Database : MEDLINE
Search on : decarboxylation [Words]
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[PMID]: 29524686
[Au] Autor:Park KY; Lee K; Kim D
[Ad] Address:Department of Civil and Environmental Engineering, Konkuk University, 120, Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea.
[Ti] Title:Characterized hydrochar of algal biomass for producing solid fuel through hydrothermal carbonization.
[So] Source:Bioresour Technol;258:119-124, 2018 Mar 02.
[Is] ISSN:1873-2976
[Cp] Country of publication:England
[La] Language:eng
[Ab] Abstract:The aim of this work was to study the characterized hydrochar of algal biomass to produce solid fuel though hydrothermal carbonization. Hydrothermal carbonization conducted at temperatures ranging from 180 to 270 °C with a 60 min reaction improved the upgrading of the fuel properties and the dewatering of wet-basis biomasses such as algae. The carbon content, carbon recovery, energy recovery, and atomic C/O and C/H ratios in all the hydrochars in this study were improved. These characteristic changes in hydrochar from algal biomass are similar to the coalification reactions due to dehydration and decarboxylation with an increase in the hydrothermal reaction temperature. The results of this study indicate that hydrothermal carbonization can be used as an effective means of generating highly energy-efficient renewable fuel resources using algal biomass.
[Pt] Publication type:JOURNAL ARTICLE
[Em] Entry month:1803
[Cu] Class update date: 180310
[Lr] Last revision date:180310
[St] Status:Publisher

  2 / 7768 MEDLINE  
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[PMID]: 29522332
[Au] Autor:Basuri P; Sarkar D; Paramasivam G; Pradeep T
[Ti] Title:Detection of Hydrocarbons by Laser Assisted Paper Spray Ionization Mass Spectrometry (LAPSI MS).
[So] Source:Anal Chem;, 2018 Mar 09.
[Is] ISSN:1520-6882
[Cp] Country of publication:United States
[La] Language:eng
[Ab] Abstract:Here we introduce a new ambient ionization technique named as laser assisted paper spray ionization mass spectrometry (LAPSI MS). In it, a 532 ± 10 nm, ≤10 mW laser pointer was shone on a triangularly cut paper along with high voltage, to effect ionization. The analyte solution was continuously pushed through a fused silica capillary, using a syringe pump, at a preferred infusion rate. LAPSI MS promises enhanced ionization with high signal intensity of polycyclic aromatic hydrocarbons (PAHs), which are normally not ionizable with similar ionization methods involving solvent sprays. LAPSI MS works both in positive and negative modes of ionization. A clear enhancement of signal intensity was visualized in the total ion chronogram for most analytes in presence of the laser. We speculate that the mechanism of ionization is field assisted photoionization. The field-induced distortion of the potential well can be large in paperspray as the fibers consisting the paper are separated at tens of nanometers apart and consequently the analyte molecules are subjected to very large electric fields of the order of 107 Vcm-1. Ionization occurs from their distorted electronic states of reduced ionization energy, using the laser. Negative ion detection is also demonstrated, occurring due to the capture of photoelectrons produced. LAPSI MS can be used for monitoring in-situ photo-assisted reactions like the decarboxylation of marcaptobenzoic acid in presence of gold and silver nanoparticles and dehydrogenation reaction of 2,3-dihydro-1H-isoindole, which were chosen as examples. As an application, we have shown that paraffin oil which is usually non-ionizable by paperspray or by electrospray ionization can be efficiently detected using this technique. Impurities like mineral oils were detected easily in commercially available coconut oil, pointing the way to applications of social relevance.
[Pt] Publication type:JOURNAL ARTICLE
[Em] Entry month:1803
[Cu] Class update date: 180309
[Lr] Last revision date:180309
[St] Status:Publisher
[do] DOI:10.1021/acs.analchem.7b05213

