroaryl-substituted dihydrochalcones through Friedel-Crafts alkylation of indoles and pyrrole.

    Science.gov (United States)

    Wang, Wentao; Liu, Xiaohua; Cao, Weidi; Wang, Jun; Lin, Lili; Feng, Xiaoming

    2010-02-01

    A highly enantioselective Friedel-Crafts (F-C) alkylation of indoles and pyrrole with chalcone derivatives catalyzed by a chiral N,N'-dioxide-Sc(OTf)(3) complex has been developed that tolerates a wide range of substrates. The reaction proceeds in moderate to excellent yields and high enantioselectivities (85-92 % enantiomeric excess) using 2 mol % (for indole) or 0.5 mol % (for pyrrole) catalyst loading, which showed the potential value of the catalyst system. Meanwhile, a strong positive nonlinear effect was observed. On the basis of the experimental results and previous reports, a possible working model is proposed to explain the origin of the activation and asymmetric induction. PMID:20013964

  1. Enantioselective Friedel-Crafts Alkylation Reactions of 3-Substituted Indoles with Electron-Deficient Alkenes.

    Science.gov (United States)

    Weng, Jian-Quan; Fan, Ren-Jie; Deng, Qiao-Man; Liu, Ren-Rong; Gao, Jian-Rong; Jia, Yi-Xia

    2016-04-01

    Highly enantioselective Friedel-Crafts C2-alkylation reactions of 3-substituted indoles with α,β-unsaturated esters and nitroalkenes were developed using chiral Lewis acids as catalysts, which afforded chiral indole derivatives bearing C2-benzylic stereogenic centers in good to excellent yields (up to 99%) and enantioselectivities (up to 96% ee). PMID:26959867

  2. A practical synthesis of 3,4-diethoxybenzthioamide based on Friedel-Crafts reaction with potassium thiocyanate in methanesulfonic acid.

    Science.gov (United States)

    Aki, Shinji; Fujioka, Takafumi; Ishigami, Masashi; Minamikawa, Jun-ichi

    2002-09-01

    The synthesis of 3,4-diethoxybenzthioamide, the key intermediate for OPC-6535, is achieved by employing Friedel-Crafts reaction of 1,2-diethoxybenzene with potassium thiocyanate in methanesulfonic acid at ambient temperature.

  3. One-pot Synthesis of Lewis Acidic Ionic Liquids for Friedel-Crafts Alkylation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Novel Lewis acidic ionic liquids containing thionyl cations and chloroaluminate anions were obtained by one-pot synthesis for the first time. Their acidities were determined by acetonitrile probe on IR spectrography. The ionic liquids were used as catalyst for Friedel-Crafts alkylation of benzene and 1-dodecene. The turnovers of 1-dodecene were higher than 99%. Monoalkylbenzene selectivity was 98%, while the 2-substituent product selectivity was 45%.

  4. Tetranuclear Zn/4f coordination clusters as highly efficient catalysts for Friedel-Crafts alkylation.

    Science.gov (United States)

    Griffiths, Kieran; Kumar, Prashant; Akien, Geoffrey R; Chilton, Nicholas F; Abdul-Sada, Alaa; Tizzard, Graham J; Coles, Simon J; Kostakis, George E

    2016-06-14

    A series of custom-designed, high yield, isoskeletal tetranuclear Zn/4f coordination clusters showing high efficiency as catalysts with low catalytic loadings in Friedel-Crafts alkylation are described for the first time. The possibility of altering the 4f centers in these catalysts without altering the core topology allows us to further confirm their stability via EPR and NMR, as well to gain insights into the plausible reaction mechanism, showcasing the usefulness of these bimetallic systems as catalysts. PMID:27248829

  5. Benzylic Phosphates in Friedel-Crafts Reactions with Activated and Unactivated Arenes: Access to Polyarylated Alkanes.

    Science.gov (United States)

    Pallikonda, Gangaram; Chakravartya, Manab

    2016-03-01

    Easily reachable electron-poor/rich primary and secondary benzylic phosphates are suitably used as substrates for Friedel-Crafts benzylation reactions with only 1.2 equiv activated/deactivated arenes (no additional solvent) to access structurally and electronically diverse polyarylated alkanes with excellent yields and selectivities at room temperature. Specifically, diversely substituted di/triarylmethanes are generated within 2-30 min using this approach. A wide number of electron-poor polyarylated alkanes are easily accomplished through this route by just tuning the phosphates. PMID:26835977

  6. Catalytic Selenium-Promoted Intermolecular Friedel-Crafts Alkylation with Simple Alkenes.

    Science.gov (United States)

    Tang, E; Zhao, Yinjiao; Li, Wen; Wang, Weilin; Zhang, Meng; Dai, Xin

    2016-03-01

    A method for conducting selenium-promoted intermolecular Friedel-Crafts (F-C) alkylation reactions has been developed with simple alkenes using trimethylsilyl trifluoromethanesulfonate as a catalyst and N-phenylselenophthalimide as an efficient selenium source. Electron-rich arenes smoothly underwent F-C alkylation with a variety of alkenes to afford alkylated products in good yield and with high regioselectivity and diastereoselectivity. The regioselectivity and stereoselectivity of arenes and alkenes as well as a preliminary mechanism of the F-C alkylation reaction are discussed. PMID:26882088

  7. Tandem Esterification/1,4-Addition-Type Friedel-Crafts Alkylation Reactions of Phenols/Naphthols with Olefinic Thioazlactones: Access to Functionalized 1,2-Dihydrobenzo[f]chromen-3-ones and 3,4-Dihydrochromen-2-ones.

    Science.gov (United States)

    Ziyaei Halimehjani, Azim; Khoshdoun, Maryam

    2016-07-01

    An efficient approach for the synthesis of novel alkyl 2,3-dihydro-3-oxo-1-aryl-1H-benzo[f]chromen-2-ylcarbamodithioates and alkyl 3,4-dihydro-2-oxo-4-aryl-2H-chromen-3-ylcarbamodithioates from 2-(alkylthio)thioazlactones (thioazlactones) and phenols or naphthols catalyzed by PTSA was developed. The reaction proceeds via a domino esterification/intramolecular 1,4-addition-type Friedel-Crafts alkylation reaction to afford interesting complex molecules by a simple procedure with high yields and diastereoselectivity. An X-ray analysis was carried out to firmly establish the stereochemistry of the products. PMID:27310869

  8. Environmentally benign Friedel-Crafts benzylation over nano-TiO2/SO4 2-

    Science.gov (United States)

    Devi, Kalathiparambil RPS; Sreeja, Puthenveetil B.; Sugunan, Sankaran

    2013-05-01

    During the past decade, much attention has been paid to the replacement of homogeneous catalysts by solid acid catalysts. Friedel-Crafts benzylation of toluene with benzyl chloride (BC) in liquid phase was carried out over highly active, nano-crystalline sulfated titania systems. These catalysts were prepared using the sol gel method. Modification was done by loading 3% of transition metal oxides over sulfated titania. Reaction parameters such as catalyst mass, molar ratio, temperature, and time have been studied. More than 80% conversion of benzyl chloride and 100% selectivity are shown by all the catalysts under optimum conditions. Catalytic activity is correlated with Lewis acidity obtained from perylene adsorption studies. The reaction appears to proceed by an electrophile, which involves the reaction of BC with the acidic titania catalyst. The catalyst was regenerated and reused up to four reaction cycles with equal efficiency as in the first run. The prepared systems are environmentally friendly and are easy to handle.

  9. A Zeolite Imidazolate Framework ZIF-8 Catalyst for Friedel-Crafts Acylation

    Institute of Scientific and Technical Information of China (English)

    LienT.L.NGUYEN; Ky K.A.LE; Nam T.S.PHAN

    2012-01-01

    A zeolite imidazolate framework,ZIF-8,was synthesized and characterized by dynamic laser light scattering,X-ray powder diffraction,scanning electron microscopy,transmission electron microscopy,thermogravimetric analysis,Fourier transform infrared,atomic absorption spectrophotometry,and nitrogen adsorption measurements.The ZIF-8 was highly crystalline and porous with a surface area of over 1600 m2/g.Friedel-Crafts acylation of anisole and benzoyl chloride proceeded well in the presence of ZIF-8 (2-6 mol%) without the need for an inert atmosphere.The reaction afforded a selectivity of 93%-95% to the p-isomer.The solid catalyst can be separated from the reaction mixture by simple centrifugation and reused without significant degradation in catalytic activity.There was no leaching of active acid species into the reaction solution.

  10. Sterically-controlled intermolecular Friedel-Crafts acylation with twisted amides via selective N-C cleavage under mild conditions.

    Science.gov (United States)

    Liu, Yongmei; Meng, Guangrong; Liu, Ruzhang; Szostak, Michal

    2016-05-21

    Highly chemoselective Friedel-Crafts acylation with twisted amides under mild conditions is reported for the first time. The reaction shows high functional group tolerance, obviating the need for preformed sensitive organometallic reagents and expensive transition metal catalysts. The high reactivity of amides is switched on by ground-state steric distortion to disrupt the amide bond nN→πCO* resonance as a critical design feature. Conceptually, this new acid-promoted mechanism of twisted amides provides direct access to bench-stable acylating reagents under mild, metal-free conditions. PMID:27139813

  11. An efficient combination of Zr-MOF and microwave irradiation in catalytic Lewis acid Friedel-Crafts benzoylation.

    Science.gov (United States)

    Doan, Tan L H; Dao, Thong Q; Tran, Hai N; Tran, Phuong H; Le, Thach N

    2016-05-01

    A zirconium-based metal-organic framework, an effective heterogeneous catalyst, has been developed for the Friedel-Crafts benzoylation of aromatic compounds under microwave irradiation. Constructed by a Zr(iv) cluster and a linker 1,4-bis(2-[4-carboxyphenyl]ethynyl)benzene (H2CPEB), the MOF, possessing large pores and high chemical stability, was appropriate for the enhancement of Lewis acid activity under microwave irradiation. The reaction studies demonstrated that the material could give high yields for a few minutes and maintain its reactivity and structure over several cycles. PMID:27064371

  12. Heteropoly acid encapsulated into zeolite imidazolate framework (ZIF-67) cage as an efficient heterogeneous catalyst for Friedel-Crafts acylation

    Science.gov (United States)

    Ammar, Muhammad; Jiang, Sai; Ji, Shengfu

    2016-01-01

    A new strategy has been developed for the encapsulation of the phosphotungstic heteropoly acid (H3PW12O40 denoted as PTA) into zeolite imidazolate framework (ZIF-67) cage and the PTA@ZIF-67(ec) catalysts with different PTA content were prepared. The structure of the catalysts was characterized by XRD, BET, SEM, FT-IR, ICP-AES and TG. The catalytic activity and recovery properties of the catalysts for the Friedel-Crafts acylation of anisole with benzoyl chloride were evaluated. The results showed that 14.6-31.7 wt% PTA were encapsulated in the ZIF-67 cage. The PTA@ZIF-67(ec) catalysts had good catalytic activity for Friedel-Crafts acylation. The conversion of anisole can reach ~100% and the selectivity of the production can reach ~94% over 26.5 wt% PTA@ZIF-67(ec) catalyst under the reaction condition of 120 °C and 6 h. After reaction, the catalyst can be easily separated from the reaction mixture by the centrifugation. The recovered catalyst can be reused five times and the selectivity can be kept over 90%.

  13. Fe3+-Exchanged Titanate Nanotubes: A New Kind of Highly Active Heterogeneous Catalyst for Friedel-Crafts Type Benzylation

    Directory of Open Access Journals (Sweden)

    Yunchen Du

    2015-01-01

    Full Text Available Heterogeneous catalysis for Friedel-Crafts type benzylation has received much attention in recent years due to its characteristic of environmental benefits. In this paper, titanate nanotubes (TNTs were employed as heterogeneous catalyst support, and a new kind of Fe3+-exchanged titanate nanotubes (Fe-TNTs catalyst with highly dispersed ferric sites was constructed by an ion exchange technique. The obtained catalyst was systematically characterized by XRD, TEM, N2 adsorption, XPS, and UV-vis spectra. As expected, Fe-TNTs showed excellent catalytic activities in the benzylation of benzene and benzene derivatives. The recycling tests for Fe-TNTs were also carried out, where the reason for the gradually decreased activity was carefully investigated. Superior to some reported catalysts, the catalytic ability of used Fe-TNTs could be easily recovered by ion exchange again, indicating that Fe-TNTs herein were a highly active and durable heterogeneous catalyst for Friedel-Crafts type benzylation. These results might be helpful for the design and preparation of novel heterogeneous catalysts by combining the structural advantages of titanate nanotubes and active metal ions.

  14. Friedel-Craft Acylation of ar-Himachalene: Synthesis of Acyl-ar-Himachalene and a New Acyl-Hydroperoxide

    Directory of Open Access Journals (Sweden)

    Abdallah Karim

    2011-07-01

    Full Text Available Friedel-Craft acylation at 100 °C of 2,5,9,9-tetramethyl-6,7,8,9-tetrahydro-5H-benzocycloheptene [ar-himachalene (1], a sesquiterpenic hydrocarbon obtained by catalytic dehydrogenation of α-, β- and γ-himachalenes, produces a mixture of two compounds: (3,5,5,9-tetramethyl-6,7,8,9-tetrahydro-5H-benzocyclohepten-2-yl-ethanone (2, in 69% yield, with a conserved reactant backbone, and 3, with a different skeleton, in 21% yield. The crystal structure of 3 reveals it to be 1-(8-ethyl-8-hydroperoxy-3,5,5-trimethyl-5,6,7,8-tetrahydronaphthalen-2-yl-ethanone. In this compound O-H…O bonds form dimers. These hydrogen-bonds, in conjunction with weaker C-H…O interactions, form a more extended supramolecular arrangement in the crystal.

  15. Metal halide hydrates as lewis acid catalysts for the conjugated friedel-crafts reactions of indoles and activated olefins

    Energy Technology Data Exchange (ETDEWEB)

    Schwalm, Cristiane S.; Ceschi, Marco Antonio; Russowsky, Dennis, E-mail: dennis@iq.ufrgs.b [Universidade Federal do Rio Grande do Sul (IQ/UFRGS), Porto Alegre, RS (Brazil). Inst. de Quimica

    2011-07-01

    Metal halide hydrates such as SnCl{sub 2{center_dot}}2H{sub 2}O, MnCl{sub 2{center_dot}}4H{sub 2}O, SrCl{sub 2{center_dot}}6H{sub 2}O, CrCl{sub 2{center_dot}}6H{sub 2}O, CoCl{sub 2{center_dot}}6H{sub 2}O e CeCl{sub 3{center_dot}}7H{sub 2}O were investigated as mild Lewis acids catalysts for the conjugate Friedel-Crafts reaction between indoles and activated olefins. The reactions were carried out with aliphatic unsaturated ketones over a period of days at room temperature, while chalcones reacted only under reflux conditions. The reactions with nitrostyrene s were either performed in solvent or under solventless conditions. In all cases reasonable to good yields were obtained. (author)

  16. Diaryl fluorene-Based Shape-Persistent Organic Nano molecular Frameworks via Iterative Friedel-Crafts Protocol toward Multicomponent Organic Semiconductors

    International Nuclear Information System (INIS)

    We describe bottom-up fluorenol approach to create soluble covalent organic nano molecular architectures (ONAs) as potential multicomponent organic semiconductors (MOSs). BPyFBFFA as a typical model of ONAs and MOSs exhibits a persistent chair-shaped geometric structure that consists of hole-transporting tri phenylamine (TPA), high-efficiency ter fluorene, and high-mobility pyrenes. BPyFBFFA was synthesized via the intermediates PyFA and BPyFA with iterative Friedel-Crafts reactions and Suzuki cross-coupling reactions. BPyFBFFA behaves as an efficient blue light-emitter without the low-energy green emission band. Complex diaryl fluorenes (CDAFs) are promising candidates for nano scale covalent organic frameworks and MOSs. Friedel-Crafts protocols offer versatile toolboxes for molecular architects to frame chemistry and materials, nano science, and molecular nano technology as well as molecular manufactures

  17. Methanetrisulfonic Acid: A Highly Efficient Strongly Acidic Catalyst for Wagner-Meerwein Rearrangement, Friedel-Crafts Alkylation and Acylation Reactions. Examples from Vitamin E Synthesis

    Directory of Open Access Journals (Sweden)

    Francesco Pace

    2009-04-01

    Full Text Available Methanetrisulfonic acid had been prepared for the first time over 140 years ago, but it was used only scarcely in chemical transformations. In the course of our activities dealing with key-steps of industrial syntheses of vitamins, e.g. economically important vitamin E (acetate, we found that methanetrisulfonic acid is an extremely effective catalyst in a variety of reactions. Examples of its applications are Wagner-Meerwein rearrangements, Friedel-Crafts alkylations and ring closures, as well as acylation reactions. Use of this catalyst in truly catalytic amounts (0.04-1.0 mol% resulted in highly selective transformations and yields over 95%. (Remark by the authors: We are describing only one example each for the various types of reactions. Therefore, it would be more appropriate to write (here and in the Introduction and in the Conclusion sections: “Wagner-Meerwein rearrangement, Friedel-Crafts alkylation and ring closure, as well as acylation reactions”

  18. Methanetrisulfonic Acid: A Highly Efficient Strongly Acidic Catalyst for Wagner-Meerwein Rearrangement, Friedel-Crafts Alkylation and Acylation Reactions. Examples from Vitamin E Synthesis

    OpenAIRE

    Francesco Pace; Thomas Netscher; Simone Hoppmann; Alois Haas; Fabrice Aquino; Werner Bonrath; Horst Pauling

    2009-01-01

    Methanetrisulfonic acid had been prepared for the first time over 140 years ago, but it was used only scarcely in chemical transformations. In the course of our activities dealing with key-steps of industrial syntheses of vitamins, e.g. economically important vitamin E (acetate), we found that methanetrisulfonic acid is an extremely effective catalyst in a variety of reactions. Examples of its applications are Wagner-Meerwein rearrangements, Friedel-Crafts alkylations and ring closures, as we...

  19. Werner-type Cobalt Complexes and Ruthenium Complexes with Substituted 2-Guanidinobenzimidazole Ligands as Catalysts for Michael and Friedel Crafts Reactions

    OpenAIRE

    Ganzmann, Carola

    2010-01-01

    In this thesis, chiral cobalt(III) complexes with en ligands (en = ethylenediamine) and ruthenium complexes with 2-guanidinobenzimidazole (GBI) and N-(2-benzimidazolyl)thiourea (BITU) ligands are developed. Their efficiency as catalysts for Friedel Crafts and Michael reactions are assayed. Chapter 1 provides an overview of the development of bifunctional thiourea catalysts and analyzes crystal structures of previously reported [Co(diamine)3]3+ complexes as well as GBI systems and correspondin...

  20. Friedel-Crafts Polyketones: Synthesis, Characterization and Antimicrobial Properties of Unsaturated Polyketones and Copolyketones Based on Difurfurylidene Cycloheptanone

    Directory of Open Access Journals (Sweden)

    Nayef S. Al-Muaikel

    2011-01-01

    Full Text Available A new type of unsaturated polyketones and copolyketones having cycloheptanone moiety in a p-conjugated main chain were synthesized via Friedel-Crafts reaction through the polymerization of the monomer: 2,7-bis furfurylidene cycloheptanone I with different diacid chlorides. The model compound was synthesized by reacting I with benzoyl chloride and characterized by 1H-NMR, IR, and elemental analyses. The polyketones and copolyketones were soluble easily in protic solvents like H2SO4 and trifluoroacetic acid. The thermal properties of these polyketones and copolyketones were evaluated and correlated to their structural units by TGA and DSC measurements. The crystallinity of some polymers was tested by X-ray analyses; also the morphological properties of selected examples of poly and copolyketones were detected by SEM. All the polyketones were tested for their biological activity against bacteria, fungi, and yeast. It was observed that the majority of the polyketones and its copolymers synthesized can be used as antibacterial and antifungal agents.

  1. Friedel-Crafts Crosslinked Highly Sulfonated Polyether Ether Ketone (SPEEK) Membranes for a Vanadium/Air Redox Flow Battery.

    Science.gov (United States)

    Merle, Géraldine; Ioana, Filipoi Carmen; Demco, Dan Eugen; Saakes, Michel; Hosseiny, Seyed Schwan

    2013-12-30

    Highly conductive and low vanadium permeable crosslinked sulfonated poly(ether ether ketone) (cSPEEK) membranes were prepared by electrophilic aromatic substitution for a Vanadium/Air Redox Flow Battery (Vanadium/Air-RFB) application. Membranes were synthesized from ethanol solution and crosslinked under different temperatures with 1,4-benzenedimethanol and ZnCl2 via the Friedel-Crafts crosslinking route. The crosslinking mechanism under different temperatures indicated two crosslinking pathways: (a) crosslinking on the sulfonic acid groups; and (b) crosslinking on the backbone. It was observed that membranes crosslinked at a temperature of 150 °C lead to low proton conductive membranes, whereas an increase in crosslinking temperature and time would lead to high proton conductive membranes. High temperature crosslinking also resulted in an increase in anisotropy and water diffusion. Furthermore, the membranes were investigated for a Vanadium/Air Redox Flow Battery application. Membranes crosslinked at 200 °C for 30 min with a molar ratio between 2:1 (mol repeat unit:mol benzenedimethanol) showed a proton conductivity of 27.9 mS/cm and a 100 times lower VO2+ crossover compared to Nafion.

  2. Synthesis of New C2- Symmetric Fluoren-9-ylidene Malonate Derived Bis(oxazoline Ligands and Their Application in Friedel-Crafts Reactions

    Directory of Open Access Journals (Sweden)

    Lei Liu

    2010-11-01

    Full Text Available A series of new C2-symmetric fluoren-9-ylidene malonate-derived bis(oxazoline ligands were synthesized from fluoren-9-ylidene malonate and enantiomerically pure amino alcohols via a convenient route. Their asymmetric catalytic properties in the Friedel-Crafts reactions of indoles with arylidene malonates were evaluated, and the Cu(OTf2 complex of a fluoren-9-ylidene malonate-derived bis(oxazoline bearing a phenyl group showed moderate to good enantioselectivity (up to 88% ee.

  3. Stereoselective Synthesis of Spiro Bis-C,C-α-arylglycosides by Tandem Heck Type C-Glycosylation and Friedel-Crafts Cyclization.

    Science.gov (United States)

    Chen, Yen-Bo; Liu, Shi-Hao; Hsieh, Min-Tsang; Chang, Chih-Shiang; Lin, Chun-Hung; Chen, Chen-Yin; Chen, Po-Yen; Lin, Hui-Chang

    2016-04-01

    Spiro bis-C,C-α-arylglycosides were synthesized in three steps in 78-85% overall yields starting from exo-glycals. The initial Heck type C-aryl addition of exo-glycals with arylboronic acids afforded α-aryl-β-substituted C-glycosides with exclusive α-stereoselectivity. Among the products, β-ethanal α-aryl C-glycosides further reacted with alkylthiol in the presence of InCl3, followed by in situ Friedel-Crafts cyclization to yield the desirable final products. We proposed a mechanism to explain how the α-aryl group serves as a main determinant of the cyclization. PMID:26986781

  4. Lipase-catalyzed synthesis of acetylated EGCG and antioxidant properties of the acetylated derivatives

    Science.gov (United States)

    (-)-Epigallocatechin-3-O-gallate (EGCG) acetylated derivatives were prepared by lipase catalyzed acylation of EGCG with vinyl acetate to improve its lipophilicity and expand its application in lipophilic media. The immobilized lipase, Lipozyme RM IM, was found to be the optimum catalyst. The optimiz...

  5. Sulfamic acid as a cost-effective and recyclable solid acid catalyst for Friedel-Crafts alkylation of indole with α,β-unsaturated carbonyl compound and benzyl alcohol

    Institute of Scientific and Technical Information of China (English)

    Jing Yang; Juan Zhang; Tian Tian Chen; De Mei Sun; Ji Li; Xue Fen Wu

    2011-01-01

    Sulfamic acid was proved to be a cost-effective and recyclable catalyst for Friedel-Crafts type reaction of indole with α,β-unsaturated carbonyl compound and benzyl alcohol. Various indoles, α,β-unsaturated carbonyl compounds and a benzyl alcohol were successfully used in this type of reaction, and the corresponding products were obtained in good to excellent yields.

  6. Alkylidene malonates and α,β-unsaturated α'-hydroxyketones as practical substrates for vinylogous Friedel-Crafts alkylations in water catalysed by scandium(III) triflate/SDS

    NARCIS (Netherlands)

    Oelerich, Jens; Roelfes, Gerard

    2015-01-01

    Alkylidene malonates and α,β-unsaturated α'-hydroxyketones are demonstrated to be efficient classes of electrophiles for the scandium(III) triflate/sodium dodecyl sulphate (SDS) catalysed vinylogous Friedel-Crafts alkylation of indoles and pyrroles in water. These substrates contain an easily remova

  7. Facile construction of pyrrolo[1,2-b]isoquinolin-10(5H)-ones via a redox-amination-aromatization-Friedel-Crafts acylation cascade reaction and discovery of novel topoisomerase inhibitors.

    Science.gov (United States)

    Wu, Shanchao; Liu, Na; Dong, Guoqiang; Ma, Lin; Wang, Shengzheng; Shi, Wencai; Fang, Kun; Chen, Shuqiang; Li, Jian; Zhang, Wannian; Sheng, Chunquan; Wang, Wei

    2016-07-21

    An efficient redox-amination-aromatization-Friedel-Crafts acylation cascade process from trans-4-hydroxyproline and 2-formylbenzoic acids has been developed for the synthesis of pyrrolo[1,2-b]isoquinolin-10(5H)-ones. Compound 3h was identified as a new potent dual topoisomerase I/II inhibitor. PMID:27400278

  8. Gold-Catalyzed Direct Assembly of Aryl-Annulated Carbazoles from 2-Alkynyl Arylazides and Alkynes.

    Science.gov (United States)

    Li, Nan; Lian, Xiao-Lei; Li, Yu-Hui; Wang, Tian-Yi; Han, Zhi-Yong; Zhang, Liming; Gong, Liu-Zhu

    2016-09-01

    An unprecedented gold-catalyzed synthetic method for the direct assembly of aryl-annulated carbazoles from 2-alkynyl arylazides and alkynes is described. The reaction is proposed to proceed via a sequential cyclopropenation and intramolecular metal carbene/arene Friedel-Crafts-type reaction, respectively, mediated by two gold carbene intermediates. PMID:27529360

  9. Pd-catalyzed cascade allylic alkylation and dearomatization reactions of indoles with vinyloxirane.

    Science.gov (United States)

    Gao, Run-Duo; Xu, Qing-Long; Dai, Li-Xin; You, Shu-Li

    2016-09-14

    We have developed Pd-catalyzed intermolecular Friedel-Crafts-type allylic alkylation and allylic dearomatization reactions of substituted indoles bearing a nucleophilic group with vinyloxirane, providing an efficient method to synthesize structurally diverse tetrahydrocarboline and spiroindolenine derivatives under mild conditions. PMID:27511802

  10. A Large Scale Formal Synthesis of CoQ{sub 10}: Highly Stereoselective Friedel-Crafts Allylation Reaction of Tetramethoxytoluene with (E)-4-Chloro-2-methyl-1-phenylsulfonyl-2-butene in the Presence of Montmorillonite K-10

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Who; Lee, Hee Bong; Kim, Bong Chan; Sadaiah, Kadivendi; Lee, Kyuwoong; Shin, Hyunik [LG Life Sciences, Ltd., Daejeon (Korea, Republic of)

    2013-04-15

    We disclosed that MK-10 is a highly effective catalyst for the Friedel-Crafts reaction of 6 and 7 in terms of yield and of stereoselectivity. Although there are numerous applications of clays in Friedel-Crafts reaction, there is very limited example which demonstrated its effect on the stereoselectivity. In that context, our result is significant and further expansion in this direction is highly envisioned. Ubiquinone, as its name represents, exists ubiquitously in human body, particularly in the heart. It mediates the electron transfer process in mitochondria and also exerts strong antioxidant effect in its reduced form. In clinical trial, it showed beneficial effect on heart-related diseases such as myocardial infarction, angina, and other related symptoms to cause decreased mortality compared to the placebo group.

  11. A facile Friedel-Crafts acylation for the synthesis of polyethylenimine-grafted multi-walled carbon nanotubes as efficient gene delivery vectors.

    Science.gov (United States)

    Nia, Azadeh Hashem; Amini, Abbas; Taghavi, Sahar; Eshghi, Hossein; Abnous, Khalil; Ramezani, Mohammad

    2016-04-11

    Low chemical reactivity of carbon nanotubes is one of the major obstacles in their functionalization via chemical reactions. As a non-destructive method, Friedel-Crafts acylation was suggested among the explored reactions for which only a few methods have been reported under harsh reaction conditions, e.g., high temperature all leading to low yields. In this study, we propose a novel method for the acylation of multi-walled carbon nanotubes (MWCNTs) at a low temperature (i.e., 42°C), using SiO2-Al2O3 as a catalyst and 6-bromohexanoic acid as the acylating agent to produce high yield functionalized MWCNTs. After acylation, MWCNTs are conjugated with polyethylenimines (PEIs) with three molecular weights (1.8, 10 and 25kDa). Three different MWCNT-PEI conjugates are synthesized and evaluated for their condensation ability, viability, size and zeta potential properties. The transfection efficiency of the functionalized MWCNTs is evaluated using luciferase assay and flow cytometry in a Neuroblastoma cell line. MWCNT-PEI (10 kDa) conjugate shows the highest transfection efficacy compared to others. For this carrier transfection efficacy exceeds the amount of PEI 25 kDa at similar carrier to plasmid weight ratio (C/P) and is around 3 times higher compared to PEI 25 kDa at C/P=0.8 as positive control regarding its high transfection efficiency and low cytotoxicity. PMID:26906459

  12. Friedel-Crafts Alkylation of Arenes with 2-Halogeno-2-CF3-styrenes under Superacidic Conditions. Access to Trifluoromethylated Ethanes and Ethenes.

    Science.gov (United States)

    Sandzhieva, Maria A; Kazakova, Anna N; Boyarskaya, Irina A; Ivanov, Alexandr Yu; Nenajdenko, Valentine G; Vasilyev, Aleksander V

    2016-06-17

    The formation of the corresponding benzyl cations [ArHC(+)-CH(X)CF3] takes place under protonation of E-/Z-2-halogeno-2-CF3 styrenes [ArCH═C(X)CF3, X = F, Cl, Br] in superacids. The structures of these new electrophiles were studied by means of NMR and theoretical DFT calculations. According to these data, in the case of bromo derivatives, the formed cations, most probably, exist as cyclic bromonium ions; however, in the cases of chloro and fluoro derivatives, open forms are more preferable. Subsequent reaction of these benzyl cations with arenes proceeds as Friedel-Crafts alkylation to afford 1,1-diaryl-2-halo-3,3,3-trifluoropropanes [Ar(Ar')CH-CH(X)CF3] in high yields (up to 96%) as a mixture of two diastereomers. The prepared halogenopropanes were easily converted into the corresponding mixtures of E-/Z-trifluoromethylated diarylethenes [Ar(Ar')C═CCF3] (in yields up to 96%) by dehydrohalogenation with base (KOH or t-BuOK). The mechanism of elimination (E2 and Ecb) depends on the nature of the leaving group and reaction conditions. PMID:27227747

  13. An efficient and green synthesis of 1-indanone and 1-tetralone via intramolecular Friedel-Crafts acylation reaction

    DEFF Research Database (Denmark)

    Tran, Phuong Hoang; Huynh, Vy Hieu; Hansen, Poul Erik;

    2015-01-01

    Metal-triflate-catalyzed intramolecular Friedel–Crafts acylation of 3-arylpropanoic and 4-arylbutanoic acids in triflate-anion ionic liquids under monomodal microwave irradiation is reported. The environmentally benign synthetic procedure allows the formation of cyclic ketones in good yields with...

  14. Chelation-assisted Pd-catalysed ortho-selective oxidative C-H/C-H cross-coupling of aromatic carboxylic acids with arenes and intramolecular Friedel-Crafts acylation: one-pot formation of fluorenones.

    Science.gov (United States)

    Sun, Denan; Li, Bijin; Lan, Jingbo; Huang, Quan; You, Jingsong

    2016-03-01

    Pd-Catalysed ortho-selective oxidative C-H/C-H cross-coupling of aromatic carboxylic acids with arenes and subsequent intramolecular Friedel-Crafts acylation has been accomplished for the first time through a chelation-assisted C-H activation strategy. Starting from the readily available substrates, a variety of fluorenone derivatives are obtained in one pot. The direct use of naturally occurring carboxylic acid functionalities as directing groups avoids unnecessary steps for installation and removal of an extra directing group. PMID:26861768

  15. Friedel-Crafts alkylations of electron-rich aromatics with 3-hydroxy-2-oxindoles: scope and limitations.

    Science.gov (United States)

    Kinthada, Lakshmana K; Ghosh, Santanu; Babu, K Naresh; Sharique, Mohd; Biswas, Soumava; Bisai, Alakesh

    2014-11-01

    A Lewis acid-catalyzed nucleophilic addition of electron rich aromatics with 3-hydroxy-2-oxindoles 5 was developed. The reaction is believed to proceed through the 2H-indol-2-one ring system 9, which eventually reacts with various electron-rich aromatics to afford a variety of 2-oxindoles with an all-carbon quaternary center at the pseudobenzylic position (4, 8, 13, and 16) in high yields. The methodology provides an expeditious route to the tetracyclic core (3) of diazonamide (1), and azonazine (2) as well as the tricyclic core of asperazine (6a), idiospermuline (6b), and calycosidine (6c) viz. C(3a)-arylpyrroloindolines 7 having an all-carbon quaternary center on further synthetic elaboration.

  16. SCANDIUM TRIFLATE CATALYZED ACETYLATION OF STARCH UNDER MILD CONDITIONS

    Science.gov (United States)

    Scandium (III) trifluoromethan sulfonate (Sc(OTf)3) was investigated as a catalyst for the acetylation of starch in order to determine the potential for preparing new types of starch esters under mild conditions. At room temperature, dry granular corn starch reacts with acetic anhydride in the pres...

  17. Iron(III)-Catalyzed Arylation of Spiro-Epoxyoxindoles with Phenols/Naphthols towards the Synthesis of Spirocyclic Oxindoles.

    Science.gov (United States)

    Luo, Mupeng; Yuan, Rongju; Liu, Xuesong; Yu, Linqian; Wei, Wanguo

    2016-07-01

    An efficient and highly regioselective iron(III)-catalyzed Friedel-Crafts-type arylation of spiro-epoxyoxindoles with phenols was developed for rapid access to 3-(3-indolyl)-oxindole-3-methanols, which could be further elaborated into benzofuranyl-spirooxindoles under Mitsunobu conditions. When spiro-epoxyoxindoles were reacted with naphthols in the presence of a catalytic amount of FeCl3 ⋅6 H2 O in dichloromethane, they underwent a tandem Friedel-Crafts-type arylation and O-cyclization to yield novel naphthofuranyl-spirooxindoles in excellent yields. This method is applied to enable the efficient and highly regioselective synthesis of a small-molecule inhibitor of the sodium channel Nav 1.7 (±)-XEN402, which is currently in a phase IIb clinical trial for the treatment of pain. PMID:27244669

  18. Calcium-Catalyzed, Dehydrative, Ring-Opening Cyclizations of Cyclopropyl Carbinols Derived from Donor-Acceptor Cyclopropanes.

    Science.gov (United States)

    Sandridge, Matthew J; France, Stefan

    2016-09-01

    A calcium-catalyzed, dehydrative, ring-opening cyclization of (hetero)aryl cyclopropyl carbinols is reported. The cyclopropyl carbinols are prepared directly from the corresponding donor-acceptor (D-A) cyclopropanes. The calcium catalyst catalyzes the formation of putative (hetero)aryl cyclopropyl carbinyl cations that undergo ring-opening to allylcarbinyl cations. Subsequent intramolecular Friedel-Crafts reaction affords (hetero)aryl-fused cyclohexa-1,3-dienes in up to 97% yield. This approach represents the first example of catalysis for this intramolecular, dehydrative ring-opening cyclization and outperforms the previous reports using stoichiometric Lewis acids. PMID:27517711

  19. Lewis Acid Catalyzed Selective Reactions of Donor-Acceptor Cyclopropanes with 2-Naphthols.

    Science.gov (United States)

    Kaicharla, Trinadh; Roy, Tony; Thangaraj, Manikandan; Gonnade, Rajesh G; Biju, Akkattu T

    2016-08-16

    Lewis acid-catalyzed reactions of 2-substituted cyclopropane 1,1-dicarboxylates with 2-naphthols is reported. The reaction exhibits tunable selectivity depending on the nature of Lewis acid employed and proceed as a dearomatization/rearomatization sequence. With Bi(OTf)3 as the Lewis acid, a highly selective dehydrative [3+2] cyclopentannulation takes place leading to the formation of naphthalene-fused cyclopentanes. Interestingly, engaging Sc(OTf)3 as the Lewis acid, a Friedel-Crafts-type addition of 2-naphthols to cyclopropanes takes place, thus affording functionalized 2-naphthols. Both reactions furnished the target products in high regioselectivity and moderate to high yields. PMID:27391792

  20. 分子内酰基化反应合成新型六环稠杂环化合物%Synthesis of Novel Hexacyclic -fused Heterocyclic Compounds via Intramolecular Friedel -Crafts Acylation

    Institute of Scientific and Technical Information of China (English)

    聂成铭; 徐良玉; 李阳; 高文涛

    2013-01-01

    The hitherto unreported benzo[h]naphtho[1′,2′,6,7]oxepino[3,4-b] quinolin-17(8H) -one (3a) was synthesized by the intramolecular Friedel -Crafts acylation reaction of 2 -(( naphthalen -2 -yloxy)methyl)benzo[h]quinoline -3-carboxylic acid 2 under the treatment of Eaton′s reagent (P2O5 -Me-SO3 ) .The precursor 2 was prepared through one -pot reaction of ethyl 2-( chloromethyl ) benzo [ h] quinoline-3-carboxylate 1 with α-naphthol or β-naphthol .The substrate 1 was obtained in good yield by a mild , effi-cient and direct reaction of α-naphthylamine with 4 -chloroacetoacetate under the treatment of Vilsmeier -Haack reagent.The structures of all the new compounds were identified by ESI -MS, IR, NMR spectra and Ele-mental analysis .%以2-氯甲基-3-苯并喹啉甲酸乙酯(1)为底物与α-萘酚、β-萘酚反应经“一锅法”合成了中间体2-(α-萘氧甲基)苯并[ h]喹啉-3-羧酸(2a)、2-(β-萘氧甲基)苯并[ H]喹啉-3-羧酸(2b)。化合物2a,2b在Eaton′s试剂作用下合成两种新型六环稠杂环化合物萘并[2′,1′,6,7]氧杂卓并[3,4-b]苯并喹啉-7(14H)-酮(3a)和萘并[1′,2′,6,7]氧杂卓并[3,4-b]苯并喹啉-15(8H)-酮(3b)。化合物2a,2b发生分子内傅一克酰基化闭环反应,所合成的新化合物2a、2b、3a、3b的结构经红外光谱、核磁共振谱、质谱及元素分析等得以确认。

  1. 以氯代酰氯为试剂的聚砜膜材料的付-克酰基化反应%Friedel-Crafts Acylation Reaction of Polysulfone Membrane Material with Chloroacyl Chlorides

    Institute of Scientific and Technical Information of China (English)

    杜瑞奎; 高保娇; 李延斌; 曾庆湘

    2011-01-01

    采用氯乙酰氯和氯丁酰氯两种ω-氯代酰氯化试剂,在Lewis酸催化剂存在下,于室温下分别对聚砜(PSF)材料实施了Friedel-Crafts酰基化反应,制备了氯代酰基化(CA)聚砜材料CAPSF。用FT-IR、1H-NMR与佛尔哈德分析法表征了该产物的化学结构与组成。结果表明:在室温(25°C)下,以CH2Cl2为溶剂,以SnCl4为Lewis酸催化剂,聚砜的氯代酰基化反应可以顺利地进行,反应3 h,即可制得氯含量为0.5 mmol/g的产物;采用氯丁酰氯对PSF进行氯代酰基化反应的效果明显好于氯乙酰氯。%Friedel-Crafts acylation reactions of polysulfone(PSF) membrane material were conducted in the presence of Lewis acid catalysts at room temperature using two kinds of ω-chloroacyl chloride,chloroacetyl chloride and chlorobutyryl chloride,and chloroacylated polysulfone(CAPSF) were prepared.The chemical structure and composition of the product were characterized by FT-IR,1H-NMR and Volhard methods.The reaction processes on the chloroacylation reactions of PSF were primarily investigated.The experimental results show that the chloroacylation reaction of PSF can be carried out successfully,and a product CAPSF with a chlorine content of 0.5 mmol/g can be obtained in 3 h at room temperature(25°C) with CH2Cl2 as solvent and SnCl4 as Lewis acid catalyst.The experimental results also indicate that chlorobutyryl chloride is better than chloroacetyl chloride in the chloroacylation reactions.

  2. 三丁基锡/SBA-15功能配合物的合成、表征及对Friedel-Crafts反应的选择性催化%Synthesis, Characterization and Catalytic Performance Toward the Friedel-Crafts Acylation of Tributyltin Functionalized SBA-15

    Institute of Scientific and Technical Information of China (English)

    荆涛; 覃志乐; 宋伟明; 赵云鹏; 邓启刚

    2013-01-01

    将三丁基氯化锡与SBA-15介孔分子筛在N2气气氛中进行回流反应,得到有机锡无机配合物(C4H9)3Sn-O-SBA-15[Bu3SnS].利用X射线衍射(XRD)、透射电子显微镜(TEM)、氮气吸附脱附、固体核磁(NMR)和吡啶吸附脱附红外光谱分析(Py-IR)等方法对产物的组成、结构和性质进行了表征.结果表明,产物Bu3 SnS具有高度有序的六方介孔结构,与SBA-15相比,Bu3 SnS比表面积、孔容和孔径变小,酸性增强.Bu3 SnS对苯甲醚Friedel-Crafts酰基化反应具有优异的催化性能,当反应温度为130℃,n(苯甲醚)∶n(苯甲酰氯)=1.0∶2.0,w(cat) =6%(相对于苯甲醚用量),反应时间为5h,苯甲醚的转化率达到76.0%,对甲氧基二苯酮(p-MBP)选择性达到97.8%.%The organotin inorganic complexes (C4H9) 3Sn-O-SBA-15 [Bu3SnS] were successfully synthesized by grafting tributyhin on SBA-15 mesoporous molecular sieves in a nitrogen atmosphere.The composition,structure and properties of the samples were characterized by X-ray diffraction (XRD),transmittance electron microscopy(TEM),Hammett indicator method,N2 adsorption-desorption,solid nuclear magnetic resonance (NMR),in-situ pyridine infrared spectroscopy(Py-IR) and so on.The results show that the hexagonal P6mm mesostructure of parent siliceous SBA-15 is maintained in Bu3SnS.The surface areas,proe size and volume of Bu3 SnS are all deceased with the increase of acidity,compared to those of SBA-15.Friedel-Crafts acylation of anisole and benzoyl chloride can be efficiently catalyzed in the presence of Bu3 SnS.The reaction conversion of anisole and the selectivity ofp-benzoylanisole are 76.0% and 97.8%,respectively,when the molar ratio of anisole to benzoyl chloride is 0.5∶ 1.0,the amount of catalyst is 6%,the reaction temperature is 130 ℃ and the reaction time is 5 h.

  3. A cell-free fluorometric high-throughput screen for inhibitors of Rtt109-catalyzed histone acetylation.

    Directory of Open Access Journals (Sweden)

    Jayme L Dahlin

    Full Text Available The lysine acetyltransferase (KAT Rtt109 forms a complex with Vps75 and catalyzes the acetylation of histone H3 lysine 56 (H3K56ac in the Asf1-H3-H4 complex. Rtt109 and H3K56ac are vital for replication-coupled nucleosome assembly and genotoxic resistance in yeast and pathogenic fungal species such as Candida albicans. Remarkably, sequence homologs of Rtt109 are absent in humans. Therefore, inhibitors of Rtt109 are hypothesized as potential and minimally toxic antifungal agents. Herein, we report the development and optimization of a cell-free fluorometric high-throughput screen (HTS for small-molecule inhibitors of Rtt109-catalyzed histone acetylation. The KAT component of the assay consists of the yeast Rtt109-Vps75 complex, while the histone substrate complex consists of full-length Drosophila histone H3-H4 bound to yeast Asf1. Duplicated assay runs of the LOPAC demonstrated day-to-day and plate-to-plate reproducibility. Approximately 225,000 compounds were assayed in a 384-well plate format with an average Z' factor of 0.71. Based on a 3σ cut-off criterion, 1,587 actives (0.7% were identified in the primary screen. The assay method is capable of identifying previously reported KAT inhibitors such as garcinol. We also observed several prominent active classes of pan-assay interference compounds such as Mannich bases, catechols and p-hydroxyarylsulfonamides. The majority of the primary active compounds showed assay signal interference, though most assay artifacts can be efficiently removed by a series of straightforward counter-screens and orthogonal assays. Post-HTS triage demonstrated a comparatively small number of confirmed actives with IC50 values in the low micromolar range. This assay, which utilizes five label-free proteins involved in H3K56 acetylation in vivo, can in principle identify compounds that inhibit Rtt109-catalyzed H3K56 acetylation via different mechanisms. Compounds discovered via this assay or adaptations thereof could

  4. 全氟辛基磺酸稀土金属盐催化氟两相Friedel-Crafts烷基化反应%Friedel-Crafts Alkylation in Fluorous Biphasic System Catalyzed by Rare Earth(Ⅲ) Perfluorooctanesulfonates

    Institute of Scientific and Technical Information of China (English)

    易文斌; 蔡春

    2006-01-01

    制备了全氟辛基磺酸稀土金属盐[RE(OSO2C8C17)3,RE:Sc,Y,La~Lu],并研究了将其作为催化剂催化氟两相烷基化反应. 全氟己烷(C6F14)、全氟甲苯(C7F8)、全氟甲基环己烷(C7F14)、全氟辛烷(C8F18)、1-溴代全氟辛烷(C8F17Br)和全氟萘烷(C10F18,顺式与反式的混合物)可作为该反应的氟溶剂. 考察了带有不同配体的稀土金属催化剂对反应的影响. 研究表明,Yb(OSO2C8F17)3和C10F18分别是最好的氟代催化剂和氟溶剂. 以Yb(OSO2C8F17)3为催化剂在C10F18中苯甲醚和苯甲醇的烷基化反应得率为96%. 含有催化剂的氟相通过简单的相分离,可回收利用. 氟相重复使用5次,其催化活性降低不大.

  5. Friedel-Crafts Acylation in Fluorous Biphasic Systems Catalyzed by Rare Earth( Ⅲ ) Perfluorooctanesulfonates%全氟辛基磺酸稀土金属盐催化氟两相Friedel-Crafts酰化反应

    Institute of Scientific and Technical Information of China (English)

    易文斌; 蔡春

    2005-01-01

    制备了全氟辛基磺酸稀土金属盐(RE(OSO2C8F17)3,RE=Y,La~Lu),研究了该催化剂作用下氟两相Friedel-Crafts酰化反应.全氟己烷(C6F14)、全氟甲苯(C7F8)、全氟甲基环己烷(C7F14)、全氟辛烷(C8F18)、1-溴代全氟辛烷(C8F17Br)和全氟萘烷(C10F18,顺式与反式的混合物)可作为该反应的氟溶剂.考察了氟相和有机相的相比与酰化试剂种类对反应的影响.结果表明,反应具有强对位选择性酰化能力;Y(OSO2C8F17)3和C10F18分别是最好的催化剂和氟溶剂,以Y(OSO2C8F17)3为催化剂在C10F18中苯甲醚和乙酸酐的Friedel-Crafts酰化反应得率为56%,对位选择性超过99%;随着氟相和有机相相比的减小,产率升高,对位选择性降低;含有催化剂的氟相通过简单的相分离,就可回收利用,氟相重复使用5次,其催化活性减少不大.

  6. N-Heterocyclic Carbene-Catalyzed Alcohol Acetylation: An Organic Experiment Using Organocatalysis

    Science.gov (United States)

    Morgan, John P.; Shrimp, Jonathan H.

    2014-01-01

    Undergraduate students in the teaching laboratory have successfully used N-heterocyclic carbenes (NHCs) as organocatalysts for the acetylation of primary alcohols, despite the high water sensitivity of uncomplexed ("free") NHCs. The free NHC readily reacted with chloroform, resulting in an air- and moisture-stable adduct that liberates…

  7. Resolution of 2-Octanol via Lipase-catalyzed Enantioselective Acetylation in Organic Solvents

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi; LI Zheng-qiang; Yu Da-hai; WENG Liang; LIU Ming; ZHANG Gui-rong; CAO Shu-gui

    2004-01-01

    The lipases from different sources were screened for their ability to catalyze the resolution of 2-octanol in organic solvents with vinyl acetate as the acylating reagent. The medium effect has been studied on the irreversible transesterification with varying water activity(aw). The influence of vinyl acetate concentration on it has also been investigated. Under the optimal conditions, the enantiomeric ratio(E value) of pseudomonas fluorescence lipase(PFL) exceeded 200 with an enantiomeric excess(e. e. ) of S-2-octanol above 99% at a 51% degree of conversion.

  8. Acetone-soluble cellulose acetate extracted from waste blended fabrics via ionic liquid catalyzed acetylation.

    Science.gov (United States)

    Sun, Xunwen; Lu, Canhui; Zhang, Wei; Tian, Dong; Zhang, Xinxing

    2013-10-15

    Isolation of cellulose from waste polyester/cotton blended fabrics (WBFs) is a bottleneck for recycling and exploiting waste textiles. The objective of this study was to provide a new environmental-friendly and efficient approach for extracting cellulose derivatives and polyester from WBFs. A Bronsted acidic ionic liquid (IL) N-methyl-imidazolium bisulfate, [Hmim]HSO4, was used as a novel catalyst for acetylation of cellulose rather than a solvent with the aim to overcome low isolation efficiency associated with the very high viscosity and relatively high costs of ILs. The extraction yield of acetone-soluble cellulose acetate (CA) was 49.3%, which corresponded to a conversion of 84.5% of the cellulose in the original WBFs; meanwhile, 96.2% of the original poly(ethylene terephthalate) (PET) was recovered. The extracted CA was characterized by (1)H NMR, FTIR, XRD and TGA analysis, and the results indicated that high purity acetone-soluble CA and carbohydrate-free PET could be isolated in this manner from WBFs.

  9. Iron-Catalyzed Intramolecular C(sp(2))-N Cyclization of 1-(N-Arylpyrrol-2-yl)ethanone O-Acetyl Oximes toward Pyrrolo[1,2-a]quinoxaline Derivatives.

    Science.gov (United States)

    Zhang, Zhiguo; Li, Junlong; Zhang, Guisheng; Ma, Nana; Liu, Qingfeng; Liu, Tongxin

    2015-07-01

    An efficient and convenient iron-catalyzed protocol has been developed for the synthesis of substituted pyrrolo[1,2-a]quinoxalines from 1-(N-arylpyrrol-2-yl)ethanone O-acetyl oximes through N-O bond cleavage and intramolecular directed C-H arylation reactions in acetic acid.

  10. Dy(OTf)3 Catalyzed Reaction of Indole with Aldehydes and Ketones in Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    MI Xue-Ling; LUO San-Zhong; HE Jia-Qi; CHENG Jin-Pei

    2003-01-01

    @@ The use of environmentally benign reaction media is very important in view of today' s environmentally con scious attitude. In connect with this, room temperature ionic liquids that are air and moisture stable have received a good deal of attention in recent years as novel solvent systems for organic synthesis. A number of reactions such as Friedel-Crafts reactions, Diels-Alder cycloadditions, hydrogenations, and Heck reactions have employed ionic liquids as solvents. Among them, the Friedel-Crafts reaction[1] is of great synthetic significance in view of laboratory synthesis and industrial production. Recent studies showed that Friedel-Crafts reaction of indole with carbonyl compounds proceeded readily in aqueous media. [2] However, the aqueous reactions suffer from some common problems,such as tedious work-up, reuse of catalyst and so on.

  11. Phenylalanine Ammonia-Lyase-Catalyzed Deamination of an Acyclic Amino Acid: Enzyme Mechanistic Studies Aided by a Novel Microreactor Filled with Magnetic Nanoparticles.

