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Decarboxylation

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https://www.readbyqxmd.com/read/28642005/expression-purification-and-crystallization-of-type-1-isocitrate-dehydrogenase-from-trypanosoma-brucei
#1
Xinying Wang, Daniel Ken Inaoka, Tomoo Shiba, Emmanuel Oluwadare Balogun, Stefan Allmann, Yoh-Ichi Watanabe, Michael Boshart, Kiyoshi Kita, Shigeharu Harada
Isocitrate dehydrogenases (IDHs) are metabolic enzymes that catalyze the oxidative decarboxylation of isocitrate to α-ketoglutarate. Depending on the electron acceptor and subcellular localization, these enzymes are classified as NADP(+)-dependent IDH1 in the cytosol or peroxisomes, NADP(+)-dependent IDH2 and NAD(+)-dependent IDH3 in mitochondria. Trypanosoma brucei is a protozoan parasite that causes African sleeping sickness in humans and Nagana disease in animals. Here, for the first time, a putative glycosomal T...
June 19, 2017: Protein Expression and Purification
https://www.readbyqxmd.com/read/28636380/a-free-radical-promoted-copper-catalyzed-decarboxylative-alkylation-of-%C3%AE-%C3%AE-unsaturated-carboxylic-acids-with-ich2cf3-and-its-analogues
#2
Yan Zhu, Juwen Gong, Yonghui Wang
A novel and efficient free radical promoted copper-catalyzed decarboxylative alkylation of α,β-unsaturated carboxylic acids with ICH2CF3 and its analogues has been developed. This methodology provides with a convenient access to the synthesis of allylic trifluoromethyl and β-CF3 ketone containing compounds as well as other biologically useful fluorinated molecules and materials.
June 21, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28636185/decarboxylative-alkynylation
#3
Joel M Smith, Tian Qin, Rohan R Merchant, Jacob T Edwards, Lara R Malins, Zhiqing Liu, Guanda Che, Zichao Shen, Scott A Shaw, Martin D Eastgate, Phil S Baran
The development of a new decarboxylative cross-coupling protocol that affords terminal and substituted alkynes from various carboxylic acids is described using both nickel- and iron-based catalysts. The use of N-hydroxytetrachlorophthalimide (TCNHPI) esters is crucial to the success of the transformation, and the reaction is amenable to in situ carboxylic acid activation. Additionally, an inexpensive, commercially-available alkyne source is employed in this formal homologation process that serves as a surrogate for other well-established alkyne syntheses...
June 21, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28634235/mechanistic-elucidation-of-the-mycofactocin-biosynthetic-radical-s-adenosylmethionine-protein-mftc
#4
Bulat Khaliullin, Richard Ayikpoe, Mason Tuttle, John A Latham
Ribosomally synthesized and posttranslationally modified peptide (RiPP) pathways produce a diverse array of natural products. A subset of these pathways depend on radical S-adenosylmethionine (RS) proteins to modify the RiPP-produced peptide. Mycofactocin biosynthesis is one example of an RS protein-dependent RiPP pathway. Recently, it has been shown that MftC catalyzes the oxidative decarboxylation of the C-terminal tyrosine (Tyr30) on the mycofactocin precursor peptide MftA; however, this product has not been verified by techniques other than MS...
June 20, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28633113/transformation-and-toxicity-assessment-of-two-uv-filters-using-uv-h2o2-process
#5
Mingguo Peng, Erdeng Du, Zhihong Li, Dongdong Li, Huajie Li
The treatment of two typical UV filters benzophenone-4 (BP4) and benzophenone-9 (BP9) was evaluated in aqueous solutions by UV/H2O2 process. High-resolution accurate mass spectrometry (HRMS) was used to identify the degradation intermediates. A total of 12 BP4 degradation products and 17 BP9 degradation products were identified. A series of OH-initiated reactions, including hydroxylation, dihydroxylation, decarboxylation, demethylation, and ring breaking, lead to the final mineralization of BP4 and BP9. The degradation mechanisms of BP4 and BP9 are also proposed, separately...