  3 / 7768 MEDLINE  
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[PMID]: 29520959
[Au] Autor:Yin X; Struik PC
[Ad] Address:Department of Plant Sciences, Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands.
[Ti] Title:The energy budget in C photosynthesis: insights from a cell-type-specific electron transport model.
[So] Source:New Phytol;, 2018 Mar 09.
[Is] ISSN:1469-8137
[Cp] Country of publication:England
[La] Language:eng
[Ab] Abstract:Extra ATP required in C photosynthesis for the CO -concentrating mechanism probably comes from cyclic electron transport (CET). As metabolic ATP : NADPH requirements in mesophyll (M) and bundle-sheath (BS) cells differ among C subtypes, the subtypes may differ in the extent to which CET operates in these cells. We present an analytical model for cell-type-specific CET and linear electron transport. Modelled NADPH and ATP production were compared with requirements. For malic-enzyme (ME) subtypes, c. 50% of electron flux is CET, occurring predominantly in BS cells for standard NADP-ME species, but in a ratio of c. 6 : 4 in BS : M cells for NAD-ME species. Some C acids follow a secondary decarboxylation route, which is obligatory, in the form of 'aspartate-malate', for the NADP-ME subtype, but facultative, in the form of phosphoenolpyruvate-carboxykinase (PEP-CK), for the NAD-ME subtype. The percentage for secondary decarboxylation is c. 25% and that for 3-phosphoglycerate reduction in BS cells is c. 40%; but these values vary with species. The 'pure' PEP-CK type is unrealistic because its is impossible to fulfil ATP : NADPH requirements in BS cells. The standard PEP-CK subtype requires negligible CET, and thus has the highest intrinsic quantum yields and deserves further studies in the context of improving canopy productivity.
[Pt] Publication type:JOURNAL ARTICLE
[Em] Entry month:1803
[Cu] Class update date: 180309
[Lr] Last revision date:180309
[St] Status:Publisher
[do] DOI:10.1111/nph.15051

  4 / 7768 MEDLINE  
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[PMID]: 29519654
[Au] Autor:Mayumi M; Tokashiki M; Tokashiki M; Uechi K; Ito S; Taira T
[Ad] Address:Department of Bioscience and Biotechnology, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan.
[Ti] Title:Characterization and induction of phenolic acid decarboxylase from Aspergillus luchuensis.
[So] Source:J Biosci Bioeng;, 2018 Mar 05.
[Is] ISSN:1347-4421
[Cp] Country of publication:Japan
[La] Language:eng
[Ab] Abstract:Awamori is a traditional distilled liquor in the Ryukyu Islands, made from steamed rice by the action of the black-koji mold Aspergillus luchuensis and awamori yeast Saccharomyces cerevisiae. One of the specific flavors in aged awamori kusu is vanillin, which is derived from ferulic acid (FA) in rice grains. FA is released from the cell wall material in the rice grain by ferulic acid esterase produced by A. luchuensis. Through decarboxylation of FA, 4-vinylguaiacol (4-VG) is produced, which is transferred to the distilled liquor, and converted to vanillin by natural oxidization during the aging process. However, the actual mechanism for conversion of FA to 4-VG in the awamori brewing process is unknown. A genetic sequence having homology to the phenolic acid decarboxylase (PAD)-encoding region from bacteria and the yeast Candida guilliermondii has been identified in A. luchuensis mut. kawachii. In the present study, recombinant PAD from A. luchuensis, designated as AlPAD, expressed as a homodimer, catalyzed the conversion of FA to 4-VG, displayed optimal catalytic activity at pH 5.7 and 40°C, and was stable up to 50°C. Both rice bran and FA could induce the bioconversion of FA to 4-VG and the expression of AlPAD in A. luchuensis. The amount of AlPAD determined using western blotting correlated with the level of FA decarboxylase activity during koji production. In awamori brewing process, AlPAD might be responsible for a part of the conversion of FA to 4-VG.
[Pt] Publication type:JOURNAL ARTICLE
[Em] Entry month:1803
[Cu] Class update date: 180309
[Lr] Last revision date:180309
[St] Status:Publisher