    Science.gov (United States)

    Weiser, Diána; Bencze, László Csaba; Bánóczi, Gergely; Ender, Ferenc; Kiss, Róbert; Kókai, Eszter; Szilágyi, András; Vértessy, Beáta G; Farkas, Ödön; Paizs, Csaba; Poppe, László

    2015-11-01

    Phenylalanine ammonia-lyase (PAL), found in many organisms, catalyzes the deamination of l-phenylalanine (Phe) to (E)-cinnamate by the aid of its MIO prosthetic group. By using PAL immobilized on magnetic nanoparticles and fixed in a microfluidic reactor with an in-line UV detector, we demonstrated that PAL can catalyze ammonia elimination from the acyclic propargylglycine (PG) to yield (E)-pent-2-ene-4-ynoate. This highlights new opportunities to extend MIO enzymes towards acyclic substrates. As PG is acyclic, its deamination cannot involve a Friedel-Crafts-type attack at an aromatic ring. The reversibility of the PAL reaction, demonstrated by the ammonia addition to (E)-pent-2-ene-4-ynoate yielding enantiopure l-PG, contradicts the proposed highly exothermic single-step mechanism. Computations with the QM/MM models of the N-MIO intermediates from L-PG and L-Phe in PAL show similar arrangements within the active site, thus supporting a mechanism via the N-MIO intermediate.

  12. Phenylalanine Ammonia-Lyase-Catalyzed Deamination of an Acyclic Amino Acid: Enzyme Mechanistic Studies Aided by a Novel Microreactor Filled with Magnetic Nanoparticles.

    Science.gov (United States)

    Weiser, Diána; Bencze, László Csaba; Bánóczi, Gergely; Ender, Ferenc; Kiss, Róbert; Kókai, Eszter; Szilágyi, András; Vértessy, Beáta G; Farkas, Ödön; Paizs, Csaba; Poppe, László

    2015-11-01

    Phenylalanine ammonia-lyase (PAL), found in many organisms, catalyzes the deamination of l-phenylalanine (Phe) to (E)-cinnamate by the aid of its MIO prosthetic group. By using PAL immobilized on magnetic nanoparticles and fixed in a microfluidic reactor with an in-line UV detector, we demonstrated that PAL can catalyze ammonia elimination from the acyclic propargylglycine (PG) to yield (E)-pent-2-ene-4-ynoate. This highlights new opportunities to extend MIO enzymes towards acyclic substrates. As PG is acyclic, its deamination cannot involve a Friedel-Crafts-type attack at an aromatic ring. The reversibility of the PAL reaction, demonstrated by the ammonia addition to (E)-pent-2-ene-4-ynoate yielding enantiopure l-PG, contradicts the proposed highly exothermic single-step mechanism. Computations with the QM/MM models of the N-MIO intermediates from L-PG and L-Phe in PAL show similar arrangements within the active site, thus supporting a mechanism via the N-MIO intermediate. PMID:26345352

  13. Amine-Catalyzed Highly Regioselective and Stereoselective C(sp(2) )-C(sp(2) ) Cross-Coupling of Naphthols with trans-α,β-Unsaturated Aldehydes.

    Science.gov (United States)

    Hu, Yang; Ma, Yueyue; Sun, Rengwei; Yu, Xinhong; Xie, Hexin; Wang, Wei

    2015-09-01

    A metal-free C(sp(2) )-C(sp(2) ) cross-coupling approach to highly congested (E)-α-naphtholylenals from simple naphthols and enals is described. The mild reaction conditions with pyridine hydrobromideperbromide (PHBP) as the bromination reagent in the presence of piperidine or diphenylprolinol trimethylsilyl (TMS) ether as promoters enable the process in good yields and with high chemoselectivity, regioselectivity, and stereoselectivity. The process involves an unprecedented pathway of in situ regioselective 4-bromination of 1-naphthols and the subsequent unusual aromatic nucleophilic substitution of the resulting 4-bromo-1-naphthols with the α-C(sp(2) ) of enals through a Michael-type Friedel-Crafts alkylation-dearomatization followed by a cyclopropanation ring-opening cascade process. The noteworthy features of this strategy are highlighted by the highly efficient creation of a C(sp(2) )-C(sp(2) ) bond from readily available unfunctionalized naphthols and enals catalyzed by non-metal, readily available cyclic secondary amines under mild reaction conditions. PMID:26096893

  14. Enantioselective total synthesis of (+)-Lingzhiol via tandem semipinacol rearrangement/Friedel-Crafts type cyclization.

    Science.gov (United States)

    Chen, Dong; Xu, Wen-Dan; Liu, Hao-Miao; Li, Ming-Ming; Yan, Yong-Min; Li, Xiao-Nian; Li, Yan; Cheng, Yong-Xian; Qin, Hong-Bo

    2016-06-30

    Enantioselective total synthesis of (+)-Lingzhiol has been achieved. It is the first example of in tandem semipinacol rearrangement reactions, the migrated aryl group further reacting with the carbonyl oxonium electrophile to furnish a polycyclic skeleton. Our synthesis involves 13 steps and proceeds in 6% overall yield. PMID:27321202

  15. Microwave-assisted facile and rapid Friedel-Crafts benzoylation of arenes catalysed by bismuth trifluoromethanesulfonate

    DEFF Research Database (Denmark)

    Tran, Phoung Hoang; Hansen, Poul Erik; Pham, Thuy Than;

    2014-01-01

    The catalytic activity of metal triflates was investigated in Friedel–Crafts benzoylation under microwave irradiation. Friedel–Crafts benzoylation with benzoyl chloride of a variety of arenes containing electron-rich and electron-poor rings using bismuth triflate under microwave irradiation is...

  16. Intramolecular hydroarylation of aryl propargyl ethers catalyzed by indium: the mechanism of the reaction and identifying the catalytic species.

    Science.gov (United States)

    Menkir, Mengistu Gemech; Lee, Shyi-Long

    2016-07-01

    The mechanism and regioselectivity of the intramolecular hydroarylation of phenyl propargyl ether catalyzed by indium in gas and solvent phases were investigated by means of the density functional theory method. The computed results revealed that the reaction proceeds through initial π-coordination of the propargyl moiety to the catalyst, which triggers the nucleophilic attack of the phenyl ring via an exo- or endo-dig pathway in a Friedel-Crafts type mechanism. Calculation results obtained employing InI2(+) as the possible catalyst show similar activation energies for the 5-exo-dig and 6-endo-dig pathways. In contrast, the neural catalyst InI3 shows a kinetic preference for 6-endo-dig versus 5-exo-dig cyclizations leading to the experimentally observed product, 2H-chromene. The calculation results suggest that InI3 could be the real catalytic species for this reaction as it shows regioselectivity in agreement with the experimental observation. Furthermore, the 6-endo-dig cyclization through deprotonation/protonation steps is kinetically more favored than the stepwise two consecutive [1,2]-H shift steps. The rate determining step of the whole catalytic cycle is the deprotonation step with an energy barrier of 18.9 kcal mol(-1) in toluene solvent. The effects of substituents on both the phenyl ring and the propargyl moiety on the selectivity and elementary steps of the hydroarylation process were investigated. A methoxy group, particularly at the meta-position, on the phenyl ring largely decreases the energy barrier of the first step for the 6-endo path, though it shows little effect on the activation energies of the second and third steps. Our calculation results are in good agreement with the experimental results. PMID:27298068

  17. Recent Progress in Metal-Catalyzed Reactions of 2(5H)-Furanones%金属催化的2(5H)-呋喃酮反应研究进展

    Institute of Scientific and Technical Information of China (English)

    毛超旭; 汪朝阳; 谭越河; 薛福玲

    2011-01-01

    2(5H)-呋喃酮结构单元广泛存在于天然产物中,同时许多2(5H)-呋喃酮类化合物也是重要的有机合成中间体.因此,基于常见2(5H)-呋喃酮的有机合成研究近年来引起了人们的关注,尤其是金属催化的2(5H)-呋喃酮反应的地位日趋彰显重要,从而成为众多化学工作者的研究热点.按照反应类型的不同,对近年来金属催化的2(5H)-呋喃酮反应的研究进展进行了综述,主要包括Sonogashira,Suzuki,Stille等偶联反应,以及Michael加成反应、Friedel-Crafts烷基化反应、Baylis-Hillman反应、亲核取代反应、还原反应等.%The unique carbon skeleton of 2(5H)-furanone is widely present in a variety of natural products, and many compounds containing 2(5H)-furanone skeleton are important synthetic intermediates. Recently, more and more attentions have been attracted to the organic synthesis based on 2(5H)-furanones, especially via the metal-catalyzed reactions of 2(5H)-furanones. Classified as different types, the recent progress in metal-catalyzed reactions of 2(5H)-furanones, mainly including Sonogashira reaction, Suzuki reaction, Stille reaction, Michael addition, Friedel-Crafts alkylation, Baylis-Hillman reaction, nucleophilic substitution, and reduction reaction, is reviewed in this paper.

  18. Acetylation Reader Proteins: Linking Acetylation Signaling to Genome Maintenance and Cancer.

    Science.gov (United States)

    Gong, Fade; Chiu, Li-Ya; Miller, Kyle M

    2016-09-01

    Chromatin-based DNA damage response (DDR) pathways are fundamental for preventing genome and epigenome instability, which are prevalent in cancer. Histone acetyltransferases (HATs) and histone deacetylases (HDACs) catalyze the addition and removal of acetyl groups on lysine residues, a post-translational modification important for the DDR. Acetylation can alter chromatin structure as well as function by providing binding signals for reader proteins containing acetyl-lysine recognition domains, including the bromodomain (BRD). Acetylation dynamics occur upon DNA damage in part to regulate chromatin and BRD protein interactions that mediate key DDR activities. In cancer, DDR and acetylation pathways are often mutated or abnormally expressed. DNA damaging agents and drugs targeting epigenetic regulators, including HATs, HDACs, and BRD proteins, are used or are being developed to treat cancer. Here, we discuss how histone acetylation pathways, with a focus on acetylation reader proteins, promote genome stability and the DDR. We analyze how acetylation signaling impacts the DDR in the context of cancer and its treatments. Understanding the relationship between epigenetic regulators, the DDR, and chromatin is integral for obtaining a mechanistic understanding of genome and epigenome maintenance pathways, information that can be leveraged for targeting acetylation signaling, and/or the DDR to treat diseases, including cancer.

  19. Preparation of mono- and diacetyl 4,4′-dimethylbiphenyl and their corresponding carboxylic acids

    DEFF Research Database (Denmark)

    Titinchi, Salam J.J.; Kamounah, Fadhil S.; Abbo, Hanna S.

    2007-01-01

    Shape selective acetylation of 4,4′-dimethylbiphenyl using anhydrous aluminum chloride as catalyst is an effective route for the production of mono- and di-acetyl-4,4′-dimethylbiphenyl. Preparations, characterization and a catalytic study of the Friedel-Crafts acetylation of 4,4′-dimethylbiphenyl...

  20. New Alkylation Route of Benzene with Ethylene Catalyzed by [bmim]Cl/FeCl3 Ionic Liquid%[bmim]Cl/FeCl3离子液体催化苯与乙烯烷基化反应的新型机理

    Institute of Scientific and Technical Information of China (English)

    孙学文; 赵锁奇; 王仁安

    2004-01-01

    Up to now the mechanism of Friedel-Crafts reactions catalyzed by ionic liquid have not been fully understood, while carbocation mechanism was assumed. It was found that the source of H+ and the route of reaction initiated the alkylation of benzene with ethylene catalyzed by [bmim]Cl/FeCl3 ionic liquid. The fact that dewatered ionic liquids have catalytic activity for the alkylation of benzene with ethylene suggests that there exists a new catalytic route. The distinctly Bronsted acid properties of 2-H in [bmim]Cl were found through FT-IR and HNMR analysis of [bmim]Cl after titration with water free KOH in alcohol solution. In addition, the chemical shifts of proton on the [bmim]Cl ring, especially 2-H, are sensitive to the change of FeCl3 content and shifted downfield when FeCl3 was added into [bmim]Cl to form ionic liquid. Thus 2-H was easy to be disengaged from imidazolium ring with formation of H+ to initiate the reaction. The isotope-substituted method was employed to prove this mechanism, through the GC-MS analysis of alkylation products of deuterated benzene with ethylene. The route of alkylation catalyzed by FeCl3 ionic liquid was found to follow the carbocation mechanism, the resource of H+ was presented and proved using HNMR analysis of ionic liquid to inspect the intensity change of 2-H. It was found that the intensity of 2-H reduced 23% after reaction showing that the H+ arising from alkylation reaction was supplied by 2-H on the imidazole ring.

  1. Indium triflate in 1-isobutyl-3-methylimidazolium dihydrogenphosphate: an efficient and green catalytic system for Friedel-Crafts acylation

    DEFF Research Database (Denmark)

    Tran, Phuong Hoang; Hoang, Huy Manh; Chau, Duy-Khiem Nguyen;

    2015-01-01

    Indium triflate in the ionic liquid, 1-isobutyl-3-methylimidazolium dihydrogen phosphate ([i-BMIM]H2PO4), was found to show enhanced catalytic activity in the Friedel–Crafts acylation of various aromatic compounds with acid anhydrides. The catalytic system was easily recovered and reused without ...

  2. Upward Trend in Catalytic Efficiency of Rare-Earth Triflate Catalysts in Friedel-Crafts Aromatic Sulfonylation Reactions

    DEFF Research Database (Denmark)

    Duus, Fritz; Le, Thach Ngoc; Nguyen, Vo Thu An

    2014-01-01

    90 % were achieved for short irradiation periods. This was the case especially for Tm(OTf)3, Yb(OTf)3, and Lu(OTf)3, of which Yb(OTf)3 was the most efficient. The upward trend in catalytic efficiency therefore correlates with the lanthanide sequence in the periodic table. The results can be explained...

  3. Efficient One-Pot Synthesis of Indol-3-yl-Glycines via Uncatalyzed Friedel-Crafts Reaction in Water

    Directory of Open Access Journals (Sweden)

    Mehdi Ghandi

    2009-03-01

    Full Text Available The three component reaction of primary aliphatic amines, glyoxalic acid and indole or N-methylindole in water at ambient temperature affords indol-3-yl or N-methylindol-3-yl-glycine in almost quantitative yields.

  4. Ga doped SBA-15 as an active and stable catalyst for Friedel-Crafts liquid-phase acylation

    OpenAIRE

    EL BERRICHI, Zohra; CHERIF, Leila; ORSEN O.; TESSONIER, Jean-Philippe; VANHAECKE, Estelle; LOUIS, Benoit; LEDOUX, Marc-Jacques; Pham-Huu, Cuong

    2013-01-01

    Gallium containing SBA-15 mesoporous materials with different Si/Ga ratio were synthesized using a post-treatment procedure with an aqueous solution of Ga(NO3)3. The materials were characterised by means of elemental analysis, BET, XRD, TEM and H/D isotope exchange techniques. It appears that stable Ga-species were anchored to the siliceous matrix of SBA-15, thus generating acid properties in their host material. The catalytic activity of Ga-SBA-15 materials has been evaluated in the FriedelC...

  5. Highly active and reusable catalyst from Fe-Mg-hydrotalcite anionic clay for Friedel-Crafts type benzylation reactions

    Indian Academy of Sciences (India)

    Vasant R Choudhary; Rani Jha; Pankaj A Choudhari

    2005-11-01

    Fe-Mg-hydrotalcite (Mg/Fe = 3) anionic clay with or without calcination (at 200-800°C) has been used for the benzylation of toluene and other aromatic compounds by benzyl chloride. Hydrotalcite before and after its calcination was characterized for surface area, crystalline phases and basicity. Both the hydrotalcite, particularly after its use in the benzylation reaction, and the catalyst derived from it by its calcination at 200-800°C show high catalytic activity for the benzylation of toluene and other aromatic compounds. The catalytically active species present in the catalyst in its most active form are the chlorides and oxides of iron on the catalyst surface.

  6. A Ruthenium/Phosphoramidite-Catalyzed Asymmetric Interrupted Metallo-ene Reaction.

    Science.gov (United States)

    Trost, Barry M; Ryan, Michael C

    2016-03-01

    Allylic chlorides prepared from commercially available trans-1,4-dichloro-2-butene were converted to trans-disubstituted 5- and 6-membered ring systems with perfect diastereoselectivity and high enantioselectivity under chiral ruthenium catalysis. These products contain stereodefined secondary and tertiary alcohols that originate from the trapping of an alkylruthenium intermediate with adventitious water. Key to the success of this transformation was the development of a new BINOL-based phosphoramidite ligand containing bulky substitution at its 3- and 3'-positions. As a demonstration of product utility, diastereoselective Friedel-Crafts reactions were performed on the chiral benzylic alcohols in high yield and stereoselectivity. PMID:26899551

  7. A SIMPLE, EFFICIENT AND SOLVENT FREE ONE POT SYNTHESIS OF 3, 3 DIHETEROAROMATIC OXINDOLE

    Directory of Open Access Journals (Sweden)

    Syed Shahed Ali

    2013-04-01

    Full Text Available Formic acid catalyzed, single step and environmentally friendly process for synthesis of 3, 3- diheteroaromatic oxindole derivatives is described. This adopted protocol for Friedel- Crafts substitution reaction has the advantage of reusability of the catalyst, high yields and ease of separation of pure products.

  8. Synthesis, X-ray Structure and Aggregation Effect of Tetramethoxy Substituted Dibenzo[fg, op]naphthacene

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiao-Hong; FU Chang-Jin

    2007-01-01

    Tetramethoxy substituted dibenzo[fg,op]naphthacene was synthesised by using Friedel-Crafts acylation, tandem Aldol-Michael solvent-free reaction and palladium catalyzed dehydrohalogenation cyclization as key steps. The X-ray structure of the product and its aggregation effect in solvent were also reported.

  9. Research Progress in the Asymmetric Reaction Catalyzed by Chiral BINOL Phosphoric Acids%BINOL衍生的手性磷酸催化的不对称反应研究进展

    Institute of Scientific and Technical Information of China (English)

    郭海明; 李建国; 王东超; 渠桂荣

    2009-01-01

    综述了近年来BINOL衍生的手性磷酸作为一类强酸性Brφnsted酸催化剂,在不对称氢转移反应、Friedel-Crafts, Mannich, Aza Diels-Alder, Aza-ene-type, Pictet-Spengler等反应中的研究进展.参考文献37篇.

  10. Alamethicin biosynthesis: acetylation of the amino terminus and attachment of phenylalaninol.

    Science.gov (United States)

    Mohr, H; Kleinkauf, H

    1978-10-12

    Alamethicin synthetase was extracted from the fungus Trichoderma viride at the end of its exponential growth phase. It is multienzyme complex with a molecular weight of approx. 480 000. The biosynthesis of alamethicin is initiated on the synthetase by acetylation of thiolester-bound aminoisobutyric acid, which remains enzyme bound. Acetyl-CoA serves as the acetate donor. Of the alamethicin constituents, glycine, alanine and valine are also acetylated when incubated alone. This acetylation is prevented by added aminoisobutyric acid, which indicates that the site on alamethicin synthetase catalyzing the acetylation has a preference for aminoisobutyric acid. Alamethicin formation on the synthetase is terminated by linkage of phenylalaninol to the carboxyl terminus of the peptide. It is unlikely that the amino alcohol is a degradation product of alamethicin or that it had been split off from the synthetase complex. Thus it is probably the reaction product of a separate enzyme system. PMID:568941

  11. Acetylation dynamics and stoichiometry in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Weinert, Brian Tate; Iesmantavicius, Vytautas; Moustafa, Tarek;

    2014-01-01

    Lysine acetylation is a frequently occurring posttranslational modification; however, little is known about the origin and regulation of most sites. Here we used quantitative mass spectrometry to analyze acetylation dynamics and stoichiometry in Saccharomyces cerevisiae. We found that acetylation...

  12. Calreticulin transacetylase mediates the acetylation of nitric oxide synthase by polyphenolic acetate

    NARCIS (Netherlands)

    Bansal, S.; Gaspari, M.; Raj, H.G.; Kumar, A.; Cuda, G.; Verheij, E.; Tyagi, Y.K.; Ponnan, P.; Rastogi, R.C.; Parmar, V.S.

    2008-01-01

    Our earlier investigations identified acetoxy drug: protein transacetylase (TAase), a unique enzyme in the endoplasmic reticulum (ER) catalyzing the transfer of acetyl groups from polyphenolic acetates (PA) to certain functional proteins. Recently we have established the identity of TAase with ER pr

  13. Lysine Acetylation Facilitates Spontaneous DNA Dynamics in the Nucleosome.

    Science.gov (United States)

    Kim, Jongseong; Lee, Jaehyoun; Lee, Tae-Hee

    2015-12-01

    The nucleosome, comprising a histone protein core wrapped around by DNA, is the fundamental packing unit of DNA in cells. Lysine acetylation at the histone core elevates DNA accessibility in the nucleosome, the mechanism of which remains largely unknown. By employing our recently developed hybrid single molecule approach, here we report how the structural dynamics of DNA in the nucleosome is altered upon acetylation at histone H3 lysine 56 (H3K56) that is critical for elevated DNA accessibility. Our results indicate that H3K56 acetylation facilitates the structural dynamics of the DNA at the nucleosome termini that spontaneously and repeatedly open and close on a ms time scale. The results support a molecular mechanism of histone acetylation in catalyzing DNA unpacking whose efficiency is ultimately limited by the spontaneous DNA dynamics at the nucleosome temini. This study provides the first and unique experimental evidence revealing a role of protein chemical modification in directly regulating the kinetic stability of the DNA packing unit.

  14. Reaction Mechanism and Structural Model of ADP-forming Acetyl-CoA Synthetase from the Hyperthermophilic Archaeon Pyrococcus furiosus: EVIDENCE FOR A SECOND ACTIVE SITE HISTIDINE RESIDUE*S⃞

    OpenAIRE

    Bräsen, Christopher; Schmidt, Marcel; Grötzinger, Joachim; Schönheit, Peter

    2008-01-01

    In Archaea, acetate formation and ATP synthesis from acetyl-CoA is catalyzed by an unusual ADP-forming acetyl-CoA synthetase (ACD) (acetyl-CoA + ADP + Pi ⇆ acetate + ATP + HS-CoA) catalyzing the formation of acetate from acetyl-CoA and concomitant ATP synthesis by the mechanism of substrate level phosphorylation. ACD belongs to the protein superfamily of nucleoside diphosphate-forming acyl-CoA synthetases, which also include succinyl-CoA synthetases (SCSs). ACD differs from SCS in domain orga...

  15. MeIQx-induced DNA adduct formation and mutagenesis in DNA repair deficient CHO cells expressing human CYP1A1 and rapid or slow acetylator NAT2

    OpenAIRE

    Bendaly, Jean; Zhao, Shuang; Neale, Jason R.; Metry, Kristin J.; Doll, Mark A; States, J. Christopher; Pierce, William M.; Hein, David W.

    2007-01-01

    2-Amino-3,8-dimethylimidazo-[4,5-f]quinoxaline (MeIQx) is one of the most potent and abundant mutagens in the western diet. Bioactivation includes N-hydroxylation catalyzed by cytochrome P450s followed by O-acetylation catalyzed by N-acetyltransferase 2 (NAT2). Nucleotide excision repair-deficient chinese hamster ovary (CHO) cells were constructed by stable transfection of human cytochrome P4501A1 (CYP1A1) and a single copy of either NAT2*4 (rapid acetylator) or NAT2*5B (slow acetylator) alle...

  16. Regulation of intermediary metabolism by protein acetylation

    OpenAIRE

    Guan, Kun-Liang; Xiong, Yue

    2010-01-01

    Extensive studies during the past four decades have identified important roles for lysine acetylation in the regulation of nuclear transcription. Recent proteomic analyses on protein acetylation uncovered a large number of acetylated proteins in the cytoplasm and mitochondria, including most enzymes involved in intermediate metabolism. Acetylation regulates metabolic enzymes by multiple mechanisms, including via enzymatic activation or inhibition, and by influencing protein stability. Convers...

  17. Density Functional Theory Study on the Histidine-assisted Mechanism of Arylamine N-Acetyltransferase Acetylation

    Institute of Scientific and Technical Information of China (English)

    QIAO Qing-An; GAO Shan-Min; JIN Yue-Qing; CHEN Xin; SUN Xiao-Min; YANG Chuan-Lu

    2008-01-01

    Arylamine N-acetyltransferases (NATs, EC 2.3.1.5) catalyze the N-acetylation of primary arylamines, and play a key role in the biotransformation and metabolism of drugs, carcinogens, etc.In this paper, three possible reaction mechanisms are investigated and the results indicate that if the acetyl group directly transfers from the donor to the acceptor, the high activation energies will make it hard to obtain the target products.When using histidine to mediate the acetylation process, these energies will drop in the 15~45 kJ/mol range.If the histidine residue is protonated, the corresponding energies will be decreased by about 35~87 kJ/mol.The calculations predict an enzymatic acetylation mechanism that undergoes a thiolate-imidazolium pair, which agrees with the experimental results very well.

  18. Fatal Intoxication with Acetyl Fentanyl.

    Science.gov (United States)

    Cunningham, Susan M; Haikal, Nabila A; Kraner, James C

    2016-01-01

    Among the new psychoactive substances encountered in forensic investigations is the opioid, acetyl fentanyl. The death of a 28-year-old man from recreational use of this compound is reported. The decedent was found in the bathroom of his residence with a tourniquet secured around his arm and a syringe nearby. Postmortem examination findings included marked pulmonary and cerebral edema and needle track marks. Toxicological analysis revealed acetyl fentanyl in subclavian blood, liver, vitreous fluid, and urine at concentrations of 235 ng/mL, 2400 ng/g, 131 ng/mL, and 234 ng/mL, respectively. Acetyl fentanyl was also detected in the accompanying syringe. Death was attributed to recreational acetyl fentanyl abuse, likely through intravenous administration. The blood acetyl fentanyl concentration is considerably higher than typically found in fatal fentanyl intoxications. Analysis of this case underscores the need for consideration of a wide range of compounds with potential opioid-agonist activity when investigating apparent recreational drug-related deaths. PMID:26389815

  19. Pyruvate dehydrogenase and 3-fluoropyruvate: chemical competence of 2-acetylthiamin pyrophosphate as an acetyl group donor to dihydrolipoamide

    International Nuclear Information System (INIS)

    The pyruvate dehydrogenase component (E1) of the pyruvate dehydrogenase complex catalyzes the decomposition of 3-fluoropyruvate to CO2, fluoride anion, and acetate. Acetylthiamin pyrophosphate (acetyl-TPP) is an intermediate in this reaction. Incubation of the pyruvate dehydrogenase complex with 3-fluoro[1,2-14]pyruvate, TPP, coenzyme A (CoASH), and either NADH or pyruvate as reducing systems leads to the formation of [14]acetyl-CoA. In this reaction the acetyl group of acetyl-TPP is partitioned by transfer to both CoASH (87 +/- 2%) and water (13 +/- 2%). When the E1 component is incubated with 3-fluoro[1,2-14]pyruvate, TPP, and dihydrolipoamide, [14]acetyldihydrolipoamide is produced. The formation of [14C]acetyldihydrolipoamide was examined as a function of dihydrolipoamide concentration (0.25-16 mM). A plot of the extent of acetyl group partitioning to dihydrolipoamide as a function of 1/[dihydrolipoamide] showed 95 +/- 2% acetyl group transfer to dihydrolipoamide when dihydrolipoamide concentration was extrapolated to infinity. It is concluded that acetyl-TPP is chemically competent as an intermediate for the pyruvate dehydrogenase complex catalyzed oxidative decarboxylation of pyruvate

  20. Synergistic catalysis of isolated Fe3+ and Fe2O3 on FeOx/HZSM-5 catalysts for Friedel-Crafts benzylation of benzene

    Institute of Scientific and Technical Information of China (English)

    Tao Lin; Xin Zhang; Rong Li; Ting Bai; Si Ying Yang

    2011-01-01

    FeOx/HZSM-5 catalyst with 8 wt.% Fe-loading (8-FeZ) exhibited significantly higher reactivity in the benzylation of benzene with benzyl chloride than FeOx/HZSM-5 catalyst with 2.5 wt.% Fe-loading (2.5-FeZ) because the synergistic catalysis between isolated Fe3+ and superfine Fe2O3 occurred on 8-FeZ in the reaction.

  1. Friedel-Crafts Fluoroacetylation of Indoles with Fluorinated Acetic Acids for the Synthesis of Fluoromethyl Indol-3-yl Ketones under Catalyst- and Additive-Free Conditions.

    Science.gov (United States)

    Yao, Shun-Jiang; Ren, Zhi-Hui; Wang, Yao-Yu; Guan, Zheng-Hui

    2016-05-20

    A simple and efficient protocol for the fluoroacetylation of indoles is reported. The reaction uses fluorinated acetic acids as the fluoroacetylation reagents to synthesize diverse fluoromethyl indol-3-yl ketones in good yields under catalyst- and additive-free conditions. In addition, the only byproduct is water in this transformation. The synthetic utility of this reaction was also demonstrated by the concise synthesis of α-(trifluoromethyl)(indol-3-yl)methanol and indole-3-carboxylic acid. PMID:27101475

  2. Brønsted Acid-Promoted Formation of Stabilized Silylium Ions for Catalytic Friedel-Crafts C-H Silylation.

    Science.gov (United States)

    Chen, Qing-An; Klare, Hendrik F T; Oestreich, Martin

    2016-06-29

    A counterintuitive approach to electrophilic aromatic substitution with silicon electrophiles is disclosed. A strong Brønsted acid that would usually promote the reverse reaction, i.e., protodesilylation, was found to initiate the C-H silylation of electron-rich (hetero)arenes with hydrosilanes. Protonation of the hydrosilane followed by liberation of dihydrogen is key to success, fulfilling two purposes: to generate the stabilized silylium ion and to remove the proton released from the Wheland intermediate. PMID:27303857

  3. Protein Acetylation in Archaea, Bacteria, and Eukaryotes

    Directory of Open Access Journals (Sweden)

    Jörg Soppa

    2010-01-01

    Full Text Available Proteins can be acetylated at the alpha-amino group of the N-terminal amino acid (methionine or the penultimate amino acid after methionine removal or at the epsilon-amino group of internal lysines. In eukaryotes the majority of proteins are N-terminally acetylated, while this is extremely rare in bacteria. A variety of studies about N-terminal acetylation in archaea have been reported recently, and it was revealed that a considerable fraction of proteins is N-terminally acetylated in haloarchaea and Sulfolobus, while this does not seem to apply for methanogenic archaea. Many eukaryotic proteins are modified by differential internal acetylation, which is important for a variety of processes. Until very recently, only two bacterial proteins were known to be acetylation targets, but now 125 acetylation sites are known for E. coli. Knowledge about internal acetylation in archaea is extremely limited; only two target proteins are known, only one of which—Alba—was used to study differential acetylation. However, indications accumulate that the degree of internal acetylation of archaeal proteins might be underestimated, and differential acetylation has been shown to be essential for the viability of haloarchaea. Focused proteomic approaches are needed to get an overview of the extent of internal protein acetylation in archaea.

  4. PCAF-primed EZH2 acetylation regulates its stability and promotes lung adenocarcinoma progression

    Institute of Scientific and Technical Information of China (English)

    Wan Junhu; Chin Y Eugene; Zhang Hongquan; Zhan Jun; Li Shuai; Ma Ji; Xu Weizhi; Liu Chang; Xue Xiaowei; Xie Yuping; Fang Weigang

    2015-01-01

    Enhancer of zeste homolog 2 ( EZH2 ) is a key epigenetic regulator that catalyzes the trimethyla-tion of H3K27 and is modulated by post-translational modifications (PTMs). However, the precise regulation of EZH2 PTMs remains elusive. We, herein, report that EZH2 is acetylated by acetyltransferase P300/CBP-associat-ed factor (PCAF) and is deacetylated by deacetylase SIRT1. We identified that PCAF interacts with and acetylates EZH2 mainly at lysine 348 (K348). Mechanistically, K348 acetylation decreases EZH2 phosphorylation at T345 and T487 and increases EZH2 stability without disrupting the formation of polycomb repressive complex 2 ( PRC2 ) . Functionally, EZH2 K348 acetylation enhances its capacity in suppression of the target genes and promotes lung cancer cell migration and invasion. Further, elevated EZH2 K348 acetylation in lung adenocarcinoma patients pre-dicts a poor prognosis. Our findings define a new mechanism underlying EZH2 modulation by linking EZH2 acety-lation to its phosphorylation that stabilizes EZH2 and promotes lung adenocarcinoma progression.

  5. Acetyl-Phosphate Is a Critical Determinant of Lysine Acetylation in E. coli

    DEFF Research Database (Denmark)

    Weinert, Brian T; Iesmantavicius, Vytautas; Wagner, Sebastian A;

    2013-01-01

    Lysine acetylation is a frequently occurring posttranslational modification in bacteria; however, little is known about its origin and regulation. Using the model bacterium Escherichia coli (E. coli), we found that most acetylation occurred at a low level and accumulated in growth-arrested cells in...... acetylate lysine residues in vitro and that AcP levels are correlated with acetylation levels in vivo, suggesting that AcP may acetylate proteins nonenzymatically in cells. These results uncover a critical role for AcP in bacterial acetylation and indicate that most acetylation in E. coli occurs at a low...

  6. Iodine Supported on 3-Aminopropyl Silica Gel as Efficient Catalyst for Acetylation of Alcohols under Solvent-free Conditions

    Institute of Scientific and Technical Information of China (English)

    MAHDAVI Hossein; GHAEMY Mosa; ZERAATPISHEH Fatemeh

    2009-01-01

    3-Aminopropyl silica gel (I2/APSG) was found to catalyze the acetylation of alcohols and phenols efficiently with acetic anhydride. The reaction is mild and selective with high yields. A wide variety of alcohols and phenols are selectively converted into the corresponding acetates using I2/APSG under solvent-free conditions at room tem-perature.

  7. Organocatalytic Asymmetric Synthesis of Dihydrobenzoxazinones Bearing Trifluoromethylated Quaternary Stereocenters.

    Science.gov (United States)

    Lou, Hengqiao; Wang, Yongtao; Jin, Enze; Lin, Xufeng

    2016-03-01

    Chiral phosphoric acid-catalyzed enantioselective aza-Friedel-Crafts reaction of trifluoromethyl benzoxazinones with pyrroles is reported. Under mild conditions, a range of enantioenriched dihydrobenzoxazinones bearing trifluoromethylated quaternary stereocenters could be obtained in good to excellent yield and ee. A remarkable fluorine effect is observed, and preliminary mechanistic studies combined with theory calculations suggest that triple-hydrogen-bonding interactions hold the transition structure rigidly and allow the bulky substituents of the catalyst to influence the enantioselectivity. PMID:26882280

  8. The different roles of a cationic gold(i) complex in catalysing hydroarylation of alkynes and alkenes with a heterocycle.

    Science.gov (United States)

    Mehrabi, Tahmineh; Ariafard, Alireza

    2016-08-01

    The mechanism of twofold hydroarylation of terminal alkynes with pyrrole catalyzed by a cationic gold(i) complex was investigated using DFT. It was found that while both the hydroarylation reactions proceed via a Friedel-Crafts-type mechanism, the first hydroarylation is directly promoted by gold(i) but the second hydroarylation by a proton released through interaction of the alkene product with gold-bound acidic organic species such as acetic acid and terminal alkynes. PMID:27377712

  9. An unprecedented benzannulation of oxindoles with enalcarbenoids: a regioselective approach to functionalized carbazoles.

    Science.gov (United States)

    Rathore, Kuldeep Singh; Lad, Bapurao Sudam; Chennamsetti, Haribabu; Katukojvala, Sreenivas

    2016-04-30

    A novel Rh(ii)/Brønsted acid catalyzed tandem benzannulation of oxindoles with enaldiazo carbonyls led to the formation of valuable 1-hydroxy-2-acylcarbazoles. This reaction is proposed to involve a formal insertion of a rhodium enalcarbenoid into an oxindole sp(2) C-O bond, an oxa-Michael addition, Friedel-Crafts reaction and a semipinacol type 1,2-carbonyl migration. PMID:26992045

  10. Synthesis and Applications of (-)-(S)-3-Aminoquinuclidine- Derived Thiourea

    OpenAIRE

    Rolava, E; Turks, M

    2015-01-01

    A synthesis of enantiopure thiourea organocatalyst based on (-)-(S)-3-aminoquinuclidine dihydrochloride was developed with quantitative product yield. The catalyst was tested in different reactions: asymmetric Michael addition of ketones and malonates to nitroalkenes, nitromethane 1,4-addition to trans-chalcone, and Friedel-Crafts alkylation of indoles with trans-β-nitrostyrene. The novel thiourea proved to catalyze the aforementioned reactions and expected products were ...

  11. Metalloproteins/metalloenzymes for the synthesis of acetyl-CoA in the Wood-Ljungdahl pathway

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper focuses on the group of metalloproteins/metalloenzymes in the acetyl-coenzyme A synthesis pathway of anaerobic microbes called Wood-Ljungdahl pathway,including formate dehydrogenase (FDH),corrinoid iron sulfur protein (CoFeSP),acetyl-CoA synthase (ACS) and CO dehydrogenase (CODH). FDH,a key metalloenzyme involved in the conversion of carbon dioxide to methyltetrahydrofolate,catalyzes the reversible oxidation of formate to carbon dioxide. CoFeSP,as a methyl group transformer,accepts the methyl group from CH3-H4 folate and then transfers it to ACS. CODH reversibly catalyzes the reduction of CO2 to CO and ACS functions for acetyl-coenzyme A synthesis through condensation of the methyl group,CO and coenzyme A,to finish the whole pathway. This paper introduces the structure,function and reaction mechanisms of these enzymes.

  12. Aspirin inhibits glucose‑6‑phosphate dehydrogenase activity in HCT 116 cells through acetylation: Identification of aspirin-acetylated sites.

    Science.gov (United States)

    Ai, Guoqiang; Dachineni, Rakesh; Kumar, D Ramesh; Alfonso, Lloyd F; Marimuthu, Srinivasan; Bhat, G Jayarama

    2016-08-01

    Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the first reaction in the pentose phosphate pathway, and generates ribose sugars, which are required for nucleic acid synthesis, and nicotinamide adenine dinucleotide phosphate (NADPH), which is important for neutralization of oxidative stress. The expression of G6PD is elevated in several types of tumor, including colon, breast and lung cancer, and has been implicated in cancer cell growth. Our previous study demonstrated that exposure of HCT 116 human colorectal cancer cells to aspirin caused acetylation of G6PD, and this was associated with a decrease in its enzyme activity. In the present study, this observation was expanded to HT‑29 colorectal cancer cells, in order to compare aspirin‑mediated acetylation of G6PD and its activity between HCT 116 and HT‑29 cells. In addition, the present study aimed to determine the acetylation targets of aspirin on recombinant G6PD to provide an insight into the mechanisms of inhibition. The results demonstrated that the extent of G6PD acetylation was significantly higher in HCT 116 cells compared with in HT‑29 cells; accordingly, a greater reduction in G6PD enzyme activity was observed in the HCT 116 cells. Mass spectrometry analysis of aspirin‑acetylated G6PD (isoform a) revealed that aspirin acetylated a total of 14 lysine residues, which were dispersed throughout the length of the G6PD protein. One of the important amino acid targets of aspirin included lysine 235 (K235, in isoform a) and this corresponds to K205 in isoform b, which has previously been identified as being important for catalysis. Acetylation of G6PD at several sites, including K235 (K205 in isoform b), may mediate inhibition of G6PD activity, which may contribute to the ability of aspirin to exert anticancer effects through decreased synthesis of ribose sugars and NADPH.

  13. In vitro phosphorylation and acetylation of the murine pocket protein Rb2/p130.

    Directory of Open Access Journals (Sweden)

    Muhammad Saeed

    Full Text Available The retinoblastoma protein (pRb and the related proteins Rb2/p130 and 107 represent the "pocket protein" family of cell cycle regulators. A key function of these proteins is the cell cycle dependent modulation of E2F-regulated genes. The biological activity of these proteins is controlled by acetylation and phosphorylation in a cell cycle dependent manner. In this study we attempted to investigate the interdependence of acetylation and phosphorylation of Rb2/p130 in vitro. After having identified the acetyltransferase p300 among several acetyltransferases to be associated with Rb2/p130 during S-phase in NIH3T3 cells in vivo, we used this enzyme and the CDK4 protein kinase for in vitro modification of a variety of full length Rb2/p130 and truncated versions with mutations in the acetylatable lysine residues 1079, 128 and 130. Mutation of these residues results in the complete loss of Rb2/p130 acetylation. Replacement of lysines by arginines strongly inhibits phosphorylation of Rb2/p130 by CDK4; the inhibitory effect of replacement by glutamines is less pronounced. Preacetylation of Rb2/p130 strongly enhances CDK4-catalyzed phosphorylation, whereas deacetylation completely abolishes in vitro phosphorylation. In contrast, phosphorylation completely inhibits acetylation of Rb2/p130 by p300. These results suggest a mutual interdependence of modifications in a way that acetylation primes Rb2/p130 for phosphorylation and only dephosphorylated Rb2/p130 can be subject to acetylation. Human papillomavirus 16-E7 protein, which increases acetylation of Rb2/p130 by p300 strongly reduces phosphorylation of this protein by CDK4. This suggests that the balance between phosphorylation and acetylation of Rb2/p130 is essential for its biological function in cell cycle control.

  14. Swelling of acetylated wood in organic liquids

    CERN Document Server

    Obataya, E; Obataya, Eiichi; Gril, Joseph

    2005-01-01

    To investigate the affinity of acetylated wood for organic liquids, Yezo spruce wood specimens were acetylated with acetic anhydride, and their swelling in various liquids were compared to those of untreated specimens. The acetylated wood was rapidly and remarkably swollen in aprotic organic liquids such as benzene and toluene in which the untreated wood was swollen only slightly and/or very slowly. On the other hand, the swelling of wood in water, ethylene glycol and alcohols remained unchanged or decreased by the acetylation. Consequently the maximum volume of wood swollen in organic liquids was always larger than that in water. The effect of acetylation on the maximum swollen volume of wood was greater in liquids having smaller solubility parameters. The easier penetration of aprotic organic liquids into the acetylated wood was considered to be due to the scission of hydrogen bonds among the amorphous wood constituents by the substitution of hydroxyl groups with hydrophobic acetyl groups.

  15. Flow properties of acetylated chickpea protein dispersions.

    Science.gov (United States)

    Liu, Li H; Hung, Tran V

    2010-06-01

    Chickpea protein concentrate was acetylated with acetic anhydride at 5 levels. Acetylated chickpea protein (ACP) dispersions at 3 levels (6%, 45%, and 49%) were chosen for this flow property study. Effects of protein concentration, temperature, concentrations of salt addition and particularly, degree of acetylation on these properties were examined. Compared with native chickpea proteins, the ACP dispersions exhibited a strong shear thinning behavior. Within measured temperature range (15 to 55 degrees C), the apparent viscosities of native chickpea protein dispersions were temperature independent; those of ACP dispersions were thermally affected. The flow index (n), consistency coefficient (m), apparent yield stress, and apparent viscosities of ACP dispersions increased progressively up to 45% acetylation but decreased at 49% acetylation level. Conformational studies by gel filtration suggested that chickpea proteins were associated or polymerized at up to 45% acetylation but the associated subunits gradually dissociated to smaller units at higher levels (49%) of acetylation.

  16. Histone Acetylation in Drug Addiction

    OpenAIRE

    Renthal, William; Nestler, Eric J.

    2009-01-01

    Regulation of chromatin structure through post-translational modifications of histones (e.g. acetylation) has emerged as an important mechanism to translate a variety of environmental stimuli, including drugs of abuse, into specific changes in gene expression. Since alterations in gene expression are thought to contribute to the development and maintenance of the addicted state, recent efforts are aimed at identifying how drugs of abuse alter chromatin structure and the enzymes which regulate...

  17. Specific synthesis of neurostatin and gangliosides O-acetylated in the outer sialic acids using a sialate transferase.

    Directory of Open Access Journals (Sweden)

    Lorenzo Romero-Ramírez

    Full Text Available Gangliosides are sialic acid containing glycosphingolipids, commonly found on the outer leaflet of the plasma membrane. O-acetylation of sialic acid hydroxyl groups is one of the most common modifications in gangliosides. Studies on the biological activity of O-acetylated gangliosides have been limited by their scarcity in nature. This comparatively small change in ganglioside structure causes major changes in their physiological properties. When the ganglioside GD1b was O-acetylated in the outer sialic acid, it became the potent inhibitor of astroblast and astrocytoma proliferation called Neurostatin. Although various chemical and enzymatic methods to O-acetylate commercial gangliosides have been described, O-acetylation was nonspecific and produced many side-products that reduced the yield. An enzyme with O-acetyltransferase activity (SOAT has been previously cloned from the bacteria Campylobacter jejuni. This enzyme catalyzed the acetylation of oligosaccharide-bound sialic acid, with high specificity for terminal alpha-2,8-linked residues. Using this enzyme and commercial gangliosides as starting material, we have specifically O-acetylated the gangliosides' outer sialic acids, to produce the corresponding gangliosides specifically O-acetylated in the sialic acid bound in alpha-2,3 and alpha-2,8 residues. We demonstrate here that O-acetylation occurred specifically in the C-9 position of the sialic acid. In summary, we present a new method of specific O-acetylation of ganglioside sialic acids that permits the large scale preparation of these modified glycosphingolipids, facilitating both, the study of their mechanism of antitumoral action and their use as therapeutic drugs for treating glioblastoma multiform (GBM patients.

  18. 5-Position-selective C-H trifluoromethylation of 8-aminoquinoline derivatives.

    Science.gov (United States)

    Kuninobu, Yoichiro; Nishi, Mitsumi; Kanai, Motomu

    2016-09-14

    We developed a copper-catalyzed 5-position-selective C-H trifluoromethylation of 8-aminoquinoline derivatives. The reaction proceeded with high functional group tolerance under mild conditions. In the case of quinolines with an amide, carbamate, urea, or sulfonamide group at the 8-position of quinoline moieties, a radical scavenger experiment indicated that the reaction proceeded via a radical pathway. The protecting group of an 8-amidoquinoline derivative could be removed by hydrolysis. On the other hand, the trifluoromethylation of 8-aminoquinolines was also promoted by other Lewis acids as well as a copper catalyst and proceeded even in the presence of a radical scavenger. These results indicated that the trifluoromethylation of 8-aminoquinolines proceeded via a Friedel-Crafts-type reaction. Interestingly, the copper salt works as either a catalyst for the formation of a CF3 radical or a Lewis acid to promote a Friedel-Crafts-type reaction, depending on the substrate. PMID:27506919

  19. The Palladium-Catalyzed Vinylation and Carbonylation of Bromoindoles and N-Acety1-bromoindoline

    OpenAIRE

    Kasahara, Akira; Izumi, Taeko; Ogata, Hideaki

    1989-01-01

    Abstracts The palladium-catalyzed vinylic substitution reaction of alkenes has been shown to proceed in moderate yields with 5- and 6-bromoindols, and N-acetyl-5-bromoindoline. 4-, 5-, 6-, and 7-Bromoindoles also undergo facile palladium-assisted carbonylation with carbon monoxide in methanol to produce methoxycarbonylindoles in moderate yields.

  20. Large acceleration of α-chymotrypsin-catalyzed dipeptide formation by 18-crown-6 in organic solvents

    NARCIS (Netherlands)

    Unen, van Dirk-Jan; Engbersen, Johan F.J.; Reinhoudt, David N.

    1998-01-01

    The effects of 18-crown-6 on the synthesis of peptides catalyzed by α-chymotrypsin are reported. Lyophilization of the enzyme in the presence of 50 equivalents of 18-crown-6 results in a 425-fold enhanced activity when the reaction between the 2-chloroethylester of N-acetyl-L-phenylalanine and L-phe

  1. A Method to determine lysine acetylation stoichiometries

    Energy Technology Data Exchange (ETDEWEB)

    Nakayasu, Ernesto S.; Wu, Si; Sydor, Michael A.; Shukla, Anil K.; Weitz, Karl K.; Moore, Ronald J.; Hixson, Kim K.; Kim, Jong Seo; Petyuk, Vladislav A.; Monroe, Matthew E.; Pasa-Tolic, Ljiljana; Qian, Weijun; Smith, Richard D.; Adkins, Joshua N.; Ansong, Charles

    2014-07-21

    A major bottleneck to fully understanding the functional aspects of lysine acetylation is the lack of stoichiometry information. Here we describe a mass spectrometry method using a combination of isotope labeling and detection of a diagnostic fragment ion to determine the stoichiometry of lysine acetylation on proteins globally. Using this technique, we determined the modification occupancy on hundreds of acetylated peptides from cell lysates and cross-validated the measurements via immunoblotting.

  2. Analysis of acetylation stoichiometry suggests that SIRT3 repairs nonenzymatic acetylation lesions

    DEFF Research Database (Denmark)

    Weinert, Brian T; Moustafa, Tarek; Iesmantavicius, Vytautas;

    2015-01-01

    Acetylation is frequently detected on mitochondrial enzymes, and the sirtuin deacetylase SIRT3 is thought to regulate metabolism by deacetylating mitochondrial proteins. However, the stoichiometry of acetylation has not been studied and is important for understanding whether SIRT3 regulates or...... suppresses acetylation. Using quantitative mass spectrometry, we measured acetylation stoichiometry in mouse liver tissue and found that SIRT3 suppressed acetylation to a very low stoichiometry at its target sites. By examining acetylation changes in the liver, heart, brain, and brown adipose tissue of...... fasted mice, we found that SIRT3-targeted sites were mostly unaffected by fasting, a dietary manipulation that is thought to regulate metabolism through SIRT3-dependent deacetylation. Globally increased mitochondrial acetylation in fasted liver tissue, higher stoichiometry at mitochondrial acetylation...

  3. Acetylation of Chinese bamboo flour and thermoplasticity

    Institute of Scientific and Technical Information of China (English)

    LI Xue-fang; CHEN Qin-hui; LIN Jin-huo; ZHUO Dong-xian; WU Xiu-ling

    2008-01-01

    Chinese bamboo flour was chemically modified by acetylation with acetic anhydride by using trichloroacetic acid as an activation agent and the optimized condition for acetylation of bamboo flour was determined as the trichloroacetic acid amount 6.0 g per 1.5-g bamboo flour, ultrasosonication duration 40 min and the reaction time 1 h at 65℃. The composition, microstructure and thermal behavior of acetylated bamboo flour were preliminarily characterized by FT-IR, DSC and SEM etc. The acetylated bamboo flour can be molded into sheets at 130℃ and 10 MPa, indicating the modified bamboo flour possesses thermalplastic performance.

  4. Acetylation of woody lignocellulose: significance and regulation

    Directory of Open Access Journals (Sweden)

    Prashant Mohan-Anupama Pawar

    2013-05-01

    Full Text Available Non-cellulosic cell wall polysaccharides constitute approximately one quarter of usable biomass for human exploitation. In contrast to cellulose, these components are usually substituted by O-acetyl groups, which affect their properties and interactions with other polymers, thus affecting their solubility and extractability. However, details of these interactions are still largely obscure. Moreover, polysaccharide hydrolysis to constituent monosaccharides, is hampered by the presence of O-acetyl groups, necessitating either enzymatic (esterase or chemical de-acetylation, increasing the costs and chemical consumption. Reduction of polysaccharide acetyl content in planta is a way to modify lignocellulose towards improved saccharification. In this review we: 1 summarize literature on lignocellulose acetylation in different tree species, 2 present data and current hypotheses concerning the role of O-acetylation in determining woody lignocellulose properties, 3 describe plant proteins involved in lignocellulose O-acetylation, 4 give examples of microbial enzymes capable to de-acetylate lignocellulose, and 5 discuss prospects for exploiting these enzymes in planta to modify xylan acetylation.

  5. Acetylation regulates Jun protein turnover in Drosophila.

    Science.gov (United States)

    Zhang, Daoyong; Suganuma, Tamaki; Workman, Jerry L

    2013-11-01

    C-Jun is a major transcription factor belonging to the activating protein 1 (AP-1) family. Phosphorylation has been shown to be critical for c-Jun activation and stability. Here, we report that Jra, the Drosophila Jun protein, is acetylated in vivo. We demonstrate that the acetylation of Jra leads to its rapid degradation in response to osmotic stress. Intriguingly, we also found that Jra phosphorylation antagonized its acetylation, indicating the opposite roles of acetylation and phosphorylation in Jra degradation process under osmotic stress. Our results provide new insights into how c-Jun proteins are precisely regulated by the interplay of different posttranslational modifications.

