• Journal of the Korean Chemical Society
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• v.28 no.5
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• pp.279-283
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• 1984

${\beta}$-Substituent effect on the reactivity of retro-ene decarboxylation of but-3-enoic acid was investigated theoretically. It was found that charge effect is important not only through ${\pi}$-electron transfer as has been claimed to rationalize experimental results but also through polarization as found for the $CH_3$ substituent. The reactivity was not determined by the charge effect alone but the HOMO-LUMO energy gap was also found to affect the reactivity. In general it was confirmed that the greater the ${\pi}$-electron donating power of the substituent, the greater is the reactivity.

• Journal of Life Science
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• v.21 no.2
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• pp.328-333
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• 2011

Melatonin has been known as an animal hormone. However, melatonin exists in diverse organisms including higher plants. The biosynthesis and physiological roles for melatonin in plants is still largely unknown, although both dicot and monocot plants have melatonin and some medicinal plants even contain large amounts of melatonin. In this study we detected melatonin in diverse Viola plants, in which melatonin had not been examined so far, by reverse phase HPLC analysis, demonstrating the wide existence of melatonin in the genus of Viola. We then fed tryptophan (Trp) and tryptamine (TAM) to the incubation medium for Viola leaf sections to test their effects on melatonin formation. Trp is also the hypothesized starting material of melatonin in plants, and TAM is the following intermediate produced by the decarboxylation of Trp. Trp feeding did not affect the contents of melatonin. In contrast, TAM feeding clearly increased the level of melatonin in Viola leaves. Because TAM is derived from Trp, we concluded that the Trp-TAM pathway exists in Viola plants as well. Ineffectiveness of Trp feeding to the change of melatonin contents supports the hypothesis that the decarboxylation step from Trp to TAM is the rate-limiting step in plant melatonin biosynthesis.

• BMB Reports
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• v.28 no.2
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• pp.107-111
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• 1995

In malonate grown Pseudomonas fluorescens, malonate decarboxylase and acetyl-CoA synthetase were induced, whereas in Acinetobacter calcoaceticus malonate decarboxylase, acetate kinase, and phosphate acetyltransferase were induced. In both bacteria malonate decarboxylase was the first, key enzyme catalyzing the decarboxylation of malonate to acetate, and it was localized in the periplasmic space. Acetate thus formed was metabolized to acetyl-CoA directly by acetyl-CoA synthetase in Pseudomonas, and to acetyl-CoA via acetyl phosphate by acetate kinase and phosphate acetyltransferase in Acinetobacter.

• Bulletin of the Korean Chemical Society
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• v.29 no.12
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• pp.2383-2389
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• 2008

• Bulletin of the Korean Chemical Society
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• v.17 no.5
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• pp.437-442
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• 1996

Electrocyclic ring-closure of 6-vinylcyclohepta-1,3,5-isocyanate has been carried out in the presence of triphenylphosphine to examine a catalyzing effect of the triphenylphosphine. The preparation of 10-(1-carboalkoxyalkyl)-2,7-methanoaza[10]annulenes by the electrocyclic ring-closure of ketenimine intermediates, which are formed by the reaction of triphenylalkylidenephosphorane and 6-vinylcyclo-hepta-1,3,5-isocyanate, is described. 10-Alkyl-2,7-methanoaza[10]annulenes were prepared by basic hydrolysis of the carboalkoxyaza[10]annulenes and decarboxylation of the acid intermediates. In the same manner, 10-(N-alkyl(or aryl))-2,7-methanoaza[10]annulenes were prepared from the reaction of the isocyanate and N-alkyl(or aryl)iminotriphenylphosphorane via electrocylic ring-closure of carbodiimide intermediate.

• Journal of Microbiology and Biotechnology
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• v.26 no.9
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• pp.1586-1592
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• 2016

Klebsiella pneumoniae is a gram-negative, non-motile, rod-shaped, and encapsulated bacterium in the normal flora of the intestines, mouth, skin, and food, and has decarboxylation activity, which results in generation of diamines (cadaverine, agmatine, and putrescine). However, there is no specific information on the exact mechanism of decarboxylation in K. pnuemoniae. Specifically lysine decarboxylases that generate cadaverine with a wide range of applications has not been shown. Therefore, we performed a functional study of lysine decarboxylases. Enzymatic characteristics such as optimal pH, temperature, and substrates were examined by overexpressing and purifying CadA and LdcC. CadA and LdcC from K. pneumoniae had a preference for L-lysine, and an optimal reaction temperature of 37℃ and an optimal pH of 7. Although the activity of purified CadA from K. pneumoniae was lower than that of CadA from E. coli, the activity of K. pneumoniae CadA in whole cell bioconversion was comparable to that of E. coli CadA, resulting in 90% lysine conversion to cadaverine with pyridoxal 5'-phosphate L-lysine.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.4
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• pp.130-137
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• 2003