  5 / 7768 MEDLINE  
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[PMID]: 29518063
[Au] Autor:Ukrainets IV; Hamza GM; Burian AA; Shishkina SV; Voloshchuk NI; Malchenko OV
[Ad] Address:Department of Pharmaceutical Chemistry, National University of Pharmacy, 53 Pushkinska st., 61002 Kharkiv, Ukraine. igor.v.ukrainets@gmail.com.
[Ti] Title:4-Methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic Acid. Peculiarities of Preparation, Structure, and Biological Properties.
[So] Source:Sci Pharm;86(1), 2018 Mar 08.
[Is] ISSN:2218-0532
[Cp] Country of publication:Austria
[La] Language:eng
[Ab] Abstract:In order to determine the regularities of the structure-analgesic activity relationship, the peculiarities of obtaining, the spatial structure, and biological properties of 4-methyl-2,2-dioxo-1 -2λ6,1-benzothiazine-3-carboxylic acid and some of its derivatives have been studied. Using nuclear magnetic resonance (NMR) spectroscopy and X-ray diffraction analysis, it has been proven that varying the reaction conditions using alkaline hydrolysis of methyl 4-methyl-2,2-dioxo-1 -2λ6,1-benzothiazine-3-carboxylate makes it possible to successfully synthesize a monohydrate of the target acid, its sodium salt, or 4-methyl-2,2-dioxo-1 -2λ6,1-benzothiazine. The derivatographic study of the thermal stability of 4-methyl-2,2-dioxo-1 -2λ6,1-benzothiazine-3-carboxylic acid monohydrate has been carried out; based on this study, the optimal conditions completely eliminating the possibility of unwanted decomposition have been proposed for obtaining its anhydrous form. It has been shown that 4-methyl-2,2-dioxo-1 -2λ6,1-benzothiazine is easily formed during the decarboxylation of not only 4-methyl-2,2-dioxo-1 -2λ6,1-benzothiazine-3-carboxylic acid, but also its sodium salt, which is capable of losing СО2 both in rather soft conditions of boiling in an aqueous solution, and in more rigid conditions of dry heating. The NMR spectra of the compounds synthesized are given; their spatial structure is discussed. To study the biological properties of 4-methyl-2,2-dioxo-1 -2λ6,1-benzothiazine-3-carboxylic acid and its sodium salt, the experimental model of inflammation caused by subplantar introduction of the carrageenan solution in one of the hind limbs of white rats was used. The anti-inflammatory activity and analgesic effect were assessed by the degree of edema reduction and the ability to affect the pain response compared to the animals of control groups. According to the results of the tests performed, it has been found that after intraperitoneal injection, the substances synthesized demonstrate a moderate anti-inflammatory action and simultaneously increase the pain threshold of the experimental animals very effectively, exceeding Lornoxicam and Diclofenac in a similar dose by their analgesic activity.
[Pt] Publication type:JOURNAL ARTICLE
[Em] Entry month:1803
[Cu] Class update date: 180308
[Lr] Last revision date:180308
[St] Status:In-Data-Review

  6 / 7768 MEDLINE  
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[PMID]: 29451724
[Au] Autor:Koy M; Sandfort F; Tlahuext-Aca A; Quach L; Daniliuc CG; Glorius F
[Ad] Address:Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
[Ti] Title:Palladium-Catalyzed Decarboxylative Heck-Type Coupling of Activated Aliphatic Carboxylic Acids Enabled by Visible Light.
[So] Source:Chemistry;, 2018 Feb 16.
[Is] ISSN:1521-3765
[Cp] Country of publication:Germany
[La] Language:eng
[Ab] Abstract:The palladium-catalyzed coupling reaction of N-hydroxyphthalimide esters and styrenes to deliver exclusively (E)-substituted olefins under irradiation with visible light is reported. This method tolerates N-hydroxyphthalimide esters derived from primary, secondary, tertiary as well as benzylic carboxylic acids. Notably, Pd(PPh ) is employed as an inexpensive palladium source and no addition of base or classical photocatalyst is required. Mechanistic studies suggest a light-mediated single-electron reduction of the activated acid by a photoexcited palladium(0) species to access alkyl radicals through decarboxylation.
[Pt] Publication type:JOURNAL ARTICLE
[Em] Entry month:1802
[Cu] Class update date: 180309
[Lr] Last revision date:180309
[St] Status:Publisher
[do] DOI:10.1002/chem.201800813