  6. Acetylation-Mediated Suppression of Transcription-Independent Memory: Bidirectional Modulation of Memory by Acetylation

    OpenAIRE

    Katja Merschbaecher; Jakob Haettig; Uli Mueller

    2012-01-01

    Learning induced changes in protein acetylation, mediated by histone acetyl transferases (HATs), and the antagonistic histone deacetylases (HDACs) play a critical role in memory formation. The status of histone acetylation affects the interaction between the transcription-complex and DNA and thus regulates transcription-dependent processes required for long-term memory (LTM). While the majority of studies report on the role of elevated acetylation in memory facilitation, we address the impact...

  7. [3H]Indole-3-acetyl-myo-inositol hydrolysis by extracts of Zea mays L. vegetative tissue

    Science.gov (United States)

    Hall, P. J.; Bandurski, R. S.

    1986-01-01

    [3H]Indole-3-acetyl-myo-inositol was hydrolyzed by buffered extracts of acetone powders prepared from 4 day shoots of dark grown Zea mays L. seedlings. The hydrolytic activity was proportional to the amount of extract added and was linear for up to 6 hours at 37 degrees C. Boiled or alcohol denatured extracts were inactive. Analysis of reaction mixtures by high performance liquid chromatography demonstrated that not all isomers of indole-3-acetyl-myo-inositol were hydrolyzed at the same rate. Buffered extracts of acetone powders were prepared from coleoptiles and mesocotyls. The rates of hydrolysis observed with coleoptile extracts were greater than those observed with mesocotyl extracts. Active extracts also catalyzed the hydrolysis of esterase substrates such as alpha-naphthyl acetate and the methyl esters of indoleacetic acid and naphthyleneacetic acid. Attempts to purify the indole-3-acetyl-myo-inositol hydrolyzing activity by chromatographic procedures resulted in only slight purification with large losses of activity. Chromatography over hydroxylapatite allowed separation of two enzymically active fractions, one of which catalyzed the hydrolysis of both indole-3-acetyl-myo-inositol and esterase substrates. With the other enzymic hydrolysis of esterase substrates was readily demonstrated, but no hydrolysis of indole-3-acetyl-myo-inositol was ever detected.

  8. [3H]Indole-3-acetyl-myo-inositol hydrolysis by extracts of Zea mays L. vegetative tissue

    International Nuclear Information System (INIS)

    [3H]Indole-3-acetyl-myo-inositol was hydrolyzed by buffered extracts of acetone powders prepared from 4 day shoots of dark grown Zea mays L. seedlings. The hydrolytic activity was proportional to the amount of extract added and was linear for up to 6 hours at 370C. Boiled or alcohol denatured extracts were inactive. Analysis of reaction mixtures by high performance liquid chromatography demonstrated that not all isomers of indole-3-acetyl-myo-inositol were hydrolyzed at the same rate. Buffered extracts of acetone powders were prepared from coleoptiles and mesocotyls. The rates of hydrolysis observed with coleoptile extracts were greater than those observed with mesocotyl extracts. Active extracts also catalyzed the hydrolysis of esterase substrates such as α-naphthyl acetate and the methyl esters of indoleacetic acid and naphthyleneacetic acid. Attempts to purify the indole-3-acetyl-myo-inositol hydrolyzing activity by chromatographic procedures resulted in only slight purification with large losses of activity. Chromatography over hydroxylapatite allowed separation of two enzymically active fractions, one of which catalyzed the hydrolysis of both indole-3-acetyl-myo-inositol and esterase substrates. With the other fraction enzymic hydrolysis of esterase substrates was readily demonstrated, but no hydrolysis of indole-3-acetyl-myo-inositol was ever detected

  9. Purification and characterization of the acetyl-CoA synthetase from Mycobacterium tuberculosis

    Institute of Scientific and Technical Information of China (English)

    Ru Li; Jing Gu; Peng Chen; Zhiping Zhang; Jiaoyu Deng; XianEn Zhang

    2011-01-01

    Acetyl-CoA (AcCoA) synthetase (Acs) catalyzes the conversion of acetate into AcCoA,which is involved in many catabolic and anabolic pathways.Although this enzyme has been studied for many years in many organisms,the properties of Mycobacterium tuberculosis Acs and the regulation of its activity remain unknown.Here,the putative acs gene of M.tuberculosis H37Rv (Mt-Acs) was expressed as a fusion protein with 6×His-tag on the C-terminus in Escherichia coli.The recombinant Mt-Acs protein was successfully purified and then its enzymatic characteristics were analyzed.The optimal pH and temperature,and the kinetic parameters of Mt-Acs were determined.To investigate whether Mt-Acs is regulated by lysine acetylation as reported for Salmonella enterica Acs,its mutant K617R was also generated.Determination of the enzymatic activity suggests that Lys-617 is critical for its function.We further demonstrated that Mt-Acs underwent auto-acetylation with acetate but not with AcCoA as the acetyl donor,which resulted in the decrease of its activity.CoA,the substrate for AcCoA formation,inhibited the auto-acetylation.Furthermore,the silent information regulator (Sir2) of M.tuberculosis (Mt-Sir2) could catalyze Mt-Acs deacetylation,which resulted in activation of Acs.These results may provide more insights into the physiological roles of Mt-Acs in M.tuberculosis central metabolism.

  10. Proteomic profiling of lysine acetylation in Pseudomonas aeruginosa reveals the diversity of acetylated proteins.

    Science.gov (United States)

    Ouidir, Tassadit; Cosette, Pascal; Jouenne, Thierry; Hardouin, Julie

    2015-07-01

    Protein lysine acetylation is a reversible and highly regulated post-translational modification with the well demonstrated physiological relevance in eukaryotes. Recently, its important role in the regulation of metabolic processes in bacteria was highlighted. Here, we reported the lysine acetylproteome of Pseudomonas aeruginosa using a proteomic approach. We identified 430 unique peptides corresponding to 320 acetylated proteins. In addition to the proteins involved in various metabolic pathways, several enzymes contributing to the lipopolysaccharides biosynthesis were characterized as acetylated. This data set illustrated the abundance and the diversity of acetylated lysine proteins in P. aeruginosa and opens opportunities to explore the role of the acetylation in the bacterial physiology. PMID:25900529

  11. Investigation of acetyl migrations in furanosides

    Directory of Open Access Journals (Sweden)

    Migaud ME

    2006-07-01

    Full Text Available Abstract Standard reaction conditions for the desilylation of acetylated furanoside (riboside, arabinoside and xyloside derivatives facilitate acyl migration. Conditions which favour intramolecular and intermolecular mechanisms have been identified with intermolecular transesterifications taking place under mild basic conditions when intramolecular orthoester formations are disfavoured. In acetyl ribosides, acyl migration could be prevented when desilylation was catalysed by cerium ammonium nitrate.

  12. The Acetylation of Starch by Reactive Extrusion

    NARCIS (Netherlands)

    Graaf, Robbert A. de; Broekroelofs, Annet; Janssen, Léon P.B.M.

    1998-01-01

    Potato starch has been acetylated in a counter rotating twin screw extruder using vinylacetate and sodium hydroxide. The desired starch acetylation reaction is accompanied by an undesired parallel base catalysed hydrolysis reaction of vinylacetate and a consecutive hydrolysis reaction of the acetyla

  13. Histone Acetylation in Fungal Pathogens of Plants

    Directory of Open Access Journals (Sweden)

    Junhyun Jeon

    2014-03-01

    Full Text Available Acetylation of histone lysine residues occurs in different organisms ranging from yeast to plants and mammals for the regulation of diverse cellular processes. With the identification of enzymes that create or reverse this modification, our understanding on histone acetylation has expanded at an amazing pace during the last two decades. In fungal pathogens of plants, however, the importance of such modification has only just begun to be appreciated in the recent years and there is a dearth of information on how histone acetylation is implicated in fungal pathogenesis. This review covers the current status of research related to histone acetylation in plant pathogenic fungi and considers relevant findings in the interaction between fungal pathogens and host plants. We first describe the families of histone acetyltransferases and deacetylases. Then we provide the cases where histone acetylation was investigated in the context of fungal pathogenesis. Finally, future directions and perspectives in epigenetics of fungal pathogenesis are discussed.

  14. Catalyzing RE Project Development

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Kate; Elgqvist, Emma; Walker, Andy; Cutler, Dylan; Olis, Dan; DiOrio, Nick; Simpkins, Travis

    2016-09-01

    This poster details how screenings done with REopt - NREL's software modeling platform for energy systems integration and optimization - are helping to catalyze the development of hundreds of megawatts of renewable energy.

  15. Catalyzing alignment processes

    DEFF Research Database (Denmark)

    Lauridsen, Erik Hagelskjær; Jørgensen, Ulrik

    2004-01-01

    This paper describes how environmental management systems (EMS) spur the circulation of processes that support the constitution of environmental issues as specific environ¬mental objects and objectives. EMS catalyzes alignmentprocesses that produce coherence among the different elements involved ...

  16. Muon Catalyzed Fusion

    Science.gov (United States)

    Armour, Edward A.G.

    2007-01-01

    Muon catalyzed fusion is a process in which a negatively charged muon combines with two nuclei of isotopes of hydrogen, e.g, a proton and a deuteron or a deuteron and a triton, to form a muonic molecular ion in which the binding is so tight that nuclear fusion occurs. The muon is normally released after fusion has taken place and so can catalyze further fusions. As the muon has a mean lifetime of 2.2 microseconds, this is the maximum period over which a muon can participate in this process. This article gives an outline of the history of muon catalyzed fusion from 1947, when it was first realised that such a process might occur, to the present day. It includes a description of the contribution that Drachrnan has made to the theory of muon catalyzed fusion and the influence this has had on the author's research.

  17. Acetylation-mediated suppression of transcription-independent memory: bidirectional modulation of memory by acetylation.

    Directory of Open Access Journals (Sweden)

    Katja Merschbaecher

    Full Text Available Learning induced changes in protein acetylation, mediated by histone acetyl transferases (HATs, and the antagonistic histone deacetylases (HDACs play a critical role in memory formation. The status of histone acetylation affects the interaction between the transcription-complex and DNA and thus regulates transcription-dependent processes required for long-term memory (LTM. While the majority of studies report on the role of elevated acetylation in memory facilitation, we address the impact of both, increased and decreased acetylation on formation of appetitive olfactory memory in honeybees. We show that learning-induced changes in the acetylation of histone H3 at aminoacid-positions H3K9 and H3K18 exhibit distinct and different dynamics depending on the training strength. A strong training that induces LTM leads to an immediate increase in acetylation at H3K18 that stays elevated for hours. A weak training, not sufficient to trigger LTM, causes an initial increase in acetylation at H3K18, followed by a strong reduction in acetylation at H3K18 below the control group level. Acetylation at position H3K9 is not affected by associative conditioning, indicating specific learning-induced actions on the acetylation machinery. Elevating acetylation levels by blocking HDACs after conditioning leads to an improved memory. While memory after strong training is enhanced for at least 2 days, the enhancement after weak training is restricted to 1 day. Reducing acetylation levels by blocking HAT activity after strong training leads to a suppression of transcription-dependent LTM. The memory suppression is also observed in case of weak training, which does not require transcription processes. Thus, our findings demonstrate that acetylation-mediated processes act as bidirectional regulators of memory formation that facilitate or suppress memory independent of its transcription-requirement.

  18. Catalytic and glycan-binding abilities of ppGalNAc-T2 are regulated by acetylation

    DEFF Research Database (Denmark)

    Zlocowski, Natacha; Sendra, Victor G; Lorenz, Virginia;

    2011-01-01

    Post-translational acetylation is an important molecular regulatory mechanism affecting the biological activity of proteins. Polypeptide GalNAc transferases (ppGalNAc-Ts) are a family of enzymes that catalyze initiation of mucin-type O-glycosylation. All ppGalNAc-Ts in mammals are type II...... of the R-type lectin domain of ppGalNAc-T2. Acetylation effect on ppGalNAc-T2 biological activity in vitro was studied using a purified human recombinant ppGalNAc-T2. Mass spectrometric analysis of acetylated ppGalNAc-T2 revealed seven acetylated amino acids (K103, S109, K111, K363, S373, K521, and S529......); the first five are located in the catalytic domain. Specific glycosyltransferase activity of ppGalNAc-T2 was reduced 95% by acetylation. The last two amino acids, K521 and S529, are located in the lectin domain, and their acetylation results in alteration of the carbohydrate-binding ability of ppGalNAc-T2...

  19. What a Role did Histidine Residue Play in Arylamine N-Acetyltransferase 2 Acetylation? A Quantum Chemistry Study

    Institute of Scientific and Technical Information of China (English)

    QIAO Qing-An; CAI Zheng-Ting; YANG Chuan-Lu; WANG Mei-Shan

    2006-01-01

    Arylamine N-acetyltransferases (NATs, EC 2.3.1.5) catalyze an acetyl group transfer from acetyl coenzyme A (AcCoA) to primary arylamines and play a very important role in the metabolism and bioactivation of drugs and carcinogens. Experiments revealed that His-107 was likely the residues responsible for mediating acetyl transfer.The full catalytic mechanism of acetylation process has been examined by density functional theory. The results indicate that, if the acetyl group is directly transferred from the donor, p-nitrophenyl acetate, to the acceptor, cysteine,the high activation energy will be a great hindrance. These energies have dropped in a little range of 20-25 k J/mol when His-107 assisted the transfer process. However, when protonated His-107 mediated the reaction, the activation energies have been dropped about 73-85 kJ/mol. Our calculations strongly supported an enzyme acetylation mechanism that experiences a thiolate-imidazolium pair, and verified the presumption from experiments.

  20. GCN5-dependent acetylation of HIV-1 integrase enhances viral integration

    Directory of Open Access Journals (Sweden)

    Albanese Alberto

    2010-03-01

    Full Text Available Abstract Background An essential event during the replication cycle of HIV-1 is the integration of the reverse transcribed viral DNA into the host cellular genome. Our former report revealed that HIV-1 integrase (IN, the enzyme that catalyzes the integration reaction, is positively regulated by acetylation mediated by the histone acetyltransferase (HAT p300. Results In this study we demonstrate that another cellular HAT, GCN5, acetylates IN leading to enhanced 3'-end processing and strand transfer activities. GCN5 participates in the integration step of HIV-1 replication cycle as demonstrated by the reduced infectivity, due to inefficient provirus formation, in GCN5 knockdown cells. Within the C-terminal domain of IN, four lysines (K258, K264, K266, and K273 are targeted by GCN5 acetylation, three of which (K264, K266, and K273 are also modified by p300. Replication analysis of HIV-1 clones carrying substitutions at the IN lysines acetylated by both GCN5 and p300, or exclusively by GCN5, demonstrated that these residues are required for efficient viral integration. In addition, a comparative analysis of the replication efficiencies of the IN triple- and quadruple-mutant viruses revealed that even though the lysines targeted by both GCN5 and p300 are required for efficient virus integration, the residue exclusively modified by GCN5 (K258 does not affect this process. Conclusions The results presented here further demonstrate the relevance of IN post-translational modification by acetylation, which results from the catalytic activities of multiple HATs during the viral replication cycle. Finally, this study contributes to clarifying the recent debate raised on the role of IN acetylated lysines during HIV-1 infection.

  1. Efficient acetylation of primary amines and amino acids in environmentally benign brine solution using acetyl chloride

    Indian Academy of Sciences (India)

    Kaushik Basu; Suchandra Chakraborty; Achintya Kumar Sarkar; Chandan Saha

    2013-05-01

    Acetyl chloride is one of the most commonly available and cheap acylating agent but its high reactivity and concomitant instability in water precludes its use to carry out acetylation in aqueous medium. The present methodology illustrates the efficient acetylation of primary amines and amino acids in brine solution by means of acetyl chloride under weakly basic condition in the presence of sodium acetate and/or triethyl amine followed by trituration with aqueous saturated bicarbonate solution. This effort represents the first efficient use of this most reactive but cheap acetylating agent to acetylate amines in excellent yields in aqueous medium. This is a potentially useful green chemical transformation where reaction takes place in environment-friendly brine solution leading to easy work-up and isolation of the amide derivatives. Mechanistic rationale of this methodology is also important.

  2. Metalloporphyrin-Based Hypercrosslinked Polymers Catalyze Hetero-Diels-Alder Reactions of Unactivated Aldehydes with Simple Dienes: A Fascinating Strategy for the Construction of Heterogeneous Catalysts.

    Science.gov (United States)

    Dou, Zhiyu; Xu, Li; Zhi, Yongfeng; Zhang, Yuwei; Xia, Hong; Mu, Ying; Liu, Xiaoming

    2016-07-11

    We describe a novel and intriguing strategy for the construction of efficient heterogeneous catalysts by hypercrosslinking catalyst molecules in a one-pot Friedel-Crafts alkylation reaction. The new hypercrosslinked polymers (HCPs) as porous solid catalysts exhibit the combined advantages of homogeneous and heterogeneous catalysis, owing to their high surface area, good stability, and tailoring of catalytic centers on the frameworks. Indeed, a new class of metalloporphyrin-based HCPs were successfully synthesized using modified iron(III) porphyrin complexes as building blocks, and the resulting networks were found to be excellent recyclable heterogeneous catalysts for the hetero-Diels-Alder reaction of unactivated aldehydes with 1,3-dienes. Moreover, this new strategy showed wide adaptability, and many kinds of homogeneous-like solid-based catalysts with high catalytic performance and excellent recyclability were also constructed. PMID:27147500

  3. A Multienzyme Complex Channels Substrates and Electrons through Acetyl-CoA and Methane Biosynthesis Pathways in Methanosarcina

    OpenAIRE

    Dillon J Lieber; Jennifer Catlett; Nandu Madayiputhiya; Renu Nandakumar; Lopez, Madeline M.; Metcalf, William W.; Buan, Nicole R.

    2014-01-01

    Multienzyme complexes catalyze important metabolic reactions in many organisms, but little is known about the complexes involved in biological methane production (methanogenesis). A crosslinking-mass spectrometry (XL-MS) strategy was employed to identify proteins associated with coenzyme M-coenzyme B heterodisulfide reductase (Hdr), an essential enzyme in all methane-producing archaea (methanogens). In Methanosarcina acetivorans, Hdr forms a multienzyme complex with acetyl-CoA decarbonylase s...

  4. Regulation and structure of the heteromeric acetyl-CoA carboxylase.

    Science.gov (United States)

    Salie, Matthew J; Thelen, Jay J

    2016-09-01

    The enzyme acetyl-CoA carboxylase (ACCase) catalyzes the committed step of the de novo fatty acid biosynthesis (FAS) pathway by converting acetyl-CoA to malonyl-CoA. Two forms of ACCase exist in nature, a homomeric and heteromic form. The heteromeric form of this enzyme requires four different subunits for activity: biotin carboxylase; biotin carboxyl carrier protein; and α- and β-carboxyltransferases. Heteromeric ACCases (htACCase) can be found in prokaryotes and the plastids of most plants. The plant htACCase is regulated by diverse mechanisms reflected by the biochemical and genetic complexity of this multienzyme complex and the plastid stroma where it resides. In this review we summarize the regulation of the plant htACCase and also describe the structural characteristics of this complex from both prokaryotes and plants. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner. PMID:27091637

  5. Levels of histone acetylation in thyroid tumors.

    Science.gov (United States)

    Puppin, Cinzia; Passon, Nadia; Lavarone, Elisa; Di Loreto, Carla; Frasca, Francesco; Vella, Veronica; Vigneri, Riccardo; Damante, Giuseppe

    2011-08-12

    Histone acetylation is a major mechanism to regulate gene transcription. This post-translational modification is modified in cancer cells. In various tumor types the levels of acetylation at several histone residues are associated to clinical aggressiveness. By using immunohistochemistry we show that acetylated levels of lysines at positions 9-14 of H3 histone (H3K9-K14ac) are significantly higher in follicular adenomas (FA), papillary thyroid carcinomas (PTC), follicular thyroid carcinomas (FTC) and undifferentiated carcinomas (UC) than in normal tissues (NT). Similar data have been obtained when acetylated levels of lysine 18 of H3 histone (H3K18ac) were evaluated. In this case, however, no difference was observed between NT and UC. When acetylated levels of lysine 12 of H4 histone (H4K12ac) were evaluated, only FA showed significantly higher levels in comparison with NT. These data indicate that modification histone acetylation is an early event along thyroid tumor progression and that H3K18 acetylation is switched off in the transition between differentiated and undifferentiated thyroid tumors. By using rat thyroid cell lines that are stably transfected with doxycyclin-inducible oncogenes, we show that the oncoproteins RET-PTC, RAS and BRAF increase levels of H3K9-K14ac and H3K18ac. In the non-tumorigenic rat thyroid cell line FRTL-5, TSH increases levels of H3K18ac. However, this hormone decreases levels of H3K9-K14ac and H4K12ac. In conclusion, our data indicate that neoplastic transformation and hormonal stimulation can modify levels of histone acetylation in thyroid cells. PMID:21763277

  6. p53 Acetylation: Regulation and Consequences

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Sara M. [Department of Pharmacology, The University of Iowa Carver College of Medicine, Iowa City, IA 52242 (United States); Medical Scientist Training Program, The University of Iowa Carver College of Medicine, Iowa City, IA 52242 (United States); Quelle, Dawn E., E-mail: dawn-quelle@uiowa.edu [Department of Pharmacology, The University of Iowa Carver College of Medicine, Iowa City, IA 52242 (United States); Medical Scientist Training Program, The University of Iowa Carver College of Medicine, Iowa City, IA 52242 (United States); Department of Pathology, The University of Iowa Carver College of Medicine, Iowa City, IA 52242 (United States)

    2014-12-23

    Post-translational modifications of p53 are critical in modulating its tumor suppressive functions. Ubiquitylation, for example, plays a major role in dictating p53 stability, subcellular localization and transcriptional vs. non-transcriptional activities. Less is known about p53 acetylation. It has been shown to govern p53 transcriptional activity, selection of growth inhibitory vs. apoptotic gene targets, and biological outcomes in response to diverse cellular insults. Yet recent in vivo evidence from mouse models questions the importance of p53 acetylation (at least at certain sites) as well as canonical p53 functions (cell cycle arrest, senescence and apoptosis) to tumor suppression. This review discusses the cumulative findings regarding p53 acetylation, with a focus on the acetyltransferases that modify p53 and the mechanisms regulating their activity. We also evaluate what is known regarding the influence of other post-translational modifications of p53 on its acetylation, and conclude with the current outlook on how p53 acetylation affects tumor suppression. Due to redundancies in p53 control and growing understanding that individual modifications largely fine-tune p53 activity rather than switch it on or off, many questions still remain about the physiological importance of p53 acetylation to its role in preventing cancer.

  7. Muon catalyzed fusion

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, K. [Advanced Meson Science Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Nagamine, K. [Muon Science Laboratory, IMSS-KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Matsuzaki, T. [Advanced Meson Science Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Kawamura, N. [Muon Science Laboratory, IMSS-KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2005-12-15

    The latest progress of muon catalyzed fusion study at the RIKEN-RAL muon facility (and partly at TRIUMF) is reported. The topics covered are magnetic field effect, muon transfer to {sup 3}He in solid D/T and ortho-para effect in dd{mu} formation.

  8. Trichoderma reesei CE16 acetyl esterase and its role in enzymatic degradation of acetylated hemicellulose

    DEFF Research Database (Denmark)

    Biely, Peter; Cziszarava, Maria; Agger, Jane W.;

    2014-01-01

    Results The combined action of GH10 xylanase and acetylxylan esterases (AcXEs) leads to formation of neutral and acidic xylooligosaccharides with a few resistant acetyl groups mainly at their non-reducing ends. We show here that these acetyl groups serve as targets for TrCE16 AcE. The most promin...

  9. Reversible lysine acetylation controls the activity of the mitochondrial enzyme acetyl-CoA synthetase 2

    DEFF Research Database (Denmark)

    Schwer, Bjoern; Bunkenborg, Jakob; Verdin, Regis O;

    2006-01-01

    by SIRT3 activates the acetyl-CoA synthetase activity of AceCS2. This report identifies the first acetylated substrate protein of SIRT3. Our findings show that a mammalian sirtuin directly controls the activity of a metabolic enzyme by means of reversible lysine acetylation. Because the activity......We report that human acetyl-CoA synthetase 2 (AceCS2) is a mitochondrial matrix protein. AceCS2 is reversibly acetylated at Lys-642 in the active site of the enzyme. The mitochondrial sirtuin SIRT3 interacts with AceCS2 and deacetylates Lys-642 both in vitro and in vivo. Deacetylation of AceCS2...

  10. Proteomic analysis of acetylation in thermophilic Geobacillus kaustophilus.

    Science.gov (United States)

    Lee, Dong-Woo; Kim, Dooil; Lee, Yong-Jik; Kim, Jung-Ae; Choi, Ji Young; Kang, Sunghyun; Pan, Jae-Gu

    2013-08-01

    Recent analysis of prokaryotic N(ε)-lysine-acetylated proteins highlights the posttranslational regulation of a broad spectrum of cellular proteins. However, the exact role of acetylation remains unclear due to a lack of acetylated proteome data in prokaryotes. Here, we present the N(ε)-lysine-acetylated proteome of gram-positive thermophilic Geobacillus kaustophilus. Affinity enrichment using acetyl-lysine-specific antibodies followed by LC-MS/MS analysis revealed 253 acetylated peptides representing 114 proteins. These acetylated proteins include not only common orthologs from mesophilic Bacillus counterparts, but also unique G. kaustophilus proteins, indicating that lysine acetylation is pronounced in thermophilic bacteria. These data complement current knowledge of the bacterial acetylproteome and provide an expanded platform for better understanding of the function of acetylation in cellular metabolism.

  11. Tritium catalyzed deuterium tokamaks

    International Nuclear Information System (INIS)

    A preliminary assessment of the promise of the Tritium Catalyzed Deuterium (TCD) tokamak power reactors relative to that of deuterium-tritium (D-T) and catalyzed deuterium (Cat-D) tokamaks is undertaken. The TCD mode of operation is arrived at by converting the 3He from the D(D,n)3He reaction into tritium, by neutron capture in the blanket; the tritium thus produced is fed into the plasma. There are three main parts to the assessment: blanket study, reactor design and economic analysis and an assessment of the prospects for improvements in the performance of TCD reactors (and in the promise of the TCD mode of operation, in general)

  12. Lipase-catalyzed highly enantioselective kinetic resolution of boron-containing chiral alcohols.

    Science.gov (United States)

    Andrade, Leandro H; Barcellos, Thiago

    2009-07-16

    The first application of enzymes as catalysts to obtain optically pure boron compounds is described. The kinetic resolution of boron-containing chiral alcohols via enantioselective transesterification catalyzed by lipases was studied. Aromatic, allylic, and aliphatic secondary alcohols containing a boronate ester or boronic acid group were resolved by lipase from Candida antartica (CALB), and excellent E values (E > 200) and high enantiomeric excesses (up to >99%) of both remaining substrates and acetylated product were obtained.

  13. Enantioselective and Regiodivergent Functionalization of N-Allylcarbamates by Mechanistically Divergent Multicatalysis.

    Science.gov (United States)

    Richmond, Edward; Khan, Ismat Ullah; Moran, Joseph

    2016-08-22

    A pair of mechanistically divergent multicatalytic reaction sequences has been developed consisting of nickel-catalyzed isomerization of N-allylcarbamates and subsequent phosphoric-acid-catalyzed enantioselective functionalization of the resulting intermediates. By appropriate selection of reaction partners, in situ generated imines and ene-carbamates are mechanistically partitioned to yield opposing functionalized products. Formal α-functionalization to give protected α-arylamines is achieved upon enantioselective Friedel-Crafts reaction with arene nucleophiles, whereas formal β-functionalization is achieved upon reaction with diarylimine electrophiles in an enantioselective Povarov-[4+2] cycloaddition. PMID:27461524

  14. Catalyzed Ceramic Burner Material

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, Amy S., Dr.

    2012-06-29

    Catalyzed combustion offers the advantages of increased fuel efficiency, decreased emissions (both NOx and CO), and an expanded operating range. These performance improvements are related to the ability of the catalyst to stabilize a flame at or within the burner media and to combust fuel at much lower temperatures. This technology has a diverse set of applications in industrial and commercial heating, including boilers for the paper, food and chemical industries. However, wide spread adoption of catalyzed combustion has been limited by the high cost of precious metals needed for the catalyst materials. The primary objective of this project was the development of an innovative catalyzed burner media for commercial and small industrial boiler applications that drastically reduce the unit cost of the catalyzed media without sacrificing the benefits associated with catalyzed combustion. The scope of this program was to identify both the optimum substrate material as well as the best performing catalyst construction to meet or exceed industry standards for durability, cost, energy efficiency, and emissions. It was anticipated that commercial implementation of this technology would result in significant energy savings and reduced emissions. Based on demonstrated achievements, there is a potential to reduce NOx emissions by 40,000 TPY and natural gas consumption by 8.9 TBtu in industries that heavily utilize natural gas for process heating. These industries include food manufacturing, polymer processing, and pulp and paper manufacturing. Initial evaluation of commercial solutions and upcoming EPA regulations suggests that small to midsized boilers in industrial and commercial markets could possibly see the greatest benefit from this technology. While out of scope for the current program, an extension of this technology could also be applied to catalytic oxidation for volatile organic compounds (VOCs). Considerable progress has been made over the course of the grant

  15. 21 CFR 172.828 - Acetylated monoglycerides.

    Science.gov (United States)

    2010-04-01

    ... molecular distillation or by steam stripping; or (2) The direct acetylation of edible monoglycerides with acetic anhydride without the use of catalyst or molecular distillation, and with the removal by vacuum distillation, if necessary, of the acetic acid, acetic anhydride, and triacetin. (b) The food additive has...

  16. Acetylated flavonol triglycosides from Ammi majus L.

    Science.gov (United States)

    Singab, A N

    1998-12-01

    Two new acetylated flavonol triglycosides: kaempferol and isorhamnetin 3-O-[2"-(4"'-acetylrhamnosyl)-6"-glucosyl] glucosides, were isolated and identified from the aerial parts of Ammi majus L. In addition, three known flavonol glycosides namely; isorhamnetin-3-O-rutinoside, kaempferol-3-O-glucoside and isorhamnetin-3-O-glucoside were detected.

  17. Oxidative Debenzylation and Acetylation of Hexabenzylhexaazaisowutzitane

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The oxidative reactivity of hexabenzylhexaazaisowutzitane(HBIW)under different conditions was studied. It was found that the N-benzyl groups were found to form benzoyl group after oxidation. They might also be first debenzylated and then acetylated by potassium permanganate in acetic anhydride/DMF.

  18. Purification, characterization and gene cloning of thermostable O-acetyl-L-serine sulfhydrylase forming β-cyano-L-alanine

    International Nuclear Information System (INIS)

    A thermophilic and cyanide ion-tolerant bacterium, Bacillus stearothermophilus CN3 isolated from a hot spring in Japan, was found to produce thermostable β-cyano-L-alanine synthase. The enzyme catalyzes the synthesis of β-cyano-L-alanine from O-acetyl-L-serine and cyanide ions. The purified enzyme has a molecular mass of approximately 70 kDa and consists of two identical sub-units. It was stable in the pH range of 6.0 to 10.0 and up to 70degC. The enzyme also catalyzes the synthesis of various β-substituted-L-alanine derivatives from O-acetyl-L-serine and nucleophilic reagents. The gene encoding the β-cyano-L-alanine synthase was isolated from B. stearothermophilus CN3. Sequence homology analysis revealed that the β-cyano-L-alanine synthase of the bacterium is O-acetyl-L-serine sulfhydrylase. A recombinant plasmid, constructed by ligation of the cloned gene and an expression vector, pKK223-3, was introduced into E. coli JM109. The transformed E. coli cells overexpressed β-cyano-L-alanine synthase. Heat stable β-cyano-L-alanine synthase can be applied to the synthesis of [4-11C]L-2,4-diaminobutyric acid as a tracer for positron emission tomography. (author)

  19. Two New Acetyl Cimicifugosides from the Rhizomes of Cimicifuga Racemosa

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Two new acetyl cimicifugosides were isolated from the rhizomes of Cimicifuga racemosa. Their structures were elucidated as 2'-O-acetyl cimicifugoside H-1 1 and 3'-O-acetyl cimicifugoside H-1 2 by the spectroscopic evidence and chemical methods.

  20. Synthesis of Cyclo[b]fused Carbazoles via SnCl4-Mediated Domino Reaction of 2-Indolylmethylpivalates with Arenes and Heteroarenes.

    Science.gov (United States)

    Saravanan, Velu; Mageshwaran, Thiyagarajan; Mohanakrishnan, Arasambattu K

    2016-09-16

    A straightforward synthesis of aryl and heteroaryl-annulated cyclo[b]carbazoles has been developed via SnCl4-mediated one-pot arylation, cyclization and aromatization reaction sequence from 3-acetyl/aroyl-2-pivaloyloxymethylindoles. The starting material is easily accessible from commercially available 2-methylindole via Friedel-Crafts acylation, bromination and pivaloylation. Remarkably, electron withdrawing/donating aroyl units including heterocyclic systems are well tolerated in the present domino reaction protocol. Furthermore, this methodology could be extended to the synthesis of dibenzofurocarbazole via bis-annulation of 2,5-bis(2-pivaloyloxymethyl)pyrrole. PMID:27564513

  1. 1-, 2-, and 4-Ethynylpyrenes in the Structure of Twisted Intercalating Nucleic Acids: Structure, Thermal Stability, and Fluorescence Relationship

    DEFF Research Database (Denmark)

    Filichev, Vyacheslav V; Astakhova, Irina V.; Malakhov, Andrei D.;

    2008-01-01

    A postsynthetic, on-column Sonogashira reaction was applied on DNA molecules modified by 2- or 4-iodophenylmethylglycerol in the middle of the sequence, to give the corresponding ortho- and para-twisted intercalating nucleic acids (TINA) with 1-, 2-, and 4-ethynylpyrene residues. The convenient...... synthesis of 2- and 4-ethynylpyrenes started from the hydrogenolysis of pyrene that has had the sulfur removed and separation of 4,5,9,10-tetrahydropyrene and 1,2,3,6,7,8-hexahydropyrene, which were later converted to the final compounds by successive Friedel-Crafts acetylation, aromatization by 2...

  2. An acetylation site in lectin domain modulates the biological activity of polypeptide GalNAc-transferase-2

    DEFF Research Database (Denmark)

    Zlocowski, Natacha; Lorenz, Virginia; Bennett, Eric Paul;

    2013-01-01

    Abstract Polypeptide GalNAc-transferases (ppGalNAc-Ts) are a family of enzymes that catalyze the initiation of mucin-type O-glycosylation. All ppGalNAc-T family members contain a common (QXW)3 motif which is present in R-type lectin group. Acetylation site K521 is part of the QKW motif of ß......-trefoil in the lectin domain of ppGalNAc-T2. We used a combination of acetylation and site-directed mutagenesis approaches to examine the functional role of K521 in ppGalNAc-T2. Binding assays of non-acetylated and acetylated forms of the mutant ppGalNAc-T2K521Q to various naked and aGalNAc-glycosylated mucin peptides...... indicated that degree of interaction of lectin domain with aGalNAc depends on the peptide sequence of mucin. Studies of inhibitory effect of various carbohydrates on interactions of ppGalNAc-T2 with MUC1aGalNAc indicate that point K521Q mutation enhance the carbohydrate specificity of lectin domain for aGalNAc...

  3. A multienzyme complex channels substrates and electrons through acetyl-CoA and methane biosynthesis pathways in Methanosarcina.

    Directory of Open Access Journals (Sweden)

    Dillon J Lieber

    Full Text Available Multienzyme complexes catalyze important metabolic reactions in many organisms, but little is known about the complexes involved in biological methane production (methanogenesis. A crosslinking-mass spectrometry (XL-MS strategy was employed to identify proteins associated with coenzyme M-coenzyme B heterodisulfide reductase (Hdr, an essential enzyme in all methane-producing archaea (methanogens. In Methanosarcina acetivorans, Hdr forms a multienzyme complex with acetyl-CoA decarbonylase synthase (ACDS, and F420-dependent methylene-H4MPT reductase (Mer. ACDS is essential for production of acetyl-CoA during growth on methanol, or for methanogenesis from acetate, whereas Mer is essential for methanogenesis from all substrates. Existence of a Hdr:ACDS:Mer complex is consistent with growth phenotypes of ACDS and Mer mutant strains in which the complex samples the redox status of electron carriers and directs carbon flux to acetyl-CoA or methanogenesis. We propose the Hdr:ACDS:Mer complex comprises a special class of multienzyme redox complex which functions as a "biological router" that physically links methanogenesis and acetyl-CoA biosynthesis pathways.

  4. Acetylation Is Indispensable for p53 Activation

    OpenAIRE

    Tang, Yi; Zhao, Wenhui; Chen, Yue; Zhao, Yingming; Gu, Wei

    2008-01-01

    The activation of the tumor suppressor p53 facilitates the cellular response to genotoxic stress; however, the p53 response can only be executed if its interaction with its inhibitor Mdm2 is abolished. There have been conflicting reports on the question of whether p53 posttranslational modifications, such as phosphorylation or acetylation, are essential or only play a subtle, fine-tuning role in the p53 response. Thus, it remains unclear whether p53 modification is absolutely required for its...

  5. p53 Acetylation: Regulation and Consequences

    OpenAIRE

    Reed, Sara M.; Quelle, Dawn E.

    2014-01-01

    Post-translational modifications of p53 are critical in modulating its tumor suppressive functions. Ubiquitylation, for example, plays a major role in dictating p53 stability, subcellular localization and transcriptional vs. non-transcriptional activities. Less is known about p53 acetylation. It has been shown to govern p53 transcriptional activity, selection of growth inhibitory vs. apoptotic gene targets, and biological outcomes in response to diverse cellular insults. Yet recent in vivo ev...

  6. Fragrance material review on acetyl cedrene.

    Science.gov (United States)

    Scognamiglio, J; Letizia, C S; Politano, V T; Api, A M

    2013-12-01

    A toxicologic and dermatologic review of acetyl cedrene when used as a fragrance ingredient is presented. Acetyl cedrene is a member of the fragrance structural group Alkyl Cyclic Ketones. The generic formula for this group can be represented as (R1)(R2)CO. These fragrances can be described as being composed of an alkyl, R1, and various substituted and bicyclic saturated or unsaturated cyclic hydrocarbons, R2, in which one of the rings may include up to 12 carbons. Alternatively, R2 may be a carbon bridge of C2-C4 carbon chain length between the ketone and cyclic hydrocarbon. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for acetyl cedrene were evaluated then summarized and includes physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, phototoxicity, photoallergy, toxicokinetics, repeated dose, reproductive toxicity, and genotoxicity data. A safety assessment of the entire Alkyl Cyclic Ketones will be published simultaneously with this document; please refer to Belsito et al. (2013) (Belsito, D., Bickers, D., Bruze, M., Calow, P., Dagli, M., Fryer, A.D., Greim, H., Miyachi, Y., Saurat, J.H., Sipes, I.G., 2013. A Toxicologic and Dermatologic Assessment of Alkyl Cyclic Ketones When Used as Fragrance Ingredients. Submitted with this manuscript.) for an overall assessment of the safe use of this material and all Alkyl Cyclic Ketones in fragrances. PMID:23907023

  7. Acetylation phenotype variation in pediatric patients with atopic dermatitis

    Directory of Open Access Journals (Sweden)

    Rafi A Majeed Al-Razzuqi

    2011-01-01

    Full Text Available Background: Few studies have been done on the relation between acetylator status and allergic diseases. Aim: To determine any possible association between acetylating phenotype in pediatric patients with atopic dermatitis (AD and the disease prognosis. Patients and Methods: Thirty-six pediatric patients and forty two healthy children as a control group were participated in the study. All participants received a single oral dose of dapsone of 1.54 mg/kg body weight, after an overnight fast. Using high performance liquid chromatography (HPLC, plasma concentrations of dapsone and its metabolite (monoacetyldapsone were estimated to phenotype the participants as slow and rapid acetylators according to their acetylation ratio (ratio of monoacetyldapsone to dapsone. Results: 72.2% of pediatric patients with AD showed slow acetylating status as compared to 69.4% of control individuals. Also, 73% of AD patients with slow acetylating phenotype had familial history of allergy. The severity of AD occurred only in slow acetylator patients. The eczematous lesions in slow acetylators presented mainly in the limbs, while in rapid acetylators, they were found mostly in face and neck. Conclusion: This study shows an association between the N-acetylation phenotype variation and clinical aspects of AD.

  8. Catalytic, Interrupted Formal Homo-Nazarov Cyclization with (Hetero)arenes: Access to α-(Hetero)aryl Cyclohexanones.

    Science.gov (United States)

    Williams, Corey W; Shenje, Raynold; France, Stefan

    2016-09-16

    The first examples of a Lewis-acid catalyzed (hetero)arene interrupted, formal homo-Nazarov cyclization have been disclosed. Using SnCl4 as the catalyst, alkenyl cyclopropyl ketones undergo ring-opening cyclization to form six-membered cyclic oxyallyl cations. Subsequent intermolecular Friedel-Crafts-type arylation with various electron-rich arenes and heteroarenes provides functionalized α-(hetero)arylated cyclohexanones, a scaffold present in many natural products and bioactive compounds, in yields up to 88% and diastereomeric ratios up to 12:1. Regiospecific arylation occurs at the α-carbon of the oxyallyl cation due to polarization caused by the ester group. PMID:27529123

  9. Determination of amphetamine by HPLC after acetylation.

    Science.gov (United States)

    Veress, T

    2000-01-01

    An analytical procedure has been developed for the HPLC determination of amphetamine by off-line pre-column derivatization. The proposed procedure consists of sample preparation by acetylation of amphetamine with acetic anhydride and a subsequent reversed-phase HPLC separation on an octadecyl silica stationary phase with salt-free mobile phase (tetrahydrofuran, acetonitrile, 0.1% triethylamine in water, 15:15:70 v/v) applying UV-detection. The applicability of the elaborated procedure is demonstrated with results obtained by analysis of real samples seized in the Hungarian black market. PMID:10641931

  10. Getting a Knack for NAC: N-Acetyl-Cysteine

    OpenAIRE

    Sansone, Randy A.; Sansone, Lori A.

    2011-01-01

    N-acetyl-cysteine, N-acetylcysteine, N-acetyl cysteine, and N-acetyl-L-cysteine are all designations for the same compound, which is abbreviated as NAC. NAC is a precursor to the amino acid cysteine, which ultimately plays two key metabolic roles. Through its metabolic contribution to glutathione production, cysteine participates in the general antioxidant activities of the body. Through its role as a modulator of the glutamatergic system, cysteine influences the reward-reinforcement pathway....

  11. Obesity, cancer, and acetyl-CoA metabolism

    OpenAIRE

    Lee, Joyce V.; Shah, Supriya A.; Wellen, Kathryn E.

    2013-01-01

    As rates of obesity soar in the Unites States and around the world, cancer attributed to obesity has emerged as major threat to public health. The link between obesity and cancer can be attributed in part to the state of chronic inflammation that develops in obesity. Acetyl-CoA production and protein acetylation patterns are highly sensitive to metabolic state and are significantly altered in obesity. In this article, we explore the potential role of nutrient-sensitive lysine acetylation in r...

  12. Acetylation of Tau Inhibits Its Degradation and Contributes to Tauopathy

    OpenAIRE

    Min, Sang-Won; Cho, Seo-Hyun; Zhou, Yungui; Schroeder, Sebastian; Haroutunian, Vahram; Seeley, William W.; Huang, Eric J.; Shen, Yong; Masliah, Eliezer; Mukherjee, Chandrani; Meyers, David; Cole, Philip A.; Ott, Melanie; Gan, Li

    2010-01-01

    Neurodegenerative tauopathies characterized by hyperphosphorylated tau include frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) and Alzheimer's disease (AD). Reducing tau levels improves cognitive function in mouse models of AD and FTDP-17, but the mechanisms regulating the turnover of pathogenic tau are unknown. We found that tau is acetylated and that tau acetylation prevents degradation of phosphorylated tau (p-tau). Using two antibodies specific for acetylated ta...

  13. Protein lysine acetylation in bacteria: Current state of the art.

    Science.gov (United States)

    Ouidir, Tassadit; Kentache, Takfarinas; Hardouin, Julie

    2016-01-01

    Post-translational modifications of proteins are key events in cellular metabolism and physiology regulation. Lysine acetylation is one of the best studied protein modifications in eukaryotes, but, until recently, ignored in bacteria. However, proteomic advances have highlighted the diversity of bacterial lysine-acetylated proteins. The current data support the implication of lysine acetylation in various metabolic pathways, adaptation and virulence. In this review, we present a broad overview of the current knowledge of lysine acetylation in bacteria. We emphasize particularly the significant contribution of proteomics in this field. PMID:26390373

  14. Synthesis of some novel D-glucuronic acid acetylated derivatives as potential anti-tumor agents.

    Science.gov (United States)

    El-Nezhawy, Ahmed O H; Adly, Frady G; Eweas, Ahmed F; Hanna, Atef G; El-Kholy, Yehya M; El-Sayed, Shahenaz H; El-Naggar, Tarek B A

    2011-10-01

    A structurally diverse series of Δ(4,5) -uronamide derivatives have been chemically synthesized starting from D-glucuronic acid itself by means of acetylation, activation, amide bond formation and base-catalyzed elimination protocols. Structure elucidation for all products along with optimization of the synthetic steps is described. The synthesized compounds were evaluated for their in-vitro anti-tumor activity against MCF-7, TK-10 and UACC-62 cell lines. The compounds 5, 11, 13, 15 and 16 were the most active against TK-10 cell line. On the other hand, the most active compounds against the MCF-7 cell line were 11 and 15. However, compounds 5, 7, 11, 13, 15 and 16 were the most active against the UACC-62 cell line.

  15. N-acetylaspartate catabolism determines cytosolic acetyl-CoA levels and histone acetylation in brown adipocytes.

    Science.gov (United States)

    Prokesch, A; Pelzmann, H J; Pessentheiner, A R; Huber, K; Madreiter-Sokolowski, C T; Drougard, A; Schittmayer, M; Kolb, D; Magnes, C; Trausinger, G; Graier, W F; Birner-Gruenberger, R; Pospisilik, J A; Bogner-Strauss, J G

    2016-04-05

    Histone acetylation depends on the abundance of nucleo-cytoplasmic acetyl-CoA. Here, we present a novel route for cytoplasmic acetyl-CoA production in brown adipocytes. N-acetylaspartate (NAA) is a highly abundant brain metabolite catabolized by aspartoacylase yielding aspartate and acetate. The latter can be further used for acetyl-CoA production. Prior to this work, the presence of NAA has not been described in adipocytes. Here, we show that accumulation of NAA decreases the brown adipocyte phenotype. We increased intracellular NAA concentrations in brown adipocytes via media supplementation or knock-down of aspartoacylase and measured reduced lipolysis, thermogenic gene expression, and oxygen consumption. Combinations of approaches to increase intracellular NAA levels showed additive effects on lipolysis and gene repression, nearly abolishing the expression of Ucp1, Cidea, Prdm16, and Ppara. Transcriptome analyses of aspartoacylase knock-down cells indicate deficiencies in acetyl-CoA and lipid metabolism. Concordantly, cytoplasmic acetyl-CoA levels and global histone H3 acetylation were decreased. Further, activating histone marks (H3K27ac and H3K9ac) in promoters/enhancers of brown marker genes showed reduced acetylation status. Taken together, we present a novel route for cytoplasmic acetyl-CoA production in brown adipocytes. Thereby, we mechanistically connect the NAA pathway to the epigenomic regulation of gene expression, modulating the phenotype of brown adipocytes.

  16. Cloning and characterization of cotton heteromeric acetyl-CoA carboxylase genes

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Heteromeric acetyl-coanzyme A(CoA)carboxylese(ACCase)catalyzes the formation of malonyl-CoA from acetyl-CoA.It plays an essential role in fatty acid synthesis in prokaryotes and most of plants.The heteromeric ACCase is composed of four subunits:biotin carboxylase (BC),biotin carboxyl carrier protein (BCCP),and α-and β-subunits of carboxyltransferese(α-andβ-CT).In this study,we cloned five novel genes encoding the subunits of heteromeric ACCese(one BC,BCCP and β-CT,and two α-CTs) from cotton (Gossypium hirsutum cv.zhongmian 35)by RACE-PCR.The deduced amino acid sequence of these cDNAs shares high similarity with other reported heteromeric ACCese subunits.The phylogenetic analysis indicated that the different subunits of heteromeric ACCase were grouped in a similar pattern.Southern blot analysis revealed the milti-copy patterns of these heteromeric ACCase genes in cotton genome.Semi-quantitative RT-PCR demonstrated that heteromeric ACCese genes were constitutively expressed in all of the cotton tissues,but the transcripts accumulated at a relatively low level in roots.To our knowledge,this is the first report about characterization of the heteromeric ACCase genes in cotton.

  17. The kinetics of the acetylation of gelatinised potato starch

    NARCIS (Netherlands)

    de Graaf, R.A.; Broekroelofs, G.A.; Janssen, L.P.B.M.; Beenackers, A.A C M

    1995-01-01

    The reaction rates, in the base-catalysed acetylation of gelatinised aqueous starch (4 wt%), by vinylacetate (ViAc), were investigated in a semibatch reactor at temperatures ranging from 20 to 50 degrees C. The desired starch acetylation reaction is accompanied by an undesired parallel base-catalyse

  18. Regulation of autophagy by cytosolic acetyl-coenzyme A

    DEFF Research Database (Denmark)

    Mariño, Guillermo; Pietrocola, Federico; Eisenberg, Tobias;

    2014-01-01

    Acetyl-coenzyme A (AcCoA) is a major integrator of the nutritional status at the crossroads of fat, sugar, and protein catabolism. Here we show that nutrient starvation causes rapid depletion of AcCoA. AcCoA depletion entailed the commensurate reduction in the overall acetylation of cytoplasmic p...

  19. Medial temporal N-acetyl-aspartate in pediatric major depression.

    Science.gov (United States)

    MacMaster, Frank P; Moore, Gregory J; Russell, Aileen; Mirza, Yousha; Taormina, S Preeya; Buhagiar, Christian; Rosenberg, David R

    2008-10-30

    The medial temporal cortex (MTC) has been implicated in the pathogenesis of pediatric major depressive disorder (MDD). Eleven MDD case-control pairs underwent proton magnetic resonance spectroscopic imaging. N-acetyl-aspartate was lower in the left MTC (27%) in MDD patients versus controls. Lower N-acetyl-aspartate concentrations in MDD patients may reflect reduced neuronal viability. PMID:18703320

  20. Medial temporal N-acetyl aspartate in pediatric major depression

    Science.gov (United States)

    MacMaster, Frank P.; Moore, Gregory J; Russell, Aileen; Mirza, Yousha; Taormina, S. Preeya; Buhagiar, Christian; Rosenberg, David R.

    2008-01-01

    The medial temporal cortex (MTC) has been implicated in the pathogenesis of pediatric major depressive disorder (MDD). Eleven MDD-case control pairs underwent proton magnetic resonance spectroscopic imaging. N-acetyl-aspartate was lower in left MTC (27%) in MDD patients versus controls. Lower N-acetyl-aspartate concentrations in MDD patients may reflect reduced neuronal viability. PMID:18703320

  1. 21 CFR 172.372 - N-Acetyl-L-methionine.

    Science.gov (United States)

    2010-04-01

    ... HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.372 N-Acetyl-L-methionine. The food additive N-acetyl-L... section. The minimum amount of the additive to achieve the desired effect must be used, and the...

  2. Trichostatin A induced histone acetylation causes decondensation of interphase chromatin.

    NARCIS (Netherlands)

    T.A. Knoch (Tobias); M. Wachsmuth (Malte); M. Frank-Stöhr (Monika); M. Stöhr (Michael); C.P. Bacher (Christian); K. Rippe (Karsten)

    2004-01-01

    textabstractThe effect of trichostatin A (TSA)-induced histone acetylation on the interphase chromatin structure was visualized in vivo with a HeLa cell line stably expressing histone H2A, which was fused to enhanced yellow fluorescent protein. The globally increased histone acetylation caused a rev

  3. A facile and practical synthesis of N-acetyl enamides.

    Science.gov (United States)

    Tang, Wenjun; Capacci, Andrew; Sarvestani, Max; Wei, Xudong; Yee, Nathan K; Senanayake, Chris H

    2009-12-18

    A facile and practical method for the synthesis of N-acetyl alpha-arylenamides has been developed from corresponding ketoximes as the starting materials with ferrous acetate as the reducing reagent. This methodology offers mild reaction conditions, simple purification procedures, and high yields for a variety of N-acetyl enamides. PMID:19921804

  4. Acetylation of FoxO1 Activates Bim Expression to Induce Apoptosis in Response to Histone Deacetylase Inhibitor Depsipeptide Treatment

    Directory of Open Access Journals (Sweden)

    Yang Yang

    2009-04-01

    Full Text Available Histone deacetylase (HDAC inhibitors have been shown to induce cell cycle arrest and apoptosis in cancer cells. However, the mechanisms of HDAC inhibitor induced apoptosis are incompletely understood. In this study, depsipeptide, a novel HDAC inhibitor, was shown to be able to induce significant apoptotic cell death in human lung cancer cells. Further study showed that Bim, a BH3-only proapoptotic protein, was significantly upregulated by depsipeptide in cancer cells, and Bim's function in depsipeptide-induced apoptosis was confirmed by knockdown of Bim with RNAi. In addition, we found that depsipeptide-induced expression of Bim was directly dependent on acetylation of forkhead box class O1 (FoxO1 that is catalyzed by cyclic adenosine monophosphate-responsive element-binding protein-binding protein, and indirectly induced by a decreased four-and-a-half LIM-domain protein 2. Moreover, our results demonstrated that FoxO1 acetylation is required for the depsipeptide-induced activation of Bim and apoptosis, using transfection with a plasmid containing FoxO1 mutated at lysine sites and a luciferase reporter assay. These data show for the first time that an HDAC inhibitor induces apoptosis through the FoxO1 acetylation-Bim pathway.

