• Title/Summary/Keyword: decarboxylation

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CoA Transferase and Malonyl-CoA Decarboxylase Activity of Malonate Decarboxylase from Acinetobacter calcoaceticus

  • Byun, Hye-Sin;Kim, Yu-Sam
    • BMB Reports
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    • v.30 no.4
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    • pp.246-252
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    • 1997
  • Malonate decarboxylase from Acinetobacter calcoaceticus is shown to have malonyl-CoA: acetate CoA transferase. acetyl-CoA: malonate CoA transferase, and malonyl-CoA decarboxylase activity. These enzyme activities were elucidated by isotope exchange reactions. The enzyme modified by N-ethylmaleimide completely lost its malonate decarboxylase activity, whereas it still kept CoA transferases and malonyl-CoA decarboxylase activities. The existence of CoA transferases and malonyl-CoA decarboxylase activity is clear, but their physiological significance is obscure. The catalytic reactions for two eoA transfers and malonyl-CoA decarboxylation proceed via a cyclic mechanism, which is through two covalent intermediates, enzyme-Smalonyl and enzyme-S-acetyL proposed for malonate decarboxylation of the enzyme.

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Syntheses of Substituted tert.-Butyl(o-tolyl)-perpropionates (tert.-Butyl ${\beta}$-(o-tolyl)-perpropionate 치환체들의 합성)

  • Hahn, Chi-Sun;Martin, Michael M.
    • Journal of the Korean Chemical Society
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    • v.8 no.4
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    • pp.153-157
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    • 1964
  • The syntheses of substituted tert.-butyl ${\beta}$-(o-tolyl)- perpropionates via intermediates obtained by chloromethylation, malonic syntheses and decarboxylation is described. The intermediates substituted with a group possessing moderate substituent effect such as bromo, chloro, and methyl group were obtained in good yields. The nitro-substituted intermediat was obtained in poor yield. The chloromethylation of toluenes containing electron donating groups resulted in polymerization.

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Weight change after high-temperature hydrothermal heat of mortar using calcium carbonate-based material as fine aggregate (탄산칼슘계 재료를 잔골재로 사용한 모르타르의 고온수열 후 중량변화)

  • Shin, Joung Hyeon;Kim, Hae Na;Hong, Sang Hun;Jung, Ui In;Kim, Bong Joo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.11a
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    • pp.75-76
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    • 2022
  • In the event of a fire in the lower space, a high temperature of 1000℃ or more and an explosive fire may occur due to the closed structural features and combustible materials. On the other hand, more than 90% of oyster shells are made of CaCO3, and when heated to about 700℃ or higher, CaO and CO2 is generated due to decarboxylation reaction. In this study, we try to infer the amount generated by CO2 changing the weight of mortar using oyster shells as fine aggregates after heating. in conclusion It is considered that the smaller the particle, the greater the decarboxylation reaction and the greater the weight change.

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Photocyclization Reactions of ($\omega$-Phthalimidoalkoxy)acetic Acids via Sequential Single Electron Transfer-Decarboxylation Pathways

  • Yoon, Ung-Chan;Lee, Chan-Woo;Oh, Sun-Wha;Oh, Sun-Wha;Hyun Jin kim;Lee, Sang-Jin
    • Journal of Photoscience
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    • v.7 no.4
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    • pp.143-148
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    • 2000
  • Studies have been conducted to explore single electron transfer(SET) promoted photocyclization of ($\omega$-phthalimidoalkoxy)acetic acids(alkoxy=ethoxy, n-propoxy and n-butyloxy). Photocyclizations occur in methanol or acetone in high yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the carboxylic group. These photocyclizations are thought to proceed through pathways involving intramolecular SET from oxygen in the $\alpha$-carboxymethoxy groups to the singlet excited state phthalimide moieties followed by decarboxylation of the intermediate $\alpha$-carboxymethoxy cation fadicals and cyclizations by radical coupling. The photocyclizations occur ca. three times faster in both methanol or acetone with one equivalent of sodium hydroxide added to the reactions and occur slower in acetone than in methanol. The efficient and regiselective cyclization reactions observed for photolyses in methanol represent synthetically useful processes for construction of heterocyclic compounds.

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Formate Decarboxylation: Initial Step for Hydrogen Production by Enterobacter aerogenes (Enterobacter aerogenes에 의한 수소 생산 초기 단계인 포메이트 탈카복시 반응 연구)

  • Choi, Jinyoung;Jho, Young Choong;Ahn, Ik-Sung
    • Applied Chemistry for Engineering
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    • v.20 no.4
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    • pp.449-452
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    • 2009
  • The absence of Fe, Se, and Mo in a minimal medium prevented the production of hydrogen from the anaerobic culture of Escherichia coli MC4100. Fe, Se, and Mo are known to be cofactors of formate dehydrogenase ($FDH_{II}$) of both E. coli and Enterobacter aerogenes. Hence when these trace elements are absent in the minimal medium, hydrogen production through formate dehydrogenation would be inhibited not only in E. coli but also in E. aerogenes. Hydrogen production by E. aerogenes 413 was delayed when lacking these trace elements. Therefore, it is believed that hydrogen production of E. aerogenes is initiated not by the reoxidation of nicotinamide adenine dinucleotide (NADH) but by formate decarboxylation.

Reaction of Potassium Fluoride with Orgarnic Halogen Compound-II. Dimerization, Fluorination, and Decarboxylation of Organic Iodo acids, Iodides, and Polychlorinated Acid Ester (有機할로겐化合物과 KF 과의 反應 (第2報) 有機요-드酸, 沃化物 及 多鹽素化有機酸, 에스텔의 雙合, 弗化 及 脫炭酸 反應에 關하여)

  • Kim, You-Sun
    • Journal of the Korean Chemical Society
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    • v.8 no.4
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    • pp.135-141
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    • 1964
  • The reaction of potassium fluoride with amyl iodide in presence of dimethylformamide at low temperature gave a fluorination product together with decane. Polyhalogenated acid such as ${\alpha}$, ${\beta}$,-dichloro-${\beta}$-phenyl-propionic acid gave ${\alpha}$-chlorostyrene, fluorinated styrene, and fluorinated acid. The same reaction with the ethyl ester did not give the fluorination product and gave a mixture of various dimerized product. Dibromostyrene gave bromostyrene together with fluorination product. Iodo acid such as m-iodo acid gave the salt and a trace quantity of dimerized product. Iodides such as m-iodotoluene and 1-amino-4-iodo-2-methyl benzene did not show any appreciable reactivity towards potassim fluoride. The reaction condition was described, and fluorination, ${\alpa}$-dehydrofluorination, decarboxylation, and dimerization were discussed.

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