  7 / 7768 MEDLINE  
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[PMID]: 29432141
[Au] Autor:Munro AW; McLean KJ; Grant JL; Makris TM
[Ad] Address:Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K. andrew.munro@manchester.ac.uk.
[Ti] Title:Structure and function of the cytochrome P450 peroxygenase enzymes.
[So] Source:Biochem Soc Trans;46(1):183-196, 2018 Feb 19.
[Is] ISSN:1470-8752
[Cp] Country of publication:England
[La] Language:eng
[Ab] Abstract:The cytochromes P450 (P450s or CYPs) constitute a large heme enzyme superfamily, members of which catalyze the oxidative transformation of a wide range of organic substrates, and whose functions are crucial to xenobiotic metabolism and steroid transformation in humans and other organisms. The P450 peroxygenases are a subgroup of the P450s that have evolved in microbes to catalyze the oxidative metabolism of fatty acids, using hydrogen peroxide as an oxidant rather than NAD(P)H-driven redox partner systems typical of the vast majority of other characterized P450 enzymes. Early members of the peroxygenase (CYP152) family were shown to catalyze hydroxylation at the α and ß carbons of medium-to-long-chain fatty acids. However, more recent studies on other CYP152 family P450s revealed the ability to oxidatively decarboxylate fatty acids, generating terminal alkenes with potential applications as drop-in biofuels. Other research has revealed their capacity to decarboxylate and to desaturate hydroxylated fatty acids to form novel products. Structural data have revealed a common active site motif for the binding of the substrate carboxylate group in the peroxygenases, and mechanistic and transient kinetic analyses have demonstrated the formation of reactive iron-oxo species (compounds I and II) that are ultimately responsible for hydroxylation and decarboxylation of fatty acids, respectively. This short review will focus on the biochemical properties of the P450 peroxygenases and on their biotechnological applications with respect to production of volatile alkenes as biofuels, as well as other fine chemicals.
[Pt] Publication type:JOURNAL ARTICLE; REVIEW
[Em] Entry month:1802
[Cu] Class update date: 180309
[Lr] Last revision date:180309
[St] Status:In-Data-Review
[do] DOI:10.1042/BST20170218

  8 / 7768 MEDLINE  
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[PMID]: 29517843
[Au] Autor:Nagel R; Peters RJ
[Ad] Address:UNITED STATES.
[Ti] Title:Traveling two diverging roads, cytochrome-P450 catalyzed demethylation and γ-lactone formation in bacterial gibberellin biosynthesis.
[So] Source:Angew Chem Int Ed Engl;, 2018 Mar 08.
[Is] ISSN:1521-3773
[Cp] Country of publication:Germany
[La] Language:eng
[Ab] Abstract:Biosynthesis of the gibberellin plant hormones evolved independently in plants and microbes, but the pathways proceed via similar transformations. The combined demethylation and -lactone ring forming transformation is of significant mechanistic interest, yet remains opaque. The relevant CYP112 from bacteria was probed via activity assays and 18O2 labeling experiments. Notably, the ability of tert-butyl hydroperoxide to drive this transformation indicates use of the ferryl-oxo (Compound I) from the CYP catalytic cycle for this reaction. Together with the confirmed loss of C-20 as CO2, this necessitates two catalytic cycles for carbon-carbon bond scission and -lactone formation. The ability of CYP112 to hydroxylate the -lactone form of GA15 shown by the labeling studies is consistent with the implied use of a further oxygenated heterocycle in the final conversion of GA24 to GA9, with the partial labeling of GA9 demonstrating that CYP112 partitions its reactants between two diverging mechanisms.
[Pt] Publication type:JOURNAL ARTICLE
[Em] Entry month:1803
[Cu] Class update date: 180308
[Lr] Last revision date:180308
[St] Status:Publisher
[do] DOI:10.1002/anie.201713403