  5. Structure of the complex of Neisseria gonorrhoeae N-acetyl-L-glutamate synthase with a bound bisubstrate analog.

    Science.gov (United States)

    Zhao, Gengxiang; Allewell, Norma M; Tuchman, Mendel; Shi, Dashuang

    2013-01-25

    N-Acetyl-L-glutamate synthase catalyzes the conversion of AcCoA and glutamate to CoA and N-acetyl-L-glutamate (NAG), the first step of the arginine biosynthetic pathway in lower organisms. In mammals, NAG is an obligate cofactor of carbamoyl phosphate synthetase I in the urea cycle. We have previously reported the structures of NAGS from Neisseria gonorrhoeae (ngNAGS) with various substrates bound. Here we reported the preparation of the bisubstrate analog, CoA-S-acetyl-L-glutamate, the crystal structure of ngNAGS with CoA-NAG bound, and kinetic studies of several active site mutants. The results are consistent with a one-step nucleophilic addition-elimination mechanism with Glu353 as the catalytic base and Ser392 as the catalytic acid. The structure of the ngNAGS-bisubstrate complex together with the previous ngNAGS structures delineates the catalytic reaction path for ngNAGS. PMID:23261468

  6. Unchanged acetylation of isoniazid by alcohol intake

    DEFF Research Database (Denmark)

    Wilcke, J T R; Døssing, M; Angelo, H R;

    2004-01-01

    no impact on the conversion of INH to its metabolite acetylisoniazid, which is catalysed by the enzyme N-acetyltranferase. Accordingly, a metabolic effect of acute alcohol intake on INH metabolism probably contributes little to the therapeutic failure of anti-tuberculosis treatment among alcoholics.......SETTING: In 10 healthy subjects, the influence of acute alcohol intake on the pharmacokinetics of isoniazid (INH) was studied. OBJECTIVE: To test the hypothesis that alcohol increases the conversion of INH by acetylation into its metabolite acetylisoniazid. DESIGN: In a crossover design, an oral...... dose of 300 mg INH was administered on 2 separate days, 14 days apart, with or without alcohol to a serum alcohol of about 21 mmol/l (1 g/l) maintained for 12 h. RESULTS: Neither the metabolism of INH nor that of acetylisoniazid was changed by acute alcohol intake. CONCLUSION: Acute alcohol intake has...

  7. The biology of lysine acetylation integrates transcriptional programming and metabolism

    Directory of Open Access Journals (Sweden)

    Mujtaba Shiraz

    2011-03-01

    Full Text Available Abstract The biochemical landscape of lysine acetylation has expanded from a small number of proteins in the nucleus to a multitude of proteins in the cytoplasm. Since the first report confirming acetylation of the tumor suppressor protein p53 by a lysine acetyltransferase (KAT, there has been a surge in the identification of new, non-histone targets of KATs. Added to the known substrates of KATs are metabolic enzymes, cytoskeletal proteins, molecular chaperones, ribosomal proteins and nuclear import factors. Emerging studies demonstrate that no fewer than 2000 proteins in any particular cell type may undergo lysine acetylation. As described in this review, our analyses of cellular acetylated proteins using DAVID 6.7 bioinformatics resources have facilitated organization of acetylated proteins into functional clusters integral to cell signaling, the stress response, proteolysis, apoptosis, metabolism, and neuronal development. In addition, these clusters also depict association of acetylated proteins with human diseases. These findings not only support lysine acetylation as a widespread cellular phenomenon, but also impel questions to clarify the underlying molecular and cellular mechanisms governing target selectivity by KATs. Present challenges are to understand the molecular basis for the overlapping roles of KAT-containing co-activators, to differentiate between global versus dynamic acetylation marks, and to elucidate the physiological roles of acetylated proteins in biochemical pathways. In addition to discussing the cellular 'acetylome', a focus of this work is to present the widespread and dynamic nature of lysine acetylation and highlight the nexus that exists between epigenetic-directed transcriptional regulation and metabolism.

  8. Reduced Wall Acetylation Proteins Play Vital and Distinct Roles in Cell Wall O-Acetylation in Arabidopsis

    DEFF Research Database (Denmark)

    Manabe, Yuzuki; Verhertbruggen, Yves; Gille, Sascha;

    2013-01-01

    . The quadruple rwa mutant can be completely complemented with the RWA2 protein expressed under 35S promoter, indicating the functional redundancy of the RWA proteins. Nevertheless, the degree of acetylation of xylan, (gluco) mannan, and xyloglucan as well as overall cell wall acetylation is affected differently...

  9. Development and validation of HPLC method for the resolution of drug intermediates: DL-3-Phenyllactic acid, DL-O-acetyl-3-phenyllactic acid and (+/-)-mexiletine acetamide enantiomers.

    Science.gov (United States)

    Tekewe, Alemu; Singh, Sawraj; Singh, Manpreet; Mohan, Utpal; Banerjee, U C

    2008-03-15

    Sensitive and specific, high-performance liquid chromatography (HPLC) methods have been developed and validated for linearity, accuracy and precision for the quantification of dl-3-phenyllactic acid, dl-O-acetyl-3-phenyllactic acid and (+/-)-mexiletine acetamide enantiomers. Chromatographic separations were performed on a Chiralcel OJ-H column (0.46 mm x 250 mm, 5 microm, Daicel Chemical Industries, Japan) based on cellulose tris-(4-methyl benzoate) chiral stationary phase. The mobile phase consists of hexane and isopropanol (IPA) in the ratio of 90:10 containing 0.1% trifluoroacetic acid (in case of dl-3-phenyllactic acid and dl-O-acetyl-3-phenyllactic acid) and hexane and IPA (95:5) containing 0.1% triethylamine (in case of (+/-)-mexiletine acetamide) and the flow rate was set at 0.5 ml/min at 25 degrees C. The detection was carried out at 261 nm for dl-3-phenyllactic acid and dl-O-acetyl-3-phenyllactic acid and at 254 nm for (+/-)-mexiletine acetamide. The developed methods were utilized for monitoring the progress of lipase catalyzed enantioselective synthesis of O-acetyl-3-phenyllactic acid and mexiletine acetamide from dl-3-phenyllactic acid and (+/-)-mexiletine, respectively. PMID:18371874

  10. Olefin metathesis and side reactions with the binary systems of WCl/sub 6/ and metal alkyls. [Bu/sub 4/Sn, Et/sub 2/Zn, Et/sub 3/Al, BuLi co-catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ichikawa, K.; Watanabe, O.; Takagi, T.; Fukuzumi, K.

    1976-09-01

    The comparison of the behaviors of the WCl/sub 6/-metal alkyl systems (metal alkyls are Bu/sub 4/Sn, Et/sub 2/Zn, Et/sub 3/Al, and BuLi) was carried out in the metathesis of 2-heptene in benzene. The WCl/sub 6/--Et/sub 2/Zn and the WCl/sub 6/--BuLi systems showed the sharp dependence of metathesis on the co-catalyst/WCl/sub 6/ ratio. The yield of the Friedel--Crafts products, heptylbenzenes, increased with a decrease in the co-catalyst/WCl/sub 6/ and the olefin/WCl/sub 6/ ratios, though the WCl/sub 6/--BuLi system barely catalyzed this side reaction. A proper amount of dicyclopentadiene, phenylacetylene, ethyl ether, ethanol, and esters repressed the Friedel--Crafts reaction, and the metathesis products were obtained in high yield and high selectivity in the metathesis of 2-heptene catalyzed by the WCl/sub 6/--Bu/sub 4/Sn system.

  11. Gold-Catalyzed Synthesis of Heterocycles

    Science.gov (United States)

    Arcadi, Antonio

    2014-04-01

    The following sections are included: * Introduction * Synthesis of Heterocycles via Gold-Catalyzed Heteroatom Addition to Unsaturated C-C Bonds * Synthesis of Heterocyclic Derivatives through Gold-Catalyzed Cyclization of Polyunsaturated Compounds * Synthesis of Heterocyclic Compounds via α-Oxo Gold Carbenoid * Synthesis of Heterocyclic Derivatives through Gold-Catalyzed Cycloaddition Reactions * Synthesis of Heterocyclic Derivatives through Gold-Catalyzed Activation of Carbonyl Groups and Alcohols * Synthesis of Heterocyclic Compounds through Gold-Mediated C-H Bond Functionalization * Gold-Catalyzed Domino Cyclization/Oxidative Coupling Reactions * Conclusions * References

  12. Partially Acetylated Sugarcane Bagasse For Wicking Oil From Contaminated Wetlands

    Science.gov (United States)

    Sugarcane bagasse was partially acetylated to enhance its oil-wicking ability in saturated environments while holding moisture for hydrocarbon biodegradation. The water sorption capacity of raw bagasse was reduced fourfold after treatment, which indicated considerably increased ...

  13. Phosphorylation and Acetylation of Acyl-CoA Synthetase- I

    DEFF Research Database (Denmark)

    Frahm, Jennifer L; Li, Lei O; Grevengoed, Trisha J;

    2011-01-01

    -translational regulation. In order to investigate the post-translational modifications of ACSL1 under different physiological conditions, we overexpressed ACSL1 in hepatocytes, brown adipocytes, and 3T3-L1 differentiated adipocytes, treated these cells with different hormones, and analyzed the resulting phosphorylated...... and acetylated amino acids by mass spectrometry. We then compared these results to the post-translational modifications observed in vivo in liver and brown adipose tissue after mice were fasted or exposed to a cold environment. We identified universal N-terminal acetylation, 15 acetylated lysines, and 25......-directed mutagenesis was used to introduce mutations at three potential acetylation and phosphorylation sites believed to be important for ACSL1 function. At the ATP/AMP binding site and at a highly conserved site near the C terminus, modifications of Ser278 or Lys676, respectively, totally inhibited ACSL1 activity...

  14. Iodine-catalyzed coal liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, J.T.; Duffield, J.E.; Davidson, M.G. (Amoco Oil Company, Naperville, IL (USA). Research and Development Dept.)

    Coals of two different ranks were liquefied in high yields using catalytic quantities of elemental iodine or iodine compounds. Iodine monochloride was found to be especially effective for enhancing both coal conversion and product quality. It appears that enhancement in coal conversion is due to the unique ability of iodine to catalyze radical-induced bond scission and hydrogen addition to the coal macromolecule or coal-derived free radicals. The starting iodine can be fully accounted for in the reaction products as both organic-bound and water-soluble forms. Unconverted coal and the heavy product fractions contain the majority of the organic-bound iodine. The results of iodine-catalyzed coal reactions emphasize the need for efficient hydrogen atom transfer along with bond scission to achieve high conversion and product quality. 22 refs., 12 tabs.

  15. Function-structure relationships of acetylated pea starches

    OpenAIRE

    J. Huang

    2006-01-01

    Cowpea, chickpea and yellow pea starches were studied and the results showed that their properties were strongly related to the chemical fine structures of the starches. Furthermore, granular starches were modified using two types of chemical acetylation reagents and then separated into different size fractions. The amount of introduced acetyl groups was found to depend on the size of the granules for the reaction with rapidly reacting reagent acetic acid anhydride, whereas the amount of intr...

  16. The growing landscape of lysine acetylation links metabolism and cell signalling

    DEFF Research Database (Denmark)

    Choudhary, Chuna Ram; Weinert, Brian Tate; Nishida, Yuya;

    2014-01-01

    Lysine acetylation is a conserved protein post-translational modification that links acetyl-coenzyme A metabolism and cellular signalling. Recent advances in the identification and quantification of lysine acetylation by mass spectrometry have increased our understanding of lysine acetylation, im...

  17. Oil spill sorption using raw and acetylated sugarcane bagasse

    Institute of Scientific and Technical Information of China (English)

    Reza Behnood; Bagher Anvaripour; Nematollah Jaafarzadeh; Masoome Farasati

    2016-01-01

    In the recent decades oil spills in the aquatic environments are one of the major sources of environmental pollutions, which are steadily growing with the increase in oil consumption. Adsorption is a rapid and cost effective processto minimize the environmental impacts of oil spills andcleanup these pollutants. In this work, the crude oil sorption capacity was examined with raw sugarcane bagasse and acetylated sugarcane bagasse. Results show that the acetylated bagasse was significantly more oleophilic than the raw bagasse and acetylation reaction can increase bagasse oil sorption ability by about 90%. The maximum sorption capacities of acetylated bagasse were obtained about 11.3 g and 9.1 g in dry system (crude oil sorption) and oil layer sorption, respectively. The physicochemical characteristics of the sorbents such as composition, water solubility, moisture content and density were measured according to ASTM standard methods. Also Fourier transform infrared spectroscopy (FTIR) of raw and acetylated bagasse was performed to investigate the effect of acetylation on sugarcane bagasse structure.

  18. Site-specific acetylation of ISWI by GCN5

    Directory of Open Access Journals (Sweden)

    Chioda Mariacristina

    2007-08-01

    Full Text Available Abstract Background The tight organisation of eukaryotic genomes as chromatin hinders the interaction of many DNA-binding regulators. The local accessibility of DNA is regulated by many chromatin modifying enzymes, among them the nucleosome remodelling factors. These enzymes couple the hydrolysis of ATP to disruption of histone-DNA interactions, which may lead to partial or complete disassembly of nucleosomes or their sliding on DNA. The diversity of nucleosome remodelling factors is reflected by a multitude of ATPase complexes with distinct subunit composition. Results We found further diversification of remodelling factors by posttranslational modification. The histone acetyltransferase GCN5 can acetylate the Drosophila remodelling ATPase ISWI at a single, conserved lysine, K753, in vivo and in vitro. The target sequence is strikingly similar to the N-terminus of histone H3, where the corresponding lysine, H3K14, can also be acetylated by GCN5. The acetylated form of ISWI represents a minor species presumably associated with the nucleosome remodelling factor NURF. Conclusion Acetylation of histone H3 and ISWI by GCN5 is explained by the sequence similarity between the histone and ISWI around the acetylation site. The common motif RKT/SxGx(KacxPR/K differs from the previously suggested GCN5/PCAF recognition motif GKxxP. This raises the possibility of co-regulation of a nucleosome remodelling factor and its nucleosome substrate through acetylation of related epitopes and suggests a direct crosstalk between two distinct nucleosome modification principles.

  19. Acetyl radical generation in cigarette smoke: Quantification and simulations

    Science.gov (United States)

    Hu, Na; Green, Sarah A.

    2014-10-01

    Free radicals are present in cigarette smoke and can have a negative effect on human health. However, little is known about their formation mechanisms. Acetyl radicals were quantified in tobacco smoke and mechanisms for their generation were investigated by computer simulations. Acetyl radicals were trapped from the gas phase using 3-amino-2, 2, 5, 5-tetramethyl-proxyl (3AP) on solid support to form stable 3AP adducts for later analysis by high-performance liquid chromatography (HPLC), mass spectrometry/tandem mass spectrometry (MS-MS/MS) and liquid chromatography-mass spectrometry (LC-MS). Simulations were performed using the Master Chemical Mechanism (MCM). A range of 10-150 nmol/cigarette of acetyl radical was measured from gas phase tobacco smoke of both commercial and research cigarettes under several different smoking conditions. More radicals were detected from the puff smoking method compared to continuous flow sampling. Approximately twice as many acetyl radicals were trapped when a glass fiber particle filter (GF/F specifications) was placed before the trapping zone. Simulations showed that NO/NO2 reacts with isoprene, initiating chain reactions to produce hydroxyl radical, which abstracts hydrogen from acetaldehyde to generate acetyl radical. These mechanisms can account for the full amount of acetyl radical detected experimentally from cigarette smoke. Similar mechanisms may generate radicals in second hand smoke.

  20. Time-resolved luminescence biosensor for continuous activity detection of protein acetylation-related enzymes based on DNA-sensitized terbium(III) probes.

    Science.gov (United States)

    Han, Yitao; Li, Hao; Hu, Yufang; Li, Pei; Wang, Huixia; Nie, Zhou; Yao, Shouzhuo

    2015-09-15

    Protein acetylation of histone is an essential post-translational modification (PTM) mechanism in epigenetic gene regulation, and its status is reversibly controlled by histone acetyltransferases (HATs) and histone deacetylases (HDACs). Herein, we have developed a sensitive and label-free time-resolved luminescence (TRL) biosensor for continuous detection of enzymatic activity of HATs and HDACs, respectively, based on acetylation-mediated peptide/DNA interaction and Tb(3+)/DNA luminescent probes. Using guanine (G)-rich DNA-sensitized Tb(3+) luminescence as the output signal, the polycationic substrate peptides interact with DNA with high affinity and subsequently replace Tb(3+), eliminating the luminescent signal. HAT-catalyzed acetylation remarkably reduces the positive charge of the peptides and diminishes the peptide/DNA interaction, resulting in the signal on detection via recovery of DNA-sensitized Tb(3+) luminescence. With this TRL sensor, HAT (p300) can be sensitively detected with a wide linear range from 0.2 to 100 nM and a low detection limit of 0.05 nM. The proposed sensor was further used to continuously monitor the HAT activity in real time. Additionally, the TRL biosensor was successfully applied to evaluating HAT inhibition by two specific inhibitors, anacardic acid and C464, and satisfactory Z'-factors above 0.73 were obtained. Moreover, this sensor is feasible to continuously monitor the HDAC (Sirt1)-catalyzed deacetylation with a linear range from 0.5 to 500 nM and a detection limit of 0.5 nM. The proposed sensor is a convenient, sensitive, and mix-and-read assay, presenting a promising platform for protein acetylation-targeted epigenetic research and drug discovery. PMID:26307596

  1. Time-resolved luminescence biosensor for continuous activity detection of protein acetylation-related enzymes based on DNA-sensitized terbium(III) probes.

    Science.gov (United States)

    Han, Yitao; Li, Hao; Hu, Yufang; Li, Pei; Wang, Huixia; Nie, Zhou; Yao, Shouzhuo

    2015-09-15

    Protein acetylation of histone is an essential post-translational modification (PTM) mechanism in epigenetic gene regulation, and its status is reversibly controlled by histone acetyltransferases (HATs) and histone deacetylases (HDACs). Herein, we have developed a sensitive and label-free time-resolved luminescence (TRL) biosensor for continuous detection of enzymatic activity of HATs and HDACs, respectively, based on acetylation-mediated peptide/DNA interaction and Tb(3+)/DNA luminescent probes. Using guanine (G)-rich DNA-sensitized Tb(3+) luminescence as the output signal, the polycationic substrate peptides interact with DNA with high affinity and subsequently replace Tb(3+), eliminating the luminescent signal. HAT-catalyzed acetylation remarkably reduces the positive charge of the peptides and diminishes the peptide/DNA interaction, resulting in the signal on detection via recovery of DNA-sensitized Tb(3+) luminescence. With this TRL sensor, HAT (p300) can be sensitively detected with a wide linear range from 0.2 to 100 nM and a low detection limit of 0.05 nM. The proposed sensor was further used to continuously monitor the HAT activity in real time. Additionally, the TRL biosensor was successfully applied to evaluating HAT inhibition by two specific inhibitors, anacardic acid and C464, and satisfactory Z'-factors above 0.73 were obtained. Moreover, this sensor is feasible to continuously monitor the HDAC (Sirt1)-catalyzed deacetylation with a linear range from 0.5 to 500 nM and a detection limit of 0.5 nM. The proposed sensor is a convenient, sensitive, and mix-and-read assay, presenting a promising platform for protein acetylation-targeted epigenetic research and drug discovery.

  2. A dysregulated acetyl/SUMO switch of FXR promotes hepatic inflammation in obesity

    OpenAIRE

    Kim, Dong-Hyun; Xiao, Zhen; Kwon, Sanghoon; Sun, Xiaoxiao; Ryerson, Daniel; Tkac, David; Ma, Ping; Wu, Shwu-Yuan; Chiang, Cheng-Ming; Zhou, Edward; Xu, H. Eric; Palvimo, Jorma J; Chen, Lin-Feng; Kemper, Byron; Kemper, Jongsook Kim

    2014-01-01

    Acetylation of transcriptional regulators is normally dynamically regulated by nutrient status but is often persistently elevated in nutrient-excessive obesity conditions. We investigated the functional consequences of such aberrantly elevated acetylation of the nuclear receptor FXR as a model. Proteomic studies identified K217 as the FXR acetylation site in diet-induced obese mice. In vivo studies utilizing acetylation-mimic and acetylation-defective K217 mutants and gene expression profilin...

  3. Enzymic synthesis of indole-3-acetyl-1-O-beta-d-glucose. I. Partial purification and characterization of the enzyme from Zea mays

    Science.gov (United States)

    Leznicki, A. J.; Bandurski, R. S.

    1988-01-01

    The first enzyme-catalyzed reaction leading from indole-3-acetic acid (IAA) to the myo-inositol esters of IAA is the synthesis of indole-3-acetyl-1-O-beta-D-glucose from uridine-5'-diphosphoglucose (UDPG) and IAA. The reaction is catalyzed by the enzyme, UDPG-indol-3-ylacetyl glucosyl transferase (IAA-glucose-synthase). This work reports methods for the assay of the enzyme and for the extraction and partial purification of the enzyme from kernels of Zea mays sweet corn. The enzyme has an apparent molecular weight of 46,500 an isoelectric point of 5.5, and its pH optimum lies between 7.3 and 7.6. The enzyme is stable to storage at zero degrees but loses activity during column chromatographic procedures which can be restored only fractionally by addition of column eluates. The data suggest either multiple unknown cofactors or conformational changes leading to activity loss.

  4. Thermodynamics of Enzyme-Catalyzed Reactions Database

    Science.gov (United States)

    SRD 74 Thermodynamics of Enzyme-Catalyzed Reactions Database (Web, free access)   The Thermodynamics of Enzyme-Catalyzed Reactions Database contains thermodynamic data on enzyme-catalyzed reactions that have been recently published in the Journal of Physical and Chemical Reference Data (JPCRD). For each reaction the following information is provided: the reference for the data, the reaction studied, the name of the enzyme used and its Enzyme Commission number, the method of measurement, the data and an evaluation thereof.

  5. Stau-catalyzed Nuclear Fusion

    OpenAIRE

    Hamaguchi, K.; Hatsuda, T.(Theoretical Research Division, Nishina Center, RIKEN, Saitama, 351-0198, Japan); Yanagida, T. T.

    2006-01-01

    We point out that the stau may play a role of a catalyst for nuclear fusions if the stau is a long-lived particle as in the scenario of gravitino dark matter. In this letter, we consider d d fusion under the influence of stau where the fusion is enhanced because of a short distance between the two deuterons. We find that one chain of the d d fusion may release an energy of O(10) GeV per stau. We discuss problems of making the stau-catalyzed nuclear fusion of practical use with the present tec...

  6. Gold-catalyzed naphthalene functionalization

    OpenAIRE

    Iván Rivilla; M. Mar Díaz-Requejo; Pedro J. Pérez

    2011-01-01

    The complexes IPrMCl (IPr = 1,3-bis(diisopropylphenyl)imidazol-2-ylidene, M = Cu, 1a; M = Au, 1b), in the presence of one equiv of NaBAr'4 (Ar' = 3,5-bis(trifluoromethyl)phenyl), catalyze the transfer of carbene groups: C(R)CO2Et (R = H, Me) from N2C(R)CO2Et to afford products that depend on the nature of the metal center. The copper-based catalyst yields exclusively a cycloheptatriene derivative from the Buchner reaction, whereas the gold analog affords a mixture of products derived either f...

  7. Monitoring the Hydrolysis of p-Nitrophenyl Acetate Catalyzed by Seryl-histidine with Electrospray Ionization Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    CHEN,Jing(陈晶); ZHANG,Yun(张韵); CAO,Xiao-Yu(曹晓宇); WANG,Jin(王津); CHEN,Yi(陈益); ZHAO,Yu-Fen(赵玉芬)

    2002-01-01

    The hydrolysis of p-nitrophenyl acetate (p-NPA) catalyzed by seryl- histidine or histidine has been monitored by electrospray ionization mass spectrometry in the presence of the internal calibration, 8-anilino-1-naphthalenesulfonic acid ammonium salt (ANS). The half-life of p-NPA in the presence of 10 mmol.L-1 seryl- histidine or histidine at25 ℃ was 370 min and70 min respectively. With the occurrence of acetyl seryl- histidine and acetyl histidine in the reaction, and the fact that p-NPA was stable in the presence of 10 mmol. L- 1 serine, an imidazolysis mechanism has been proposed, which is in accordance with the reported work.

  8. Monitoring the Hydrolysis of p—Nitrophenyl Acetate Catalyzed by Seryl—histidine with Electrospray Ionization Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    陈益; 赵玉芬; 陈晶; 张韵; 曹晓宇; 王津

    2002-01-01

    The hydrolysis of p-nitrophenyl acetate(p-NPA)catalyzed by seryl-histidine or histidine has been monitored by electrospray ionization mass spectrometry in the presence of the internal calibration,8-anilino-1-naphthalenesulfonic acid ammonium salt (ANS).The half-life of p-NPA in the presence of 10 mmol·L-1 seryl-histidine or histidine at 25℃ was 370min and 70min respectively.With the occurrence of acetyl seryl-histidine and acetyl histidine in the reaction,and the fact that p-NPA was stable in the presence of 10mmol·L-1 serine,an imidazolysis mechanism has been proposed,Which is in accordance with the reported work.

  9. Histones of Chlamydomonas reinhardtii. Synthesis, acetylation, and methylation

    International Nuclear Information System (INIS)

    Histones of the green alga Chlamydomonas reinhardtii were prepared by a new method and fractionated by reversed-phase high-performance liquid chromatography. Acid-urea-Triton gel analysis and tritiated acetate labeling demonstrated high levels of steady-state acetylation for the single histone H3 protein, in contrast to low levels on histones H4 and H2B. Twenty percent of histone H3 is subject to dynamic acetylation with, on average, three acetylated lysine residues per protein molecule. Histone synthesis in light-dark-synchronized cultures was biphasic with pattern differences between two histone H1 variants, between two H2A variants, and between H2B and ubiquitinated H2B. Automated protein sequence analysis of histone H3 demonstrated a site-specific pattern of steady-state acetylation between 7 and 17% at five of the six amino-terminal lysines and of monomethylation between 5 and 81% at five of the eight amino-terminal lysines in a pattern that may limit dynamic acetylation. An algal histone H3 sequence was confirmed by protein sequencing with a since threonine as residue 28 instead of the serine(28)-alanine(29) sequence, present in all other known plant and animal H3 histones

  10. Curcumin-induced Histone Acetylation in Malignant Hematologic Cells

    Institute of Scientific and Technical Information of China (English)

    Junbin HU; Yan WANG; Yan CHEN

    2009-01-01

    This study investigated the inhibitory effects of curcumin on proliferation of hemato-logical malignant cells in vitro and the anti-tumor mechanism at histone acetylation/histone deacety-lation levels.The effects of curcumin and histone deacetylase inhibitor trichostatin A (TSA) on the growth of Raji cells were tested by MTT assay.The expression of acetylated histone-3 (H3) in Raji,HL60 and K562 cells,and peripheral blood mononuclear cells (PBMCs) treated with curcumin or TSA was detected by immunohistochemistry and FACS.The results showed curcumin inhibited pro-liferation of Raji cells significantly in a time- and dose-dependent fashion,while exhibited low toxic-ity in PBMCs.Curcumin induced up-regulation of the expression of acetylated H3 dose-dependently in all malignant cell lines tested.In conclusion,curcumin inhibited proliferation of Raji cells selec-tively,enhanced the level of acetylated H3 in Raji,HL60,and K562 cells,which acted as a histone deacetylase inhibitor like TSA.Furthermore,up-regulation of H3 acetylation may play an important role in regulating the proliferation of Raji cells.

  11. Recycling and Reuse of Ionic Liquid in Homogeneous Cellulose Acetylation

    Institute of Scientific and Technical Information of China (English)

    HUANG Kelin; WU Rui; CAO Yan; LI Huiquan; WANG Jinshu

    2013-01-01

    Molecular distillation was used to recover ionic liquid (IL) 1-allyl-3-methylimidazolium chloride (AmimC1) in homogeneous cellulose acetylation.The five factors that affect the separation efficiency of molecular distillation,namely,feed flow rate,distillation temperature,feed temperature,wiper rotating speed,and distillation pressure,are discussed.The optimal recovery condition was determined via orthogonal experiments using an OA9(34) design.The IL was recycled and reused 5 times in the homogeneous cellulose acetylation system under optimal conditions.The purity of recycled IL the 5th time reached 99.56%.FT-IR (Fourier transform infrared spectroscopy) and 1H NMR (nuclear magnetic resonance) spectroscopy showed that the structure of the recovered IL is not changed.This work proves that AmirnCl has excellent reusability,and that molecular distillation is an effective method for recovering IL in homogeneous cellulose acetylation.

  12. H4K44 Acetylation Facilitates Chromatin Accessibility during Meiosis

    Directory of Open Access Journals (Sweden)

    Jialei Hu

    2015-12-01

    Full Text Available Meiotic recombination hotspots are associated with histone post-translational modifications and open chromatin. However, it remains unclear how histone modifications and chromatin structure regulate meiotic recombination. Here, we identify acetylation of histone H4 at Lys44 (H4K44ac occurring on the nucleosomal lateral surface. We show that H4K44 is acetylated at pre-meiosis and meiosis and displays genome-wide enrichment at recombination hotspots in meiosis. Acetylation at H4K44 is required for normal meiotic recombination, normal levels of double-strand breaks (DSBs during meiosis, and optimal sporulation. Non-modifiable H4K44R results in increased nucleosomal occupancy around DSB hotspots. Our results indicate that H4K44ac functions to facilitate chromatin accessibility favorable for normal DSB formation and meiotic recombination.

  13. Structural analysis, plastid localization, and expression of the biotin carboxylase subunit of acetyl-coenzyme A carboxylase from tobacco.

    Science.gov (United States)

    Shorrosh, B S; Roesler, K R; Shintani, D; van de Loo, F J; Ohlrogge, J B

    1995-06-01

    Acetyl-coenzyme A carboxylase (ACCase, EC 6.4.1.2) catalyzes the synthesis of malonyl-coenzyme A, which is utilized in the plastid for de novo fatty acid synthesis and outside the plastid for a variety of reactions, including the synthesis of very long chain fatty acids and flavonoids. Recent evidence for both multifunctional and multisubunit ACCase isozymes in dicot plants has been obtained. We describe here the isolation of a tobacco (Nicotiana tabacum L. cv bright yellow 2 [NT1]) cDNA clone (E3) that encodes a 58.4-kD protein that shares 80% sequence similarity and 65% identity with the Anabaena biotin carboxylase subunit of ACCase. Similar to other biotin carboxylase subunits of acetyl-CoA carboxylase, the E3-encoded protein contains a putative ATP-binding motif but lacks a biotin-binding site (methionine-lysine-methionine or methionine-lysine-leucine). The deduced protein sequence contains a putative transit peptide whose function was confirmed by its ability to direct in vitro chloroplast uptake. The subcellular localization of this biotin carboxylase has also been confirmed to be plastidial by western blot analysis of pea (Pisum sativum), alfalfa (Medicago sativa L.), and castor (Ricinus communis L.) plastid preparations. Northern blot analysis indicates that the plastid biotin carboxylase transcripts are expressed at severalfold higher levels in castor seeds than in leaves. PMID:7610168

  14. Dynamic Histone Acetylation of H3K4me3 Nucleosome Regulates MCL1 Pre-mRNA Splicing.

    Science.gov (United States)

    Khan, Dilshad H; Gonzalez, Carolina; Tailor, Nikesh; Hamedani, Mohammad K; Leygue, Etienne; Davie, James R

    2016-10-01

    Pre-mRNA splicing is a cotranscriptional process affected by the chromatin architecture along the body of coding genes. Recruited to the pre-mRNA by splicing factors, histone deacetylases (HDACs) and K-acetyltransferases (KATs) catalyze dynamic histone acetylation along the gene. In colon carcinoma HCT 116 cells, HDAC inhibition specifically increased KAT2B occupancy as well as H3 and H4 acetylation of the H3K4 trimethylated (H3K4me3) nucleosome positioned over alternative exon 2 of the MCL1 gene, an event paralleled with the exclusion of exon 2. These results were reproduced in MDA-MB-231, but not in MCF7 breast adenocarcinoma cells. These later cells have much higher levels of demethylase KDM5B than either HCT 116 or MDA-MB-231 cells. We show that H3K4me3 steady-state levels and H3K4me3 occupancy at the end of exon 1 and over exon 2 of the MCL1 gene were lower in MCF7 than in MDA-MB-231 cells. Furthermore, in MCF7 cells, there was minimal effect of HDAC inhibition on H3/H4 acetylation and H3K4me3 levels along the MCL1 gene and no change in pre-mRNA splicing choice. These results show that, upon HDAC inhibition, the H3K4me3 mark plays a critical role in the exclusion of exon 2 from the MCL1 pre-mRNA. J. Cell. Physiol. 231: 2196-2204, 2016. © 2016 Wiley Periodicals, Inc. PMID:26864447

  15. Synthesis of polyrotaxanes from acetyl-β-cyclodextrin

    Science.gov (United States)

    Ristić, I. S.; Nikolić, L.; Nikolić, V.; Ilić, D.; Budinski-Simendić, J.

    2011-12-01

    Polyrotaxanes are intermediary products in the synthesis of topological gels. They are created by inclusion complex formation of hydrophobic linear macromolecules with cyclodextrins or their derivatives. Then, pairs of cyclodextrin molecules with covalently linkage were practically forming the nodes of the semi-flexible polymer network. Such gels are called topological gels and they can absorb huge quantities of water due to the net flexibility allowing the poly(ethylene oxide) chains to slide through the cyclodextrin cavities, without being pulled out altogether. For polyrotaxane formation poly(ethylene oxide) was used like linear macromolecules. There are hydroxyl groups at poly(ethylene oxide) chains, whereby the linking of the voluminous molecules should be made. To avoid the reaction of cyclodextrin OH groups with stoppers, they should be protected by, e.g., acetylation. In this work, the acetylation of the OH groups of β-cyclodextrin was performed by acetic acid anhydride with iodine as the catalyst. The acetylation reaction was assessed by the FTIR and HPLC method. By the HPLC analysis was found that the acetylation was completed in 20 minutes. Inserting of poly(ethylene oxide) with 4000 g/mol molecule mass into acetyl-β-cyclodextrin with 2:1 poly(ethylene oxide) monomer unit to acetyl-β-cyclodextrin ratio was also monitored by FTIR, and it was found that the process was completed in 12 h at the temperature of 10°C. If the process is performed at temperatures above 10°C, or for periods longer than 12 hours, the process of uncontrolled hydrolysis of acetate groups was initiated.

  16. Synthesis of 5-alkenylated D4T analogues via the Pd-catalyzed cross-coupling reaction.

    Science.gov (United States)

    Ciurea, A; Fossey, C; Benzaria, S; Gavriliu, D; Delbederi, Z; Lelong, B; Ladurée, D; Aubertin, A M; Kirn, A

    2001-09-01

    The target compounds 5-[N-(6-amino-hexyl)-acrylamide]-2',3'-didehydro-2',3'-dideoxy-uridine (12) and 5-[N-[5-(methoxycarbonyl)-pentyl]-acrylamide]-2',3'-didehydro-2',3'- dideoxy-uridine (15) were prepared by the palladium acetate-triphenylphosphine-catalyzed reaction of the 5'-O-acetyl-5-iodo-d4T analogue (3). These compounds 12 and 15 can be used to prepare nucleotide probes carrying fluorescent labels and were nevertheless screened for their anti-HIV activity. The biological data demonstrated that none of them were active against HIV-1. PMID:11580192

  17. Oxidative 4-dechlorination of polychlorinated phenols is catalyzed by extracellular fungal lignin peroxidases

    International Nuclear Information System (INIS)

    The extracellular lignin peroxidases (ligninases) of Phanerochaete chrysosporium catalyzed H2O2-dependent spectral changes in several environmentally significant polychlorinated phenols: 2,4-dichloro-, 2,4,5-trichloro-, 2,4,6-trichloro-, and pentachlorophenol. Gas chromatography/mass spectrometry of reduced and acetylated reaction products showed that, in each case, lignin peroxidase catalyzed a 4-dechlorination of the starting phenol to yield a p-benzoquinone. The oxidation of 2,4-dichlorophenol also yielded a dechlorinated coupling dimer, tentatively identified as 2-chloro-6-(2,4-dichlorophenoxy)-p-benzoquinone. Experiments on the stoichiometry of 2,4,6-trichlorophenol oxidation showed that this substrate was quantitatively dechlorinated to give the quinone and inorganic chloride. H218O-labeling experiments on 2,4,6-trichlorophenol oxidation demonstrated that water was the source of the new 4-oxo substituent in 2,6-di-chloro-p-benzoquinone. The results indicate a mechanism whereby lignin peroxidase oxidizes a 4-chlorinated phenol to an electrophilic intermediate, perhaps the 4-chlorocyclohexadienone cation. Nucleophilic attack by water and elimination of HCl then ensue at the 4-position, which produces the quinone. Lignin peroxidases have previously been implicated in the degradation by Phanerochaete of several nonphenolic aromatic pollutants. It appears likely from their results that these peroxidases could also catalyze the initial dechlorination of certain polychlorinated phenols in vivo

  18. Study on Reactions of 2-Acetyl-7-methylaminotropone with Pyridinecarboxyaldehydes

    Institute of Scientific and Technical Information of China (English)

    GAO Wen-Tao; ZHENG Zhuo

    2003-01-01

    @@ Cinnamoyl group is a versatile constituent because of bearing active carbonyl group and α, β-unsaturated car bon-carbon double bond. A wide variety of heterocycle-fused troponoid compounds have been derived from cinnamoyl-substituted tropones. For examples, the 3-(4-aryl-3-cyano-2- methoxypyridin-6-yl)tropones were synthesized by the reactions of 2-acetyl-7-methylaminotropone with malononitrile via michael addition and cyclization. [1] There have been some reports about the synthesis of 2-cinnamoyl-7-methylaminotropone, [2,3] herein we further report the synthesis of this kind of compounds by the reactions of 2-acetyl-7-methylaminotropone with pyridinecarboxyaldehydes.

  19. Can laccases catalyze bond cleavage in lignin?

    DEFF Research Database (Denmark)

    Munk, Line; Sitarz, Anna Katarzyna; Kalyani, Dayanand;

    2015-01-01

    illustrations of the putative laccase catalyzed reactions, including the possible reactions of the reactive radical intermediates taking place after the initial oxidation of the phenol-hydroxyl groups, we show that i) Laccase activity is able to catalyze bond cleavage in low molecular weight phenolic lignin...

  20. Lipozyme TL IM as Catalyst for the Synthesis of Eugenyl Acetate in Solvent-Free Acetylation.

    Science.gov (United States)

    Silva, María José A; Loss, Raquel A; Laroque, Denise A; Lerin, Lindomar A; Pereira, Gabriela N; Thon, Élise; Oliveira, J Vladimir; Ninow, Jorge L; Hense, Haiko; Oliveira, Débora

    2015-06-01

    The ability of commercial immobilized lipase from Thermomyces lanuginosus (Lipozyme TL IM) to catalyze the acetylation of essential clove oil with acetic anhydride in a solvent-free system was studied, and the antimicrobial activity of the ester formed was evaluated as well. Experimental design based on two variables (eugenol to acetic anhydride molar ratio and temperature) was employed to evaluate the experimental conditions of eugenyl acetate ester production. The maximum conversion yield (92.86 %) was obtained using Lipozyme TL IM (5 wt%, based on the total amount of substrates), with eugenol to acetic anhydride molar ratio of 1:5 at 70 °C. The chemical structure of the eugenyl acetate ester obtained at the optimized condition, and purified, was confirmed by the proton nuclear magnetic resonance ((1)H-NMR) analysis. The antimicrobial activity of eugenyl acetate ester was proven effective on Gram-positive and Gram-negative bacteria, with means of 16.62 and 17.55 mm of inhibition halo. PMID:25875787

  1. New lysine-acetylated proteins screened by immunoaffinity and liquid chromatography-mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The lack of selective extraction specific for lysine-acetylated proteins has been a major problem in the field of acetylation biology,though acetylation plays a key role in many biological processes.In this paper,we report for the first time the proteomic screening of lysine-acetylated proteins from a mouse liver tissue,by a new approach of immunoaffinity purification of lysine-acetylated peptides combined with nano-HPLC/MS/MS analysis.We have found 20 lysine-acetylated proteins with 21 lysine-acetylated sites,among which 12 lysine-acetylated proteins and 16 lysine-acetylated sites have never been reported before.Notably,three acetyltransferases harboring in mitochondrion are newly discovered acetyltransferases responsible for the acetylation of nonhistone proteins.We have explored the significant patterns of residue preference by the hierarchical clustering analysis of amino acid residues surrounding acetylation sites,which could be helpful to the prediction of new sites of lysine acetylation.Our findings provide more candidates for studying the important roles played by acetylation in diverse cellular pathways and related human diseases.

  2. Gold-catalyzed naphthalene functionalization

    Directory of Open Access Journals (Sweden)

    Iván Rivilla

    2011-05-01

    Full Text Available The complexes IPrMCl (IPr = 1,3-bis(diisopropylphenylimidazol-2-ylidene, M = Cu, 1a; M = Au, 1b, in the presence of one equiv of NaBAr'4 (Ar' = 3,5-bis(trifluoromethylphenyl, catalyze the transfer of carbene groups: C(RCO2Et (R = H, Me from N2C(RCO2Et to afford products that depend on the nature of the metal center. The copper-based catalyst yields exclusively a cycloheptatriene derivative from the Buchner reaction, whereas the gold analog affords a mixture of products derived either from the formal insertion of the carbene unit into the aromatic C–H bond or from its addition to a double bond. In addition, no byproducts derived from carbene coupling were observed.

  3. Catalyzed electrolytic plutonium oxide dissolution

    International Nuclear Information System (INIS)

    Catalyzed electrolytic plutonium oxide dissolution (CEPOD) was first demonstrated at Pacific Northwest Laboratory (PNL) in early 1974 in work funded by the Exxon Corporation. The work, aimed at dissolution of Pu-containing residues remaining after the dissolution of spent mixed-oxide reactor fuels, was first publicly disclosed in 1981. The process dissolves PuO2 in an anolyte containing small (catalytic) amounts of elements that form kinetically fast, strongly oxidizing ions. These are continuously regenerated at the anode. Catalysts used, in their oxidized form, include Ag2+, Ce4+, Co3+, and AmO22+. This paper reviews the chemistry involved in CEPOD and the results of its application to the dissolution of the Pu content of a variety of PuO2-containing materials such as off-standard oxide, fuels dissolution residues, incinerator ash, contaminated soils, and other scraps or wastes. Results are presented for both laboratory-scale and plant-scale dissolves

  4. Hydrogen evolution catalyzed by cobaloximes.

    Science.gov (United States)

    Dempsey, Jillian L; Brunschwig, Bruce S; Winkler, Jay R; Gray, Harry B

    2009-12-21

    Natural photosynthesis uses sunlight to drive the conversion of energy-poor molecules (H(2)O, CO(2)) to energy-rich ones (O(2), (CH(2)O)(n)). Scientists are working hard to develop efficient artificial photosynthetic systems toward the "Holy Grail" of solar-driven water splitting. High on the list of challenges is the discovery of molecules that efficiently catalyze the reduction of protons to H(2). In this Account, we report on one promising class of molecules: cobalt complexes with diglyoxime ligands (cobaloximes). Chemical, electrochemical, and photochemical methods all have been utilized to explore proton reduction catalysis by cobaloxime complexes. Reduction of a Co(II)-diglyoxime generates a Co(I) species that reacts with a proton source to produce a Co(III)-hydride. Then, in a homolytic pathway, two Co(III)-hydrides react in a bimolecular step to eliminate H(2). Alternatively, in a heterolytic pathway, protonation of the Co(III)-hydride produces H(2) and Co(III). A thermodynamic analysis of H(2) evolution pathways sheds new light on the barriers and driving forces of the elementary reaction steps involved in proton reduction by Co(I)-diglyoximes. In combination with experimental results, this analysis shows that the barriers to H(2) evolution along the heterolytic pathway are, in most cases, substantially greater than those of the homolytic route. In particular, a formidable barrier is associated with Co(III)-diglyoxime formation along the heterolytic pathway. Our investigations of cobaloxime-catalyzed H(2) evolution, coupled with the thermodynamic preference for a homolytic route, suggest that the rate-limiting step is associated with formation of the hydride. An efficient water splitting device may require the tethering of catalysts to an electrode surface in a fashion that does not inhibit association of Co(III)-hydrides. PMID:19928840

  5. The cyclic keto-enol insecticide spirotetramat inhibits insect and spider mite acetyl-CoA carboxylases by interfering with the carboxyltransferase partial reaction.

    Science.gov (United States)

    Lümmen, Peter; Khajehali, Jahangir; Luther, Kai; Van Leeuwen, Thomas

    2014-12-01

    Acetyl-CoA carboxylase (ACC) catalyzes the committed and rate-limiting step in fatty acid biosynthesis. The two partial reactions, carboxylation of biotin followed by carboxyl transfer to the acceptor acetyl-CoA, are performed by two separate domains in animal ACCs. The cyclic keto-enol insecticides and acaricides have been proposed to inhibit insect ACCs. In this communication, we show that the enol derivative of the cylic keto-enol insecticide spirotetramat inhibited ACCs partially purified from the insect species Myzus persicae and Spodoptera frugiperda, as well as the spider mite (Tetranychus urticae) ACC which was expressed in insect cells using a recombinant baculovirus. Steady-state kinetic analysis revealed competitive inhibition with respect to the carboxyl acceptor, acetyl-CoA, indicating that spirotetramat-enol bound to the carboxyltransferase domain of ACC. Interestingly, inhibition with respect to the biotin carboxylase substrate ATP was uncompetitive. Amino acid residues in the carboxyltransferase domains of plant ACCs are important for binding of established herbicidal inhibitors. Mutating the spider mite ACC at the homologous positions, for example L1736 to either isoleucine or alanine, and A1739 to either valine or serine, did not affect the inhibition of the spider mite ACC by spirotetramat-enol. These results indicated different binding modes of the keto-enols and the herbicidal chemical families.

  6. Expression of Genes Related to Oxidative Stress in Yeast Treated with Ionizing Radiation and N-acetyl -L-cysteine

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Young; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain)

    2010-10-15

    Ionizing radiation (IR) induces water radiolysis, which generates highly reactive hydroxyl radicals. Reactive oxygen species (ROS) cause apoptosis and cell damage including DNA strand breaks (DSBs), base damage, protein damage and lipid-hydroperoxide. Detoxifying enzymes are immediately triggered for ROS scavenging. Yeast contains two forms of superoxide dismutase (SOD). SOD1 as a cytosolic copper-zinc superoxide dismutase is located in the cytoplasm and cytosol. SOD2 as a manganese containing enzyme is act in mitochondria matrix and mitochondrion. These enzymes scavenge superoxide radicals by catalyzing the conversion of two of these radicals into hydrogen peroxide and molecular oxygen. The hydrogen peroxide formed by superoxide dismutase and by other processes is scavenged by catalase, a ubiquitous heme protein that catalyzes the dismutation of hydrogen peroxide into water and molecular oxygen. Yeast contains two catalases. Catalase A (CTA1) and Cytosolic catalase T (CTT1) is located in peroxisome and cytoplasm, respectively. Yeast has two glutathione (GSH) peroxidases, which are GPX1 and GPX2. GPX1 and GPX2 are component of cellular component and cytoplasm, respectively. The biochemical function of GSH peroxidase is to reduce lipid-hydroperoxides to their corresponding alcohols and to reduce free hydrogen peroxide to water. Otherwise, chemicals and materials help ROS detoxification against oxidative damage. N-acetyl-Lcysteine (NAC) having a thiol, a precursor for glutathione (GSH), is known as one of the antioxidants. In this study, we examined the effect of NAC through gene expressions related to protective enzyme against oxidative stress in yeast

  7. The potential role of wood acetylation in climate change mitigation

    NARCIS (Netherlands)

    Van der Lugt, P.; Vogtländer, J.G.; Alexander, J.; Bongers, F.; Stebbins, H.

    2014-01-01

    In a carbon footprint assessment, the greenhouse gas emissions during the life cycle of a material can be measured, and compared to alternative products in terms of kg CO2 equivalent. If applied correctly, wood acetylation opens up a range of new innovative applications in which high performance yet

  8. Surface effects in the acetylation of granular potato starch

    NARCIS (Netherlands)

    Steeneken, P.A.M.; Woortman, A.J.J.

    2008-01-01

    The occurrence of surface effects in the acetylation of granular potato starch with acetic anhydride to degrees of substitution 0.04-0.2 was studied by two different approaches. The first approach involved the fractionation of granular starch acetates into five different size classes and analysis of

  9. Predicting post-translational lysine acetylation using support vector machines

    DEFF Research Database (Denmark)

    Gnad, Florian; Ren, Shubin; Choudhary, Chunaram;

    2010-01-01

    spectrometry to identify 3600 lysine acetylation sites on 1750 human proteins covering most of the previously annotated sites and providing the most comprehensive acetylome so far. This dataset should provide an excellent source to train support vector machines (SVMs) allowing the high accuracy in silico...

  10. Lysine Ubiquitination and Acetylation of Human Cardiac 20S Proteasomes

    Science.gov (United States)

    Lau, Edward; Choi, Howard JH; Ng, Dominic CM; Meyer, David; Fang, Caiyun; Li, Haomin; Wang, Ding; Zelaya, Ivette M; Yates, John R; Lam, Maggie PY

    2016-01-01

    Purpose Altered proteasome functions are associated with multiple cardiomyopathies. While the proteasome targets poly-ubiquitinated proteins for destruction, it itself is modifiable by ubiquitination. We aim to identify the exact ubiquitination sites on cardiac proteasomes and examine whether they are also subject to acetylations. Experimental design Assembled cardiac 20S proteasome complexes were purified from five human hearts with ischemic cardiomyopathy, then analyzed by high-resolution MS to identify ubiquitination and acetylation sites. We developed a library search strategy that may be used to complement database search in identifying PTM in different samples. Results We identified 63 ubiquitinated lysines from intact human cardiac 20S proteasomes. In parallel, 65 acetylated residues were also discovered, 39 of which shared with ubiquitination sites. Conclusion and clinical relevance This is the most comprehensive characterization of cardiac proteasome ubiquitination to-date. There are significant overlaps between the discovered ubiquitination and acetylation sites, permitting potential crosstalk in regulating proteasome functions. The information presented here will aid future therapeutic strategies aimed at regulating the functions of cardiac proteasomes. PMID:24957502

  11. Function-structure relationships of acetylated pea starches

    NARCIS (Netherlands)

    Huang, J.

    2006-01-01

    Cowpea, chickpea and yellow pea starches were studied and the results showed that their properties were strongly related to the chemical fine structures of the starches. Furthermore, granular starches were modified using two types of chemical acetylation reagents and then separated into different si

  12. File list: His.Prs.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  13. File list: His.Brs.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Brs.20.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Breast... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Brs.20.Pan_lysine_acetylation.AllCell.bed ...

  14. File list: His.ALL.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.ALL.20.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation All c...ell types SRX099890 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.ALL.20.Pan_lysine_acetylation.AllCell.bed ...

  15. File list: His.Bld.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bld.50.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Blood ...http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Bld.50.Pan_lysine_acetylation.AllCell.bed ...

  16. File list: His.Liv.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Liv.20.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Liver ...http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Liv.20.Pan_lysine_acetylation.AllCell.bed ...