June 17, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28631868/mn-i-catalyzed-regio-and-stereoselective-1-2-diheteroarylation-of-allenes-combination-of-c-h-activation-and-smiles-rearrangement
#6
Shi-Yong Chen, Xiang-Lei Han, Jia-Qiang Wu, Qingjiang Li, Yunyun Chen, Honggen Wang
Heteroarenes are important structural motif in functional molecules. Reported herein is a Mn(I)-catalyzed 1,2-diheteroarylation of allenes via a C-H activation/Smiles rearrangement cascade. The reaction occurred under additive-free or even solvent-free conditions which allowed the creation of two C-C and one C-N bonds in a single operation. A series of structurally diverse bicyclic or tricyclic compounds bearing an exocyclic double bond were constructed in good to excellent efficiency. The decarboxylative ring-opening of the products led to the facile synthesis of vicinal biheteroaryls...
June 20, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28631846/visible-light-mediated-dual-decarboxylative-coupling-of-redox-active-esters-with-alpha-beta-unsaturated-carboxylic-acids
#7
Xin-Hua Duan, Jin-Jiang Zhang, Jun-Cheng Yang, Li-Na Guo
An efficient visible-light-induced decarboxylative coupling between alpha, beta-unsaturated carboxylic acids and alkyl N-hydroxyphthalimide esters has been developed. A wide range of redox-active esters derived from aliphatic carboxylic acids (1o, 2o and 3o) proved viable in this dual decarboxylation process, affording a broad scope of substituted alkenes in moderate to excellent yields with good E/Z selectivities. This redox-neutral procedure was highlighted by its mild conditions, operational simplicity, easy accessibility of carboxylic acids, and excellent functional-group tolerance...
June 20, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28627452/engineering-of-unconventional-yeast-yarrowia-lipolytica-for-efficient-succinic-acid-production-from-glycerol-at-low-ph
#8
Zhiyong Cui, Cuijuan Gao, Jiaojiao Li, Jin Hou, Carol Sze Ki Lin, Qingsheng Qi
Yarrowia lipolytica is considered as a potential candidate for succinic acid production because of its innate ability to accumulate citric acid cycle intermediates and its tolerance to acidic pH. Previously, a succinate-production strain was obtained through the deletion of succinate dehydrogenase subunit encoding gene Ylsdh5. However, the accumulation of by-product acetate limited further improvement of succinate production. Meanwhile, additional pH adjustment procedure increased the downstream cost in industrial application...
June 13, 2017: Metabolic Engineering
https://www.readbyqxmd.com/read/28627009/iron-catalyzed-radical-decarboxylative-oxyalkylation-of-terminal-alkynes-with-alkyl-peroxides
#9
Xiaotao Zhu, Changqing Ye, Yajun Li, Hongli Bao
We report an iron-catalyzed oxyalkylation of alkynes with alkyl peroxides as the alkylating reagents. Alkyl peroxides are readily available from aliphatic acids and serve simultaneously as the alkylating reagents and internal oxidants. Primary, secondary, and tertiary alkyl groups of aliphatic acids were readily incorporated into C-C triple bonds and diverse α-alkylated ketones were synthesized. Mechanism studies revealed that this reaction involves highly reactive alkyl free radicals. A unique equilibrium between lauric acid and water catalyzed by the iron(III) catalyst was observed...
June 18, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28626614/identification-of-two-cigads-from-caragana-intermedia-and-their-transcriptional-responses-to-abiotic-stresses-and-exogenous-abscisic-acid
#10
Jing Ji, Lingyu Zheng, Jianyun Yue, Xiamei Yao, Ermei Chang, Tiantian Xie, Nan Deng, Lanzhen Chen, Yuwen Huang, Zeping Jiang, Shengqing Shi
BACKGROUND: Glutamate decarboxylase (GAD), as a key enzyme in the γ -aminobutyric acid (GABA) shunt, catalyzes the decarboxylation of L-glutamate to form GABA. This pathway has attracted much interest because of its roles in carbon and nitrogen metabolism, stress responses, and signaling in higher plants. The aim of this study was to isolate and characterize genes encoding GADs from Caragana intermedia, an important nitrogen-fixing leguminous shrub. METHODS: Two full-length cDNAs encoding GADs (designated as CiGAD1 and CiGAD2) were isolated and characterized...