In this study, Isolation was attempted to acquire a phenol utilizing bacterium for PAH degradation and to investigate the characteristics of PAH degradation. The isolate was identified by BIOLOG test as Stenotrophomonas maltophilia. Lower first order reaction constant was detected in the presence of lower phenol concentration. The yield coefficient of phenol was 0.1447mg cell/mg phenol. In the presence of naphthalene and phenol, phenol degradation was favorable. The isolate was capable of utilize naphthalene and phenanthrene as growth substrate but PAH, containing over 4-ring structure such as pyrene, was not degradable. The possible phenanthrene degradation pathway would be the addition of two hydroxy group on C-1 and C-2 position, followed by ortho cleavage, and then decarboxylation.

• Korean Journal of Environmental Agriculture
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• v.19 no.1
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• pp.58-61
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• 2000

This study was conducted to determine the effect of low dose ${\gamma}-ray$ on the germination rate and physiology of germinative seeds of welsh onion ( Allicm fistulosum L. cv. Sukchangwoidae ) and spinach ( Spinacia oleracea L. cv. Chungrok ). The germination rate of irradiation group was much higher than that of the control. Especially it was noticeably higher in 1 or 2 Gy irradiation groups in the sowing spinach seeds on paper towel. On the welsh onion, the germination rate of the 1 Gy irradiation group increased by 17% compared to that of the control. Ion leakage from seeds irradiated with low dose of ${\gamma}-ray$ was decreased compared to that from the control especially at the early stage of incubation when examined by means of electric conductance. This tendency was confirmed in seeds of welsh onion and spinach. Starch hydrolysis was stimulated by ${\gamma}-ray$ irradiation in welsh onion. Furthermore ${\gamma}-ray$ irradiation was beneficial to keeping the vitality of seeds as determined through decarboxylation of glutamic acid.

• Journal of the Korean Chemical Society
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• v.7 no.3
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• pp.189-196
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• 1963

Reactions between potassium fluoride with organic halogen-containing carboxylic acids in dimethyl formamide solvent gave a decarboxylation reaction for the case of fluoro carboxylic acids of the type of $CF_3\;COOH,\;C_3F_7COOH,\;and\;C_2F_5COOH,$ whereas an additional partial fluorination together with dimerization reaction occurred for the chlorine containing acids of the type of $CH_2ClCOOH,\;CH_3CHClCOOH, \;CHCl_2COOH\;and\;o-Cl-C_6H_4-COOH.$ The phenyl halides showed no reactivity, but the halides with two electron attracting substituents on the benzene ring gave mainly dimerization reaction. The esters and alcohols gave an usual fluorination reaction. The same reactions in absence of the solvent at the elevated temperature increase the yield of the dimerized product and gave the cyclized product, fluorenone, in case of ο-chlorobenzoic acid. It was found that the fluorination usually precede the decarboxylation reaction by checking the stiochemical sequence of reaction. Catalytic influence of potassium fluoride were discussed and the mechanism of the reaction was considered.

• Journal of Microbiology and Biotechnology
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• v.22 no.5
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• pp.668-673
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• 2012

Biohydrogen production from organic wastewater by anaerobically activated sludge fermentation has already been extensively investigated, and it is known that hydrogen can be produced by glucose fermentation through three metabolic pathways, including the oxidative decarboxylation of pyruvic acid to acetyl-CoA, oxidation of NADH to $NAD^+$, and acetogenesis by hydrogen-producing acetogens. However, the exact or dominant pathways of hydrogen production in the anaerobically activated sludge fermentation process have not yet been identified. Thus, a continuous stirred-tank reactor (CSTR) was introduced and a specifically acclimated acidogenic fermentative microflora obtained under certain operation conditions. The hydrogen production activity and potential hydrogen-producing pathways in the acidogenic fermentative microflora were then investigated using batch cultures in Erlenmeyer flasks with a working volume of 500 ml. Based on an initial glucose concentration of 10 g/l, pH 6.0, and a biomass of 1.01 g/l of a mixed liquid volatile suspended solid (MLVSS), 247.7 ml of hydrogen was obtained after a 68 h cultivation period at $35{\pm}1^{\circ}C$. Further tests indicated that 69% of the hydrogen was produced from the oxidative decarboxylation of pyruvic acid, whereas the remaining 31% was from the oxidation of NADH to $NAD^+$. There were no hydrogen-producing acetogens or they were unable to work effectively in the anaerobically activated sludge with a hydraulic retention time (HRT) of less than 8 h.