  17. File list: His.Emb.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Emb.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Embryo... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Emb.10.Pan_lysine_acetylation.AllCell.bed ...

  18. File list: His.Gon.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Gon.50.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Gonad... http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Gon.50.Pan_lysine_acetylation.AllCell.bed ...

  19. File list: His.Unc.05.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Unc.05.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Unclas...sified http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Unc.05.Pan_lysine_acetylation.AllCell.bed ...

  20. File list: His.Utr.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Utr.20.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Uterus... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Utr.20.Pan_lysine_acetylation.AllCell.bed ...

  1. File list: His.ALL.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.ALL.10.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation All c...ell types SRX099890 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.ALL.10.Pan_lysine_acetylation.AllCell.bed ...

  2. File list: His.Bld.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bld.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Blood ...http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Bld.10.Pan_lysine_acetylation.AllCell.bed ...

  3. File list: His.Bld.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bld.10.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Blood... http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Bld.10.Pan_lysine_acetylation.AllCell.bed ...

  4. File list: His.PSC.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.PSC.50.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Pluri...potent stem cell http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.PSC.50.Pan_lysine_acetylation.AllCell.bed ...

  5. File list: His.PSC.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.PSC.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Plurip...otent stem cell http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.PSC.10.Pan_lysine_acetylation.AllCell.bed ...

  6. File list: His.Adp.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adp.50.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Adipo...cyte http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Adp.50.Pan_lysine_acetylation.AllCell.bed ...

  7. File list: His.Prs.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Prs.50.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Prosta...te http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Prs.50.Pan_lysine_acetylation.AllCell.bed ...

  8. File list: His.Neu.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Neu.50.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Neural... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.50.Pan_lysine_acetylation.AllCell.bed ...

  9. File list: His.CDV.05.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.CDV.05.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Cardi...ovascular http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.CDV.05.Pan_lysine_acetylation.AllCell.bed ...

  10. File list: His.Gon.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Gon.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Gonad ...SRX099893,SRX099896 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Gon.10.Pan_lysine_acetylation.AllCell.bed ...

  11. File list: His.Bon.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bon.20.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Bone ...http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Bon.20.Pan_lysine_acetylation.AllCell.bed ...

  12. File list: His.Dig.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Dig.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Digest...ive tract http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Dig.10.Pan_lysine_acetylation.AllCell.bed ...

  13. File list: His.Bld.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bld.20.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Blood... http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Bld.20.Pan_lysine_acetylation.AllCell.bed ...

  14. File list: His.Unc.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Unc.50.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Uncla...ssified http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Unc.50.Pan_lysine_acetylation.AllCell.bed ...

  15. File list: His.Utr.05.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Utr.05.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Uteru...s http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Utr.05.Pan_lysine_acetylation.AllCell.bed ...

  16. File list: His.Liv.05.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Liv.05.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Liver ...http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Liv.05.Pan_lysine_acetylation.AllCell.bed ...

  17. File list: His.Dig.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Dig.20.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Diges...tive tract http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Dig.20.Pan_lysine_acetylation.AllCell.bed ...

  18. File list: His.ALL.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.ALL.50.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation All ce...ll types SRX099893,SRX099896 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.ALL.50.Pan_lysine_acetylation.AllCell.bed ...

  19. File list: His.Lng.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lng.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Lung h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Lng.10.Pan_lysine_acetylation.AllCell.bed ...

  20. File list: His.Liv.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Liv.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Liver ...http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Liv.10.Pan_lysine_acetylation.AllCell.bed ...

  1. File list: His.Bld.05.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bld.05.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Blood ...http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Bld.05.Pan_lysine_acetylation.AllCell.bed ...

  2. File list: His.Bld.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bld.20.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Blood ...http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Bld.20.Pan_lysine_acetylation.AllCell.bed ...

  3. File list: His.Pan.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Pan.10.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Pancr...eas http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Pan.10.Pan_lysine_acetylation.AllCell.bed ...

  4. File list: His.Epd.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Epd.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Epider...mis http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Epd.10.Pan_lysine_acetylation.AllCell.bed ...

  5. File list: His.Pan.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Pan.50.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Pancr...eas http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Pan.50.Pan_lysine_acetylation.AllCell.bed ...

  6. File list: His.Oth.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Oth.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Others... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Oth.10.Pan_lysine_acetylation.AllCell.bed ...

  7. File list: His.PSC.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.PSC.50.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Plurip...otent stem cell http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.PSC.50.Pan_lysine_acetylation.AllCell.bed ...

  8. File list: His.Neu.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Neu.10.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Neura...l http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Neu.10.Pan_lysine_acetylation.AllCell.bed ...

  9. File list: His.ALL.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.ALL.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation All ce...ll types SRX099893,SRX099896 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.ALL.10.Pan_lysine_acetylation.AllCell.bed ...

  10. File list: His.Plc.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Plc.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Placen...ta http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Plc.10.Pan_lysine_acetylation.AllCell.bed ...

  11. File list: His.Plc.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Plc.10.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Place...nta http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Plc.10.Pan_lysine_acetylation.AllCell.bed ...

  12. File list: His.Prs.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Prs.10.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Prost...ate http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Prs.10.Pan_lysine_acetylation.AllCell.bed ...

  13. File list: His.Bon.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bon.50.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Bone h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Bon.50.Pan_lysine_acetylation.AllCell.bed ...

  14. File list: His.Oth.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Oth.20.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Others... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Oth.20.Pan_lysine_acetylation.AllCell.bed ...

  15. File list: His.Kid.05.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Kid.05.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Kidney... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Kid.05.Pan_lysine_acetylation.AllCell.bed ...

  16. File list: His.Myo.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Myo.20.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Muscle... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Myo.20.Pan_lysine_acetylation.AllCell.bed ...

  17. File list: His.Lng.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lng.20.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Lung ...SRX099890 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Lng.20.Pan_lysine_acetylation.AllCell.bed ...

  18. File list: His.Pan.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Pan.20.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Pancr...eas http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Pan.20.Pan_lysine_acetylation.AllCell.bed ...

  19. File list: His.Unc.05.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Unc.05.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Uncla...ssified http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Unc.05.Pan_lysine_acetylation.AllCell.bed ...

  20. File list: His.CDV.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.CDV.20.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Cardi...ovascular http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.CDV.20.Pan_lysine_acetylation.AllCell.bed ...

  1. File list: His.Dig.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Dig.50.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Diges...tive tract http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Dig.50.Pan_lysine_acetylation.AllCell.bed ...

  2. File list: His.Unc.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Unc.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Unclas...sified http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Unc.10.Pan_lysine_acetylation.AllCell.bed ...

  3. File list: His.Prs.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Prs.20.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Prost...ate http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Prs.20.Pan_lysine_acetylation.AllCell.bed ...

  4. File list: His.Bon.05.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bon.05.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Bone h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Bon.05.Pan_lysine_acetylation.AllCell.bed ...

  5. File list: His.Adp.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adp.20.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Adipo...cyte http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Adp.20.Pan_lysine_acetylation.AllCell.bed ...

  6. File list: His.Utr.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Utr.10.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Uteru...s http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Utr.10.Pan_lysine_acetylation.AllCell.bed ...

  7. File list: His.Unc.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Unc.10.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Uncla...ssified http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Unc.10.Pan_lysine_acetylation.AllCell.bed ...

  8. File list: His.Oth.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Oth.50.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Others... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Oth.50.Pan_lysine_acetylation.AllCell.bed ...

  9. File list: His.Adp.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adp.20.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Adipoc...yte http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Adp.20.Pan_lysine_acetylation.AllCell.bed ...

  10. File list: His.Gon.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Gon.50.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Gonad ...SRX099893,SRX099896 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Gon.50.Pan_lysine_acetylation.AllCell.bed ...

  11. File list: His.Dig.05.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Dig.05.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Digest...ive tract http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Dig.05.Pan_lysine_acetylation.AllCell.bed ...

  12. File list: His.Adp.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adp.10.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Adipo...cyte http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Adp.10.Pan_lysine_acetylation.AllCell.bed ...

  13. File list: His.Dig.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Dig.10.Pan_lysine_acetylation.AllCell hg19 Histone Pan lysine acetylation Diges...tive tract http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Dig.10.Pan_lysine_acetylation.AllCell.bed ...

  14. File list: His.Neu.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Neu.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Neural... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.10.Pan_lysine_acetylation.AllCell.bed ...

  15. File list: His.Brs.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Brs.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Breast... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Brs.10.Pan_lysine_acetylation.AllCell.bed ...

  16. File list: His.Neu.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Neu.20.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Neural... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.20.Pan_lysine_acetylation.AllCell.bed ...

  17. File list: His.Myo.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Myo.10.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Muscle... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Myo.10.Pan_lysine_acetylation.AllCell.bed ...

  18. File list: His.Lng.05.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lng.05.Pan_lysine_acetylation.AllCell mm9 Histone Pan lysine acetylation Lung h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Lng.05.Pan_lysine_acetylation.AllCell.bed ...

  19. File list: His.CDV.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  5. The Acetyl Group Buffering Action of Carnitine Acetyltransferase Offsets Macronutrient-Induced Lysine Acetylation of Mitochondrial Proteins

    Directory of Open Access Journals (Sweden)

    Michael N. Davies

    2016-01-01

    Full Text Available Lysine acetylation (AcK, a posttranslational modification wherein a two-carbon acetyl group binds covalently to a lysine residue, occurs prominently on mitochondrial proteins and has been linked to metabolic dysfunction. An emergent theory suggests mitochondrial AcK occurs via mass action rather than targeted catalysis. To test this hypothesis, we performed mass spectrometry-based acetylproteomic analyses of quadriceps muscles from mice with skeletal muscle-specific deficiency of carnitine acetyltransferase (CrAT, an enzyme that buffers the mitochondrial acetyl-CoA pool by converting short-chain acyl-CoAs to their membrane permeant acylcarnitine counterparts. CrAT deficiency increased tissue acetyl-CoA levels and susceptibility to diet-induced AcK of broad-ranging mitochondrial proteins, coincident with diminished whole body glucose control. Sub-compartment acetylproteome analyses of muscles from obese mice and humans showed remarkable overrepresentation of mitochondrial matrix proteins. These findings reveal roles for CrAT and L-carnitine in modulating the muscle acetylproteome and provide strong experimental evidence favoring the nonenzymatic carbon pressure model of mitochondrial AcK.

  6. N-acetyl-L-glutamate and the urea cycle in gulf toadfish (Opsanus beta) and other fish.

    Science.gov (United States)

    Julsrud, E A; Walsh, P J; Anderson, P M

    1998-02-01

    Carbamoyl phosphate synthetase I (CPSase I) catalyzes the first reaction of the urea cycle in mammalian ureotelic species. The positive allosteric cofactor N-acetyl-L-glutamate (AGA) is required for CPSase I activity and is important for regulation of the urea cycle. A similar enzyme, CPSase III, catalyzes this reaction in fish; CPSase III differs from CPSase I in that it utilizes glutamine as the nitrogen-donating substrate instead of ammonia. AGA also stimulates the CPSase III-catalyzed reaction, but is not absolutely required for activity if the glutamine concentration is high. There has been no report of the presence or function of AGA in fish. Here we report that AGA is present in those species and tissues of fish that have significant levels of CPSase III and urea cycle activity; the levels of AGA were higher in liver of adult gulf toadfish (Opsanus beta) and spiny dogfish shark (Squalus acanthias), both of which have high CPSase III activity, than in bass (Micropterus salmoides) or trout (Oncorhynchus mykiss), which have much lower or no CPSase III activity, respectively. In the toadfish the levels of AGA in liver and muscle tissue were considerably higher in the fed than in the fasting state, as is observed in mammalian species; in liver, but not in muscle, the level of AGA increased when the toadfish were confined (stressed), which has been shown to induce a ureotelic response. Toadfish muscle had CPSase III and ornithine carbamoyltransferase activities; the increase in AGA concentration in muscle when fed suggests that the presence of these first two enzymes of the urea cycle in muscle may be physiologically significant. The results indicate that the fish investigated have physiologically significant levels of AGA and that the levels correlate with parameters related to urea cycle activity. PMID:9466820

  7. Precision Synthesis of Functional Polysaccharide Materials by Phosphorylase-Catalyzed Enzymatic Reactions

    Directory of Open Access Journals (Sweden)

    Jun-ichi Kadokawa

    2016-04-01

    Full Text Available In this review article, the precise synthesis of functional polysaccharide materials using phosphorylase-catalyzed enzymatic reactions is presented. This particular enzymatic approach has been identified as a powerful tool in preparing well-defined polysaccharide materials. Phosphorylase is an enzyme that has been employed in the synthesis of pure amylose with a precisely controlled structure. Similarly, using a phosphorylase-catalyzed enzymatic polymerization, the chemoenzymatic synthesis of amylose-grafted heteropolysaccharides containing different main-chain polysaccharide structures (e.g., chitin/chitosan, cellulose, alginate, xanthan gum, and carboxymethyl cellulose was achieved. Amylose-based block, star, and branched polymeric materials have also been prepared using this enzymatic polymerization. Since phosphorylase shows a loose specificity for the recognition of substrates, different sugar residues have been introduced to the non-reducing ends of maltooligosaccharides by phosphorylase-catalyzed glycosylations using analog substrates such as α-d-glucuronic acid and α-d-glucosamine 1-phosphates. By means of such reactions, an amphoteric glycogen and its corresponding hydrogel were successfully prepared. Thermostable phosphorylase was able to tolerate a greater variance in the substrate structures with respect to recognition than potato phosphorylase, and as a result, the enzymatic polymerization of α-d-glucosamine 1-phosphate to produce a chitosan stereoisomer was carried out using this enzyme catalyst, which was then subsequently converted to the chitin stereoisomer by N-acetylation. Amylose supramolecular inclusion complexes with polymeric guests were obtained when the phosphorylase-catalyzed enzymatic polymerization was conducted in the presence of the guest polymers. Since the structure of this polymeric system is similar to the way that a plant vine twines around a rod, this polymerization system has been named

  8. Histone H3 acetylation in the postmortem Parkinson's disease primary motor cortex.

    Science.gov (United States)

    Gebremedhin, Kibrom G; Rademacher, David J

    2016-08-01

    Although the role of epigenetics in Parkinson's disease (PD) has not been extensively studied, α-synuclein, the main component of Lewy bodies, decreased histone H3 acetylation. Here, we determined if there were histone acetylation changes in the primary motor cortex which, according to the Braak model, is one of the last brain regions affected in PD. Net histone H3 acetylation, histone H3 lysine 9 (H3K9), histone H3 lysine 14 (H3K14), histone H3 lysine 18 (H3K18), and histone H3 lysine 23 (H3K23) acetylation was assessed in the primary motor cortex of those affected and unaffected by PD. There was net increase in histone H3 acetylation due to increased H3K14 and H3K18 acetylation. There was a decrease in H3K9 acetylation. No between-groups difference was detected in H3K23 acetylation. Relationships between Unified Lewy Body Staging scores and histone H3 acetylation and substantia nigra depigmentation scores and histone H3 acetylation were observed. No relationships were detected between postmortem interval and histone H3 acetylation and expired age and histone H3 acetylation. These correlational data support the notion that the histone H3 acetylation changes observed here are not due to the postmortem interval or aging. Instead, they are due to PD and/or factors that covary with PD. The data suggest enhanced gene transcription in the primary motor cortex of the PD brain due to increase H3K14 and H3K18 acetylation. This effect is partially offset by a decreased H3K9 acetylation, which might repress gene transcription. PMID:27241718

  9. Recent advances in the ruthenium-catalyzed hydroarylation of alkynes with aromatics: synthesis of trisubstituted alkenes.

    Science.gov (United States)

    Manikandan, Rajendran; Jeganmohan, Masilamani

    2015-11-14

    The hydroarylation of alkynes with substituted aromatics in the presence of a metal catalyst via chelation-assisted C-H bond activation is a powerful method to synthesize trisubstituted alkenes. Chelation-assisted C-H bond activation can be done by two ways: (a) an oxidative addition pathway and (b) a deprotonation pathway. Generally, a mixture of cis and trans stereoisomeric as well as regioisomeric trisubstituted alkenes was observed in an oxidative addition pathway. In the deprotonation pathway, the hydroarylation reaction can be done in a highly regio- and stereoselective manner, and enables preparation of the expected trisubstituted alkenes in a highly selective manner. Generally, ruthenium, rhodium and cobalt complexes are used as catalysts in the reaction. In this review, a ruthenium-catalyzed hydroarylation of alkynes with substituted aromatics is covered completely. The hydroarylation reaction of alkynes with amide, azole, carbamate, phosphine oxide, amine, acetyl, sulfoxide and sulphur directed aromatics is discussed.

  10. Lipase-Catalyzed Kinetic Resolution of Novel Antifungal N-Substituted Benzimidazole Derivatives.

    Science.gov (United States)

    Łukowska-Chojnacka, Edyta; Staniszewska, Monika; Bondaryk, Małgorzata; Maurin, Jan K; Bretner, Maria

    2016-04-01

    A series of new N-substituted benzimidazole derivatives was synthesized and their antifungal activity against Candida albicans was evaluated. The chemical step included synthesis of appropriate ketones containing benzimidazole ring, reduction of ketones to the racemic alcohols, and acetylation of alcohols to the esters. All benzimidazole derivatives were obtained with satisfactory yields and in relatively short times. All synthesized compounds exhibit significant antifungal activity against Candida albicans 900028 ATCC (% cell inhibition at 0.25 μg concentration > 98%). Additionally, racemic mixtures of alcohols were separated by lipase-catalyzed kinetic resolution. In the enzymatic step a transesterification reaction was applied and the influence of a lipase type and solvent on the enantioselectivity of the reaction was studied. The most selective enzymes were Novozyme SP 435 and lipase Amano AK from Pseudomonas fluorescens (E > 100). PMID:26922853

  11. Mixing Up the Pieces of the Desferrioxamine B Jigsaw Defines the Biosynthetic Sequence Catalyzed by DesD.

    Science.gov (United States)

    Telfer, Thomas J; Gotsbacher, Michael P; Soe, Cho Zin; Codd, Rachel

    2016-05-20

    Late-stage assembly of the trimeric linear siderophore desferrioxamine B (DFOB) native to Streptomyces pilosus involves two DesD-catalyzed condensation reactions between one N-acetyl-N-hydroxy-1,5-diaminopentane (AHDP) unit and two N-succinyl-N-hydroxy-1,5-diaminopentane (SHDP) units. AHDP and SHDP are products of DesBC-catalyzed reactions of the native diamine substrate 1,5-diaminopentane (DP). The sequence of DesD-catalyzed DFOB biosynthesis was delineated by analyzing the distribution of DFOB analogues and dimeric precursors assembled by S. pilosus in medium containing 1,4-diamino-2(E)-butene (E-DBE). Seven unsaturated DFOB analogues were produced that were partially resolved by liquid chromatography (LC). Mass spectrometry (MS) measurements reported on the combination of E-DBE- and DP-derived substrates in each trimer (uDFOA1 series, 1:2; uDFOA2 series, 2:1; uDFOA3, 3:0). MS/MS fragmentation patterns reported on the absolute position of the substrate derivative at the N-acetylated terminus, the internal region, or the amine terminus of the trimer. The uDFOA1 and uDFOA2 series each comprised three constitutional isomers (binary notation (DP-derived substrate "0," E-DBE-derived substrate "1"); direction, N-acetylated-internal-amine): uDFOA1[001], uDFOA1[010], uDFOA1[100]; and uDFOA2[011], uDFOA2[110], and uDFOA2[101]. E-DBE completely replaced DP in uDFOA3[111]. Relative concentrations of the uDFOA1 series were uDFOA1[001] ≫ uDFOA1[100] > uDFOA1[010] and of the uDFOA2 series, uDFOA2[101] > uDFOA2[011] ≫ uDFOA2[110]. Dimeric compounds assembled from one N-acetylated and one N-succinylated substrate derivative were detected as trimer precursors: dDFX[00-] ≫ udDFX[10-] > udDFX[01-] (d = dimer, vacant position "-"). Relative concentrations of all species were consistent with the biosynthetic sequence: (i) SHDP activation, (ii) condensation with AHDP to form AHDP-SHDP, (iii) SHDP activation, and (iv) condensation with AHDP-SHDP to form DFOB. PMID:27004785

  12. ACETYLATION INCREASES EWS-FLI1 DNA BINDING AND TRANSCRIPTIONAL ACTIVITY

    Directory of Open Access Journals (Sweden)

    Silke eSchlottmann

    2012-09-01

    Full Text Available Ewing Sarcoma (ES is associated with a balanced chromosomal translocation that in most cases leads to the expression of the oncogenic fusion protein and transcription factor EWS-FLI1. EWS-FLI1 has been shown to be crucial for ES cell survival and tumor growth. However, its regulation is still enigmatic. To date, no functionally significant posttranslational modifications of EWS-FLI1 have been shown. Since ES are sensitive to histone deacetylase inhibitors, and these inhibitors are advancing in clinical trials, we sought to identify if EWS-FLI1 is directly acetylated. We convincingly show acetylation of the C-terminal FLI1 (FLI1-CTD domain, which is the DNA binding domain of EWS-FLI1. In vitro acetylation studies showed that acetylated FLI1-CTD has higher DNA binding activity than the non-acetylated protein. Over-expression of PCAF or treatment with histone deacetylase inhibitors (HDI increased the transcriptional activity of EWS-FLI1, when co-expressed in COS7 cells. However, our data that evaluates the acetylation of ful-length EWS-FLI1 remains unclear, despite creating acetylation specific antibodies to four potential acetylation sites. We conclude that EWS-FLI1 may either gain access to chromatin as a result of histone acetylation or undergo regulation by direct acetylation. These data should be considered when patients are treated with HDAC inhibitors. Further investigation of this phenomenon will reveal if this potential acetylation has an impact on tumor response.

  13. N-Acetyltransferase 2 (NAT2) in Tunisian Population: Correlation Between Acetylation Phenotype and Genotype

    International Nuclear Information System (INIS)

    One hundred tuberculous patients were studied during 2004-2005 to determine acetylation phenotype, frequent mutations of NAT2 gene and to compare acetylation phenotype with NAT2 genotype in Tunisian population. Acetylation phenotype was determined by determination of acetylation index. Five mutations of NAT2 gene were evaluated by PCR/RFLP. Results show bimodal distribution of acetylation SA and RA phenotype, 75% and 25% and genotype 56% and 44%, respectively. Ten NAT2 alleles were found, NAT2*4 being the major one. Thirty-two different genotypes were found (9 RA and 23 SA). The major one was NAT2*6 B/NAT2*4. The concordance value was 79%. A good sensibility (98, 2%) of acetylation test for SA detection was found. Thus, acetylation phenotype in SA is predicted with poor error risk. (author)

  14. Histone acetylation dependent energy landscapes in tri-nucleosome revealed by residue-resolved molecular simulations

    Science.gov (United States)

    Chang, Le; Takada, Shoji

    2016-01-01

    Histone tail acetylation is a key epigenetic marker that tends to open chromatin folding and activate transcription. Despite intensive studies, precise roles of individual lysine acetylation in chromatin folding have only been poorly understood. Here, we revealed structural dynamics of tri-nucleosomes with several histone tail acetylation states and analyzed histone tail interactions with DNA by performing molecular simulations at an unprecedentedly high resolution. We found versatile acetylation-dependent landscapes of tri-nucleosome. The H4 and H2A tail acetylation reduced the contact between the first and third nucleosomes mediated by the histone tails. The H3 tail acetylation reduced its interaction with neighboring linker DNAs resulting in increase of the distance between consecutive nucleosomes. Notably, two copies of the same histone in a single nucleosome have markedly asymmetric interactions with DNAs, suggesting specific pattern of nucleosome docking albeit high inherent flexibility. Estimated transcription factor accessibility was significantly high for the H4 tail acetylated structures. PMID:27698366

  15. The potential role of wood acetylation in climate change mitigation

    OpenAIRE

    Van der Lugt, P.; Vogtländer, J.G.; J. Alexander; Bongers, F.; Stebbins, H.

    2014-01-01

    In a carbon footprint assessment, the greenhouse gas emissions during the life cycle of a material can be measured, and compared to alternative products in terms of kg CO2 equivalent. If applied correctly, wood acetylation opens up a range of new innovative applications in which high performance yet carbon intensive non-renewable materials such as metals, plastics and concrete may be replaced by abundantly available nondurable wood species. To better understand the difference in greenhouse ga...

  16. 4-Acetyl-1H-pyrrole-2-carbaldehyde

    Directory of Open Access Journals (Sweden)

    Tao Sun

    2012-10-01

    Full Text Available The title compound, C7H7NO2, was synthesized via a one-pot Vilsmeier–Haack and subsequent Friedel–Crafts reaction. The pyrazole ring makes dihedral angles of 4.50 (9 and 2.06 (8°, respectively, with the aldehyde and acetyl groups. In the crystal, classical N—H...O hydrogen bonds and weak C—H...O interactions assemble the molecules into a chain along the b axis.

  17. Acetylation modification regulates GRP78 secretion in colon cancer cells.

    Science.gov (United States)

    Li, Zongwei; Zhuang, Ming; Zhang, Lichao; Zheng, Xingnan; Yang, Peng; Li, Zhuoyu

    2016-01-01

    High glucose-regulated protein 78 (GRP78) expression contributes to the acquisition of a wide range of phenotypic cancer hallmarks, and the pleiotropic oncogenic functions of GRP78 may result from its diverse subcellular distribution. Interestingly, GRP78 has been reported to be secreted from solid tumour cells, participating in cell-cell communication in the tumour microenvironment. However, the mechanism underlying this secretion remains elusive. Here, we report that GRP78 is secreted from colon cancer cells via exosomes. Histone deacetylase (HDAC) inhibitors blocked GRP78 release by inducing its aggregation in the ER. Mechanistically, HDAC inhibitor treatment suppressed HDAC6 activity and led to increased GRP78 acetylation; acetylated GRP78 then bound to VPS34, a class III phosphoinositide-3 kinase, consequently preventing the sorting of GRP78 into multivesicular bodies (MVBs). Of note, we found that mimicking GRP78 acetylation by substituting the lysine at residue 633, one of the deacetylated sites of HDAC6, with a glutamine resulted in decreased GRP78 secretion and impaired tumour cell growth in vitro. Our study thus reveals a hitherto-unknown mechanism of GRP78 secretion and may also provide implications for the therapeutic use of HDAC inhibitors. PMID:27460191

  18. Acetylation modification regulates GRP78 secretion in colon cancer cells

    Science.gov (United States)

    Li, Zongwei; Zhuang, Ming; Zhang, Lichao; Zheng, Xingnan; Yang, Peng; Li, Zhuoyu

    2016-01-01

    High glucose-regulated protein 78 (GRP78) expression contributes to the acquisition of a wide range of phenotypic cancer hallmarks, and the pleiotropic oncogenic functions of GRP78 may result from its diverse subcellular distribution. Interestingly, GRP78 has been reported to be secreted from solid tumour cells, participating in cell-cell communication in the tumour microenvironment. However, the mechanism underlying this secretion remains elusive. Here, we report that GRP78 is secreted from colon cancer cells via exosomes. Histone deacetylase (HDAC) inhibitors blocked GRP78 release by inducing its aggregation in the ER. Mechanistically, HDAC inhibitor treatment suppressed HDAC6 activity and led to increased GRP78 acetylation; acetylated GRP78 then bound to VPS34, a class III phosphoinositide-3 kinase, consequently preventing the sorting of GRP78 into multivesicular bodies (MVBs). Of note, we found that mimicking GRP78 acetylation by substituting the lysine at residue 633, one of the deacetylated sites of HDAC6, with a glutamine resulted in decreased GRP78 secretion and impaired tumour cell growth in vitro. Our study thus reveals a hitherto-unknown mechanism of GRP78 secretion and may also provide implications for the therapeutic use of HDAC inhibitors. PMID:27460191

  19. Astrocyte Reactivity Following Blast Exposure Involves Aberrant Histone Acetylation

    Science.gov (United States)

    Bailey, Zachary S.; Grinter, Michael B.; VandeVord, Pamela J.

    2016-01-01

    Blast induced neurotrauma (BINT) is a prevalent injury within military and civilian populations. The injury is characterized by persistent inflammation at the cellular level which manifests as a multitude of cognitive and functional impairments. Epigenetic regulation of transcription offers an important control mechanism for gene expression and cellular function which may underlie chronic inflammation and result in neurodegeneration. We hypothesize that altered histone acetylation patterns may be involved in blast induced inflammation and the chronic activation of glial cells. This study aimed to elucidate changes to histone acetylation occurring following injury and the roles these changes may have within the pathology. Sprague Dawley rats were subjected to either a 10 or 17 psi blast overpressure within an Advanced Blast Simulator (ABS). Sham animals underwent the same procedures without blast exposure. Memory impairments were measured using the Novel Object Recognition (NOR) test at 2 and 7 days post-injury. Tissues were collected at 7 days for Western blot and immunohistochemistry (IHC) analysis. Sham animals showed intact memory at each time point. The novel object discrimination decreased significantly between two and 7 days for each injury group (p processes. We have shown aberrant histone acetylation patterns involved in blast induced astrogliosis and cognitive impairments. Further understanding of their role in the injury progression may lead to novel therapeutic targets. PMID:27551260

  20. Selective cleavage enhanced by acetylating the side chain of lysine.

    Science.gov (United States)

    Fu, Leixiaomeng; Chen, Tingting; Xue, Gaiqing; Zu, Lily; Fang, Weihai

    2013-01-01

    Selective cleavage is of great interest in mass spectrometry studies as it can help sequence identification by promoting simple fragmentation pattern of peptides and proteins. In this work, the collision-induced dissociation of peptides containing internal lysine and acetylated lysine residues were studied. The experimental and computational results revealed that multiple fragmentation pathways coexisted when the lysine residue was two amino acid residues away from N-terminal of the peptide. After acetylation of the lysine side-chain, b(n)+ ions were the most abundant primary fragment products and the Lys(Ac)-Gly amide bond became the dominant cleavage site via an oxazolone pathway. Acetylating the side-chain of lysine promoted the selective cleavage of Lys-Xxx amide bond and generated much more information of the peptide backbone sequence. The results re-evaluate the selective cleavage due to the lysine basic side-chain and provide information for studying the post-translational modification of proteins and other bio-molecules containing Lys residues. PMID:23303756

  1. MeIQx-induced DNA adduct formation and mutagenesis in DNA repair deficient CHO cells expressing human CYP1A1 and rapid or slow acetylator NAT2

    Science.gov (United States)

    Bendaly, Jean; Zhao, Shuang; Neale, Jason R.; Metry, Kristin J.; Doll, Mark A.; States, J. Christopher; Pierce, William M.; Hein, David W.

    2007-01-01

    2-Amino-3,8-dimethylimidazo-[4,5-f]quinoxaline (MeIQx) is one of the most potent and abundant mutagens in the western diet. Bioactivation includes N-hydroxylation catalyzed by cytochrome P450s followed by O-acetylation catalyzed by N-acetyltransferase 2 (NAT2). Nucleotide excision repair-deficient chinese hamster ovary (CHO) cells were constructed by stable transfection of human cytochrome P4501A1 (CYP1A1) and a single copy of either NAT2*4 (rapid acetylator) or NAT2*5B (slow acetylator) alleles. CYP1A1 and NAT2 catalytic activities were undetectable in untransfected CHO cell lines. CYP1A1 activity did not differ significantly (p > 0.05) among the CYP1A1-transfected cell lines. Cells transfected with NAT2*4 had significantly higher levels of sulfamethazine N-acetyltransferase (p = 0.0001) and N-hydroxy-MeIQx O-acetyltransferase (p = 0.0093) catalytic activity than cells transfected with NAT2*5B. Only cells transfected with both CYP1A1 and NAT2*4 showed concentration-dependent cytotoxicity and hypoxanthine phosphoribosyl transferase (hprt) mutagenesis following MeIQx treatment. dG-C8-MeIQx was the primary DNA adduct formed and levels were dose-dependent in each cell line and in the order: untransfected < transfected with CYP1A1 < transfected with CYP1A1 & NAT2*5B < transfected with CYP1A1 & NAT2*4. MeIQx DNA adduct levels were significantly higher (p < 0.001) in CYP1A1/NAT2*4 than CYP1A1/NAT2*5B cells at all concentrations of MeIQx tested. MeIQx-induced DNA adduct levels correlated very highly (r2 = 0.88) with MeIQx-induced mutants. These results strongly support extrahepatic activation of MeIQx by CYP1A1 and a robust effect of human NAT2 genetic polymorphism on MeIQx –induced DNA adducts and mutagenesis. The results provide laboratory-based support for epidemiological studies reporting higher frequency of heterocyclic amine-related cancers in rapid NAT2 acetylators. PMID:17627018

  2. PURIFICATION OF L-METHIONINE AND N-ACETYL-D-METHIONINE FROM THE MIXTURE OF ENZYMATICALLY DEACYLATED N-ACETYL-DL-METHIONINE

    Institute of Scientific and Technical Information of China (English)

    YAN Xiaomin; ZHAO Lin; SHAO Jianhui; TAN Xin; SONG Zhengxiao

    2004-01-01

    N-acetyl-D-methionine, NaAc and the remains of N-acetyl-L-methionine dramatically affect the purification of L-methionine when purified from the mixture of enzymatically deacylated N-acetyl-DL-methionine, leading to a low yield conventionally. Here, this paper reports a successful separation and purification of both L-methionine and N-acetyl-D-methionine by an H ion-exchange column. The pH, L-Met concentration and the ratio between the content of sodium cation and the ion-exchange capacity were optimized to obtain the maximum yield. Experimental results indicate that, under the optimized conditions, the yields of L-methionine and N-acetyl-D-methionine can reach as high as 85% and 75%, respectively.

  3. Cell differentiation along multiple pathways accompanied by changes in histone acetylation status.

    Science.gov (United States)

    Legartová, Soňa; Kozubek, Stanislav; Franek, Michal; Zdráhal, Zbyněk; Lochmanová, Gabriela; Martinet, Nadine; Bártová, Eva

    2014-04-01

    Post-translational modification of histones is fundamental to the regulation of basic nuclear processes and subsequent cellular events, including differentiation. In this study, we analyzed acetylated forms of histones H2A, H2B, and H4 during induced differentiation in mouse (mESCs) and human (hESCs) embryonic stem cells and during induced enterocytic differentiation of colon cancer cells in vitro. Endoderm-like differentiation of mESCs induced by retinoic acid and enterocytic differentiation induced by histone deacetylase inhibitor sodium butyrate were accompanied by increased mono-, di-, and tri-acetylation of histone H2B and a pronounced increase in di- and tri-acetylation of histone H4. In enterocytes, mono-acetylation of histone H2A also increased and tetra-acetylation of histone H4 appeared only after induction of this differentiation pathway. During differentiation of hESCs, we observed increased mono-acetylation and decreased tri-acetylation of H2B. Mono-, di-, and tri-acetylation of H4 were reduced, manifested by a significant increase in nonacetylated H4 histones. Levels of acetylated histones increased during induced differentiation in mESCs and during histone deacetylase (HDAC) inhibitor-induced enterocytic differentiation, whereas differentiation of human ESCs was associated with reduced acetylation of histones H2B and H4.

  4. Acetylator genotype-dependent formation of 2-aminofluorene-hemoglobin adducts in rapid and slow acetylator Syrian hamsters congenic at the NAT2 locus.

    Science.gov (United States)

    Feng, Y; Rustan, T D; Ferguson, R J; Doll, M A; Hein, D W

    1994-01-01

    Arylamine-hemoglobin adducts are a valuable dosimeter for assessing arylamine exposures and carcinogenic risk. The effects of age, sex, time-course, dose, and acetylator genotype on levels of 2-aminofluorene-hemoglobin adducts were investigated in homozygous rapid (Bio. 82.73/H-Patr) and slow (Bio. 82.73/H-Pats) acetylator hamsters congenic at the polymorphic (NAT2) acetylator locus. Following administration of a single ip dose of [3H]2-aminofluorene, peak 2-aminofluorene-hemoglobin adduct levels were achieved at 12-18 hr and retained a plateau up to 72 hr postinjection in both rapid and slow acetylator congenic hamsters. 2-Aminofluorene-hemoglobin adduct levels did not differ significantly between young (5-6 weeks) and old (32-49 weeks) hamsters or between male and female hamsters within either acetylator genotype. 2-Aminofluorene-hemoglobin adduct levels increased in a dose-dependent manner (r = 0.95, p = 0.0001) and were consistently higher in slow versus rapid acetylator congenic hamsters in studies of both time-course and dose-effect. The magnitude of the acetylator genotype-dependent difference was a function of dose; 2-aminofluorene-hemoglobin adduct levels were 1.5-fold higher in slow acetylator congenic hamsters following a 60 mg/kg 2-aminofluorene dose (p = 0.0013) but 2-fold higher following a 100 mg/kg 2-aminofluorene dose (p < 0.0001). These results show a specific and significant role for NAT2 acetylator genotype in formation of arylamine-hemoglobin adducts, which may reflect the relationship between acetylator genotype and the incidence of different cancers from arylamine exposures. PMID:8291051

  5. Synthesis of Bioactive Natural Polymethoxyflavones and Their Vinyl Ether Derivatives

    Institute of Scientific and Technical Information of China (English)

    CAI Shuang-lian; LIU Shuang; LIU Li; WANG Qiu-an

    2012-01-01

    Bioactive natural polymethoxyflavones 1-6 and their vinyl ether derivatives 7-15 were synthesized by bromination,aromatic nucleophilic substitution,methylation,benzyl protection,Friedel-Crafts acetylation,aldol condensation,cyclization,DDQ dehydrogenation,regioselective demethylation,debenzylation and O-prenylation or O-farnesylation with resorcinol and appropriate substituted benzaldehydes as starting materials.Among them,compounds 7-15 are new compounds.Natural products 2-4 were firstly total synthesized.The syntheses of compounds 1,5 and 6 were efficiently improved by the new synthetic routes.The structures of all synthetic compounds were confirmed by NMR,IR spectra and MS.

  6. A random sequential mechanism of aminoglycoside acetylation by Mycobacterium tuberculosis Eis protein.

    Directory of Open Access Journals (Sweden)

    Oleg V Tsodikov

    Full Text Available An important cause of bacterial resistance to aminoglycoside antibiotics is the enzymatic acetylation of their amino groups by acetyltransferases, which abolishes their binding to and inhibition of the bacterial ribosome. Enhanced intracellular survival (Eis protein from Mycobacterium tuberculosis (Mt is one of such acetyltransferases, whose upregulation was recently established as a cause of resistance to aminoglycosides in clinical cases of drug-resistant tuberculosis. The mechanism of aminoglycoside acetylation by MtEis is not completely understood. A systematic analysis of steady-state kinetics of acetylation of kanamycin A and neomycin B by Eis as a function of concentrations of these aminoglycosides and the acetyl donor, acetyl coenzyme A, reveals that MtEis employs a random-sequential bisubstrate mechanism of acetylation and yields the values of the kinetic parameters of this mechanism. The implications of these mechanistic properties for the design of inhibitors of Eis and other aminoglycoside acetyltransferases are discussed.

  7. Palladium-Catalyzed Amination of Bromoanthancene

    Institute of Scientific and Technical Information of China (English)

    YU Ming-Xin; CHEN Xiao-Hang; CHENG Chien-Hong

    2003-01-01

    @@ Triarylamines are an important class of compounds, because they have been used as the hole-transport layer in electroluminescent devices. [1] New palladium catalyzed methods to form arylamines have emerged recently from Hartwing and Bucchwald . [2,3] Our group have investigated unusual diboration of allenes catalyzed by palladium complex and organic iodides. [4] Here we will report that arylamines react with bromoanthrancene (or dibromoanthancene) to afford triarylamines in the presence of Ligand-palladium complex. The structures of products were de termined by 1H NMR, 13C NMR, 13C (DEPT), IR and MS (HREI and EI) spectra.

  8. Attractor Explosions and Catalyzed Vacuum Decay

    Energy Technology Data Exchange (ETDEWEB)

    Green, Daniel; Silverstein, Eva; Starr, David

    2006-05-05

    We present a mechanism for catalyzed vacuum bubble production obtained by combining moduli stabilization with a generalized attractor phenomenon in which moduli are sourced by compact objects. This leads straightforwardly to a class of examples in which the Hawking decay process for black holes unveils a bubble of a different vacuum from the ambient one, generalizing the new endpoint for Hawking evaporation discovered recently by Horowitz. Catalyzed vacuum bubble production can occur for both charged and uncharged bodies, including Schwarzschild black holes for which massive particles produced in the Hawking process can trigger vacuum decay. We briefly discuss applications of this process to the population and stability of metastable vacua.

  9. Acetylated starch nanocrystals: Preparation and antitumor drug delivery study.

    Science.gov (United States)

    Xiao, Huaxi; Yang, Tao; Lin, Qinlu; Liu, Gao-Qiang; Zhang, Lin; Yu, Fengxiang; Chen, Yuejiao

    2016-08-01

    In this study, we developed a new nanoparticulate system for acetylated starch nanocrystals (ASN) using broken rice. ASN with different degrees of substitution (DS) of 0.04, 0.08 and 0.14 were prepared using acetic anhydride as acetylating agent through reaction with starch nanocrystals (SN). The resulting ASN were investigated for the capability to load and release doxorubicin hydrochloride (DOX), and the antitumor activities of DOX-loaded SN and DOX-loaded ASN were evaluated as potential drug delivery systems for cancer therapy. Cellular uptake and cytotoxicity of nanocrystals and the DOX-loaded nanocrystals were investigated using fluorescence microscopy and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay. Compared with acetylated starches (AS) and native starches (NS), ASN with DS 0.14 loaded up to 6.07% of DOX with a higher loading efficiency of 91.1% and had steadier drug-release rates. Toxicity analysis using the rat hepatocytes model suggested that ASN was biocompatible and could be used for drug delivery. Furthermore, ASN were taken up by cancer cells in vitro and significantly enhanced the cytotoxicity of DOX against HeLa human cervical carcinoma cells. The IC50 value of DOX-loaded ASN-DS 0.14 was 3.8μg/mL for 24h of treatment, which was significantly lower than that of free DOX (21μg/mL). These results indicate that the prepared ASN using broken rice is a promising vehicle for the controlled delivery of DOX for cancer therapy. PMID:27156696

  10. Acetic Acid Can Catalyze Succinimide Formation from Aspartic Acid Residues by a Concerted Bond Reorganization Mechanism: A Computational Study

    Directory of Open Access Journals (Sweden)

    Ohgi Takahashi

    2015-01-01

    Full Text Available Succinimide formation from aspartic acid (Asp residues is a concern in the formulation of protein drugs. Based on density functional theory calculations using Ace-Asp-Nme (Ace = acetyl, Nme = NHMe as a model compound, we propose the possibility that acetic acid (AA, which is often used in protein drug formulation for mildly acidic buffer solutions, catalyzes the succinimide formation from Asp residues by acting as a proton-transfer mediator. The proposed mechanism comprises two steps: cyclization (intramolecular addition to form a gem-diol tetrahedral intermediate and dehydration of the intermediate. Both steps are catalyzed by an AA molecule, and the first step was predicted to be rate-determining. The cyclization results from a bond formation between the amide nitrogen on the C-terminal side and the side-chain carboxyl carbon, which is part of an extensive bond reorganization (formation and breaking of single bonds and the interchange of single and double bonds occurring concertedly in a cyclic structure formed by the amide NH bond, the AA molecule and the side-chain C=O group and involving a double proton transfer. The second step also involves an AA-mediated bond reorganization. Carboxylic acids other than AA are also expected to catalyze the succinimide formation by a similar mechanism.

  11. Acetyl hexapeptide-3 in a cosmetic formulation acts on skin mechanical properties - clinical study

    OpenAIRE

    Kassandra Azevedo Tadini; Daiane Garcia Mercurio; Patrícia Maria Berardo Gonçalves Maia Campos

    2015-01-01

    abstract Acetyl hexapeptide-3 has been used in anti-aging topical formulations aimed at improving skin appearance. However, few basic studies address its effects on epidermis and dermis, when vehiculated in topical formulations. Thus, the objective of this study was to determine the clinical efficacy of acetyl hexapeptide-3 using biophysical techniques. For this purpose, formulations with and without acetyl hexapeptide-3 were applied to the ventral forearm and the face area of forty female vo...

  12. Core promoter acetylation is not required for high transcription from the phosphoenolpyruvate carboxylase promoter in maize

    Directory of Open Access Journals (Sweden)

    Horst Ina

    2009-12-01

    Full Text Available Abstract Background Acetylation of promoter nucleosomes is tightly correlated and mechanistically linked to gene activity. However, transcription is not necessary for promoter acetylation. It seems, therefore, that external and endogenous stimuli control histone acetylation and by this contribute to gene regulation. Photosynthetic genes in plants are excellent models with which to study the connection between stimuli and chromatin modifications because these genes are strongly expressed and regulated by multiple stimuli that are easily manipulated. We have previously shown that acetylation of specific histone lysine residues on the photosynthetic phosphoenolpyruvate carboxylase (Pepc promoter in maize is controlled by light and is independent of other stimuli or gene activity. Acetylation of upstream promoter regions responds to a set of other stimuli which include the nutrient availability of the plant. Here, we have extended these studies by analysing histone acetylation during the diurnal and circadian rhythm of the plant. Results We show that histone acetylation of individual lysine residues is removed from the core promoter before the end of the illumination period which is an indication that light is not the only factor influencing core promoter acetylation. Deacetylation is accompanied by a decrease in gene activity. Pharmacological inhibition of histone deacetylation is not sufficient to prevent transcriptional repression, indicating that deacetylation is not controlling diurnal gene regulation. Variation of the Pepc promoter activity during the day is controlled by the circadian oscillator as it is maintained under constant illumination for at least 3 days. During this period, light-induced changes in histone acetylation are completely removed from the core promoter, although the light stimulus is continuously applied. However, acetylation of most sites on upstream promoter elements follows the circadian rhythm. Conclusion Our results

  13. Autoimmune regulator is acetylated by transcription coactivator CBP/p300

    Energy Technology Data Exchange (ETDEWEB)

    Saare, Mario, E-mail: mario.saare@ut.ee [Molecular Pathology, Institute of General and Molecular Pathology, University of Tartu, 19th Ravila Str, Tartu (Estonia); Rebane, Ana [Molecular Pathology, Institute of General and Molecular Pathology, University of Tartu, 19th Ravila Str, Tartu (Estonia); SIAF, Swiss Institute of Allergy and Asthma Research, University of Zuerich, Davos (Switzerland); Rajashekar, Balaji; Vilo, Jaak [BIIT, Bioinformatics, Algorithmics and Data Mining group, Institute of Computer Science, University of Tartu, Tartu (Estonia); Peterson, Paert [Molecular Pathology, Institute of General and Molecular Pathology, University of Tartu, 19th Ravila Str, Tartu (Estonia)

    2012-08-15

    The Autoimmune Regulator (AIRE) is a regulator of transcription in the thymic medulla, where it controls the expression of a large set of peripheral-tissue specific genes. AIRE interacts with the transcriptional coactivator and acetyltransferase CBP and synergistically cooperates with it in transcriptional activation. Here, we aimed to study a possible role of AIRE acetylation in the modulation of its activity. We found that AIRE is acetylated in tissue culture cells and this acetylation is enhanced by overexpression of CBP and the CBP paralog p300. The acetylated lysines were located within nuclear localization signal and SAND domain. AIRE with mutations that mimicked acetylated K243 and K253 in the SAND domain had reduced transactivation activity and accumulated into fewer and larger nuclear bodies, whereas mutations that mimicked the unacetylated lysines were functionally similar to wild-type AIRE. Analogously to CBP, p300 localized to AIRE-containing nuclear bodies, however, the overexpression of p300 did not enhance the transcriptional activation of AIRE-regulated genes. Further studies showed that overexpression of p300 stabilized the AIRE protein. Interestingly, gene expression profiling revealed that AIRE, with mutations mimicking K243/K253 acetylation in SAND, was able to activate gene expression, although the affected genes were different and the activation level was lower from those regulated by wild-type AIRE. Our results suggest that the AIRE acetylation can influence the selection of AIRE activated genes. -- Highlights: Black-Right-Pointing-Pointer AIRE is acetylated by the acetyltransferases p300 and CBP. Black-Right-Pointing-Pointer Acetylation occurs between CARD and SAND domains and within the SAND domain. Black-Right-Pointing-Pointer Acetylation increases the size of AIRE nuclear dots. Black-Right-Pointing-Pointer Acetylation increases AIRE protein stability. Black-Right-Pointing-Pointer AIRE acetylation mimic regulates a different set of AIRE

  14. p53 targets simian virus 40 large T antigen for acetylation by CBP.

    Science.gov (United States)

    Poulin, Danielle L; Kung, Andrew L; DeCaprio, James A

    2004-08-01

    Simian virus 40 (SV40) large T antigen (T Ag) interacts with the tumor suppressor p53 and the transcriptional coactivators CBP and p300. Binding of these cellular proteins in a ternary complex has been implicated in T Ag-mediated transformation. It has been suggested that the ability of CBP/p300 to modulate p53 function underlies p53's regulation of cell proliferation and tumorigenesis. In this study, we provide further evidence that CBP activity may be mediated through its synergistic action with p53. We demonstrate that SV40 T Ag is acetylated in vivo in a p53-dependent manner and T Ag acetylation is largely mediated by CBP. The acetylation of T Ag is dependent on its interaction with p53 and on p53's interaction with CBP. We have mapped the site of acetylation on T Ag to the C-terminal lysine residue 697. This acetylation site is conserved between the T antigens of the human polyomaviruses JC and BK, which are also known to interact with p53. We show that both JC and BK T antigens are also acetylated at corresponding sites in vivo. While other proteins are known to be acetylated by CBP/p300, none are known to depend on p53 for acetylation. T Ag acetylation may provide a regulatory mechanism for T Ag binding to a cellular factor or play a role in another aspect of T Ag function. PMID:15254196

  15. Acetylation of cyclin-dependent kinase 5 is mediated by GCN5

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Juhyung; Yun, Nuri; Kim, Chiho [Department of Systems Biology, Yonsei University College of Life Science and Biotechnology, Seoul 120-749 (Korea, Republic of); Song, Min-Young; Park, Kang-Sik [Department of Physiology and Biomedical Science Institute, Kyung Hee University School of Medicine, Seoul 130-701 (Korea, Republic of); Oh, Young J., E-mail: yjoh@yonsei.ac.kr [Department of Systems Biology, Yonsei University College of Life Science and Biotechnology, Seoul 120-749 (Korea, Republic of)

    2014-04-25

    Highlights: • Cyclin-dependent kinase 5 (CDK5) is present as an acetylated form. • CDK5 is acetylated by GCN5. • CDK5’s acetylation site is mapped at Lys33. • Its acetylation may affect CDK5’s kinase activity. - Abstract: Cyclin-dependent kinase 5 (CDK5), a member of atypical serine/threonine cyclin-dependent kinase family, plays a crucial role in pathophysiology of neurodegenerative disorders. Its kinase activity and substrate specificity are regulated by several independent pathways including binding with its activator, phosphorylation and S-nitrosylation. In the present study, we report that acetylation of CDK5 comprises an additional posttranslational modification within the cells. Among many candidates, we confirmed that its acetylation is enhanced by GCN5, a member of the GCN5-related N-acetyl-transferase family of histone acetyltransferase. Co-immunoprecipitation assay and fluorescent localization study indicated that GCN5 physically interacts with CDK5 and they are co-localized at the specific nuclear foci. Furthermore, liquid chromatography in conjunction with a mass spectrometry indicated that CDK5 is acetylated at Lys33 residue of ATP binding domain. Considering this lysine site is conserved among a wide range of species and other related cyclin-dependent kinases, therefore, we speculate that acetylation may alter the kinase activity of CDK5 via affecting efficacy of ATP coordination.