2017: PeerJ
https://www.readbyqxmd.com/read/28625056/enantioselective-construction-of-acyclic-quaternary-carbon-stereocen-ters-palladium-catalyzed-decarboxylative-allylic-alkylation-of-fully-substituted-amide-enolates
#11
Pavel Starkov, Jared T Moore, Douglas C Duquette, Brian M Stoltz, Ilan Marek
We report a divergent and modular protocol for the preparation of acyclic molecular frameworks con-taining newly created quaternary carbon stereocenters. Central to this approach is a sequence composed of a (1) regioselective and -retentive preparation of allyloxycar-bonyl-trapped fully-substituted stereodefined amide eno-lates and of a (2) enantioselective palladium-catalyzed decarboxylative allylic alkylation reaction using a novel bisphosphine ligand.
June 19, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28622140/reactive-nitrogen-species-rns-resistant-microbes-adaptation-and-medical-implications
#12
Sujeenthar Tharmalingam, Azhar Alhasawi, Varun P Appanna, Joe Lemire, Vasu D Appanna
Nitrosative stress results from an increase in reactive nitrogen species (RNS) within the cell. Though the RNS - nitric oxide (NO) and peroxynitrite (ONOO-) - play pivotal physiological roles, at elevated concentrations, these moieties can be poisonous to both prokaryotic and eukaryotic cells alike due to their capacity to disrupt a variety of essential biological processes. Numerous microbes are known to adapt to nitrosative stress by elaborating intricate strategies aimed at neutralizing RNS. In this review, we will discuss both the enzymatic systems dedicated to the elimination of RNS as well as the metabolic networks that are tailored to generate RNS-detoxifying metabolites - α-keto-acids...
June 15, 2017: Biological Chemistry
https://www.readbyqxmd.com/read/28619717/photoinduced-decarboxylative-borylation-of-carboxylic-acids
#13
Alexander Fawcett, Johan Pradeilles, Yahui Wang, Tatsuya Mutsuga, Eddie L Myers, Varinder K Aggarwal
The conversion of widely available carboxylic acids into versatile boronic esters would be highly enabling for synthesis. Here we report that this transformation can be effected by illuminating the N-hydroxyphthalimide ester derivative of the carboxylic acid under visible light at room temperature in the presence of the diboron reagent, bis(catecholato)diboron. A simple workup allows isolation of the pinacol boronic ester. Experimental evidence suggests that boryl radical intermediates are involved in the process...
June 15, 2017: Science
https://www.readbyqxmd.com/read/28618358/identifying-structural-characteristics-of-humic-acid-to-static-and-dynamic-fluorescence-quenching-of-phenanthrene-9-phenanthrol-and-naphthalene
#14
Lin Wang, Hao Li, Yu Yang, Di Zhang, Min Wu, Bo Pan, Baoshan Xing
Fluorescence quenching is a sensitive and fast method to quantify the interactions between a fluorescent organic contaminant and a quencher, such as dissolved organic matter (DOM). Dynamic fluorescence quenching is resulted from molecular collision, not the real binding, and thus it complicates the binding data interpretation. On the other hand, static fluorescence quenching occurs for fluorescent contaminants of ground states, which decreases the concentration of freely dissolved contaminants. However, how a particular structure in DOM contributes to the static and dynamic fluorescence quenching of a fluorescent contaminant is still unclear, which has greatly hindered the application of fluorescence quenching technique...
June 12, 2017: Water Research
https://www.readbyqxmd.com/read/28618222/de-novo-biosynthesis-of-glutarate-via-%C3%AE-keto-acid-carbon-chain-extension-and-decarboxylation-pathway-in-escherichia-coli
#15
Jian Wang, Yifei Wu, Xinxiao Sun, Qipeng Yuan, Yajun Yan
Microbial based bioplastics are promising alternatives to petroleum based synthetic plastics due to their renewability and economic feasibility. Glutarate is one of the most potential building blocks for bioplastics. The recent biosynthetic routes for glutarate were mostly based on the l-lysine degradation pathway from Pseudomonas putida that required lysine either by feeding or lysine overproduction via genetic manipulations. Herein, we established a novel glutarate biosynthetic pathway by incorporation of a "+1" carbon chain extension pathway from α-ketoglutarate (α-KG) in combination with α-keto acid decarboxylation pathway in Escherichia coli...