  9 / 7768 MEDLINE  
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[PMID]: 29517170
[Au] Autor:Hemmerling F; Lebe K; Wunderlich J; Hahn F
[Ad] Address:Leibniz Universitat Hannover, GERMANY.
[Ti] Title:An Unusual FAAL-ACP Didomain in Ambruticin Biosynthesis.
[So] Source:Chembiochem;, 2018 Mar 08.
[Is] ISSN:1439-7633
[Cp] Country of publication:Germany
[La] Language:eng
[Ab] Abstract:The divinylcyclopropane (DVC) fragment of the ambruticins is proposed to be formed via a unique polyene cyclization mechanism in which the unusual didomain AmbG plays a key role. It is proposed to activate the branched thioester carboxylic acid resulting from the polyene cyclisation and to transfer it to its associated ACP. After oxidative decarboxylation, the intermediate is channeled back into polyketide synthase (PKS) processing. AmbG was previously annotated as an adenylation-thiolation didomain with a very unusual substrate selectivity code, but has not yet been biochemically studied. Based on sequence and homology model analysis, we reannotate AmbG as a fatty acyl:adenylate ligase-acyl carrier protein didomain with unusual substrate specificity. The expected adenylate-forming activity on fatty acids was confirmed by in vitro studies. AmbG also adenylates a number of structurally diverse carboxylic acids, including functionalized fatty acids, unsaturated and aromatic carboxylic acids. HPLC-MS analysis and competition experiments showed that AmbG preferentially acylates its ACP with long-chain hydrophobic acids and tolerates a p-system and a branch near the carboxylic acid. AmbG is the first characterized example of an FAAL-ACP didomain that is centrally located in a PKS and apparently activates a polyketidic intermediate. This is an important step towards deeper biosynthetic studies such as a partial reconstitution of the ambruticin pathway to elucidate DVC formation.
[Pt] Publication type:JOURNAL ARTICLE
[Em] Entry month:1803
[Cu] Class update date: 180308
[Lr] Last revision date:180308
[St] Status:Publisher
[do] DOI:10.1002/cbic.201800084

  10 / 7768 MEDLINE  
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[PMID]: 29516424
[Au] Autor:Ren M; Liu H; Qu J; Zhang Y; Ma Y; Yuan X
[Ad] Address:School of Environment, Northeast Normal University, Changchun, Jilin, 130024, China.
[Ti] Title:The different paths and potential risks of photo(-electro)-catalytic degradation for rhodamine B in water by graphene/TiO membrane.
[So] Source:Environ Sci Pollut Res Int;, 2018 Mar 07.
[Is] ISSN:1614-7499
[Cp] Country of publication:Germany
[La] Language:eng
[Ab] Abstract:The graphene (GR)/TiO membrane was prepared by the sol-gel method and coated on the indium tin oxide (ITO) conductive glass, which showed high and stable photo(-electro)-catalytic activities to rhodamine B (Rh-B) in water. Characterization results showed that the GR was dispersed and wrapped in the needle-like TiO . With GR/TiO membrane and simulated sunlight irradiation, the removal efficiency of Rh-B (10 mg l and pH at 5.4) arrived at 87.6% within 300 min. However, the higher removal efficiency for Rh-B reached to 97.8% by the photo-electro-catalytic degradation with the applied voltage 4 v for 30 min. The ·OH that generated in the photo-catalytic degradation process were responsible for Rh-B decomposition. The ·O played the significant role in the photo-electro-catalytic degradation of Rh-B. Furthermore, the decarboxylation was also occurred in the photo-electro-catalytic degradation for the Rh-B in water except for the deethylation and hydroxylation in the photo-catalytic degradation. In addition, the toxicities of the intermediates were calculated using the ECOSAR program and the EPIWIN software. The results indicated that the toxicities of intermediates from photo-electro-catalytic degradation for the Rh-B were higher than photo-catalytic degradation, due to the generation of decarboxylate.
[Pt] Publication type:JOURNAL ARTICLE
[Em] Entry month:1803
[Cu] Class update date: 180308
[Lr] Last revision date:180308
[St] Status:Publisher
[do] DOI:10.1007/s11356-018-1611-4


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