  16. Ionizing radiation induces immediate protein acetylation changes in human cardiac microvascular endothelial cells

    International Nuclear Information System (INIS)

    Reversible lysine acetylation is a highly regulated post-translational protein modification that is known to regulate several signaling pathways. However, little is known about the radiation-induced changes in the acetylome. In this study, we analyzed the acute post-translational acetylation changes in primary human cardiac microvascular endothelial cells 4 h after a gamma radiation dose of 2 Gy. The acetylated peptides were enriched using anti-acetyl conjugated agarose beads. A total of 54 proteins were found to be altered in their acetylation status, 23 of which were deacetylated and 31 acetylated. Pathway analyses showed three protein categories particularly affected by radiation-induced changes in the acetylation status: the proteins involved in the translation process, the proteins of stress response, and mitochondrial proteins. The activation of the canonical and non-canonical Wnt signaling pathways affecting actin cytoskeleton signaling and cell cycle progression was predicted. The protein expression levels of two nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases, sirtuin 1 and sirtuin 3, were significantly but transiently upregulated 4 but not 24 h after irradiation. The status of the p53 protein, a target of sirtuin 1, was found to be rapidly stabilized by acetylation after radiation exposure. These findings indicate that post-translational modification of proteins by acetylation and deacetylation is essentially affecting the radiation response of the endothelium. (author)

  17. Partial acetylation in situ of cellulosic fabric and its resistance to microbial and actinic degradation

    Directory of Open Access Journals (Sweden)

    K. L. Maheshwari

    1963-04-01

    Full Text Available Partial acetylation in situ of cotton fabrics can be achieved satisfactorily when it is carried out using 0.03 percent perchloricacid as the catalyst at a temperature not exceeding 30DegreeC. Increase in concentration of perchloric acid or temperature adversely affects the tensile strength of the fabrics. The acetylation of fabrics confers resistance to leaching. Scouring of the fabric prior to acetylation does not materially influence the extent of substitution of hydroxyl groups by acetyl ones. The acetylating mixture can be repeatedly used but fresh addition of the catalyst is necessary. With increase in the period of acetylation or in the quantity of catalyst, there is a progressive increase in acetic acid yield but the tensile strength of the fabric shows a corresponding decrease. Partial acetylation affords protection against microbial attack when the acetyl content of the acetylated fabrics is 14-15 percent. The treatment does not however afford protection against degradation by artificial light, or sunlight or weathering.

  18. Sirtuin-dependent reversible lysine acetylation of glutamine synthetases reveals an autofeedback loop in nitrogen metabolism.

    Science.gov (United States)

    You, Di; Yin, Bin-Cheng; Li, Zhi-Hai; Zhou, Ying; Yu, Wen-Bang; Zuo, Peng; Ye, Bang-Ce

    2016-06-14

    In cells of all domains of life, reversible lysine acetylation modulates the function of proteins involved in central cellular processes such as metabolism. In this study, we demonstrate that the nitrogen regulator GlnR of the actinomycete Saccharopolyspora erythraea directly regulates transcription of the acuA gene (SACE_5148), which encodes a Gcn5-type lysine acetyltransferase. We found that AcuA acetylates two glutamine synthetases (GlnA1 and GlnA4) and that this lysine acetylation inactivated GlnA4 (GSII) but had no significant effect on GlnA1 (GSI-β) activity under the conditions tested. Instead, acetylation of GlnA1 led to a gain-of-function that modulated its interaction with the GlnR regulator and enhanced GlnR-DNA binding. It was observed that this regulatory function of acetylated GSI-β enzymes is highly conserved across actinomycetes. In turn, GlnR controls the catalytic and regulatory activities (intracellular acetylation levels) of glutamine synthetases at the transcriptional and posttranslational levels, indicating an autofeedback loop that regulates nitrogen metabolism in response to environmental change. Thus, this GlnR-mediated acetylation pathway provides a signaling cascade that acts from nutrient sensing to acetylation of proteins to feedback regulation. This work presents significant new insights at the molecular level into the mechanisms underlying the regulation of protein acetylation and nitrogen metabolism in actinomycetes. PMID:27247389

  19. Synthesis of Andrographolide Glucopyranoside and Selective Cleavage of O-acetyl Groups in Sugar Moiety

    Institute of Scientific and Technical Information of China (English)

    WANG Shao-Min; LIU Hong-Min

    2008-01-01

    Andrographolide glucopyranosides were synthesized from andrographolide and tetra-O-acetyl-β-D-glucopyranosyl bromide via a Koenigs-Knorr reaction and deacetylation with a moderate deacetylation reagent dibutyltin oxide in methanol for the first time.The structures of the andrographolide derivatives were confirmed by IR, NMR,and HRMS.Deprotection of the acetylated andrographolide glucopyranoside with dibutyltin oxide in methanol selectively removed all acetyl groups of the sugar moiety, whereas the acetyl group of the andrographolide part and the base- or acid-sensitive functional groups were retained.

  20. Glutamine Assimilation and Feedback Regulation of L-acetyl-N-glutamate Kinase Activity in Chlorella variabilis NC64A Results in Changes in Arginine Pools.

    Science.gov (United States)

    Minaeva, Ekaterina; Forchhammer, Karl; Ermilova, Elena

    2015-11-01

    Glutamine is a metabolite of central importance in nitrogen metabolism of microorganisms and plants. The Chlorella PII signaling protein controls, in a glutamine-dependent manner, the key enzyme of the ornithine/arginine biosynthesis pathway, N-acetyl-L-glutamate kinase (NAGK) that leads to arginine formation. We provide evidence that glutamine promotes effective growth of C. variabilis strain NC64A. The present study shows that externally supplied glutamine directly influences the internal pool of arginine in NC64A. Glutamine synthetase (GS) catalyzes the ATP-dependent conversion of glutamate and ammonium to glutamine. The results of this study demonstrate that glutamine acts as a negative effector of GS activity. These data emphasize the importance of glutamine-dependent coupling of metabolism and signaling as components of an efficient pathway allowing the maintenance of metabolic homeostasis and sustaining growth of Chlorella.

  1. A Novel One-Pot and One-Step Microwave-Assisted Cyclization-Methylation Reaction of Amino Alcohols and Acetylated Derivatives with Dimethyl Carbonate and TBAC

    Science.gov (United States)

    Ochoa-Terán, Adrián; Guerrero, Leticia; Rivero, Ignacio A.

    2014-01-01

    A simple and efficient microwave-assisted methodology for the synthesis of 4-substituted-3-methyl-1,3-oxazolidin-2-ones from amino alcohols catalyzed by a ionic liquid was developed. This novel one-pot and one-step cyclization-methylation reaction represents an easier and faster method than any other reported protocols that can be used to obtain the desired products in good yields and high purity. Applying microwave irradiation at 130°C in the presence of TBAC, dimethyl carbonate acts simultaneously as carbonylating and methylating agent and surprisingly promotes an in situ basic trans esterification when a N-acetylated amino alcohol is used as starting material. Furthermore, dimethyl carbonate worked better than diethyl carbonate in performing this reaction. PMID:25692177

  2. A novel one-pot and one-step microwave-assisted cyclization-methylation reaction of amino alcohols and acetylated derivatives with dimethyl carbonate and TBAC.

    Science.gov (United States)

    Ochoa-Terán, Adrián; Guerrero, Leticia; Rivero, Ignacio A

    2014-01-01

    A simple and efficient microwave-assisted methodology for the synthesis of 4-substituted-3-methyl-1,3-oxazolidin-2-ones from amino alcohols catalyzed by a ionic liquid was developed. This novel one-pot and one-step cyclization-methylation reaction represents an easier and faster method than any other reported protocols that can be used to obtain the desired products in good yields and high purity. Applying microwave irradiation at 130°C in the presence of TBAC, dimethyl carbonate acts simultaneously as carbonylating and methylating agent and surprisingly promotes an in situ basic trans esterification when a N-acetylated amino alcohol is used as starting material. Furthermore, dimethyl carbonate worked better than diethyl carbonate in performing this reaction. PMID:25692177

  3. Glutamine Assimilation and Feedback Regulation of L-acetyl-N-glutamate Kinase Activity in Chlorella variabilis NC64A Results in Changes in Arginine Pools.

    Science.gov (United States)

    Minaeva, Ekaterina; Forchhammer, Karl; Ermilova, Elena

    2015-11-01

    Glutamine is a metabolite of central importance in nitrogen metabolism of microorganisms and plants. The Chlorella PII signaling protein controls, in a glutamine-dependent manner, the key enzyme of the ornithine/arginine biosynthesis pathway, N-acetyl-L-glutamate kinase (NAGK) that leads to arginine formation. We provide evidence that glutamine promotes effective growth of C. variabilis strain NC64A. The present study shows that externally supplied glutamine directly influences the internal pool of arginine in NC64A. Glutamine synthetase (GS) catalyzes the ATP-dependent conversion of glutamate and ammonium to glutamine. The results of this study demonstrate that glutamine acts as a negative effector of GS activity. These data emphasize the importance of glutamine-dependent coupling of metabolism and signaling as components of an efficient pathway allowing the maintenance of metabolic homeostasis and sustaining growth of Chlorella. PMID:26356535

  4. A Novel One-Pot and One-Step Microwave-Assisted Cyclization-Methylation Reaction of Amino Alcohols and Acetylated Derivatives with Dimethyl Carbonate and TBAC

    Directory of Open Access Journals (Sweden)

    Adrián Ochoa-Terán

    2014-01-01

    Full Text Available A simple and efficient microwave-assisted methodology for the synthesis of 4-substituted-3-methyl-1,3-oxazolidin-2-ones from amino alcohols catalyzed by a ionic liquid was developed. This novel one-pot and one-step cyclization-methylation reaction represents an easier and faster method than any other reported protocols that can be used to obtain the desired products in good yields and high purity. Applying microwave irradiation at 130°C in the presence of TBAC, dimethyl carbonate acts simultaneously as carbonylating and methylating agent and surprisingly promotes an in situ basic trans esterification when a N-acetylated amino alcohol is used as starting material. Furthermore, dimethyl carbonate worked better than diethyl carbonate in performing this reaction.

  5. Sulfation of p-nitrophenyl-N-acetyl-beta-D-galactosaminide with a microsomal fraction from cultured chondrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Habuchi, O.; Conrad, H.E.

    1985-10-25

    Chick embryo chondrocyte microsomes containing intact Golgi vesicles took up 3'-phosphoadenosine-5'-phospho(TVS)sulfate ((TVS)PAPS) in a time- and temperature-dependent, substrate-saturable manner. When (TVS)PAPS and p-nitrophenyl-N-acetyl-beta-D-galactosaminide (pNP-GalNAc) were added to the incubation in the absence of detergent, the microsomes catalyzed the transfer of sulfate from (TVS)PAPS to pNP-GalNAc to form pNP-GalNAc-6-TVSO4. The apparent Km values for PAPS in the uptake and the pNP-GalNAc sulfation reactions were 2 X 10(-7) and 2 X 10(-6) M, respectively. The sulfation of pNP-GalNAc by the microsomal preparation was inhibited by detergent. The microsomal fraction also catalyzed the transfer of sulfate from (TVS)PAPS to oligosaccharides prepared from chondroitin. However, in contrast to the sulfation of pNP-GalNAc, the rate of sulfation of these oligosaccharides was low in the absence of detergent and was markedly stimulated when detergent was added. Sulfation of pNP-GalNAc by the freeze-thawed microsomes was inhibited when the octasaccharide prepared from chondroitin was present in the reaction mixture. As the PAPS that had been internalized in the microsomal vesicles was consumed in the sulfation of pNP-GalNAc, more (TVS)PAPS was taken up and the sulfated pNP-GalNAc was released from the vesicles. These observations suggest that pNP-GalNAc may serve as a model membrane-permeable substrate for study of the 6-sulfo-transferase reaction involved in sulfation of chondroitin sulfate in intact Golgi vesicles.

  6. Meat consumption, N-acetyl transferase 1 and 2 polymorphism and risk of breast cancer, in Danish postmenopausal women

    DEFF Research Database (Denmark)

    Egeberg, Rikke; Olsen, Anja; Autrup, Herman;

    2008-01-01

    total meat intake and red meat intake and breast cancer risk were confined to intermediate/fast N-acetyl transferase 2 acetylators (P-interaction=0.03 and 0.04). Our findings support an association between meat consumption and breast cancer risk and that N-acetyl transferase 2 polymorphism has......The aim of this study was to investigate whether polymorphisms in N-acetyl transferase 1 and 2 modify the association between meat consumption and risk of breast cancer. A nested case-control study was conducted among 24697 postmenopausal women included in the 'Diet, Cancer and Health' cohort study...... increment in intake. Compared with slow acetylators, the IRR (95% confidence interval) among fast N-acetyl transferase 1 acetylators was 1.43 (1.03-1.99) and 1.13 (0.83-1.54) among intermediate/fast N-acetyl transferase 2 acetylators. Interaction analyses revealed that the positive associations between...

  7. Comparative analysis of pharmacological treatments with N-acetyl-dl-leucine (Tanganil) and its two isomers (N-acetyl-L-leucine and N-acetyl-D-leucine) on vestibular compensation: Behavioral investigation in the cat.

    Science.gov (United States)

    Tighilet, Brahim; Leonard, Jacques; Bernard-Demanze, Laurence; Lacour, Michel

    2015-12-15

    Head roll tilt, postural imbalance and spontaneous nystagmus are the main static vestibular deficits observed after an acute unilateral vestibular loss (UVL). In the UVL cat model, these deficits are fully compensated over 6 weeks as the result of central vestibular compensation. N-Acetyl-dl-leucine is a drug prescribed in clinical practice for the symptomatic treatment of acute UVL patients. The present study investigated the effects of N-acetyl-dl-leucine on the behavioral recovery after unilateral vestibular neurectomy (UVN) in the cat, and compared the effects of each of its two isomers N-acetyl-L-leucine and N-acetyl-D-leucine. Efficacy of these three drug treatments has been evaluated with respect to a placebo group (UVN+saline water) on the global sensorimotor activity (observation grids), the posture control (support surface measurement), the locomotor balance (maximum performance at the rotating beam test), and the spontaneous vestibular nystagmus (recorded in the light). Whatever the parameters tested, the behavioral recovery was strongly and significantly accelerated under pharmacological treatments with N-acetyl-dl-leucine and N-acetyl-L-leucine. In contrast, the N-acetyl-D-leucine isomer had no effect at all on the behavioral recovery, and animals of this group showed the same recovery profile as those receiving a placebo. It is concluded that the N-acetyl-L-leucine isomer is the active part of the racemate component since it induces a significant acceleration of the vestibular compensation process similar (and even better) to that observed under treatment with the racemate component only. PMID:26607469

  8. Palladium catalyzed hydrogenation of bio-oils and organic compounds

    Science.gov (United States)

    Elliott, Douglas C.; Hu, Jianli; Hart, Todd R.; Neuenschwander, Gary G.

    2008-09-16

    The invention provides palladium-catalyzed hydrogenations of bio-oils and certain organic compounds. Experimental results have shown unexpected and superior results for palladium-catalyzed hydrogenations of organic compounds typically found in bio-oils.

  9. Enyne Metathesis Catalyzed by Ruthenium Carbene Complexes

    DEFF Research Database (Denmark)

    Poulsen, Carina Storm; Madsen, Robert

    2003-01-01

    Enyne metathesis combines an alkene and an alkyne into a 1,3-diene. The first enyne metathesis reaction catalyzed by a ruthenium carbene complex was reported in 1994. This review covers the advances in this transformation during the last eight years with particular emphasis on methodology...

  10. Palladium Catalyzed Allylic C-H Alkylation

    DEFF Research Database (Denmark)

    Engelin, Casper Junker; Fristrup, Peter

    2011-01-01

    The atom-efficiency of one of the most widely used catalytic reactions for forging C-C bonds, the Tsuji-Trost reaction, is limited by the need of preoxidized reagents. This limitation can be overcome by utilization of the recently discovered palladium-catalyzed C-H activation, the allylic C...

  11. Mechanochemical ruthenium-catalyzed olefin metathesis.

    Science.gov (United States)

    Do, Jean-Louis; Mottillo, Cristina; Tan, Davin; Štrukil, Vjekoslav; Friščić, Tomislav

    2015-02-25

    We describe the development of a mechanochemical approach for Ru-catalyzed olefin metathesis, including cross-metathesis and ring-closing metathesis. The method uses commercially available catalysts to achieve high-yielding, rapid, room-temperature metathesis of solid or liquid olefins on a multigram scale using either no or only a catalytic amount of a liquid.

  12. Data, Leadership, and Catalyzing Culture Change

    Science.gov (United States)

    Benson, R. Todd; Trower, Cathy A.

    2012-01-01

    It is crucial to understand today's tenure-track workers so that colleges and universities can continue to attract and retain a large subset of them by understanding and supporting their satisfaction and success at work. In this article, the authors talk about data, leadership, and catalyzing culture change. They discuss data use in the academy…

  13. Pinacol Coupling Reactions Catalyzed by Active Zinc

    Institute of Scientific and Technical Information of China (English)

    Hui ZHAO; Wei DENG; Qing Xiang GUO

    2005-01-01

    Pinacol coupling reactions catalyzed by active zinc revealed high activity and extensive suitability. The efficiency of the reaction was improved apparently owing to decreasing reductive potential of zinc. In addition, the results indicated that the zinc activity has a direct relation to the coupling reactivity compared to untreated zinc or other general active zinc.

  14. Rhodium-catalyzed restructuring of carbon frameworks.

    Science.gov (United States)

    Murakami, Masahiro

    2010-10-01

    Metal-catalyzed reactions involving an elementary step which cleaves a carbon-carbon bond provide unique organic transformations. Restructuring reactions recently developed in our laboratory, through which the carbon framework of a starting substance is restructured into a totally different carbon framework, are discussed, with the possibility of applying such methods to the synthesis of natural products.

  15. Mechanochemical ruthenium-catalyzed olefin metathesis.

    Science.gov (United States)

    Do, Jean-Louis; Mottillo, Cristina; Tan, Davin; Štrukil, Vjekoslav; Friščić, Tomislav

    2015-02-25

    We describe the development of a mechanochemical approach for Ru-catalyzed olefin metathesis, including cross-metathesis and ring-closing metathesis. The method uses commercially available catalysts to achieve high-yielding, rapid, room-temperature metathesis of solid or liquid olefins on a multigram scale using either no or only a catalytic amount of a liquid. PMID:25668586

  16. Zeolite 5A Catalyzed Etherification of Diphenylmethanol

    Science.gov (United States)

    Cooke, Jason; Henderson, Eric J.; Lightbody, Owen C.

    2009-01-01

    An experiment for the synthetic undergraduate laboratory is described in which zeolite 5A catalyzes the room temperature dehydration of diphenylmethanol, (C[subscript 6]H[subscript 5])[subscript 2]CHOH, producing 1,1,1',1'-tetraphenyldimethyl ether, (C[subscript 6]H[subscript 5])[subscript 2]CHOCH(C[subscript 6]H[subscript 5])[subscript 2]. The…

  17. Biodiesel production by enzyme-catalyzed transesterification

    Directory of Open Access Journals (Sweden)

    Stamenković Olivera S.

    2005-01-01

    Full Text Available The principles and kinetics of biodiesel production from vegetable oils using lipase-catalyzed transesterification are reviewed. The most important operating factors affecting the reaction and the yield of alkyl esters, such as: the type and form of lipase, the type of alcohol, the presence of organic solvents, the content of water in the oil, temperature and the presence of glycerol are discussed. In order to estimate the prospects of lipase-catalyzed transesterification for industrial application, the factors which influence the kinetics of chemically-catalysed transesterification are also considered. The advantages of lipase-catalyzed transesterification compared to the chemically-catalysed reaction, are pointed out. The cost of down-processing and ecological problems are significantly reduced by applying lipases. It was also emphasized that lipase-catalysed transesterification should be greatly improved in order to make it commercially applicable. The further optimization of lipase-catalyzed transesterification should include studies on the development of new reactor systems with immobilized biocatalysts and the addition of alcohol in several portions, and the use of extra cellular lipases tolerant to organic solvents, intracellular lipases (i.e. whole microbial cells and genetically-modified microorganisms ("intelligent" yeasts.

  18. The Metabolic Fate of Deoxynivalenol and Its Acetylated Derivatives in a Wheat Suspension Culture: Identification and Detection of DON-15-O-Glucoside, 15-Acetyl-DON-3-O-Glucoside and 15-Acetyl-DON-3-Sulfate

    Directory of Open Access Journals (Sweden)

    Clemens Schmeitzl

    2015-08-01

    Full Text Available Deoxynivalenol (DON is a protein synthesis inhibitor produced by the Fusarium species, which frequently contaminates grains used for human or animal consumption. We treated a wheat suspension culture with DON or one of its acetylated derivatives, 3-acetyl-DON (3-ADON, 15-acetyl-DON (15-ADON and 3,15-diacetyl-DON (3,15-diADON, and monitored the metabolization over a course of 96 h. Supernatant and cell extract samples were analyzed using a tailored LC-MS/MS method for the quantification of DON metabolites. We report the formation of tentatively identified DON-15-O-β-D-glucoside (D15G and of 15-acetyl-DON-3-sulfate (15-ADON3S as novel deoxynivalenol metabolites in wheat. Furthermore, we found that the recently identified 15-acetyl-DON-3-O-β-D-glucoside (15-ADON3G is the major metabolite produced after 15-ADON challenge. 3-ADON treatment led to a higher intracellular content of toxic metabolites after six hours compared to all other treatments. 3-ADON was exclusively metabolized into DON before phase II reactions occurred. In contrast, we found that 15-ADON was directly converted into 15-ADON3G and 15-ADON3S in addition to metabolization into deoxynivalenol-3-O-β-D-glucoside (D3G. This study highlights significant differences in the metabolization of DON and its acetylated derivatives.

  19. The dynamic organization of fungal acetyl-CoA carboxylase

    Science.gov (United States)

    Hunkeler, Moritz; Stuttfeld, Edward; Hagmann, Anna; Imseng, Stefan; Maier, Timm

    2016-04-01

    Acetyl-CoA carboxylases (ACCs) catalyse the committed step in fatty-acid biosynthesis: the ATP-dependent carboxylation of acetyl-CoA to malonyl-CoA. They are important regulatory hubs for metabolic control and relevant drug targets for the treatment of the metabolic syndrome and cancer. Eukaryotic ACCs are single-chain multienzymes characterized by a large, non-catalytic central domain (CD), whose role in ACC regulation remains poorly characterized. Here we report the crystal structure of the yeast ACC CD, revealing a unique four-domain organization. A regulatory loop, which is phosphorylated at the key functional phosphorylation site of fungal ACC, wedges into a crevice between two domains of CD. Combining the yeast CD structure with intermediate and low-resolution data of larger fragments up to intact ACCs provides a comprehensive characterization of the dynamic fungal ACC architecture. In contrast to related carboxylases, large-scale conformational changes are required for substrate turnover, and are mediated by the CD under phosphorylation control.

  20. Crystal Structure of the Golgi-Associated Human Nα-Acetyltransferase 60 Reveals the Molecular Determinants for Substrate-Specific Acetylation.

    Science.gov (United States)

    Støve, Svein Isungset; Magin, Robert S; Foyn, Håvard; Haug, Bengt Erik; Marmorstein, Ronen; Arnesen, Thomas

    2016-07-01

    N-Terminal acetylation is a common and important protein modification catalyzed by N-terminal acetyltransferases (NATs). Six human NATs (NatA-NatF) contain one catalytic subunit each, Naa10 to Naa60, respectively. In contrast to the ribosome-associated NatA to NatE, NatF/Naa60 specifically associates with Golgi membranes and acetylates transmembrane proteins. To gain insight into the molecular basis for the function of Naa60, we developed an Naa60 bisubstrate CoA-peptide conjugate inhibitor, determined its X-ray structure when bound to CoA and inhibitor, and carried out biochemical experiments. We show that Naa60 adapts an overall fold similar to that of the catalytic subunits of ribosome-associated NATs, but with the addition of two novel elongated loops that play important roles in substrate-specific binding. One of these loops mediates a dimer to monomer transition upon substrate-specific binding. Naa60 employs a catalytic mechanism most similar to Naa50. Collectively, these data reveal the molecular basis for Naa60-specific acetyltransferase activity with implications for its Golgi-specific functions.

  1. Kinetics of aggregation growth with competition between catalyzed birth and catalyzed death

    Institute of Scientific and Technical Information of China (English)

    Wang Hai-Feng; Lin Zhen-Quan; Gao Yan

    2008-01-01

    An aggregation growth model of three species A, B and C with the competition between catalyzed birth and catalyzed death is proposed. Irreversible aggregation occurs between any two aggregates of the like species with the constant rate kernels In(n = 1, 2, 3). Meanwhile, a monomer birth of an A species aggregate of size k occurs under the catalysis of a B species aggregate of size j with the catalyzed birth rate kernel K(k,j) = Kkjv, and a monomer death of an A species aggregate of size k occurs under the catalysis of a C species aggregate of size j with the catalyzed death rate kernel L(k, j) = Lkjv, where v is a parameter reflecting the dependence of the catalysis reaction rates of birth and death on the size of catalyst aggregate. The kinetic evolution behaviours of the three species are investigated by the rate equation approach based on the mean-field theory. The form of the aggregate size distribution of A species ak(t) is found to be dependent crucially on the competition between the catalyzed birth and death of A species, as well as the irreversible aggregation processes of the three species: (1) In the v < 0 case, the irreversible aggregation dominates the process, and ak(t) satisfies the conventional scaling form; (2) In the v ≥ 0 case, the competition between the catalyzed birth and death dominates the process. When the catalyzed birth controls the process, ak(t) takes the conventional or generalized scaling form. While the catalyzed death controls the process, the scaling description of the aggregate size distribution breaks down completely.

  2. Changes in acetyl CoA levels during the early embryonic development of Xenopus laevis.

    Science.gov (United States)

    Tsuchiya, Yugo; Pham, Uyen; Hu, Wanzhou; Ohnuma, Shin-Ichi; Gout, Ivan

    2014-01-01

    Coenzyme A (CoA) is a ubiquitous and fundamental intracellular cofactor. CoA acts as a carrier of metabolically important carboxylic acids in the form of CoA thioesters and is an obligatory component of a multitude of catabolic and anabolic reactions. Acetyl CoA is a CoA thioester derived from catabolism of all major carbon fuels. This metabolite is at a metabolic crossroads, either being further metabolised as an energy source or used as a building block for biosynthesis of lipids and cholesterol. In addition, acetyl CoA serves as the acetyl donor in protein acetylation reactions, linking metabolism to protein post-translational modifications. Recent studies in yeast and cultured mammalian cells have suggested that the intracellular level of acetyl CoA may play a role in the regulation of cell growth, proliferation and apoptosis, by affecting protein acetylation reactions. Yet, how the levels of this metabolite change in vivo during the development of a vertebrate is not known. We measured levels of acetyl CoA, free CoA and total short chain CoA esters during the early embryonic development of Xenopus laevis using HPLC. Acetyl CoA and total short chain CoA esters start to increase around midblastula transition (MBT) and continue to increase through stages of gastrulation, neurulation and early organogenesis. Pre-MBT embryos contain more free CoA relative to acetyl CoA but there is a shift in the ratio of acetyl CoA to CoA after MBT, suggesting a metabolic transition that results in net accumulation of acetyl CoA. At the whole-embryo level, there is an apparent correlation between the levels of acetyl CoA and levels of acetylation of a number of proteins including histones H3 and H2B. This suggests the level of acetyl CoA may be a factor, which determines the degree of acetylation of these proteins, hence may play a role in the regulation of embryogenesis. PMID:24831956

  3. Changes in acetyl CoA levels during the early embryonic development of Xenopus laevis.

    Directory of Open Access Journals (Sweden)

    Yugo Tsuchiya

    Full Text Available Coenzyme A (CoA is a ubiquitous and fundamental intracellular cofactor. CoA acts as a carrier of metabolically important carboxylic acids in the form of CoA thioesters and is an obligatory component of a multitude of catabolic and anabolic reactions. Acetyl CoA is a CoA thioester derived from catabolism of all major carbon fuels. This metabolite is at a metabolic crossroads, either being further metabolised as an energy source or used as a building block for biosynthesis of lipids and cholesterol. In addition, acetyl CoA serves as the acetyl donor in protein acetylation reactions, linking metabolism to protein post-translational modifications. Recent studies in yeast and cultured mammalian cells have suggested that the intracellular level of acetyl CoA may play a role in the regulation of cell growth, proliferation and apoptosis, by affecting protein acetylation reactions. Yet, how the levels of this metabolite change in vivo during the development of a vertebrate is not known. We measured levels of acetyl CoA, free CoA and total short chain CoA esters during the early embryonic development of Xenopus laevis using HPLC. Acetyl CoA and total short chain CoA esters start to increase around midblastula transition (MBT and continue to increase through stages of gastrulation, neurulation and early organogenesis. Pre-MBT embryos contain more free CoA relative to acetyl CoA but there is a shift in the ratio of acetyl CoA to CoA after MBT, suggesting a metabolic transition that results in net accumulation of acetyl CoA. At the whole-embryo level, there is an apparent correlation between the levels of acetyl CoA and levels of acetylation of a number of proteins including histones H3 and H2B. This suggests the level of acetyl CoA may be a factor, which determines the degree of acetylation of these proteins, hence may play a role in the regulation of embryogenesis.

  4. Regioselective Alcoholysis of Silychristin Acetates Catalyzed by Lipases

    Directory of Open Access Journals (Sweden)

    Eva Vavříková

    2015-05-01

    Full Text Available A panel of lipases was screened for the selective acetylation and alcoholysis of silychristin and silychristin peracetate, respectively. Acetylation at primary alcoholic group (C-22 of silychristin was accomplished by lipase PS (Pseudomonas cepacia immobilized on diatomite using vinyl acetate as an acetyl donor, whereas selective deacetylation of 22-O-acetyl silychristin was accomplished by Novozym 435 in methyl tert-butyl ether/ n-butanol. Both of these reactions occurred without diastereomeric discrimination of silychristin A and B. Both of these enzymes were found to be capable to regioselective deacetylation of hexaacetyl silychristin to afford penta-, tetra- and tri-acetyl derivatives, which could be obtained as pure synthons for further selective modifications of the parent molecule.

  5. Triphenylsilane-fused Porphyrins.

    Science.gov (United States)

    Kato, Kenichi; Kim, Jun Oh; Yorimitsu, Hideki; Kim, Dongho; Osuka, Atsuhiro

    2016-06-01

    A reaction sequence of 2-(diphenylsilyl)phenylation by Negishi coupling and intramolecular sila-Friedel-Crafts reaction has been explored for the synthesis of mono-triphenylsilane-fused porphyrins 5 M and 6 M (M= Ni, Zn) and bis-triphenylsilane-fused porphyrins 7 M and 8 Ni. A triply linked triphenylsilane-fused Ni(II) porphyrin, 13 Ni, was synthesized in a stepwise manner involving the above reaction sequence and a final Pd-catalyzed C-H activating arylative cyclization. The silicon atom in 13 Ni takes a distorted planarized structure with an almost perpendicular Si-phenyl group, causing an electronic effect due to effective σ*-π* interaction. PMID:27124659

  6. Enantioselective Total Synthesis of (-)-Alstoscholarisine A.

    Science.gov (United States)

    Liang, Xiao; Jiang, Shi-Zhi; Wei, Kun; Yang, Yu-Rong

    2016-03-01

    We report a concise and highly enantioselective total synthesis of (-)-alstoscholarisine A (1), a recently isolated monoterpenoid indole alkaloid that has significant bioactivity in promoting adult neuronal stem cells proliferation. A highly enantioselective (99% ee), intramolecular Ir-catalyzed Friedel-Crafts alkylation of indole 9 with a secondary allylic alcohol was utilized to establish the first stereogenic center upon which the other three contiguous chiral centers were readily set by a highly stereoselective tandem 1,4-addition and aldol reaction. The key tetrahydropyran was constructed through a hemiacetal reduction, and the final aminal bridge was forged by a one-pot reductive amination/cyclization. The conciseness of this approach was highlighted by building core bonds in each step with a minimalist protecting group strategy. PMID:26882407

  7. Saturation mutagenesis on Arg244 of the tryptophan C4-prenyltransferase FgaPT2 leads to enhanced catalytic ability and different preferences for tryptophan-containing cyclic dipeptides.

    Science.gov (United States)

    Fan, Aili; Li, Shu-Ming

    2016-06-01

    FgaPT2 from Aspergillus fumigatus catalyzes a Friedel-Crafts alkylation at C-4 of L-tryptophan and is involved in the biosynthesis of the ergot alkaloids fumigaclavines. Several tryptophan-containing cyclic dipeptides had also been prenylated by FgaPT2, but the turnover rate (k cat) was low. Here, we report the generation of FgaPT2 mutants by saturation mutagenesis at the amino acid residue Arg244 to improve its catalytic efficiency toward cyclic dipeptides. Thirteen mutated enzymes demonstrated up to 76-fold higher turnover number toward seven cyclic dipeptides than the non-mutated FgaPT2. More importantly, the mutated enzymes exhibited different preferences toward these substrates. This study provides a convenient approach for creation of new biocatalysts for production of C4-prenylated cyclic dipeptides. PMID:26875876

  8. Chemical inhibition of acetyl-CoA carboxylase suppresses self-renewal growth of cancer stem cells

    Science.gov (United States)

    Corominas-Faja, Bruna; Cuyàs, Elisabet; Gumuzio, Juan; Bosch-Barrera, Joaquim; Leis, Olatz; Martin, Ángel G.; Menendez, Javier A.

    2014-01-01

    Cancer stem cells (CSC) may take advantage of the Warburg effect-induced siphoning of metabolic intermediates into de novo fatty acid biosynthesis to increase self-renewal growth. We examined the anti-CSC effects of the antifungal polyketide soraphen A, a specific inhibitor of the first committed step of lipid biosynthesis catalyzed by acetyl-CoA carboxylase (ACACA). The mammosphere formation capability of MCF-7 cells was reduced following treatment with soraphen A in a dose-dependent manner. MCF-7 cells engineered to overexpress the oncogene HER2 (MCF-7/HER2 cells) were 5-fold more sensitive than MCF-7 parental cells to soraphen A-induced reductions in mammosphere-forming efficiency. Soraphen A treatment notably decreased aldehyde dehydrogenase (ALDH)-positive CSC-like cells and impeded the HER2's ability to increase the ALDH+-stem cell population. The following results confirmed that soraphen A-induced suppression of CSC populations occurred through ACACA-driven lipogenesis: a.) exogenous supplementation with supraphysiological concentrations of oleic acid fully rescued mammosphere formation in the presence of soraphen A and b.) mammosphere cultures of MCF-7 cells with stably silenced expression of the cytosolic isoform ACACA1, which specifically participates in de novo lipogenesis, were mostly refractory to soraphen A treatment. Our findings reveal for the first time that ACACA may constitute a previously unrecognized target for novel anti-breast CSC therapies. PMID:25246709

  9. Location of the O-acetyl substituents on a nonasaccharide repeating unit of sycamore extracellular xyloglucan.

    Science.gov (United States)

    York, W S; Oates, J E; van Halbeek, H; Darvill, A G; Albersheim, P; Tiller, P R; Dell, A

    1988-02-15

    The locations of the O-acetyl substituents on the major nonasaccharide repeating unit of the xyloglucan isolated from sycamore extracellular polysaccharides were determined by a combination of analytical methods, including f.a.b.-m.s. and 1H-n.m.r. spectroscopy. The O-2-linked-beta-D-galactosyl residue of the nonasaccharide was found to be the dominant site of O-acetyl substitution. Both mono-O-acetylated and di-O-acetylated beta-D-galactosyl residues were detected. The degree of O-acetylation of the beta-D-galactosyl residue, was estimated by 1H-n.m.r. spectroscopy to be 55-60% at O-6, 15-20% at O-4, and 20-25% at O-3. 1H-n.m.r. spectroscopy also indicated that approximately 50% of the beta-D-galactosyl residues are mono-O-acetylated, 25-30% are di-O-acetylated, and 20% are not acetylated.

  10. Lysine acetylation targets protein complexes and co-regulates major cellular functions

    DEFF Research Database (Denmark)

    Choudhary, Chuna Ram; Kumar, Chanchal; Gnad, Florian;

    2009-01-01

    Lysine acetylation is a reversible posttranslational modification of proteins and plays a key role in regulating gene expression. Technological limitations have so far prevented a global analysis of lysine acetylation's cellular roles. We used high-resolution mass spectrometry to identify 3600 ly...

  11. A dysregulated acetyl/SUMO switch of FXR promotes hepatic inflammation in obesity.

    Science.gov (United States)

    Kim, Dong-Hyun; Xiao, Zhen; Kwon, Sanghoon; Sun, Xiaoxiao; Ryerson, Daniel; Tkac, David; Ma, Ping; Wu, Shwu-Yuan; Chiang, Cheng-Ming; Zhou, Edward; Xu, H Eric; Palvimo, Jorma J; Chen, Lin-Feng; Kemper, Byron; Kemper, Jongsook Kim

    2015-01-13

    Acetylation of transcriptional regulators is normally dynamically regulated by nutrient status but is often persistently elevated in nutrient-excessive obesity conditions. We investigated the functional consequences of such aberrantly elevated acetylation of the nuclear receptor FXR as a model. Proteomic studies identified K217 as the FXR acetylation site in diet-induced obese mice. In vivo studies utilizing acetylation-mimic and acetylation-defective K217 mutants and gene expression profiling revealed that FXR acetylation increased proinflammatory gene expression, macrophage infiltration, and liver cytokine and triglyceride levels, impaired insulin signaling, and increased glucose intolerance. Mechanistically, acetylation of FXR blocked its interaction with the SUMO ligase PIASy and inhibited SUMO2 modification at K277, resulting in activation of inflammatory genes. SUMOylation of agonist-activated FXR increased its interaction with NF-κB but blocked that with RXRα, so that SUMO2-modified FXR was selectively recruited to and trans-repressed inflammatory genes without affecting FXR/RXRα target genes. A dysregulated acetyl/SUMO switch of FXR in obesity may serve as a general mechanism for diminished anti-inflammatory response of other transcriptional regulators and provide potential therapeutic and diagnostic targets for obesity-related metabolic disorders. PMID:25425577

  12. Nε-lysine acetylation of a bacterial transcription factor inhibits Its DNA-binding activity.

    Directory of Open Access Journals (Sweden)

    Sandy Thao

    Full Text Available Evidence suggesting that eukaryotes and archaea use reversible N(ε-lysine (N(ε-Lys acetylation to modulate gene expression has been reported, but evidence for bacterial use of N(ε-Lys acetylation for this purpose is lacking. Here, we report data in support of the notion that bacteria can control gene expression by modulating the acetylation state of transcription factors (TFs. We screened the E. coli proteome for substrates of the bacterial Gcn5-like protein acetyltransferase (Pat. Pat acetylated four TFs, including the RcsB global regulatory protein, which controls cell division, and capsule and flagellum biosynthesis in many bacteria. Pat acetylated residue Lys180 of RcsB, and the NAD(+-dependent Sir2 (sirtuin-like protein deacetylase (CobB deacetylated acetylated RcsB (RcsB(Ac, demonstrating that N(ε-Lys acetylation of RcsB is reversible. Analysis of RcsB(Ac and variant RcsB proteins carrying substitutions at Lys180 provided biochemical and physiological evidence implicating Lys180 as a critical residue for RcsB DNA-binding activity. These findings further the likelihood that reversible N(ε-Lys acetylation of transcription factors is a mode of regulation of gene expression used by all cells.

  13. Proteomic analysis of lysine acetylation sites in rat tissues reveals organ specificity and subcellular patterns

    DEFF Research Database (Denmark)

    Lundby, Alicia; Hansen, Kasper Lage; Weinert, Brian Tate;

    2012-01-01

    Lysine acetylation is a major posttranslational modification involved in a broad array of physiological functions. Here, we provide an organ-wide map of lysine acetylation sites from 16 rat tissues analyzed by high-resolution tandem mass spectrometry. We quantify 15,474 modification sites on 4,54...

  14. The Effect of Acetyl-L-Carnitine Administration on Persons with Down Syndrome

    Science.gov (United States)

    Pueschel, Siegfried M.

    2006-01-01

    Since previous investigations reported improvements in cognition of patients with dementia after acetyl-L-carnitine therapy and since there is an increased risk for persons with Down syndrome to develop Alzheimer disease, this study was designed to investigate the effect of acetyl-L-carnitine administration on neurological, intellectual, and…

  15. Acetylation of Starch with Vinyl Acetate in Imidazolium Ionic Liquids and Characterization of Acetate Distribution

    Science.gov (United States)

    Starch was acetylated with vinyl acetate in different 1-butyl-3-methylimidazolium (BMIM) salts as solvent in effort to produce starches with different acetylation patterns. Overall degree of substitution was much higher for basic anions such as acetate and dicyanimide (dca) than for neutral anions ...

  16. chiral Synthesis of 13-Acetyl-12-hydroxy-podocarpane-8, 11,13-triene-7-one

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An enantioselective synthetic route to (+)-13-acetyl-12-hydroxy-podocarpane-8,11,13-triene-7-one 1a and (-)-13-acetyl-12-hydroxy-podocarpane-8,11,13-triene-7-one 1b was developed from (S)-(-)-a -cyclocitral 8a and (R)-(+)-a -cyclocitral 8b.

  17. Histone Acetylation is Recruited in Consolidation as a Molecular Feature of Stronger Memories

    Science.gov (United States)

    Federman, Noel; Fustinana, Maria Sol; Romano, Arturo

    2009-01-01

    Gene expression is a key process for memory consolidation. Recently, the participation of epigenetic mechanisms like histone acetylation was evidenced in long-term memories. However, until now the training strength required and the persistence of the chromatin acetylation recruited are not well characterized. Here we studied whether histone…

  18. Effect of Acetyl Group on Mechanical Properties of Chitin/Chitosan Nanocrystal: A Molecular Dynamics Study

    Directory of Open Access Journals (Sweden)

    Junhe Cui

    2016-01-01

    Full Text Available Chitin fiber is the load-bearing component in natural chitin-based materials. In these materials, chitin is always partially deacetylated to different levels, leading to diverse material properties. In order to understand how the acetyl group enhances the fracture resistance capability of chitin fiber, we constructed atomistic models of chitin with varied acetylation degree and analyzed the hydrogen bonding pattern, fracture, and stress-strain behavior of these models. We notice that the acetyl group can contribute to the formation of hydrogen bonds that can stabilize the crystalline structure. In addition, it is found that the specimen with a higher acetylation degree presents a greater resistance against fracture. This study describes the role of the functional group, acetyl groups, in crystalline chitin. Such information could provide preliminary understanding of nanomaterials when similar functional groups are encountered.

  19. Effects of Partially N-acetylated Chitosans to Elicit Resistance Reaction on Brassica napus L.

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xue-kun; TANG Zhang-lin; CHEN Li; GUO Yi-hong; CHEN Yun-ping; LI Jia-na

    2002-01-01

    The effects to elicit resistance reaction on oilseed rape (Brassica napus L. cv Xinongchangjiao )by four partially N-acetylated chitosan 7B, 8B, 9B and 10B (Degree of acetylation (D. A. ) is 30%, 20%,10%, 0%, respectively) and Glycol chitosan (GC, D.A. is 0%) were investigated and compared. Results showed that chitosan were similar to salicylic acid (SA), and could induce resistance reaction, but the reaction was influenced by the degree of acetylation of chitosan. Fully deacetylated chitosans, 10B and GC, elicited chitinase activity, but partially acetylated chitosan, 7B, 8B and 9B, inhibited chitinase activity. Phenyalanine ammonia-lyase (PAL) was also elicited. Elicitor activity increased with on increasing degree of acetylation, 7B induced highest PAL activity among all chitosans. All chitosans induced peroxidase (POD) in a similar level.After elicited by glycol chitosan, like SA treatment, the seedlings increased disease resistance to Sclerotinia sclerotiorum significantly.

  20. Acetylation of barnyardgrass starch with acetic anhydride under iodine catalysis.

    Science.gov (United States)

    Bartz, Josiane; Goebel, Jorge Tiago; Giovanaz, Marcos Antônio; Zavareze, Elessandra da Rosa; Schirmer, Manoel Artigas; Dias, Alvaro Renato Guerra

    2015-07-01

    Barnyardgrass (Echinochloa crus-galli) is an invasive plant that is difficult to control and is found in abundance as part of the waste of the paddy industry. In this study, barnyardgrass starch was extracted and studied to obtain a novel starch with potential food and non-food applications. We report some of the physicochemical, functional and morphological properties as well as the effect of modifying this starch with acetic anhydride by catalysis with 1, 5 or 10mM of iodine. The extent of the introduction of acetyl groups increased with increasing iodine levels as catalyst. The shape of the granules remained unaltered, but there were low levels of surface corrosion and the overall relative crystallinity decreased. The pasting temperature, enthalpy and other gelatinisation temperatures were reduced by the modification. There was an increase in the viscosity of the pastes, except for the peak viscosity, which was strongly reduced in 10mM iodine.

  1. Parameters critical to muon-catalyzed fusion

    International Nuclear Information System (INIS)

    We have demonstrated that muon catalysis cycling rates increase rapidly with increasing deuterium-tritium gas temperatures and densities. Furthermore, muon-capture losses are significantly smaller than predicted before the experiments. There remains a significant gap between observation and theoretical expectation for the muon-alpha sticking probability in dense d-t mixtures. We have been able to achieve muon-catalyzed yields of 150 fusion/muon (average). While the fusion energy thereby released significantly exceeds expectations, enhancements by nearly a factor of twenty would be needed to realize energy applications for a pure (non-hybrid) muon-catalyzed fusion reactor. The process could be useful in tritium-breeding schemes. We have also explored a new form of cold nuclear fusion which occurs when hydrogen isotopes are loaded into metals. 22 refs., 10 figs

  2. Palladium-Catalyzed Environmentally Benign Acylation.

    Science.gov (United States)

    Suchand, Basuli; Satyanarayana, Gedu

    2016-08-01

    Recent trends in research have gained an orientation toward developing efficient strategies using innocuous reagents. The earlier reported transition-metal-catalyzed carbonylations involved either toxic carbon monoxide (CO) gas as carbonylating agent or functional-group-assisted ortho sp(2) C-H activation (i.e., ortho acylation) or carbonylation by activation of the carbonyl group (i.e., via the formation of enamines). Contradicting these methods, here we describe an environmentally benign process, [Pd]-catalyzed direct carbonylation starting from simple and commercially available iodo arenes and aldehydes, for the synthesis of a wide variety of ketones. Moreover, this method comprises direct coupling of iodoarenes with aldehydes without activation of the carbonyl and also without directing group assistance. Significantly, the strategy was successfully applied to the synthesis n-butylphthalide and pitofenone. PMID:27377566

  3. Acetylated Lysozyme as Impurity in Lysozyme Crystals: Constant Distribution Coefficient

    Science.gov (United States)

    Thomas, B. R.; Chernov, A. A.

    2000-01-01

    Hen egg white lysozyme (HEWL) was acetylated to modify molecular charge keeping the molecular size and weight nearly constant. Two derivatives, A and B, more and less acetylated, respectively, were obtained, separated, purified and added to the solution from which crystals of tetragonal HEWL crystals were grown. Amounts of the A or B impurities added were 0.76, 0.38 and 0.1 milligram per millimeter while HEWL concentration were 20, 30 and 40 milligram per milliliter. The crystals grown in 18 experiments for each impurity were dissolved and quantities of A or B additives in these crystals were analyzed by cation exchange high performance liquid chromatography. All the data for each set of 18 samples with the different impurity and regular HEWL concentrations is well described by one distribution coefficient K = 2.15 plus or minus 0.13 for A and K = 3.42 plus or minus 0.25 for B. The observed independence of the distribution coefficient on both the impurity concentration and supersaturation is explained by the dilution model described in this paper. It shows that impurity adsorption and incorporation rate is proportional to the impurity concentration and that the growth rate is proportional to the crystallizing protein in solution. With the kinetic coefficient for crystallization, beta = 5.10(exp -7) centimeters per second, the frequency at which an impurity molecule near the growing interface irreversibly joins a molecular site on the crystal was found to be 3 1 per second, much higher than the average frequency for crystal molecules. For best quality protein crystals it is better to have low microheterogeneous protein impurity concentration and high supers aturation.

  4. Antioxidant activity of N-acetyl-glucosamine based thiazolidine derivative

    Institute of Scientific and Technical Information of China (English)

    Li Chunlei; Yang Yan; Han Baoqin; Liu Wanshun

    2007-01-01

    N-acetyl-glucosamine,the monomer of chitin,was cyclo-condensed with L-cysteine to prepare thiazolidine derivative:2-N-acetyl-glucosamine-thiazolidine-4(R)-carboxylic acid(GlcNAcCys).The stability of GlcNAcCys was evaluated by high performance liquid chromatography(HPLC)measurement.The results showed that GlcNAcCys Was more stable than other TCA derivatives,especially in alkaline condition.The direct in vitro antioxidative properties of GlcNAcCys were investigated by using UV radiation-induced lipid peroxidation(LPO)in mitochondria and nuclei and.OH-induced LPO in red blood cell (RBC)ghosts models.UV radiation caused dose-dependent LPO in both mitochondria and nuclei,this effect Was catalvzed by addition of Fd2+ while prevented by co-incubation with GlcNAcCys.When nuclei and mitochondria Was treated with 100μl,300μl,500μl of GlcNAcCys and co-incubated at 37℃ for 30min,LPO was decreased to 96%,72%,68%in nuclei and 95%,72%,68% in mitochondria when compared to the UV radiation group respectively.Hydroxyl radicals(.OH)generated by Fenton reaction induced LPO in RBC ghosts.Pretreatment of RBC ghosts with GlcNAcCys could induce antioxidant RBC ghosts and inhibit concentration-dependent malondialdehyde(MDA)formation in antioxidant RBC ghosts.Its inhibition percent Was 14%,35%,36%,42%at 10,20,30,40ms/ml respectively.In a conclusion,the data suggest that GlcNAcCys has antioxidant ability and can significantly inhibit lipid peroxidation in biological samples tested in vitro.

  5. Identification and functional characterization of N-terminally acetylated proteins in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Sandra Goetze

    2009-11-01

    Full Text Available Protein modifications play a major role for most biological processes in living organisms. Amino-terminal acetylation of proteins is a common modification found throughout the tree of life: the N-terminus of a nascent polypeptide chain becomes co-translationally acetylated, often after the removal of the initiating methionine residue. While the enzymes and protein complexes involved in these processes have been extensively studied, only little is known about the biological function of such N-terminal modification events. To identify common principles of N-terminal acetylation, we analyzed the amino-terminal peptides from proteins extracted from Drosophila Kc167 cells. We detected more than 1,200 mature protein N-termini and could show that N-terminal acetylation occurs in insects with a similar frequency as in humans. As the sole true determinant for N-terminal acetylation we could extract the (XPX rule that indicates the prevention of acetylation under all circumstances. We could show that this rule can be used to genetically engineer a protein to study the biological relevance of the presence or absence of an acetyl group, thereby generating a generic assay to probe the functional importance of N-terminal acetylation. We applied the assay by expressing mutated proteins as transgenes in cell lines and in flies. Here, we present a straightforward strategy to systematically study the functional relevance of N-terminal acetylations in cells and whole organisms. Since the (XPX rule seems to be of general validity in lower as well as higher eukaryotes, we propose that it can be used to study the function of N-terminal acetylation in all species.

  6. Hair Analysis for Determination of Isoniazid Concentrations and Acetylator Phenotype during Antituberculous Treatment

    Directory of Open Access Journals (Sweden)

    Michael Eisenhut

    2012-01-01

    Full Text Available Background. Analysis of isoniazid (INH uptake has been based on measurement of plasma concentrations providing a short-term and potentially biased view. Objectives. To establish hair analysis as a tool to measure long-term uptake of INH and to assess whether acetylator phenotype in hair reflects N-acetyltransferase-2 (NAT2 genotype. Design and Methods. INH and acetyl-INH concentrations in hair were determined in patients on INH treatment for M. tuberculosis infection using high pressure liquid chromatography/mass spectrometry. Acetyl-INH/INH ratios were correlated with NAT-2 genotype. Results. Hair concentrations of INH, determined in 40 patients, were not dependent on ethnic group or body mass index and were significantly higher in male compared to female patients (median (range 2.37 ng/mg (0.76–4.9 versus 1.11 ng/mg (0.02–7.20 (P=0.02. Acetyl-INH/INH ratios were a median of 15.2% (14.5 to 31.7 in homozygous rapid acetylator NAT-2 genotype and 37.3% (1.73 to 51.2 in the heterozygous rapid acetylator NAT-2 genotype and both significantly higher than in the slow acetylator NAT-2 genotype with 5.8% (0.53 to 14.4 (P<0.05. Conclusions. Results of hair analysis for INH showed lower concentrations in females. Acetyl-INH/INH ratios were significantly lower in patients with slow acetylator versus rapid acetylator genotypes.

  7. Copper Catalyzed Oceanic Methyl Halide Production

    OpenAIRE

    Robin Kim, Jae Yun; Rhew, Robert

    2014-01-01

    Methyl halides are found in all of Earth’s biomes, produced naturally or through manmade means. Their presence in the atmosphere is problematic, as they catalyze depletion of stratospheric ozone. To understand the full environmental impact of these compounds, it is important to identify their chemical cycling processes. Iron increases methyl halide production in soils and oceans, yet copper’s influence remains unknown despite its similar chemical oxidation properties to iron. I experimentally...