June 23, 2017: ACS Synthetic Biology
https://www.readbyqxmd.com/read/28618178/a-new-route-for-de-carboxylation-of-lactones-over-zn-zsm-5-elucidation-of-structure-and-molecular-interactions
#16
Edman Shik Chi Tsang, Lin Ye, Ben Lo, Qi Song, Junlin Zheng, Dejing Kong, Claire A Murray, Chiu Tang
Here, we report a catalytic process of decarboxylating gamma-valerolactone, GVL (the biomass derived lactone as an example) over Zn/ZSM-5 to butene, followed by aromatization at high yield with co-feed water. Evaluation of catalytic performance at prolonged time shows that water molecule is essential in maintaining the decarboxylation/ aromatization activity without rapid deactivation. Synchrotron X-ray diffraction and Rietveld refinement are then used to elucidate the adsorbed structures of GVL and immobilized Zn-species with the support of EXAFS and NMR...
June 15, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28617504/biomimetic-iterative-method-for-polyketide-synthesis
#17
Kengo Akagawa, Kazuaki Kudo
An iterative method for synthesizing polyketides was demonstrated, in which the chain elongation of a carboxylic acid was performed by decarboxylative dehydration condensation with a malonic acid half thioester. After transforming the resulting β-ketothioester into an appropriate form, the carboxylic acid functionality was regenerated for the next elongation step.
June 15, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28614742/transformation-of-halobenzoquinones-with-the-presence-of-amino-acids-in-water-products-pathways-and-toxicity
#18
Penghui Du, He Zhao, Hongbin Cao, Ching-Hua Huang, Wen Liu, Yao Li
The transformation and detoxification of halobenzoquinones (HBQs), a class of emerging disinfection byproducts (DBPs), was studied in the presence of amino acids (AAs). The reaction activity of three HBQs with AAs generally ranked as 2-chlorobenzoquinone (CBQ) < 2,6-dichlorobezoquinone (DCBQ) < tetrachloroquinone (TCBQ), consistent with their halogenation degree and the calculated electron affinity (EA) results. According to mass spectrometry and density functional theory (DFT) calculations, AAs can easily covalently incorporate into HBQs via nucleophilic addition (CBQ and DCBQ) or substitution (TCBQ) through CNC or CSC linkages...
June 5, 2017: Water Research
https://www.readbyqxmd.com/read/28614741/iopromide-exposure-in-typha-latifolia-l-evaluation-of-uptake-translocation-and-different-transformation-mechanisms-in-planta
#19
Hao Cui, Martin Hrabě de Angelis, Peter Schröder
Iopromide is frequently detected in water bodies due to its widespread use as an X-ray contrast agent in medicine. Due to its rapid clearance from the human body and its incomplete removal by wastewater treatment, an elevation of its concentration in the environment is observed that might lead to a serious impact on human and environmental health. Alternative or additional removal technologies may be more effective to remove iopromide from the effluents of wastewater treatment facilities, like phytoremediation with aquatic macrophytes...
June 4, 2017: Water Research
https://www.readbyqxmd.com/read/28613344/ag-i-catalyzed-oxidative-decarboxylation-of-difluoroacetates-with-activated-alkenes-to-form-difluorooxindoles
#20
Wen Wan, Jialiang Li, Guobin Ma, Yunrong Chen, Haizhen Jiang, Hongmei Deng, Jian Hao
A silver-catalyzed oxidative decarboxylative gem-difluoromethylenation of difluoroacetates with activated alkenes under mild reaction conditions has been developed. This radical cascade reaction provides a new method for the construction of a variety of gem-difluoromethylenated oxindoles.
June 14, 2017: Organic & Biomolecular Chemistry
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