  8. Antibody-Catalyzed Degradation of Cocaine

    Science.gov (United States)

    Landry, Donald W.; Zhao, Kang; Yang, Ginger X.-Q.; Glickman, Michael; Georgiadis, Taxiarchis M.

    1993-03-01

    Immunization with a phosphonate monoester transition-state analog of cocaine provided monoclonal antibodies capable of catalyzing the hydrolysis of the cocaine benzoyl ester group. An assay for the degradation of radiolabeled cocaine identified active enzymes. Benzoyl esterolysis yields ecgonine methyl ester and benzoic acid, fragments devoid of cocaine's stimulant activity. Passive immunization with such an artificial enzyme could provide a treatment for dependence by blunting reinforcement.

  9. Study on the Synthesis of 3,6-Disubstituted Asymmetric Carbazole Derivatives%3,6-位不对称二取代咔唑衍生物的合成研究

    Institute of Scientific and Technical Information of China (English)

    赵三虎; 刘瑞琴; 亢丽娜; 葛海霞; 赵明根

    2011-01-01

    以咔唑为主要合成原料,通过N-烷基化、付克酰基化、硝化以及付克烷基化等反应合成了两个结构新颖的3,6-位不对称二取代咔唑衍生物.探讨了原料摩尔比、催化剂用量、反应温度及反应时间等因素对反应的影响,得到最佳反应条件:(1)傅克酰基化反应:n(N-乙基咔唑):n(三氯化铝):n(乙酰氯)=1:1.2:1.5,反应温度室温,反应时间4h,产品收率82%;(2)硝化反应:n(N-乙基咔唑):n(65%硝酸)=1:1.15,反应温度5~10℃,反应时间2h,产品收率89%;(3)傅克烷基化反应:n(3-乙酰基-N-乙基咔唑):n(氯化锌):n(叔丁基氯)=1:1.5:1.5,反应温度室温,反应时间12 h,产品收率64%.所得产品结构经FTIR、1 H NMR、13C NMR、及MS表征.%With carbazole as mainly synthetic material,two novel compounds of 3,6-disubstituted asymmetric carbazole derivatives were prepared by a serious of reactions, such as N- alkylation,Friedel-Crafts acyla-tion, nitration and Friedel-Crafts alkylation. The factors affected the reactions,such as the mol ratio of substrates, the quantity of catalyst,reaction temperature and reaction time were explored and the optimum reaction conditions are as follows; (1) For the reaction of Friedel-Crafts acylation,with the mol ratio 1 : 1. 2 ':1. 5 of N-ethylcarbazole,anhydrous aluminum chloride and acetyl chloride,82% yield of the product was obtained at room temperature for 4 h;(2) For the reaction of nitration, with the mol ratio 1:1. 15 of the N-ethylcarbazole and 65% nitric,89% yield of the object product was obtained at 5 - 10 °C for 2 h;(3) For the reaction of Friedel-Crafts alkylation, with the mol ratio 1 : 1. 5 : 1. 5 of 3-acetyl-N-ethylcarbazol,anhydrous zinc chloride and tert. -butyl chloride,64% yield of the product was obtained at room temperature for 12 h. The structures of object products were characterized by FTIR、1H NMR、13C NMR and MS.

  10. File list: His.NoD.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  11. File list: His.NoD.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  12. File list: His.EmF.05.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  13. File list: His.EmF.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  14. File list: His.NoD.20.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  15. File list: His.EmF.50.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  16. File list: His.NoD.10.Pan_lysine_acetylation.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  17. Synthesis of chitin and chitosan stereoisomers by thermostable α-glucan phosphorylase-catalyzed enzymatic polymerization of α-D-glucosamine 1-phosphate.

    Science.gov (United States)

    Kadokawa, Jun-ichi; Shimohigoshi, Riko; Yamashita, Kento; Yamamoto, Kazuya

    2015-04-14

    The relationship between two aminopolysaccharide stereoisomers, namely α-(1→4)- and β-(1→4)-linked (N-acetyl)-D-glucosamine polymers, is of significant interest within the field of polysaccharide science, as they correspond to amino analogs of the representative abundant natural polysaccharides, viz. amylose and cellulose. While the latter glucosamine polymer is the basis of well-known natural polysaccharides, chitin and chitosan (linear polysaccharides composed of β-(1→4)-linked N-acetyl-D-glucosamine and D-glucosamine), to the best of our knowledge, the former (α-(1→4)-linked) has not been observed in nature. For the purpose of these studies, the synthesis of such non-natural aminopolysaccharides was performed by the thermostable α-glucan phosphorylase (from Aquifex aeolicus VF5)-catalyzed enzymatic polymerization of α-D-glucosamine 1-phosphate (GlcN-1-P), via successive α-glucosaminylations, in ammonia buffer containing Mg(2+) ions, resulting in the production of the α-(1→4)-linked D-glucosamine polymers, corresponding to the structure of the chitosan stereoisomer. Subsequent N-acetylation of the products gave the aminopolysaccharides, corresponding to the chitin stereoisomer. PMID:25766841

  18. Genetic Construction of Truncated and Chimeric Metalloproteins Derived from the Alpha Subunit of Acetyl-CoA Synthase from Clostridium thermoaceticum

    Energy Technology Data Exchange (ETDEWEB)

    Huay-Keng Loke; Xiangshi Tan; Paul A. Lindahl

    2002-06-28

    In this study, a genetics-based method is used to truncate acetyl-coenzyme A synthase from Clostridium thermoaceticum (ACS), an alpha2beta2 tetrameric 310 kda bifunctional enzyme. ACS catalyzes the reversible reduction of CO2 to CO and the synthesis of acetyl-CoA from CO (or CO2 in the presence of low-potential reductants), CoA, and a methyl group bound to a corrinoid-iron sulfur protein (CoFeSP). ACS contains 7 metal-sulfur clusters of 4 different types called A, B, C, and D. The B, C, and D clusters are located in the 72 kda beta subunit while the A-cluster, a Ni-X-Fe4S4 cluster that serves as the active site for acetyl-CoA synthase activity, is located in the 82 kda alpha subunit. The extent to which the essential properties of the cluster, including catalytic, redox, spectroscopic, and substrate-binding properties, were retained as ACS was progressively truncated was determined. Acetyl-CoA synthase catalytic activity remained when the entire alpha subunit was removed, as long as CO, rather than CO2 and a low-potential reductant, was used as a substrate. Truncating an {approx} 30 kda region from the N-terminus of the alpha subunit yielded a 49 kda protein that lacked catalytic activity but exhibited A-cluster-like spectroscopic, redox, and CO binding properties. Further truncation afforded a 23 kda protein that lacked recognizable A-cluster properties except for UV-vis spectra typical of [Fe4S4]2+ clusters. Two chimeric proteins were constructed by fusing the gene encoding a ferredoxin from Chromatium vinosum to genes encoding the 49 kda and 82 kda fragments of the alpha subunit. The chimeric proteins exhibited EPR signals that were not the simple sum of the signals from the separate proteins, suggesting magnetic interactions between clusters. This study highlights the potential for using genetics to simplify the study of complex multi-centered metalloenzymes and to generate new complex metalloenzymes with interesting properties.

  19. Arabidopsis Acetyl-Amido Synthetase GH3.5 Involvement in Camalexin Biosynthesis through Conjugation of Indole-3-Carboxylic Acid and Cysteine and Upregulation of Camalexin Biosynthesis Genes

    Institute of Scientific and Technical Information of China (English)

    Mu-Yang Wang; Xue-Ting Liu; Ying Chen; Xiao-Jing Xu; Biao Yu; Shu-Qun Zhang; Qun Li; Zu-Hua He

    2012-01-01

    Camalexin (3-thiazol-2'-yl-indole) is the major phytoalexin found in Arabidopsis thaliana.Several key intermediates and corresponding enzymes have been identified in camalexin biosynthesis through mutant screening and biochemical experiments.Camalexin is formed when indole-3-acetonitrile (IAN)is catalyzed by the cytochrome P450 monooxygenase CYP71A13.Here,we demonstrate that the Arabidopsis GH3.5 protein,a multifunctional acetyl-amido synthetase,is involved in camalexin biosynthesis via conjugating indole-3-carboxylic acid (ICA) and cysteine (Cys) and regulating camalexin biosynthesis genes.Camalexin levels were increased in the activation-tagged mutant gh3.5-1D in both Col-0 and cyp71A13-2 mutant backgrounds after pathogen infection.The recombinant GH3.5 protein catalyzed the conjugation of ICA and Cys to form a possible intermediate indole-3-acyl-cysteinate (ICA(Cys)) in vitro.In support of the in vitro reaction,feeding with ICA and Cys increased camalexin levels in Col-0 and gh3.5-1D.Dihydrocamalexic acid (DHCA),the precursor of camalexin and the substrate for PAD3,was accumulated in gh3.5-1Dlpad3-1,suggesting that ICA(Cys) could be an additional precursor of DHCA for camalexin biosynthesis.Furthermore,expression of the major camalexin biosynthesis genes CYP79B2,CYP71A12,CYP71A13 and PAD3 was strongly induced in gh3.5-1D.Our study suggests that GH3.5 is involved in camalexin biosynthesis through direct catalyzation of the formation of ICA(Cys),and upregulation of the major biosynthetic pathway genes.

  20. Proteomic investigations of lysine acetylation identify diverse substrates of mitochondrial deacetylase sirt3.

    Directory of Open Access Journals (Sweden)

    Eri Maria Sol

    Full Text Available Lysine acetylation is a posttranslational modification that is dynamically regulated by the activity of acetyltransferases and deacetylases. The human and mouse genomes encode 18 different lysine deacetylases (KDACs which are key regulators of many cellular processes. Identifying substrates of KDACs and pinpointing the regulated acetylation sites on target proteins may provide important information about the molecular basis of their functions. Here we apply quantitative proteomics to identify endogenous substrates of the mitochondrial deacetylase Sirtuin 3 (Sirt3 by comparing site-specific acetylation in wild-type murine embryonic fibroblasts to Sirt3 knockout cells. We confirm Sirt3-regulated acetylation of several mitochondrial proteins in human cells by comparing acetylation in U2OS cells overexpressing Sirt3 to U2OS cells in which Sirt3 expression was reduced by shRNA. Our data demonstrate that ablation of Sirt3 significantly increases acetylation at dozens of sites on mitochondrial proteins. Substrates of Sirt3 are implicated in various metabolic pathways, including fatty acid metabolism and the tricarboxylic acid cycle. These results imply broader regulatory roles of Sirt3 in the mitochondria by modulating acetylation on diverse substrates. The experimental strategy described here is generic and can be applied to identify endogenous substrates of other lysine deacetylases.

  1. The effects of acetylation on properties of flax fibre and its polypropylene composites

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available Flax fibre was modified with acetylation. The influence of the acetylation on the structure and properties of flax fibre were investigated as well as modified flax fibre reinforced polypropylene composites were also prepared. The catalyst was used to accelerate acetylation reaction rate. Flax fibre was characterised after modification. Surface morphology, moisture absorption property, components content, degree of polymerisation, crystallinity of cellulose and thermal stability of flax fibres were studied. Due to acetylation, the flax fibre surface morphology and moisture resistance properties improved remarkably. Flax fibre (modified and unmodified reinforced polypropylene composites were fabricated with 30 wt% fibre loading. The mechanical properties were investigated for those composites. Tensile and flexural strengths of composites were found to increase with increasing degree of acetylation up to 18% and then decreased. Charpy impact strengths of composites were found to decrease with increasing degree of acetylation. Owing to addition of coupling agent (maleated polypropylene -MAH, the tensile and flexural strength properties were found to increase in between 20 to 35% depending on degree of acetylation.

  2. Histone Acetylation near the Nucleosome Dyad Axis Enhances Nucleosome Disassembly by RSC and SWI/SNF.

    Science.gov (United States)

    Chatterjee, Nilanjana; North, Justin A; Dechassa, Mekonnen Lemma; Manohar, Mridula; Prasad, Rashmi; Luger, Karolin; Ottesen, Jennifer J; Poirier, Michael G; Bartholomew, Blaine

    2015-12-01

    Signaling associated with transcription activation occurs through posttranslational modification of histones and is best exemplified by lysine acetylation. Lysines are acetylated in histone tails and the core domain/lateral surface of histone octamers. While acetylated lysines in histone tails are frequently recognized by other factors referred to as "readers," which promote transcription, the mechanistic role of the modifications in the lateral surface of the histone octamer remains unclear. By using X-ray crystallography, we found that acetylated lysines 115 and 122 in histone H3 are solvent accessible, but in biochemical assays they appear not to interact with the bromodomains of SWI/SNF and RSC to enhance recruitment or nucleosome mobilization, as previously shown for acetylated lysines in H3 histone tails. Instead, we found that acetylation of lysines 115 and 122 increases the predisposition of nucleosomes for disassembly by SWI/SNF and RSC up to 7-fold, independent of bromodomains, and only in conjunction with contiguous nucleosomes. Thus, in combination with SWI/SNF and RSC, acetylation of lateral surface lysines in the histone octamer serves as a crucial regulator of nucleosomal dynamics distinct from the histone code readers and writers.

  3. Proteomic Analysis of Lysine Acetylation Sites in Rat Tissues Reveals Organ Specificity and Subcellular Patterns

    Directory of Open Access Journals (Sweden)

    Alicia Lundby

    2012-08-01

    Full Text Available Lysine acetylation is a major posttranslational modification involved in a broad array of physiological functions. Here, we provide an organ-wide map of lysine acetylation sites from 16 rat tissues analyzed by high-resolution tandem mass spectrometry. We quantify 15,474 modification sites on 4,541 proteins and provide the data set as a web-based database. We demonstrate that lysine acetylation displays site-specific sequence motifs that diverge between cellular compartments, with a significant fraction of nuclear sites conforming to the consensus motifs G-AcK and AcK-P. Our data set reveals that the subcellular acetylation distribution is tissue-type dependent and that acetylation targets tissue-specific pathways involved in fundamental physiological processes. We compare lysine acetylation patterns for rat as well as human skeletal muscle biopsies and demonstrate its general involvement in muscle contraction. Furthermore, we illustrate that acetylation of fructose-bisphosphate aldolase and glycerol-3-phosphate dehydrogenase serves as a cellular mechanism to switch off enzymatic activity.

  4. Improved Species-Specific Lysine Acetylation Site Prediction Based on a Large Variety of Features Set.

    Science.gov (United States)

    Wuyun, Qiqige; Zheng, Wei; Zhang, Yanping; Ruan, Jishou; Hu, Gang

    2016-01-01

    Lysine acetylation is a major post-translational modification. It plays a vital role in numerous essential biological processes, such as gene expression and metabolism, and is related to some human diseases. To fully understand the regulatory mechanism of acetylation, identification of acetylation sites is first and most important. However, experimental identification of protein acetylation sites is often time consuming and expensive. Therefore, the alternative computational methods are necessary. Here, we developed a novel tool, KA-predictor, to predict species-specific lysine acetylation sites based on support vector machine (SVM) classifier. We incorporated different types of features and employed an efficient feature selection on each type to form the final optimal feature set for model learning. And our predictor was highly competitive for the majority of species when compared with other methods. Feature contribution analysis indicated that HSE features, which were firstly introduced for lysine acetylation prediction, significantly improved the predictive performance. Particularly, we constructed a high-accurate structure dataset of H.sapiens from PDB to analyze the structural properties around lysine acetylation sites. Our datasets and a user-friendly local tool of KA-predictor can be freely available at http://sourceforge.net/p/ka-predictor. PMID:27183223

  5. Acetylation of Wood Flour from Four Wood Species Grown in Nigeria Using Vinegar and Acetic Anhydride

    Directory of Open Access Journals (Sweden)

    Yakubu Azeh

    2013-01-01

    Full Text Available Effect of acetylation on pretreated wood flour of four different wood species, Boabab (Adansonia digitata, Mahoganny (Daniella oliveri, African locust bean (Parkia biglobosa and Beech wood (Gmelina arborea, had been investigated. The first batch of wood species were acetylated using acetic anhydride while the second batch were acetylated with commercial vinegar. Both experiments were conducted in the presence of varying amount of CaCl2 as catalyst and at temperature of 120°C for 3 h. The success of acetylation was determined based on Weight Percent Gain for each sample treated with either chemicals used. FT-IR, a veritable tool was used for the analysis of both treated and untreated samples to further investigate the success of acetylation. The results showed the presence of important band such as carbonyl absorptions at 1743, 1744, 1746, 1731, 1718 and 1696 cm−1 as appeared separately in the spectra of acetylated samples, confirming esterification occurred. The purpose of this work was to investigate the applicability of vinegar for acetylation of lignocellulosic fibers. Blends/composites were prepared by solution casting and their kinetics investigated in distilled water. The results indicated they could be used in outdoor applications such as, decking and packaging.

  6. Aberrant histone H4 acetylation in dead somatic cell-cloned calves

    Institute of Scientific and Technical Information of China (English)

    Lei Zhang; Shaohua Wang; Qiang Li; Xiangdong Ding; Yunping Dai; Ning Li

    2008-01-01

    In somatic cell-cloned animals, inefficient epigenetic reprogramming can result in an inappropriate gene expression and histone H4 acetylation is one of the key epigenetic modifications regulating gene expression. In this study, we investigated the levels of histone H4 acetylation of 11 development-related genes and expression levels of 19 genes in lungs of three normal control calves and nine aber-rant somatic cell-cloned calves. The results showed that nine studied genes had decreased acetylation levels in aberrant clones (p 0.05). Whereas 13 genes had significantly decreased expression (p 0.05), and only one gene had higher expression level in clones (p < 0.05). Furthermore, FGFR, GHR, HGFR and IGF1 genes showed lowered levels of both histone H4 acetylation and expression in aberrant clones than in controls, and the level of histone H4 acetylation was even more lowered in aberrant clones than those in controls. It was suggested that the lower levels of histone H4 acetylation in aberrant clones caused by the previous memory of cell differentiation might not support enough chromatin reprogramming, thus affecting appropriate gene expressions, and growth and development of the cloned calves. To our knowledge, this is the first study on how histone H4 acetylation affects gene expression in organs of somatic cell-cloned calves.

  7. 2-Amino-3,8-dimethylimidazo-[4,5-f]quinoxaline-induced DNA adduct formation and mutagenesis in DNA repair-deficient Chinese hamster ovary cells expressing human cytochrome P4501A1 and rapid or slow acetylator N-acetyltransferase 2.

    Science.gov (United States)

    Bendaly, Jean; Zhao, Shuang; Neale, Jason R; Metry, Kristin J; Doll, Mark A; States, J Christopher; Pierce, William M; Hein, David W

    2007-07-01

    2-Amino-3,8-dimethylimidazo-[4,5-f]quinoxaline (MeIQx) is one of the most potent and abundant mutagens in the western diet. Bioactivation includes N-hydroxylation catalyzed by cytochrome P450s followed by O-acetylation catalyzed by N-acetyltransferase 2 (NAT2). In humans, NAT2*4 allele is associated with rapid acetylator phenotype, whereas NAT2*5B allele is associated with slow acetylator phenotype. We hypothesized that rapid acetylator phenotype predisposes humans to DNA damage and mutagenesis from MeIQx. Nucleotide excision repair-deficient Chinese hamster ovary cells were constructed by stable transfection of human cytochrome P4501A1 (CYP1A1) and a single copy of either NAT2*4 (rapid acetylator) or NAT2*5B (slow acetylator) alleles. CYP1A1 and NAT2 catalytic activities were undetectable in untransfected Chinese hamster ovary cell lines. CYP1A1 activity did not differ significantly (P > 0.05) among the CYP1A1-transfected cell lines. Cells transfected with NAT2*4 had 20-fold significantly higher levels of sulfamethazine N-acetyltransferase (P = 0.0001) and 6-fold higher levels of N-hydroxy-MeIQx O-acetyltransferase (P = 0.0093) catalytic activity than cells transfected with NAT2*5B. Only cells transfected with both CYP1A1 and NAT2*4 showed concentration-dependent cytotoxicity and hypoxanthine phosphoribosyl transferase mutagenesis following MeIQx treatment. Deoxyguanosine-C8-MeIQx was the primary DNA adduct formed and levels were dose dependent in each cell line and in the following order: untransfected < transfected with CYP1A1 < transfected with CYP1A1 and NAT2*5B < transfected with CYP1A1 and NAT2*4. MeIQx DNA adduct levels were significantly higher (P < 0.001) in CYP1A1/NAT2*4 than CYP1A1/NAT2*5B cells at all concentrations of MeIQx tested. MeIQx-induced DNA adduct levels correlated very highly (r2 = 0.88) with MeIQx-induced mutants. These results strongly support extrahepatic activation of MeIQx by CYP1A1 and a robust effect of human NAT2 genetic polymorphism

  8. Transport and metabolism of indole-3-acetyl-myo-inositol-galactoside in seedlings of Zea mays

    Science.gov (United States)

    Komoszynski, M.; Bandurski, R. S.

    1986-01-01

    Indole-3-acetyl-myo-inositol galactoside labeled with 3H in the indole and 14C in the galactose moieties was applied to kernels of 5 day old germinating seedlings of Zea mays. Indole-3-acetyl-myo-inositol galactoside was not transported into either the shoot or root tissue as the intact molecule but was instead hydrolyzed to yield [3H]indole-3-acetyl-myo-inositol and [3H]indole-3-acetic acid which were then transported to the shoot with little radioactivity going to the root. With certain assumption concerning the equilibration of applied [3H]indole-3-acetyl-myo-inositol-[U-14C]galactose with the endogenous pool, it may be concluded that indole-3-acetyl-myo-inositol galactoside in the endosperm supplies about 2 picomoles per plant per hour of indole-3-acetyl-myo-inositol and 1 picomole per plant per hour of indole-3-acetic acid to the shoot and thus is comparable to indole-3-acetyl-myo-inositol as a source of indole-acetic acid for the shoot. Quantitative estimates of the amount of galactose in the kernels suggest that [3H]indole-3-acetyl-myo-inositol-[14C]galactose is hydrolyzed after the compound leaves the endosperm but before it reaches the shoot. In addition, [3H]indole-3-acetyl-myo-inositol-[14C]galactose supplies appreciable amounts of 14C to the shoot and both 14C and 3H to an uncharacterized insoluble fraction of the endosperm.

  9. Acetate/acetyl-CoA metabolism associated with cancer fatty acid synthesis: overview and application.

    Science.gov (United States)

    Yoshii, Yukie; Furukawa, Takako; Saga, Tsuneo; Fujibayashi, Yasuhisa

    2015-01-28

    Understanding cancer-specific metabolism is important for identifying novel targets for cancer diagnosis and therapy. Induced acetate/acetyl CoA metabolism is a notable feature that is related to fatty acid synthesis supporting tumor growth. In this review, we focused on the recent findings related to cancer acetate/acetyl CoA metabolism. We also introduce [1-¹¹C]acetate positron emission tomography (PET), which is a useful tool to visualize up-regulation of acetate/acetyl CoA metabolism in cancer, and discuss the utility of [1-¹¹C]acetate PET in cancer diagnosis and its application to personalized medicine.

  10. Ligand Intermediates in Metal-Catalyzed Reactions

    Energy Technology Data Exchange (ETDEWEB)

    Gladysz, John A.

    1999-07-31

    The longest-running goal of this project has been the synthesis, isolation, and physical chemical characterization of homogeneous transition metal complexes containing ligand types believed to be intermediates in the metal-catalyzed conversion of CO/H{sub 2}, CO{sub 2}, CH{sub 4}, and similar raw materials to organic fuels, feedstocks, etc. In the current project period, complexes that contain unusual new types of C{sub x}(carbide) and C{sub x}O{sub y} (carbon oxide) ligands have been emphasized. A new program in homogeneous fluorous phase catalysis has been launched as described in the final report.

  11. Chiral Diamine-catalyzed Asymmetric Aldol Reaction

    Institute of Scientific and Technical Information of China (English)

    LI Hui; XU Da-zhen; WU Lu-lu; WANG Yong-mei

    2012-01-01

    A highly efficient catalytic system composed of a simple and commercially available chiral primary diamine (1R,2R)-cyclohexane-1,2-diamine(6) and trifluoroacetic acid(TFA) was employed for asymmetric Aldol reaction in i-PrOH at room temperature.A loading of 10%(molar fraction) catalyst 6 with TFA as a cocatalyst could catalyze the Aldol reactions of various ketones or aldehydes with a series of aromatic aldehydes,furnishing Aldol products in moderate to high yields(up to >99%) with enantioselectivities of up to >99% and diastereoselectivities of up to 99:1.

  12. Expression and purification of histone H3 proteins containing multiple sites of lysine acetylation using nonsense suppression.

    Science.gov (United States)

    Young, Isaac A; Mittal, Chitvan; Shogren-Knaak, Michael A

    2016-02-01

    Lysine acetylation is a common post-translational modification, which is especially prevalent in histone proteins in chromatin. A number of strategies exist for generating histone proteins containing lysine acetylation, but an especially attractive approach is to genetically encode acetyl-lysine residues using nonsense suppression. This strategy has been successfully applied to single sites of histone acetylation. However, because histone acetylation can often occur at multiple sites simultaneously, we were interested in determining whether this approach could be extended. Here we show that we can express histone H3 proteins that incorporate up to four sites of lysine acetylation on the histone tail. Because the amount of expressed multi-acetylated histone is reduced relative to the wild type, a purification strategy involving affinity purification and ion exchange chromatography was optimized. This expression and purification strategy ultimately generates H3 histone uniformly acetylated at the desired position at levels and purity sufficient to assemble histone octamers. Histone octamers containing four sites of lysine acetylation were assembled into mononucleosomes and enzymatic assays confirmed that this acetylation largely blocks further acetylation by the yeast SAGA acetyltransferase complex.

  13. An MRM-based workflow for absolute quantitation of lysine-acetylated metabolic enzymes in mouse liver.

    Science.gov (United States)

    Xu, Leilei; Wang, Fang; Xu, Ying; Wang, Yi; Zhang, Cuiping; Qin, Xue; Yu, Hongxiu; Yang, Pengyuan

    2015-12-01

    As a key post-translational modification mechanism, protein acetylation plays critical roles in regulating and/or coordinating cell metabolism. Acetylation is a prevalent modification process in enzymes. Protein acetylation modification occurs in sub-stoichiometric amounts; therefore extracting biologically meaningful information from these acetylation sites requires an adaptable, sensitive, specific, and robust method for their quantification. In this work, we combine immunoassays and multiple reaction monitoring-mass spectrometry (MRM-MS) technology to develop an absolute quantification for acetylation modification. With this hybrid method, we quantified the acetylation level of metabolic enzymes, which could demonstrate the regulatory mechanisms of the studied enzymes. The development of this quantitative workflow is a pivotal step for advancing our knowledge and understanding of the regulatory effects of protein acetylation in physiology and pathophysiology.

  14. Proteome-wide mapping of the Drosophila acetylome demonstrates a high degree of conservation of lysine acetylation

    DEFF Research Database (Denmark)

    Weinert, Brian T; Wagner, Sebastian A; Horn, Heiko;

    2011-01-01

    . With high-resolution mass spectrometry, we identified 1981 lysine acetylation sites in the proteome of Drosophila melanogaster. We used data sets of experimentally identified acetylation and phosphorylation sites in Drosophila and humans to analyze the evolutionary conservation of these modification...... sites between flies and humans. Site-level conservation analysis revealed that acetylation sites are highly conserved, significantly more so than phosphorylation sites. Furthermore, comparison of lysine conservation in Drosophila and humans with that in nematodes and zebrafish revealed that acetylated...... that acetylation of ubiquitin-conjugating E2 enzymes was evolutionarily conserved, and mutation of a conserved acetylation site impaired the function of the human E2 enzyme UBE2D3. This systems-level analysis of comparative posttranslational modification showed that acetylation is an anciently...

  15. Efficacy of N-acetyl cysteine in traumatic brain injury.

    Directory of Open Access Journals (Sweden)

    Katharine Eakin

    Full Text Available In this study, using two different injury models in two different species, we found that early post-injury treatment with N-Acetyl Cysteine (NAC reversed the behavioral deficits associated with the TBI. These data suggest generalization of a protocol similar to our recent clinical trial with NAC in blast-induced mTBI in a battlefield setting, to mild concussion from blunt trauma. This study used both weight drop in mice and fluid percussion injury in rats. These were chosen to simulate either mild or moderate traumatic brain injury (TBI. For mice, we used novel object recognition and the Y maze. For rats, we used the Morris water maze. NAC was administered beginning 30-60 minutes after injury. Behavioral deficits due to injury in both species were significantly reversed by NAC treatment. We thus conclude NAC produces significant behavioral recovery after injury. Future preclinical studies are needed to define the mechanism of action, perhaps leading to more effective therapies in man.

  16. Experimental thermochemical study of 3-acetyl-2-methyl-5-phenylthiophene

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro da Silva, Manuel A.V., E-mail: risilva@fc.up.p [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Santos, Ana Filipa L.O.M. [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)

    2010-01-15

    The standard (p{sup 0}=0.1MPa) massic energy of combustion, in oxygen, of the crystalline 3-acetyl-2-methyl-5-phenylthiophene was measured, at T = 298.15 K, by rotating-bomb combustion calorimetry, from which the standard molar enthalpy of formation, in the condensed phase, was calculated as DELTA{sub f}H{sub m}{sup 0}(cr)=-(104.3+-3.1)kJ.mol{sup -1}. The corresponding standard molar enthalpy of sublimation, at T = 298.15 K, DELTA{sub cr}{sup g}H{sub m}{sup 0}=(108.9+-0.4)kJ.mol{sup -1}, was derived by the Clausius-Clapeyron equation, from the temperature dependence of the vapour pressures of this compound, measured by the Knudsen effusion mass-loss technique. From the results presented above, the standard molar enthalpy of formation, in the gaseous phase, at T = 298.15 K, was derived, DELTA{sub f}H{sub m}{sup 0}(g)=(4.6+-3.1)kJ.mol{sup -1}. This value, in conjunction with the literature values of the experimental enthalpies of formation of thiophene, 2-methylthiophene, and 3-acetylthiophene, was used to predict the enthalpic increment due to the introduction of a phenyl group in the position 2- of the thiophene ring. The calculated increment was compared with the corresponding ones in benzene and pyridine derivatives.

  17. Blends of Poly (lactic acid) with Thermoplastic Acetylated Starch

    Institute of Scientific and Technical Information of China (English)

    ZHANG Kun-yu; RAN Xiang-hai; ZHUANG Yu-gang; YAO Bin; DONG Li-song

    2009-01-01

    Blends of poly(lactic acid)(PLA) and thermoplastic acetylated starch(ATPS) were prepared by means of the melt mixing method. The results show that PLA and ATPS were partially miscible, which was confirmed with the measurement of T_g by dynamic mechanical analysis(DMA) and differrential scanning calorimetry(DSC). The mechanical and thermal properties of the blends were improved. With increasing the ATPS content, the elongation at break and impact strength were increased. The elongation at break increased from 5% of neat PLA to 25% of the blend PLA/ATPS40. It was found that the cold crystallization behavior of PLA changed evidently by addition of ATPS. The cold crystallization temperature(T_(cc)) of each of PLA/ATPS blends was found to shift to a lower temperature and the width of exothermic peak became narrow compared with that of neat PLA. The thermogravimetry analy-sis(TGA) results showed that the peak of derivative weight for ATPS moved to higher temperature with increasing PLA content in PLA/ATPS blends. It can be concluded that PLA could increase the thermal stability of ATPS. The rheological measurement reveals the melt elasticity and viscosity of the blends decreased with the increased concentration of ATPS, which was favorable to the processing properties of PLA.

  18. N-acetyl cysteine therapy in acute viral hepatitis

    Institute of Scientific and Technical Information of China (English)

    Huseyin Gunduz; Oguz Karabay; Ali Tamer; Resat Ozaras; Ali Mert; Omer Fehmi Tabak

    2003-01-01

    AIM: To investigate the effect of N-acetyl cysteine (NAC)on acute viral hepatitis (AVH).METHODS: We administered 200 mg oral NAC three times daily (600 mg/day) to the study group and placebo capsules to the control group. All patients were hospitalized and diagnosed as AVH. Blood total and direct bilirubin, ALT, AST,alkaline phosphatese, albumin and globulin levels of each patient were measured twice weekly until total bilirubin level dropped under 2 mg/dl, ALT level under 100 U/L, follow up was continued and then the patients were discharged.RESULTS: A total of 41(13 female and 28 male) AVH patients were included in our study. The period for normalization of ALT and total bilirubin in the study group was 19.7±6.9 days and 13.7±8.5 days respectively. In the control group it was 20.4±6.5 days and 16.9±7.8 days respectively (P>0.05).CONCLUSION: NAC administration effected neither the time necessary for normalization of ALT and total bilirubin values nor duration of hospitalization, so we could not suggest NAC for the treatment of icteric AVH cases. However, our results have shown that this drug is not harmful to patients with AVH.

  19. Reference intervals for acetylated fetal hemoglobin in healthy newborns

    Directory of Open Access Journals (Sweden)

    Renata Paleari

    2014-09-01

    Full Text Available The acetylated fetal hemoglobin (AcHbF derives from an enzyme-mediated post-translational modification occurring on the N-terminal glycine residues of γ-chains. At present, no established data are available on reference intervals for AcHbF in newborns. A total of 92 healthy infants, with gestational age between 37 and 41 weeks were selected for the establishment of AcHbF reference intervals. Blood samples were collected by heel pricking, when collecting routine neonatal screening, and the hemoglobin pattern was analyzed by high-performance liquid chromatography. AcHbF results were then normalized for HbF content in order to account for differences in hemoglobin switch. No difference was found in AcHbF values between genders (P=0.858. AcHbF results were as follow: 12.8±0.8% (mean±standard deviation, reference interval: 11.3-14.3%. This finding could facilitate further studies aimed to assess the possible use of AcHbF, for instance as a possible fetal metabolic biomarker during pregnancy.

  20. Carbohydrate-linked asparagine-101 of prothrombin contains a metal ion protected acetylation site. Acetylation of this site causes loss of metal ion induced protein fluorescence change

    International Nuclear Information System (INIS)

    Prothrombin fragment 1 (prothrombin residues 1-156) contains two acetylation sites that are protected from derivatization by calcium. The first site was protected by only calcium while the second site was protected by magnesium as well. To identify this second acetylation site, fragment 1 was first acetylated with unlabeled reagent in the presence of magnesium. Metal ions were removed, and the protein was acetylated with radiolabeled reagent. The incorporated radiolabel was stable over long periods of time and at acidic or basic pH as long as elevated temperatures were avoided. The radiolabel was removed by treatment of the protein at pH 10 and 50 0C or with 0.2 M hydroxylamine at 50 0C for at least 30 min. Proteolytic degradation of the protein showed that the radioactivity appeared in a tryptic peptide corresponding to residues 94-111 of prothrombin. Amino acid sequence analysis revealed that the radiolabel was associated with an unextracted sequence product. The major radiolabeled product contained Asn101-Ser102 along with the expected chitobiose attached to Asn-101. NMR analysis revealed the presence of three acetate groups which would correspond to two from the chitobiose plus the incorporated acetate residue. Mass spectral analysis showed the correct mass for this glycopeptide plus a single added acetyl group. Amide 1H NMR analysis showed only three amide protons rather than the anticipated four. On the basis of these several observations, it is postulated that the site of acetylation is the β-amide nitrogen of Asn-101. Consequently, these studies showed an unusual chemical reactivity in prothrombin fragment 1. They further show that metal ion binding to prothrombin fragment 1 and subsequent protein fluorescence quenching involve sites ion the kringle region of the protein

  1. Preparation and structural characterization of O-acetyl agarose with low degree of substitution

    Directory of Open Access Journals (Sweden)

    Rosangela B. Garcia

    2000-09-01

    Full Text Available Among the biodegradable polymers, the polysaccharides have been found to be promising carriers for bioactive molecules. From a general standpoint, they present several reactive groups, such as hydroxyl, carboxyl and amine, that can be modified in a number of ways, giving rise to suitable devices for controlled release. In this paper, agarose was submitted to O-acetylation reactions under heterogeneous conditions, using acetic anhydride and pyridine, aiming to observe the effect of acetyl groups on the agarose properties. The products were characterized by Infrared and ¹H NMR spectroscopies. In the range of average acetylation degrees (DA 0.07-0.48, the polymers presented partial solubility in boiling water and in common organic solvents. The ¹H NMR spectra presented evidences of non-homogeneous acetyl group distribution along the chains, as concluded from the solubility of only one of the fractions with DA<0.09, in boiling water .

  2. N-acetyl-L-phenylalanyl-L-phenylalaninol a metabolite of Emericellopsis salmosynnemata.

    Science.gov (United States)

    Argoudelis, A D; Mizsak, S A; Baczynskyj, L

    1975-10-01

    A new metabolite N-acetyl-L-phenylalanyl-L-phenylalaninol was isolated from culture filtrates of Emericellopsis salmosynnemata which produces zervamicins I and II. The structure was assigned from spectral properties and degradative studies. PMID:1184465

  3. Acetylation Enhances the Promoting Role of AIB1 in Breast Cancer Cell Proliferation

    Science.gov (United States)

    You, Dingyun; Zhao, Hongbo; Wang, Yan; Jiao, Yang; Lu, Minnan; Yan, Shan

    2016-01-01

    The oncogene nuclear receptor coactivator amplified in breast cancer 1 (AIB1) is a transcriptional coactivator, which is overexpressed in various types of human cancers, including breast cancer. However, the molecular mechanisms regulating AIB1 function remain largely unknown. In this study, we present evidence demonstrating that AIB1 is acetylated by MOF in human breast cancer cells. Moreover, we also found that the acetylation of AIB1 enhances its function in promoting breast cancer cell proliferation. We further showed that the acetylation of AIB1 is required for its recruitment to E2F1 target genes by E2F1. More importantly, we found that the acetylation levels of AIB1 are greatly elevated in human breast cancer cells compared with that in non-cancerous cells. Collectively, our results shed light on the molecular mechanisms that regulate AIB1 function in breast cancer. PMID:27665502

  4. Histone acetylation in astrocytes suppresses GFAP and stimulates a reorganization of the intermediate filament network

    NARCIS (Netherlands)

    Kanski, Regina; Sneeboer, Marjolein A M; van Bodegraven, Emma J; Sluijs, Jacqueline A; Kropff, Wietske; Vermunt, Marit W.; Creyghton, Menno P; De Filippis, Lidia; Vescovi, Angelo; Aronica, Eleonora; van Tijn, P.; van Strien, Miriam E; Hol, Elly M

    2014-01-01

    Glial fibrillary acidic protein (GFAP) is the main intermediate filament in astrocytes and is regulated by epigenetic mechanisms during development. We demonstrate that histone acetylation also controls GFAP expression in mature astrocytes. Inhibition of histone deacetylases (HDACs) with trichostati

  5. Acetylation regulates monopolar attachment at multiple levels during meiosis I in fission yeast

    OpenAIRE

    Kagami, Ayano; Sakuno, Takeshi; Yamagishi, Yuya; Ishiguro, Tadashi; Tsukahara, Tatsuya; Shirahige, Katsuhiko; Tanaka, Koichi; Watanabe, Yoshinori

    2011-01-01

    This study shows that multiple acetylations are crucial for establishing and maintaining core centromere cohesion in meiosis. Eso1 establishes it during S phase, whereas Moa1 maintains cohesion after S phase.

  6. The Synthesis of Some Novel N-[a-(Isoflavone-7-O-)Acetyl ] Amino Acid Derivatives

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A series of novel N-[(α)-(isoflavone-7-O-)acetyl] amino acid methyl esters were prepared from the efficient and regioselective alkylation of isoflavones with chloroacetyl amino acid derivatives under mild condition.

  7. Effect of histone acetylate modification on the plasminogen activator inhibitor 1 gene regulation in mesangial cells

    Institute of Scientific and Technical Information of China (English)

    刘念

    2013-01-01

    Objective To investigate the effect of histone acetylation change on the transforming growth factor β1(TGF-β1)-associated plasminogen activator inhibitor 1(PAI-1)regulation in mesangial cells(MCs). Methods MCs were

  8. Catalytic dehalogenation of N-acetyl-L-4-chloro- and N-acetyl-L-4-iodophenylalanine amide in the presence of deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Oehlke, J.; Bienert, M.; Niedrich, H.; Zoepfl, H.-J.; Franke, P.

    1986-09-01

    As a model for the tritium labeling of peptides, the catalytic dehalogenation of N-Acetyl-L-4-chloro- and N-Acetyl-L-4-iodo-phenylalanine amide was investigated in the presence of deuterium, using different reaction conditions. A catalyst-mediated transfer of the solvent-hydrogen to the substrate was found to be the most probable reason for the exchange of halogen by hydrogen instead of deuterium. This unwanted transfer was most intensive in the presence of water. An incorporation of additional deuterium besides the 4-position of phenylalanine takes place simultaneously with the dehalogenation especially of the chloro derivative.

  9. Palladium-Catalyzed Arylation of Fluoroalkylamines

    Science.gov (United States)

    Brusoe, Andrew T.; Hartwig, John F.

    2015-01-01

    We report the synthesis of fluorinated anilines by palladium-catalyzed coupling of fluoroalkylamines with aryl bromides and aryl chlorides. The products of these reactions are valuable because anilines typically require the presence of an electron-withdrawing substituent on nitrogen to suppress aerobic or metabolic oxidation, and the fluoroalkyl groups have steric properties and polarity distinct from those of more common electron-withdrawing amide and sulfonamide units. The fluoroalkylaniline products are unstable under typical conditions for C–N coupling reactions (heat and strong base). However, the reactions conducted with the weaker base KOPh, which has rarely been used in cross-coupling to form C–N bonds, occurred in high yield in the presence of a catalyst derived from commercially available AdBippyPhos and [Pd(allyl)Cl]2. Under these conditions, the reactions occur with low catalyst loadings (<0.50 mol % for most substrates) and tolerate the presence of various functional groups that react with the strong bases that are typically used in Pd-catalyzed C–N cross-coupling reactions of aryl halides. The resting state of the catalyst is the phenoxide complex, (BippyPhosPd(Ar)OPh); due to the electron-withdrawing property of the fluoroalkyl substituent, the turnover-limiting step of the reaction is reductive elimination to form the C–N bond. PMID:26065341

  10. Novel myelin penta- and hexa-acetyl-galactosyl-ceramides: structural characterization and immunoreactivity in cerebrospinal fluid

    DEFF Research Database (Denmark)

    Podbielska, Maria; Dasgupta, Somsankar; Levery, Steven B;

    2010-01-01

    Fast migrating cerebrosides (FMC) are derivatives of galactosylceramide (GalCer). The structures of the most hydrophobic FMC-5, FMC-6, and FMC-7 were determined by electrospray ionization linear ion-trap mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy complementing previous......GL-II from Mycoplasma fermentans. The cross-reactivity of highly acetylated GalCer with microbial acyl-glycolipid raises the possibility that myelin-O-acetyl-cerebrosides, bacterial infection, and neurological disease are linked....

  11. Ku70 acetylation mediates neuroblastoma cell death induced by histone deacetylase inhibitors

    OpenAIRE

    Subramanian, Chitra; Opipari, Anthony W.; Bian, Xin; Castle, Valerie P; Kwok, Roland P S

    2005-01-01

    Histone deacetylase inhibitors (HDACIs) are therapeutic drugs that inhibit deacetylase activity, thereby increasing acetylation of many proteins, including histones. HDACIs have antineoplastic effects in preclinical and clinical trials and are being considered for cancers with unmet therapeutic need, including neuroblastoma (NB). Uncertainty of how HDACI-induced protein acetylation leads to cell death, however, makes it difficult to determine which tumors are likely to be responsive to these ...

  12. Hippocampal histone acetylation regulates object recognition and the estradiol-induced enhancement of object recognition

    OpenAIRE

    Zhao, Zaorui; Fan, Lu; Fortress, Ashley M.; Boulware, Marissa I.; Frick, Karyn M.

    2012-01-01

    Histone acetylation has recently been implicated in learning and memory processes, yet necessity of histone acetylation for such processes has not been demonstrated using pharmacological inhibitors of histone acetyltransferases (HATs). As such, the present study tested whether garcinol, a potent HAT inhibitor in vitro, could impair hippocampal memory consolidation and block the memory-enhancing effects of the modulatory hormone 17β-estradiol (E2). We first showed that bilateral infusion of ga...

  13. Targeted amino-terminal acetylation of recombinant proteins in E. coli.

    Directory of Open Access Journals (Sweden)

    Matthew Johnson

    Full Text Available One major limitation in the expression of eukaryotic proteins in bacteria is an inability to post-translationally modify the expressed protein. Amino-terminal acetylation is one such modification that can be essential for protein function. By co-expressing the fission yeast NatB complex with the target protein in E.coli, we report a simple and widely applicable method for the expression and purification of functional N-terminally acetylated eukaryotic proteins.

  14. Hair Analysis for Determination of Isoniazid Concentrations and Acetylator Phenotype during Antituberculous Treatment

    OpenAIRE

    Michael Eisenhut; Detlef Thieme; Dagmar Schmid; Sybille Fieseler; Hans Sachs

    2012-01-01

    Background. Analysis of isoniazid (INH) uptake has been based on measurement of plasma concentrations providing a short-term and potentially biased view. Objectives. To establish hair analysis as a tool to measure long-term uptake of INH and to assess whether acetylator phenotype in hair reflects N-acetyltransferase-2 (NAT2) genotype. Design and Methods. INH and acetyl-INH concentrations in hair were determined in patients on INH treatment for M. tuberculosis infection using high pressure liq...

  15. AMPK/Snf1 signaling regulates histone acetylation: Impact on gene expression and epigenetic functions.

    Science.gov (United States)

    Salminen, Antero; Kauppinen, Anu; Kaarniranta, Kai

    2016-08-01

    AMP-activated protein kinase (AMPK) and its yeast homolog, Snf1, are critical regulators in the maintenance of energy metabolic balance not only stimulating energy production but also inhibiting energy-consuming processes. The AMPK/Snf1 signaling controls energy metabolism by specific phosphorylation of many metabolic enzymes and transcription factors, enhancing or suppressing their functions. The AMPK/Snf1 complexes can be translocated from cytoplasm into nuclei where they are involved in the regulation of transcription. Recent studies have indicated that AMPK/Snf1 activation can control histone acetylation through different mechanisms affecting not only gene transcription but also many other epigenetic functions. For instance, AMPK/Snf1 enzymes can phosphorylate the histone H3S10 (yeast) and H2BS36 (mammalian) sites which activate specific histone acetyltransferases (HAT), consequently enhancing histone acetylation. Moreover, nuclear AMPK can phosphorylate type 2A histone deacetylases (HDAC), e.g. HDAC4 and HDAC5, triggering their export from nuclei thus promoting histone acetylation reactions. AMPK activation can also increase the level of acetyl CoA, e.g. by inhibiting fatty acid and cholesterol syntheses. Acetyl CoA is a substrate for HATs, thus increasing their capacity for histone acetylation. On the other hand, AMPK can stimulate the activity of nicotinamide phosphoribosyltransferase (NAMPT) which increases the level of NAD(+). NAD(+) is a substrate for nuclear sirtuins, especially for SIRT1 and SIRT6, which deacetylate histones and transcription factors, e.g. those regulating ribosome synthesis and circadian clocks. Histone acetylation is an important epigenetic modification which subsequently can affect chromatin remodeling, e.g. via bromodomain proteins. We will review the signaling mechanisms of AMPK/Snf1 in the control of histone acetylation and subsequently clarify their role in the epigenetic regulation of ribosome synthesis and circadian clocks

  16. Synthesis and characterization of branched polymers from lipase-catalyzed trimethylolpropane copolymerizations.

    Science.gov (United States)

    Kulshrestha, Ankur S; Gao, Wei; Fu, Hongyong; Gross, Richard A

    2007-06-01

    Lipase-catalyzed terpolymerizations were performed with the monomers trimethylolpropane (B3), 1,8-octanediol (B2), and adipic acid (A2). Polymerizations were performed in bulk, at 70 degrees C, for 42 h, using immobilized lipase B from Candida antartica (Novozyme-435) as a catalyst. To determine the substitution pattern of trimethylolpropane (TMP) in copolymers, model compounds with variable degrees of acetylation were synthesized. Inverse-gated 13C NMR spectra were recorded to first determine the chemical shift positions for mono-, di-, and trisubstituted TMP units and, subsequently, to determine substitution of TMP units along chains. Variation of TMP in the monomer feed gave copolymers with degrees of branching (DB) from 20% to 67%. In one example, a hyperbranched copolyester with 53 mol % TMP adipate units was formed in 80% yield, with Mw 14 100 (relative to polystyrene standards), Mw/Mn 5.3, and DB 36%. Thermal and crystalline properties of the copolyesters were studied by thermogravimetric analysis and differential scanning calorimetry.

  17. Glycolic acid-catalyzed deamidation of asparagine residues in degrading PLGA matrices: a computational study.

    Science.gov (United States)

    Manabe, Noriyoshi; Kirikoshi, Ryota; Takahashi, Ohgi

    2015-03-31

    Poly(lactic-co-glycolic acid) (PLGA) is a strong candidate for being a drug carrier in drug delivery systems because of its biocompatibility and biodegradability. However, in degrading PLGA matrices, the encapsulated peptide and protein drugs can undergo various degradation reactions, including deamidation at asparagine (Asn) residues to give a succinimide species, which may affect their potency and/or safety. Here, we show computationally that glycolic acid (GA) in its undissociated form, which can exist in high concentration in degrading PLGA matrices, can catalyze the succinimide formation from Asn residues by acting as a proton-transfer mediator. A two-step mechanism was studied by quantum-chemical calculations using Ace-Asn-Nme (Ace = acetyl, Nme = NHCH3) as a model compound. The first step is cyclization (intramolecular addition) to form a tetrahedral intermediate, and the second step is elimination of ammonia from the intermediate. Both steps involve an extensive bond reorganization mediated by a GA molecule, and the first step was predicted to be rate-determining. The present findings are expected to be useful in the design of more effective and safe PLGA devices.

  18. Effects of N-acetyl-L-cysteine on gene expression of antioxidant enzymes in yeast cells after irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Kyu; Park, Ji Young; Ryu, Tae Ho; Roh, Chang Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain)

    2012-04-15

    Ionizing radiation induces water radiolysis, which generates highly reactive hydroxyl radicals. Reactive oxygen species (ROS) cause apoptosis and cell damage. When exposed to ionizing radiation, cells activates ROS scavenging detoxifying enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase. SOD scavenges superoxide radicals by catalyzing the conversion of two of these radicals into hydrogen peroxide and molecular oxygen. The hydrogen peroxide formed by superoxide dismutase and by other processes is scavenged by catalase, a ubiquitous heme protein that catalyzes the dismutation of hydrogen peroxide into water and molecular oxygen. Yeast has two catalase and three GPx proteins. The biochemical function of GPx is to reduce lipid-hydroperoxides to their corresponding alcohols and to reduce free hydrogen peroxide to water. N-acetylL-cysteine (NAC) having a thiol, a precursor for glutathione (GSH), is known as one of the antioxidants. NAC prevents the depletion of GSH by radiation, increases the production of GSH, and improves enzymes activity and alkaline phosphatase. In this study, the role of NAC as an antioxidant and a radioprotector was examined on cell survival, transcriptional level, and protein level. through observing viability of cells, analyzing the gene expression of antioxidant enzyme, measuring the SOD activity and intracellular GSH levels in yeast W303-1A strain The cell viability of haploid S. cerevisiae W303-1A strain was reduced significantly at the low dose (10∼30 Gy). The half-lethal dose of the strain was about 20 Gy. The CFU assay result confirmed that NAC could not rescue the cells from radiation-induced death. When irradiated with 100 Gy, an increase in the transcriptional expression was observed in the antioxicant genes. The expression of these genes decreased by treatment of NAC in irradiated cells. NAC decline SOD activity and intracellular GSH levels. The present study shows that NAC can directly scavenge

  19. Acetyl-coenzyme A: a metabolic master regulator of autophagy and longevity.

    Science.gov (United States)

    Schroeder, Sabrina; Pendl, Tobias; Zimmermann, Andreas; Eisenberg, Tobias; Carmona-Gutierrez, Didac; Ruckenstuhl, Christoph; Mariño, Guillermo; Pietrocola, Federico; Harger, Alexandra; Magnes, Christoph; Sinner, Frank; Pieber, Thomas R; Dengjel, Jörn; Sigrist, Stephan J; Kroemer, Guido; Madeo, Frank

    2014-07-01

    As the major lysosomal degradation pathway, autophagy represents the guardian of cellular homeostasis, removing damaged and potentially harmful material and replenishing energy reserves in conditions of starvation. Given its vast physiological importance, autophagy is crucially involved in the process of aging and associated pathologies. Although the regulation of autophagy strongly depends on nutrient availability, specific metabolites that modulate autophagic responses are poorly described. Recently, we revealed nucleo-cytosolic acetyl-coenzyme A (AcCoA) as a phylogenetically conserved inhibitor of starvation-induced and age-associated autophagy. AcCoA is the sole acetyl-group donor for protein acetylation, explaining why pharmacological or genetic manipulations that modify the concentrations of nucleo-cytosolic AcCoA directly affect the levels of protein acetylation. The acetylation of histones and cytosolic proteins inversely correlates with the rate of autophagy in yeast and mammalian cells, respectively, despite the fact that the routes of de novo AcCoA synthesis differ across phyla. Thus, we propose nucleo-cytosolic AcCoA to act as a conserved metabolic rheostat, linking the cellular metabolic state to the regulation of autophagy via effects on protein acetylation.

  20. Quantitating the specificity and selectivity of Gcn5-mediated acetylation of histone H3.

    Directory of Open Access Journals (Sweden)

    Yin-Ming Kuo

    Full Text Available Lysine acetyltransferases (KATs play a unique role in regulating gene transcription as well as maintaining the epigenetic state of the cell. KATs such as Gcn5 and p300/CBP can modify multiple residues on a single histone; however, order and specificity of acetylation can be altered by factors such as histone chaperones, subunit proteins or external stimulus. While the importance of acetylation is well documented, it has been difficult to quantitatively measure the specificity and selectivity of acetylation at different residues within a histone. In this paper, we demonstrate a label-free quantitative high throughput mass spectrometry-based assay capable of quantitatively monitoring all known acetylation sites of H3 simultaneously. Using this assay, we are able to analyze the steady-state enzyme kinetics of Gcn5, an evolutionarily conserved KAT. In doing so, we measured Gcn5-mediated acetylation at six residues (K14>K9 ≈ K23> K18> K27 ≈ K36 and the catalytic efficiency (k(cat/K(m for K9, K14, K18, and K23 as well as the nonenzymatic acetylation rate. We observed selectivity differences of up to -4 kcal/mol between K14 and K18, the highest and lowest measurable k(cat/K(m. These data provide a first look at quantitating the specificity and selectivity of multiple lysines on a single substrate (H3 by Gcn5.

  1. Dichotomy in the Epigenetic Mark Lysine Acetylation is Critical for the Proliferation of Prostate Cancer Cells

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, Ravi [Department of Structural and Chemical Biology, Mount Sinai School of Medicine, 1425 Madison Ave, New York, NY 10029 (United States); Philizaire, Marc [Medgar Evers College, City University of New York, 1638 Bedford Ave, 403D, Brooklyn, NY 11225 (United States); Mujtaba, Shiraz, E-mail: smujtaba@mec.cuny.edu [Department of Structural and Chemical Biology, Mount Sinai School of Medicine, 1425 Madison Ave, New York, NY 10029 (United States); Medgar Evers College, City University of New York, 1638 Bedford Ave, 403D, Brooklyn, NY 11225 (United States)

    2015-08-19

    The dynamics of lysine acetylation serve as a major epigenetic mark, which regulates cellular response to inflammation, DNA damage and hormonal changes. Microarray assays reveal changes in gene expression, but cannot predict regulation of a protein function by epigenetic modifications. The present study employs computational tools to inclusively analyze microarray data to understand the potential role of acetylation during development of androgen-independent PCa. The data revealed that the androgen receptor interacts with 333 proteins, out of which at least 92 proteins were acetylated. Notably, the number of cellular proteins undergoing acetylation in the androgen-dependent PCa was more as compared to the androgen-independent PCa. Specifically, the 32 lysine-acetylated proteins in the cellular models of androgen-dependent PCa were mainly involved in regulating stability as well as pre- and post-processing of mRNA. Collectively, the data demonstrate that protein lysine acetylation plays a crucial role during the transition of androgen-dependent to -independent PCa, which importantly, could also serve as a functional axis to unravel new therapeutic targets.

  2. Intrinsic Tau Acetylation Is Coupled to Auto-Proteolytic Tau Fragmentation.

    Directory of Open Access Journals (Sweden)

    Todd J Cohen

    Full Text Available Tau proteins are abnormally aggregated in a range of neurodegenerative tauopathies including Alzheimer's disease (AD. Recently, tau has emerged as an extensively post-translationally modified protein, among which lysine acetylation is critical for normal tau function and its pathological aggregation. Here, we demonstrate that tau isoforms have different propensities to undergo lysine acetylation, with auto-acetylation occurring more prominently within the lysine-rich microtubule-binding repeats. Unexpectedly, we identified a unique intrinsic property of tau in which auto-acetylation induces proteolytic tau cleavage, thereby generating distinct N- and C-terminal tau fragments. Supporting a catalytic reaction-based mechanism, mapping and mutagenesis studies showed that tau cysteines, which are required for acetyl group transfer, are also essential for auto-proteolytic tau processing. Further mass spectrometry analysis identified the C-terminal 2nd and 4th microtubule binding repeats as potential sites of auto-cleavage. The identification of acetylation-mediated auto-proteolysis provides a new biochemical mechanism for tau self-regulation and warrants further investigation into whether auto-catalytic functions of tau are implicated in AD and other tauopathies.

  3. PW/SiO2 aerogel的制备及其在芘的Friedel-Crafts酰基化反应中的催化性能%Preparation and catalytic performance of PW/SiO2 aerogel for Friedel-Crafts acylation of pyrene to 1-benzoylpyrene

    Institute of Scientific and Technical Information of China (English)

    陈敏; 徐露璐; 王志伟; 魏巍; 殷恒波

    2015-01-01

    采用常压干燥法制备二氧化硅气凝胶(SiO2 aerogel),并以其作为载体,采用浸渍法制备出SiO2气凝胶负载磷钨酸(PW/SiO2 aerogel)催化剂.采用BET,XRD,TEM和NH3-TPD等方法对其进行表征.将所制备的PW/SiO2 aerogel用于催化芘与苯甲酸酐的Friedel-Crafts酰基化反应,在温和条件下合成了重要的精细化工品1-苯甲酰芘,考察了PW/SiO2 aerogel催化性能.结果表明:当磷钨酸负载量为40%,反应温度为60℃,反应时间为40 min时,PW/SiO2 aerogel达到最佳的催化活性,目标产物1-苯甲酰芘的收率和选择性分别可达75.9%和100.0%.通过5次重复试验考察PW/SiO2 aerogel催化剂的重复使用性能,可见PW/SiO2 aerogel催化剂重复使用效果良好.

  4. 全氟辛基磺酰亚胺稀土(Ⅲ)催化氟两相Friedel-Crafts烷基化反应%Recyclable Rare Earth Metal(Ⅲ) Bis(perfluorooctanesulfonyl)imide Complex for Catalytic Friedel-Crafts Alkylation Reaction in Fluorous Biphase System

    Institute of Scientific and Technical Information of China (English)

    洪梅; 沈明贵; 蔡春

    2010-01-01

    制备了全氟辛基磺酰亚胺盐(M[N(SO_2C_8F_(17))_2]_n,n:3,4),并用于催化氟两相烷基化反应.考察了催化剂种类、反应时间、反应温度和催化剂用量对烷基化反应的影响,同时探讨了Yb[N(SO_2C_8F_(17))_2]_3对烷基化试剂摩尔比为0.2%时,催化烷基化试剂与不同芳烃的反应,表明Yb[N(SO_2C_8F_(17))_2]_3是一种有效的烷基化催化剂.含有催化剂的氟相通过简单的相分离后,可回收利用.氟相重复使用5次,其催化活性降低不大.

  5. The effect of N-acetyl cysteine on laryngopharyngeal reflux.

    Directory of Open Access Journals (Sweden)

    Payman Dabirmoghaddam

    2013-11-01

    Full Text Available Laryngopharyngeal reflux (LPR is a variant of gastroesophageal reflux disease (GERD in which the stomach contents go up into the pharynx and then down into the larynx. LPR causes a wide spectrum of manifestations mainly related to the upper and the lower respiratory system such as laryngitis, asthma, chronic obstructive pulmonary disease, cough, hoarseness, postnasal drip disease, sinusitis, otitis media, recurrent pneumonia, laryngeal cancer and etc. The object of this study was to examine the effect of N-acetyl Cysteine (NAC with and without Omeprazole on laryngitis and LPR. Ninety patients with laryngitis or its symptoms were referred and randomly assigned into three groups. The first group was treated by Omeprazole and NAC. The second group was treated by Omeprazole and placebo and the last group was treated by NAC and placebo. Duration of treatment was 3 months and all patients were evaluated at the beginning of study, one month and three month after treatment of sign and symptoms, based on reflux symptom index (RSI and reflex finding score (RFS. Based on the results of this study, despite therapeutic efficacy of all treatment protocols, the RSI before and after 3 months treatment had significant difference in (NAS+ Omeprazole and (Omeprazole+ placebo group (P<0.001 in the first group, P<0.001 in the second group and P=0.35 in the third group. Whereas RFS before and after 3 month treatment had significant difference in all groups. (P<0.001 in each group in comparison with itself but this results had not significant difference after 1 month treatment. Our results showed that the combination therapy with Omeprazole and NAC treatment had the most effect on both subjective and objective questionnaire at least after 3 months treatment. Based on the results of the present study, it seems that the use objective tools are more accurate than subjective tools in evaluation of therapeutic effects in patients with GERD-related laryngitis.

  6. Synthetic applications of gold-catalyzed ring expansions

    Directory of Open Access Journals (Sweden)

    Cristina Nevado

    2011-06-01

    Full Text Available The development of new methodologies catalyzed by late transition metals involving cycloisomerizations of strained rings can open new venues for the synthesis of structurally complex molecules with interesting biological activities. Herein we summarize, from both a synthetic as well as a mechanistic point of view, the most recent developments in gold-catalyzed ring expansions.

  7. The renaissance of palladium(II)-catalyzed oxidation chemistry

    OpenAIRE

    Sigman, Matthew S.; Schultz, Mitchell J.

    2004-01-01

    Palladium(II)-catalyzed oxidations constitute a paramount reaction class but have remained immature over the past few decades. Recently, this field has reappeared at the forefront of organometallic catalysis. This emerging area article outlines recent developments in palladium(II)-catalyzed oxidation chemistry with discussion of potential future growth.

  8. Toward Efficient Palladium-Catalyzed Allylic C-H Alkylation

    DEFF Research Database (Denmark)

    Jensen, Thomas; Fristrup, Peter

    2009-01-01

    Recent breakthroughs have proved that direct palladium (II)-catalyzed allylic C-H alkylation can be achieved. This new procedure shows that the inherent requirement for a leaving group in the Tsuji-Trost palladium-catalyzed allylic alkylation can be lifted. These initial reports hold great promise...

  9. Acetylated α-Tubulin Regulated by N-Acetyl-Seryl-Aspartyl-Lysyl-Proline(Ac-SDKP) Exerts the Anti-fibrotic Effect in Rat Lung Fibrosis Induced by Silica.

    Science.gov (United States)

    Xiaojun, Wang; Yan, Liu; Hong, Xu; Xianghong, Zhang; Shifeng, Li; Dingjie, Xu; Xuemin, Gao; Lijuan, Zhang; Bonan, Zhang; Zhongqiu, Wei; Ruimin, Wang; Brann, Darrell; Fang, Yang

    2016-08-31

    Silicosis is the most serious occupational disease in China. The objective of this study was to screen various proteins related to mechanisms of the pathogenesis of silicosis underlying the anti-fibrotic effect of N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) using proteomic profile analysis. We also aimed to explore a potential mechanism of acetylated α-tubulin (α-Ac-Tub) regulation by Ac-SDKP. Two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) were used to assess the different protein expression profiles between control and silicosis rats treated with or without Ac-SDKP. Twenty-nine proteins were identified to be potentially involved in the progression of silicosis and the anti-fibrotic effect of Ac-SDKP. Our current study finds that 1) the lost expression of Ac-Tub-α may be a new mechanism in rat silicosis; 2) treatment of silicotic rats with N-acetyl-Seryl-Aspartyl-Lysyl-Proline (Ac-SDKP) inhibits myofibroblast differentiation and collagen deposition accompanied by stabilizing the expression of α-Ac-Tub in vivo and in vitro, which is related with deacetylase family member 6 (HDAC6) and α-tubulin acetyl transferase (α-TAT1). Our data suggest that α-Ac-Tub regulation by Ac-SDKP may potentially be a new anti-fibrosis mechanism.

  10. Acetylated α-Tubulin Regulated by N-Acetyl-Seryl-Aspartyl-Lysyl-Proline(Ac-SDKP) Exerts the Anti-fibrotic Effect in Rat Lung Fibrosis Induced by Silica

    Science.gov (United States)

    Xiaojun, Wang; Yan, Liu; Hong, Xu; Xianghong, Zhang; Shifeng, Li; Dingjie, Xu; Xuemin, Gao; Lijuan, Zhang; Bonan, Zhang; Zhongqiu, Wei; Ruimin, Wang; Brann, Darrell; Fang, Yang

    2016-01-01

    Silicosis is the most serious occupational disease in China. The objective of this study was to screen various proteins related to mechanisms of the pathogenesis of silicosis underlying the anti-fibrotic effect of N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) using proteomic profile analysis. We also aimed to explore a potential mechanism of acetylated α-tubulin (α-Ac-Tub) regulation by Ac-SDKP. Two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) were used to assess the different protein expression profiles between control and silicosis rats treated with or without Ac-SDKP. Twenty-nine proteins were identified to be potentially involved in the progression of silicosis and the anti-fibrotic effect of Ac-SDKP. Our current study finds that 1) the lost expression of Ac-Tub-α may be a new mechanism in rat silicosis; 2) treatment of silicotic rats with N-acetyl-Seryl-Aspartyl-Lysyl-Proline (Ac-SDKP) inhibits myofibroblast differentiation and collagen deposition accompanied by stabilizing the expression of α-Ac-Tub in vivo and in vitro, which is related with deacetylase family member 6 (HDAC6) and α-tubulin acetyl transferase (α-TAT1). Our data suggest that α-Ac-Tub regulation by Ac-SDKP may potentially be a new anti-fibrosis mechanism. PMID:27577858

  11. Transition Metal Catalyzed Synthesis of Aryl Sulfides

    Directory of Open Access Journals (Sweden)

    Chad C. Eichman

    2011-01-01

    Full Text Available The presence of aryl sulfides in biologically active compounds has resulted in the development of new methods to form carbon-sulfur bonds. The synthesis of aryl sulfides via metal catalysis has significantly increased in recent years. Historically, thiolates and sulfides have been thought to plague catalyst activity in the presence of transition metals. Indeed, strong coordination of thiolates and thioethers to transition metals can often hinder catalytic activity; however, various catalysts are able to withstand catalyst deactivation and form aryl carbon-sulfur bonds in high-yielding transformations. This review discusses the metal-catalyzed arylation of thiols and the use of disulfides as metal-thiolate precursors for the formation of C-S bonds.

  12. Theoretical survey of muon catalyzed fusion

    International Nuclear Information System (INIS)

    The main steps in the muon-catalyzed d-t fusion cycle are given in this report. Most of the stages are very fast, and therefore do not contribute significantly to the cycling time. Thus at liquid H2 densities (/phi/ = 1 in the standard convention) the time for stopping the negative muon, its subsequent capture and deexcitation to the ground state is estimated to be /approximately/ 10/sup/minus/11/ sec.1 The muon spends essentially all of its time in either the (dμ) ground state, waiting for transfer to a (tμ) ground state to occur, or in the (tμ) ground state, writing for molecular formation to occur. Following the formation of this ''mesomolecule'' (actually a muonic molecular ion), deexcitation and fusion are again fast. Then the muon is (usually) liberated to go around again. We will discuss these steps in some detail. 5 refs., 3 figs

  13. Catalyzed deuterium fueled tandem mirror reactor assessment

    International Nuclear Information System (INIS)

    This study was part of a Department of Energy supported alternate fusion fuels program at Science Applications International Corp. The purpose of this portion of the study is to perform an assessment of a conceptual tandem mirror reactor (TMR) that is fueled by the catalyzed-deuterium (Cat-d) fuel cycle with respect to the physics, technology, safety, and cost. Achievable stable betas and magnet configurations are found to be comparable for the Cat-d and d-t fueled TMR. A comparison with respect to cost, reactor performance, and technology requirements for a Cat-d fueled reactor and a comparable d-t fueled reactor such as MARS is also made

  14. Gallium-Catalyzed Silicon Oxide Nanowire Growth

    Institute of Scientific and Technical Information of China (English)

    Zheng Wei Pan; Sheng Dai; Douglas H.Lowndes

    2005-01-01

    Silicon oxide nanowires tend to assemble into various complex morphologies through a metalcatalyzed vapor-liquid-solid (VLS) growth process. This article summarizes our recent efforts in the controlled growth of silicon oxide nanowire assemblies by using molten gallium as the catalyst and silicon wafer,SiO powder, or silane (SiH4) as the silicon sources. Silicon oxide nanowire assemblies with morphologies of carrotlike, cometlike, gourdlike, spindlelike, badmintonlike, sandwichlike, etc. were obtained. Although the morphologies of the nanowire assemblies are temperature- and silicon source-dependent, they share similar structural and compositional features: all the assemblies contain a microscale spherical liquid Ga ball and a highly aligned, closely packed amorphous silicon oxide nanowire bunch. The Ga-catalyzed silicon oxide nanowire growth reveals several interesting new nanowire growth phenomena that expand our knowledge of the conventional VLS nanowire growth mechanism.

  15. Direct conversion of muon catalyzed fusion energy

    International Nuclear Information System (INIS)

    In this paper a method of direct conversion of muon catalyzed fusion (MCF) energy is proposed in order to reduce the cost of muon production. This MCF concept is based on a pellet composed of many thin solid deuterium-tritium (DT) rods encircled by a metallic circuit immersed in a magnetic field. The direct energy conversion is the result of the heating of the pellet by beam injection and fusion alphas. The expanding DT rods causes the change of magnetic flux linked by the circuit. Our calculation shows that the direct conversion method reduces the cost of one muon by a factor of approximately 2.5 over the previous methods. The present method is compatible with a reactor using the pellet concept, where the muon sticking is reduced by the ion cyclotron resonance heating and the confinement of the exploding pellet is handled by magnetic fields and the coronal plasma. 17 refs., 6 figs

  16. Heterogeneously Catalyzed Oxidation Reactions Using Molecular Oxygen

    DEFF Research Database (Denmark)

    Beier, Matthias Josef

    . Compared to alcohol oxidation the epoxidation of olefins with molecular oxygen is more difficult. Using N,N-dimethylformamide (DMF) as a solvent the Co-based metal-organic framework (MOF) STA-12(Co) catalyzed the epoxidation of styrene, (E)- and (Z)-stilbene. While the stilbene isomers were converted....... XAS revealed that silver was in the metallic state. Silver particle sizes estimated from XAS were significantly smaller (2- 3 nm) than from transmission electron microscopy (TEM) and X-ray diffraction (XRD; ca. 30 nm). It was proposed that silver-oxygen species might cause local disorder which would...... of silver was observed with the impregnated silver catalyst. By using silver supported on CeO2-SiO2 prepared by flame spray pyrolysis, leaching could be limited significantly. XAS investigation revealed that the active catalyst is most likely metallic silver. Compared to silver on silica calcined at 500 °C...

  17. Enzyme-catalyzed degradation of carbon nanomaterials

    Science.gov (United States)

    Kotchey, Gregg P.

    Carbon nanotubes and graphene, the nanoscale sp 2 allotropes of carbon, have garnered widespread attention as a result of their remarkable electrical, mechanical, and optical properties and the promise of new technologies that harness these properties. Consequently, these carbon nanomaterials (CNMs) have been employed for diverse applications such as electronics, sensors, composite materials, energy conversion devices, and nanomedicine. The manufacture and eventual disposal of these products may result in the release of CNMs into the environment and subsequent exposure to humans, animals, and vegetation. Given the possible pro-inflammatory and toxic effects of CNMs, much attention has been focused on the distribution, toxicity, and persistence of CNMs both in living systems and the environment. This dissertation will guide the reader though recent studies aimed at elucidating fundamental insight into the persistence of CNMs such as carbon nanotubes (CNTs) and graphene derivatives (i.e., graphene oxide and reduced graphene oxide). In particular, in-testtube oxidation/degradation of CNMs catalyzed by peroxidase enzymes will be examined, and the current understanding of the mechanisms underlying these processes will be discussed. Finally, an outlook of the current field including in vitro and in vivo biodegradation experiments, which have benefits in terms of human health and environmental safety, and future directions that could have implications for nanomedical applications such as imaging and drug delivery will be presented. Armed with an understanding of how and why CNMs undergo enzyme-catalyzed oxidation/biodegradation, researchers can tailor the structure of CNMs to either promote or inhibit these processes. For example, in nanomedical applications such as drug delivery, the incorporation of carboxylate functional groups could facilitate biodegradation of the nanomaterial after delivery of the cargo. Also, the incorporation of CNMs with defect sites in consumer

  18. PSG gene expression is up-regulated by lysine acetylation involving histone and nonhistone proteins.

    Directory of Open Access Journals (Sweden)

    Soledad A Camolotto

    Full Text Available BACKGROUND: Lysine acetylation is an important post-translational modification that plays a central role in eukaryotic transcriptional activation by modifying chromatin and transcription-related factors. Human pregnancy-specific glycoproteins (PSG are the major secreted placental proteins expressed by the syncytiotrophoblast at the end of pregnancy and represent early markers of cytotrophoblast differentiation. Low PSG levels are associated with complicated pregnancies, thus highlighting the importance of studying the mechanisms that control their expression. Despite several transcription factors having been implicated as key regulators of PSG gene family expression; the role of protein acetylation has not been explored. METHODOLOGY/PRINCIPAL FINDINGS: Here, we explored the role of acetylation on PSG gene expression in the human placental-derived JEG-3 cell line. Pharmacological inhibition of histone deacetylases (HDACs up-regulated PSG protein and mRNA expression levels, and augmented the amount of acetylated histone H3 associated with PSG 5'regulatory regions. Moreover, PSG5 promoter activation mediated by Sp1 and KLF6, via the core promoter element motif (CPE, -147/-140, was markedly enhanced in the presence of the HDAC inhibitor trichostatin A (TSA. This effect correlated with an increase in Sp1 acetylation and KLF6 nuclear localization as revealed by immunoprecipitation and subcellular fractionation assays. The co-activators PCAF, p300, and CBP enhanced Sp1-dependent PSG5 promoter activation through their histone acetylase (HAT function. Instead, p300 and CBP acetyltransferase domain was dispensable for sustaining co-activation of PSG5 promoter by KLF6. CONCLUSIONS/SIGNIFICANCE: Results are consistent with a regulatory role of lysine acetylation on PSG expression through a relaxed chromatin state and an increase in the transcriptional activity of Sp1 and KLF6 following an augmented Sp1 acetylation and KLF6 nuclear localization.

  19. Effect of acetylation on antioxidant and cytoprotective activity of polysaccharides isolated from pumpkin (Cucurbita pepo, lady godiva).

    Science.gov (United States)

    Song, Yi; Yang, Yang; Zhang, Yuyu; Duan, Liusheng; Zhou, Chunli; Ni, Yuanying; Liao, Xiaojun; Li, Quanhong; Hu, Xiaosong

    2013-10-15

    Acetylation of pumpkin (Cucurbita pepo, lady godiva variety) polysaccharide using acetic anhydride with pyridines as catalyst under different conditions was conducted to obtain different degrees of acetylation on a laboratory scale. Furthermore, antioxidant activities and cytoprotective effects of pumpkin polysaccharide and its acetylated derivatives were investigated employing various established in vitro systems. Results showed that addition of pyridine as catalyst could increase the degree of substitution, whereas volume of acetic anhydride had little effect. The acetylated polysaccharides in DPPH scavenging radical activity assay, superoxide anion radical activity assay and reducing power assay exhibited higher antioxidant activity than that of unmodified polysaccharide. H2O2-induced oxidative damages on rat thymic lymphocyte were also prevented by pumpkin polysaccharide and its acetylated derivatives and the derivatives presented higher protective effects. On the whole, acetylated polysaccharide showed relevant antioxidant activity both in vitro and in a cell system. PMID:23987399

  20. Behavioral Neuroadaptation to Alcohol: From Glucocorticoids to Histone Acetylation

    Science.gov (United States)

    Mons, Nicole; Beracochea, Daniel

    2016-01-01

    neuroadaptive changes during withdrawal from chronic alcohol intake. It then highlights the role of cAMP–PKA–CREB signaling cascade and histone acetylation within the PFC and limbic structures in alcohol-induced anxiety and behavioral impairments, and how an understanding of functional alterations of these pathways might lead to better treatments for neuropsychiatric disorders. PMID:27766083

  1. N-acetyl-L-tyrosine (NAT) as a substrate for mushroom tyrosinase.

    Science.gov (United States)

    Kahn, V; Ben-Shalom, N

    1998-02-01

    N-acetyl tyrosine (NAT) is hydroxylated by mushroom tyrosinase and the N-acetyl dopa formed is oxidized by the enzyme to N-acetyl dopaquinone (lambda max = 390 +/- 10 nm). H2O2 and NH2OH each shortened the lag period of NAT hydroxylation by the enzyme. H2O2 had an effect on the changes with time in the spectrum of product(s) formed and on the spectrum of the final product(s) obtained when NAT was hydroxylated by mushroom tyrosinase, in a manner suggesting that H2O2 converts N-acetyl dopaquinone to a pink-violet product(s) (lambda max = 490 nm), whereas such a product(s) was not formed in the absence of H2O2. A pink-violet product(s) (lambda max 490 +/- 20 nm) was also formed when NAT was hydroxylated by mushroom tyrosinase in the presence of NH2OH or para amino benzoic acid (PABA), probably as a result of an interaction between N-acetyl dopaquinone and NH2OH or PABA forming mono- or di-oximes. Kojic acid (5-hydroxy-2-hydroxymethyl)-4H-pyran-4-one) inhibited effectively the rate of NAT hydroxylation by mushroom tyrosinase in the absence or presence of H2O2. When NAT was oxidized by the enzyme in the absence of kojic acid, N-acetyl dopaquinone was formed at once and a shoulder at 490-530 nm appeared later. Under identical conditions but in the presence of kojic acid, a yellow product(s), characterized by a peak at 320 +/- 10 nm, was detected, suggesting that N-acetyl dopaquinone oxidizes kojic acid to the yellow product(s). Maltol (3-hydroxy-2-methyl-4H-pyran-4-one), a gamma-pyrone derivative structurally related to kojic acid, also inhibited the rate of NAT hydroxylation by mushroom tyrosinase. The addition of maltol at the plateau phase of the reaction resulted in an immediate decline in absorbance at 400 nm, suggesting that maltol conjugates with N-acetyl dopaquinone, yielding a product(s) characterized by a lower extinction coefficient at 400 nm than that of N-acetyl dopaquinone alone. The final brown-red product(s) formed when NAT was hydroxylated by mushroom

  2. Human borna disease virus infection impacts host proteome and histone lysine acetylation in human oligodendroglia cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xia [Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Department of Neurology, The Fifth People' s Hospital of Shanghai, School of Medicine, Fudan University, Shanghai, 200240 (China); Zhao, Libo [Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Department of Neurology, The Third People' s Hospital of Chongqing, 400014 (China); Yang, Yongtao [Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Chongqing Key Laboratory of Neurobiology, Chongqing Medical University, Chongqing, 400016 (China); Institute of Neuroscience, Chongqing Medical University, Chongqing, 400016 (China); Bode, Liv [Bornavirus Research Group affiliated to the Free University of Berlin, Berlin (Germany); Huang, Hua [Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Chongqing Key Laboratory of Neurobiology, Chongqing Medical University, Chongqing, 400016 (China); Institute of Neuroscience, Chongqing Medical University, Chongqing, 400016 (China); Liu, Chengyu [Chongqing Key Laboratory of Neurobiology, Chongqing Medical University, Chongqing, 400016 (China); Institute of Neuroscience, Chongqing Medical University, Chongqing, 400016 (China); Huang, Rongzhong [Department of Rehabilitative Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010 (China); Zhang, Liang [Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Chongqing Key Laboratory of Neurobiology, Chongqing Medical University, Chongqing, 400016 (China); Institute of Neuroscience, Chongqing Medical University, Chongqing, 400016 (China); and others

    2014-09-15

    Background: Borna disease virus (BDV) replicates in the nucleus and establishes persistent infections in mammalian hosts. A human BDV strain was used to address the first time, how BDV infection impacts the proteome and histone lysine acetylation (Kac) of human oligodendroglial (OL) cells, thus allowing a better understanding of infection-driven pathophysiology in vitro. Methods: Proteome and histone lysine acetylation were profiled through stable isotope labeling for cell culture (SILAC)-based quantitative proteomics. The quantifiable proteome was annotated using bioinformatics. Histone acetylation changes were validated by biochemistry assays. Results: Post BDV infection, 4383 quantifiable differential proteins were identified and functionally annotated to metabolism pathways, immune response, DNA replication, DNA repair, and transcriptional regulation. Sixteen of the thirty identified Kac sites in core histones presented altered acetylation levels post infection. Conclusions: BDV infection using a human strain impacted the whole proteome and histone lysine acetylation in OL cells. - Highlights: • A human strain of BDV (BDV Hu-H1) was used to infect human oligodendroglial cells (OL cells). • This study is the first to reveal the host proteomic and histone Kac profiles in BDV-infected OL cells. • BDV infection affected the expression of many transcription factors and several HATs and HDACs.

  3. Acetyl hexapeptide-3 in a cosmetic formulation acts on skin mechanical properties - clinical study

    Directory of Open Access Journals (Sweden)

    Kassandra Azevedo Tadini

    2015-12-01

    Full Text Available abstract Acetyl hexapeptide-3 has been used in anti-aging topical formulations aimed at improving skin appearance. However, few basic studies address its effects on epidermis and dermis, when vehiculated in topical formulations. Thus, the objective of this study was to determine the clinical efficacy of acetyl hexapeptide-3 using biophysical techniques. For this purpose, formulations with and without acetyl hexapeptide-3 were applied to the ventral forearm and the face area of forty female volunteers. Skin conditions were evaluated after 2 and 4-week long daily applications, by analyzing the stratum corneum water content and the skin mechanical properties, using three instruments, the Corneometer(r CM 825, CutometerSEM 575 and ReviscometerRV600. All formulations tested increased the stratum corneum water content in the face region, which remained constant until the end of the study. In contrast, only formulations containing acetyl hexapeptide-3 exhibit a significant effect on mechanical properties, by decreasing the anisotropy of the face skin. No significant effects were observed in viscoelasticity parameters. In conclusion, the effects of acetyl hexapeptide-3 on the anisotropy of face skin characterize the compound as an effective ingredient for improving conditions of the cutaneous tissue, when used in anti-aging cosmetic formulations.

  4. Histone H4 lysine 20 acetylation is associated with gene repression in human cells.

    Science.gov (United States)

    Kaimori, Jun-Ya; Maehara, Kazumitsu; Hayashi-Takanaka, Yoko; Harada, Akihito; Fukuda, Masafumi; Yamamoto, Satoko; Ichimaru, Naotsugu; Umehara, Takashi; Yokoyama, Shigeyuki; Matsuda, Ryo; Ikura, Tsuyoshi; Nagao, Koji; Obuse, Chikashi; Nozaki, Naohito; Takahara, Shiro; Takao, Toshifumi; Ohkawa, Yasuyuki; Kimura, Hiroshi; Isaka, Yoshitaka

    2016-01-01

    Histone acetylation is generally associated with gene activation and chromatin decondensation. Recent mass spectrometry analysis has revealed that histone H4 lysine 20, a major methylation site, can also be acetylated. To understand the function of H4 lysine 20 acetylation (H4K20ac), we have developed a specific monoclonal antibody and performed ChIP-seq analysis using HeLa-S3 cells. H4K20ac was enriched around the transcription start sites (TSSs) of minimally expressed genes and in the gene body of expressed genes, in contrast to most histone acetylation being enriched around the TSSs of expressed genes. The distribution of H4K20ac showed little correlation with known histone modifications, including histone H3 methylations. A motif search in H4K20ac-enriched sequences, together with transcription factor binding profiles based on ENCODE ChIP-seq data, revealed that most transcription activators are excluded from H4K20ac-enriched genes and a transcription repressor NRSF/REST co-localized with H4K20ac. These results suggest that H4K20ac is a unique acetylation mark associated with gene repression. PMID:27064113

  5. Solvent-free acetylation of cellulose nanofibers for improving compatibility and dispersion.

    Science.gov (United States)

    Ashori, Alireza; Babaee, Mehran; Jonoobi, Mehdi; Hamzeh, Yahya

    2014-02-15

    Cellulose nanofibers (CNFs), as bio-materials derived from wood or non-wood plants, have the advantages of being biodegradable, renewable, low cost, and having good mechanical properties compared to synthetic nanofibers. CNFs have been used as reinforcement in polymeric matrices, however, due to their polar surface, their dispersibility in non-polar solvents and compatibility with hydrophobic matrices are poor. In this work, the chemical modification of CNFs, using acetic anhydride in the presence of pyridine as a catalyst, was studied with the aim of changing the surface properties. Native and chemically modified CNFs were characterized in terms of dynamic absorption, thermal stability, surface chemistry, morphology, and crystal structure. The reaction of acetylation between the acetyl groups and the hydroxyl groups of the CNFs was examined using Fourier transform infrared (FT-IR) analysis, while its extent was assessed by titration. The ester content of CNFs was higher for the acetylated samples compared to the control samples. It was also shown that the crystallinity decreased moderately as a result of esterification. Thermal stability of the modified nanofibers was slightly increased. Unlike native CNFs, a stable aqueous suspension was obtained with the modified nanofibers in both ethanol and acetone. The contact angle measurements confirmed that the surface characteristics of acetylated CNFs were changed from hydrophilic to more hydrophobic. In addition, the obtained acetylated CNFs showed more hydrophobic surface, which is in favor of enhancing the hydrophobic non-polar mediums. PMID:24507293

  6. The extracellular release of Schistosoma mansoni HMGB1 nuclear protein is mediated by acetylation

    Energy Technology Data Exchange (ETDEWEB)

    Coutinho Carneiro, Vitor; Moraes Maciel, Renata de; Caetano de Abreu da Silva, Isabel; Furtado Madeira da Costa, Rodrigo [Instituto de Bioquimica Medica, Programa de Biotecnologia e Biologia Molecular, Universidade Federal do Rio de Janeiro, CCS, Ilha do Fundao, Rio de Janeiro 21941-590 (Brazil); Neto Paiva, Claudia; Torres Bozza, Marcelo [Departamento de Imunologia, Instituto de Microbiologia Professor Paulo de Goes, Universidade Federal do Rio de Janeiro, CCS, Ilha do Fundao, Rio de Janeiro 21941-590 (Brazil); Rosado Fantappie, Marcelo, E-mail: fantappie@bioqmed.ufrj.br [Instituto de Bioquimica Medica, Programa de Biotecnologia e Biologia Molecular, Universidade Federal do Rio de Janeiro, CCS, Ilha do Fundao, Rio de Janeiro 21941-590 (Brazil)

    2009-12-25

    Schistosoma mansoni HMGB1 (SmHMGB1) was revealed to be a substrate for the parasite histone acetyltransferases SmGCN5 and SmCBP1. We found that full-length SmHMGB1, as well as its HMG-box B (but not HMG-box A) were acetylated in vitro by SmGCN5 and SmCBP1. However, SmCBP1 was able to acetylate both substrates more efficiently than SmGCN5. Interestingly, the removal of the C-terminal acidic tail of SmHMGB1 (SmHMGB1{Delta}C) resulted in increased acetylation of the protein. We showed by mammalian cell transfection assays that SmHMGB1 and SmHMGB1{Delta}C were transported from the nucleus to the cytoplasm after sodium butyrate (NaB) treatment. Importantly, after NaB treatment, SmHMGB1 was also present outside the cell. Together, our data suggest that acetylation of SmHMGB1 plays a role in cellular trafficking, culminating with its secretion to the extracellular milieu. The possible role of SmHMGB1 acetylation in the pathogenesis of schistosomiasis is discussed.

  7. Asymmetric distribution of glucose and indole-3-acetyl-myo-inositol in geostimulated Zea mays seedlings

    Science.gov (United States)

    Momonoki, Y. S.; Bandurski, R. S. (Principal Investigator)

    1988-01-01

    Indole-3-acetyl-myo-inositol occurs in both the kernel and vegetative shoot of germinating Zea mays seedlings. The effect of a gravitational stimulus on the transport of [3H]-5-indole-3-acetyl-myo-inositol and [U-14C]-D-glucose from the kernel to the seedling shoot was studied. Both labeled glucose and labeled indole-3-acetyl-myo-inositol become asymmetrically distributed in the mesocotyl cortex of the shoot with more radioactivity occurring in the bottom half of a horizontally placed seedling. Asymmetric distribution of [3H]indole-3-acetic acid, derived from the applied [3H]indole-3-acetyl-myo-inositol, occurred more rapidly than distribution of total 3H-radioactivity. These findings demonstrate that the gravitational stimulus can induce an asymmetric distribution of substances being transported from kernel to shoot. They also indicate that, in addition to the transport asymmetry, gravity affects the steady state amount of indole-3-acetic acid derived from indole-3-acetyl-myo-inositol.

  8. Effects of histone acetylation on superoxide dismutase 1 gene expression in the pathogenesis of senile cataract

    Science.gov (United States)

    Rong, Xianfang; Qiu, Xiaodi; Jiang, Yongxiang; Li, Dan; Xu, Jie; Zhang, Yinglei; Lu, Yi

    2016-01-01

    Histone acetylation plays key roles in gene expression, but its effects on superoxide dismutase 1 (SOD1) expression in senile cataract remains unknown. To address this problem, the study was to investigate the influence of histone acetylation on SOD1 expression and its effects in the pathogenesis of senile cataract. Senile cataract was classified into three types—nuclear cataract (NC), cortical cataract (CC), and posterior subcapsular cataract (SC)—using the Lens Opacities Classification System III. In senile cataracts, SOD1 expression decreased significantly. Both H3 and H4 were deacetylated at −600 bp of the SOD1 promoter of cataract lenses, and hypoacetylated at −1500, −1200, and −900 bp. In hypoacetylated histones, the hypoacetylation pattern differed among the cataracts. In vitro, anacardic acid (AA) significantly reduced H3 and H4 acetylation at the SOD1 promoter, decreased protein expression, and induced cataract formation in rabbits. AA also inhibited HLEC viability and increased cell apoptosis. In contrast, trichostatin A (TSA) was able to efficaciously stop AA’s effects on both rabbit lenses and HLECs. Decreased histone acetylation at the SOD1 promoter is associated with declined SOD1 expression in senile cataracts. Histone acetylation plays an essential role in the regulation of SOD1 expression and in the pathogenesis of senile cataracts. PMID:27703255

  9. The Caenorhabditis elegans Elongator complex regulates neuronal alpha-tubulin acetylation.

    Directory of Open Access Journals (Sweden)

    Jachen A Solinger

    2010-01-01

    Full Text Available Although acetylated alpha-tubulin is known to be a marker of stable microtubules in neurons, precise factors that regulate alpha-tubulin acetylation are, to date, largely unknown. Therefore, a genetic screen was employed in the nematode Caenorhabditis elegans that identified the Elongator complex as a possible regulator of alpha-tubulin acetylation. Detailed characterization of mutant animals revealed that the acetyltransferase activity of the Elongator is indeed required for correct acetylation of microtubules and for neuronal development. Moreover, the velocity of vesicles on microtubules was affected by mutations in Elongator. Elongator mutants also displayed defects in neurotransmitter levels. Furthermore, acetylation of alpha-tubulin was shown to act as a novel signal for the fine-tuning of microtubules dynamics by modulating alpha-tubulin turnover, which in turn affected neuronal shape. Given that mutations in the acetyltransferase subunit of the Elongator (Elp3 and in a scaffold subunit (Elp1 have previously been linked to human neurodegenerative diseases, namely Amyotrophic Lateral Sclerosis and Familial Dysautonomia respectively highlights the importance of this work and offers new insights to understand their etiology.

  10. Human borna disease virus infection impacts host proteome and histone lysine acetylation in human oligodendroglia cells

    International Nuclear Information System (INIS)

    Background: Borna disease virus (BDV) replicates in the nucleus and establishes persistent infections in mammalian hosts. A human BDV strain was used to address the first time, how BDV infection impacts the proteome and histone lysine acetylation (Kac) of human oligodendroglial (OL) cells, thus allowing a better understanding of infection-driven pathophysiology in vitro. Methods: Proteome and histone lysine acetylation were profiled through stable isotope labeling for cell culture (SILAC)-based quantitative proteomics. The quantifiable proteome was annotated using bioinformatics. Histone acetylation changes were validated by biochemistry assays. Results: Post BDV infection, 4383 quantifiable differential proteins were identified and functionally annotated to metabolism pathways, immune response, DNA replication, DNA repair, and transcriptional regulation. Sixteen of the thirty identified Kac sites in core histones presented altered acetylation levels post infection. Conclusions: BDV infection using a human strain impacted the whole proteome and histone lysine acetylation in OL cells. - Highlights: • A human strain of BDV (BDV Hu-H1) was used to infect human oligodendroglial cells (OL cells). • This study is the first to reveal the host proteomic and histone Kac profiles in BDV-infected OL cells. • BDV infection affected the expression of many transcription factors and several HATs and HDACs

  11. Ach1 is involved in shuttling mitochondrial acetyl units for cytosolic C2 provision in Saccharomyces cerevisiae lacking pyruvate decarboxylase

    DEFF Research Database (Denmark)

    Chen, Yun; Zhang, Yiming; Siewers, Verena;

    2015-01-01

    Acetyl-coenzyme A (acetyl-CoA) is not only an essential intermediate in central carbon metabolism, but also an important precursor metabolite for native or engineered pathways that can produce many products of commercial interest such as pharmaceuticals, chemicals or biofuels. In the yeast Saccha...... mitochondria and the cytosol. These results will increase our fundamental understanding of intracellular transport of acetyl units, and also help to develop microbial cell factories for many kinds of acetyl-CoA derived products.......Acetyl-coenzyme A (acetyl-CoA) is not only an essential intermediate in central carbon metabolism, but also an important precursor metabolite for native or engineered pathways that can produce many products of commercial interest such as pharmaceuticals, chemicals or biofuels. In the yeast......-fermentative yeast strain. We found that mitochondrial Ach1 can convert acetyl-CoA in this compartment into acetate, which crosses the mitochondrial membrane before being converted into acetyl-CoA in the cytosol. Based on our finding we propose a model in which acetate can be used to exchange acetyl units between...

  12. N-terminal acetylation inhibits protein targeting to the endoplasmic reticulum.

    Directory of Open Access Journals (Sweden)

    Gabriella M A Forte

    2011-05-01

    Full Text Available Amino-terminal acetylation is probably the most common protein modification in eukaryotes with as many as 50%-80% of proteins reportedly altered in this way. Here we report a systematic analysis of the predicted N-terminal processing of cytosolic proteins versus those destined to be sorted to the secretory pathway. While cytosolic proteins were profoundly biased in favour of processing, we found an equal and opposite bias against such modification for secretory proteins. Mutations in secretory signal sequences that led to their acetylation resulted in mis-sorting to the cytosol in a manner that was dependent upon the N-terminal processing machinery. Hence N-terminal acetylation represents an early determining step in the cellular sorting of nascent polypeptides that appears to be conserved across a wide range of species.

  13. Glutamine Triggers Acetylation-Dependent Degradation of Glutamine Synthetase via the Thalidomide Receptor Cereblon.

    Science.gov (United States)

    Nguyen, T Van; Lee, J Eugene; Sweredoski, Michael J; Yang, Seung-Joo; Jeon, Seung-Je; Harrison, Joseph S; Yim, Jung-Hyuk; Lee, Sang Ghil; Handa, Hiroshi; Kuhlman, Brian; Jeong, Ji-Seon; Reitsma, Justin M; Park, Chul-Seung; Hess, Sonja; Deshaies, Raymond J

    2016-03-17

    Cereblon (CRBN), a substrate receptor for the cullin-RING ubiquitin ligase 4 (CRL4) complex, is a direct protein target for thalidomide teratogenicity and antitumor activity of immunomodulatory drugs (IMiDs). Here we report that glutamine synthetase (GS) is an endogenous substrate of CRL4(CRBN). Upon exposing cells to high glutamine concentration, GS is acetylated at lysines 11 and 14, yielding a degron that is necessary and sufficient for binding and ubiquitylation by CRL4(CRBN) and degradation by the proteasome. Binding of acetylated degron peptides to CRBN depends on an intact thalidomide-binding pocket but is not competitive with IMiDs. These findings reveal a feedback loop involving CRL4(CRBN) that adjusts GS protein levels in response to glutamine and uncover a new function for lysine acetylation.

  14. Hydrolysis of Wheat Arabinoxylan by Two Acetyl Xylan Esterases from Chaetomium thermophilum

    DEFF Research Database (Denmark)

    Tong, Xiaoxue; Lange, Lene; Grell, Morten Nedergaard;

    2015-01-01

    The thermophilic filamentous ascomycete Chaetomium thermophilum produces functionally diverse hemicellulases when grown on hemicellulose as carbon source. Acetyl xylan esterase (EC 3.1.1.72) is an important accessory enzyme in hemicellulose biodegradation. Although the genome of C. thermophilum has...... been sequenced, its carbohydrate esterases are not annotated yet. We applied peptide pattern recognition (PPR) tool for sequence analysis of the C. thermophilum genome, and 11 carbohydrate esterase genes were discovered. Furthermore, we cloned and heterologously expressed two putative acetyl xylan...... esterase genes, CtAxeA and CtAxeB, in Pichia pastoris. The recombinant proteins, rCtAxeA and rCtAxeB, released acetic acids from p-nitrophenyl acetate and water-insoluble wheat arabinoxylan. These results indicate that CtAxeA and CtAxeB are true acetyl xylan esterases. For both recombinant esterases, over...

  15. 2-acetyl-1-pyrroline - key aroma compound in Mediterranean dried sausages

    DEFF Research Database (Denmark)

    Stahnke, Marie Louise Heller

    2000-01-01

    In a study characterising sausage types from various parts of Europe, ten Mediterranean and Northern European fermented, dried sausages were compared using static headspace gas chromatography-olfactometry and a sniffing panel of five members. The greatest difference between the Northern...... and Southern types were attributed to a burned coffee odour from smoke in the smoked sausages and a popcorn note in the Mediterranean products covered with mould. The two compounds were 2-furfurylthiol and 2-acetyl-1-pyrroline, respectively. An analysis of five dried, moulded sausages showed that the surface...... edge of the sausages contained higher amounts of 2-acetyl-1-pyrroline than the core, indicating that the mould growing on the surface of Mediterranean products produces 2-acetyl-1-pyrroline....

  16. Preparation of Acetylated Guar Gum – Unsaturated Polyester Composites & Effect of Water on Their Properties

    Directory of Open Access Journals (Sweden)

    David D’Melo

    2012-07-01

    Full Text Available Guar gum has seen extensive use in blends, however, its application as a filler in thermoset composites has as yet not been investigated. The effect of the addition of guar gum and its acetyl derivatives on the kinetics of water diffusion in unsaturated polyester composites was studied. The effect of water on the mechanical properties of the composites was studied with respect to the nature of filler, filler concentration and time of immersion. All the mechanical properties were observed to decrease on exposure to water. Further, it was observed that acetylated guar gum, with a degree of substitution of 0.21, showed the best mechanical properties, surpassing the other filled composites and that of the pure unsaturated polyester. Thus, acetylated guar gum showed promise as eco-friendly filler in composite formulation.

  17. Mechanisms of bacterially catalyzed reductive dehalogenation

    Energy Technology Data Exchange (ETDEWEB)

    Picardal, F.W.

    1992-12-31

    Nine bacteria were tested for the ability to dehalogenate tetrachloromethane (CT), tetrachloroethene (PCE), and 1, 1, 1-trichloroethane (TCA) under anaerobic conditions. Three bacteria were able to reductively dehalogenate CT. Dehalogenation ability was not readily linked to a common metabolism or changes in culture redox potential. None of the bacteria tested were able to dehalogenate PCE or TCA. One of the bacteria capable of dehalogenating CT, Shewanella putrefaciens, was chosen as a model organism to study mechanisms of bacterially catalyzed reductive dehalogenation. The effect of a variety of alternate electron acceptors on CT dehalogenation ability by S. putrefaciens was determined. oxygen and nitrogen oxides were inhibitory but Fe (III), trimethylamine oxide, and fumarate were not. A model of the electron transport chain of S. putrefaciens was developed to explain inhibition patterns. A period of microaerobic growth prior to CT exposure increased the ability of S. putrefaciens to dehalogenate CT. A microaerobic growth period also increased cytochrome concentrations. A relationship between cytochrome content and dehalogenation ability was developed from studies in which cytochrome concentrations in S. putrefaciens were manipulated by changing growth conditions. Stoichiometry studies using {sup 14}C-CT suggested that CT was first reduced to form a trichloromethyl radical. Reduction of the radical to produce chloroform and reaction of the radical with cellular biochemicals explained observed product distributions. Carbon dioxide or other fully dehalogenated products were not found.

  18. Stereoselective Palladium Catalyzed Cyclizations of Enediyne Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Chang Ho; Rhim, Chul Yun; Jung, Hyung Hoon; Jung, Seung Hyun [Hanyang University, Seoul (Korea, Republic of)

    1999-06-15

    Hydropalladium carboxylates, formed from {pi}-allylpalladium chloride dimer plus carboxylic acids, have been shown to catalyze cyclization of structurally diverse enediynes to form the corresponding six- or five-membered rings depending upon the reaction conditions. Some enediynes having an oxygen linker in an appropriate position under the similar condition yielded the corresponding cyclopropanation products in highly stereoselective manner. A study using deuterated formic acid has proven that the alkylpalladium intermediates formed in our conditions were reduced by the pendant formate ligand. The dienediyne 10 yielded only the tricyclic product 12 in 67% yield, although it was expected to form the cyclic product 11. All these cyclizations seemed to occur via the corresponding alkylpalladium intermediates I, which could proceed to the corresponding cyclic products depending on the reaction conditions and the substrates. The study using deuterated formic acid could provide an important information to understand the present cyclization mechanism. Overall the present study could play an important role in developing new synthetic methodologies for constructing complex polycyclic compounds

  19. An Efficient One-pot Synthesis of β-Amino/β-Acetamido Car-bonyl Compounds via ZrCl4-catalyzed Mannich-type Reaction

    Institute of Scientific and Technical Information of China (English)

    SANJEEVA REDDY,Cherkupally; PURNACHANDRA REDDY,Gurrala

    2008-01-01

    Zirconium(IV) chloride catalyzed efficient one-pot synthesis of β-amino/β-acetamido carbonyl compounds at room temperature is described. In the presence of ZrCl4, the three-component Mannich-type reaction via a variety of in situ generated aldimines, with various ketones, aromatic aldehydes and aromatic amines in ethanol, led to the formation of β-amino carbonyl compounds and the four-component Mannich-type reaction of aromatic aldehydes with various ketones, acetonitrile and acetyl chloride resulted in the corresponding β-acetamido carbonyl com-pounds in high to excellent yields. This methodology has also been applied towards the synthesis of dimeric β-amino/β-acetamido carbonyl compounds.

  20. Hydroxyapatite catalyzed aldol condensation: Synthesis, spectral linearity, antimicrobial and insect antifeedant activities of some 2,5-dimethyl-3-furyl chalcones

    Science.gov (United States)

    Subramanian, M.; Vanangamudi, G.; Thirunarayanan, G.

    2013-06-01

    A series of 2,5-dimethyl-3-furyl chalcones [2E-1-(2,5-dimethyl-3-furyl)-3-(substituted phenyl)-2-propen-1-ones] have been synthesized by Hydrotalcite catalyzed aldol condensation between 3-acetyl-2,5-dimethylfuron and substituted benzaldehydes. Yields of chalcones are more than 80%. These chalcones were characterized by their physical constants and spectral data. The group frequencies of infrared ν(cm-1) of CO s-cis and s-trans, CH in-plane and out of plane, CHdbnd CH out of plane, lbond2 Cdbnd Crbond2 out of plane modes, NMR chemical shifts δ(ppm) of Hα, Hβ, CO, Cα and Cβ of these chalcones were correlated with Hammett substituent constants, F and R parameters using single and multi-regression analyses. From the results of statistical analyses, the effects of substituents on the group frequencies are explained. Antibacterial, antifungal and insect antifeedant activities of these chalcones have been studied.