• Journal of the Korean Chemical Society
• /
• v.40 no.12
• /
• pp.760-762
• /
• 1996

• Journal of the Korean Chemical Society
• /
• v.15 no.6
• /
• pp.352-358
• /
• 1971

The interaction between dimethylsulfoxide molecules and some organic molecules, i.e.nitrobenzene, m-dinitrobenzene, o-dinitrobenzene, 1,3,5-trinitrobenzene, m-xylene, mesitylene, bibenzyl, biphenyl, o-phenanthrene, naphthalene, has been studied. The organic molecules exhibit negative deviation from Raoult's law due to the formation of the charge transfer complexes with dimethylsulfoxide. The stability constants of the complexes were determined spectrophotometrically, and also some thermodynamic functions were calculated. The binding energies of the complexes appear in the range of -1 ∼ -4 kcal/mole. The stability depends on the polarity and basicity of the solvent used.

• BMB Reports
• /
• v.29 no.2
• /
• pp.111-115
• /
• 1996

A novel glutathione S-transferase from Pseudomonas sp. DJ77 was expressed in E. coli and purified by glutathione-affinity chromatography. The enzyme was composed of two identical subunits. The molecular size of the enzyme was 42 kDa by sephadex G-150 gel permeation chromatography and Mr of each subunit was 23 kDa by sodium dodecylsulfate-polyacrylamide gel electrophoresis. pI value of the enzyme was approximately 5.8 by isoelectric focusing. This enzyme showed the highest activity toward 1-chloro-2,4-dinitrobenzene as the electrophilic substrate. The relative activities toward p-nitrobenzyl chloride and 1,2-dichloro-4-nitrobenzene were 3.8% and 1.3% of the activity toward 1-chloro-2,4-dinitrobenzene, respectively. $K_m$ and $V_{max}$ values for 1-chloro-2,4-dinitrobenzene calculated by Lineweaver-Burk plot were 0.76 mM and $14.81\;{\mu}mol/min/mg$, respectively, and those for glutathione were 6.23 mM and $64.93\;{\mu}mol/min/mg$, respectively. The enzyme showed highest glutathione S-transferase activity at pH 8.0 and was stable between pH 6.0 and 9.0. The enzyme retained its activity up to $35^{\circ}C$ for 90 min but was unstable above $45^{\circ}C$.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.26 no.5
• /
• pp.693-698
• /
• 2012

This study was designed to investigate the effects of 1-fluoro-2,4 dinitrobenzene (DNFB) on Induction of dermatitis in mice. We investigated the effects of DNFB on induction of dermatitis in terms of changes in body weights, ear thickness, ear weight, spleen/body ratio, histopathological observation and cytokine productions in inflammed tissue of contact dermatitis (CD) mice. In our experiments, we induced CD by using two different methods. First, mice were sensitized and challenged on the back of each ear (topical induction). Second, mice were sensitized on shaved back and challenged back of each ear (systemic induction). In our results, average weights were lowered in both topical and systemic group. But, there was no statistical significance between topical and systemic group. Treatment with DNFB enlarged ear weights and thicknesses in both topical and systemic groups. In addition, both groups were showed almost same features such as immune cell infiltration, spongiosis and hyperplasia in histopathological observations. Finally production levels of TNF-a, IFN-g and IL-6 were markedly elevated in both topical and systemic groups. On the other hand, systemic induction was more effective in spleen/body ratio and IL-6 production compared to topical induction respectively. These results suggest that dermatitis model using DNFB was used as model of CD, not for atopic dermatitis model.

• Journal of the Korean Chemical Society
• /
• v.32 no.1
• /
• pp.71-78
• /
• 1988

The crown ether ring of 20, 21, 24, 25-tetranitrodibenzo-18-crown-6(TNDB-18-C-6) was cleaved by various alcoholic bases to give 2,4,5-trialkoxynitrobenzene derivatives and 4,5-dialkoxy-1,2-dinitrobenzene derivatives as the major products, and bis[(alkoxynitrophenoxy)ethyl]ether derivatives from partially cleaved crown ether ring as the minor products. The ring cleavage reaction of TNDB-18-C-6 with ethylene glycolic base resulted ring contraction through intramolecular nucleophilic cyclization of the initially formed ring cleavage product to give nitro derivatives of DB-14-C-4.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.8
• /
• pp.2371-2374
• /
• 2014

A kinetic study is reported on SNAr reaction of 1-fluoro-2,4-dinitrobenzene with a series of primary amines including hydrazine in $H_2O$ at $25.0^{\circ}C$. The plots of $k_{obsd}$ vs. [amine] are linear and pass through the origin, indicating that general-base catalysis by a second amine molecule is absent. The Br${\o}$nsted-type plot exhibits an excellent linear correlation with ${\beta}_{nuc}$ = 0.46 when hydrazine is excluded from the correlation. The reaction has been suggested to proceed through a stepwise mechanism, in which expulsion of the leaving group occurs after the rate-determining step (RDS). Hydrazine is ca. 10 times more reactive than similarly basic glycylglycine (i.e., the ${\alpha}$-effect). A five-membered cyclic intermediate has been suggested for the reaction with hydrazine, in which intramolecular H-bonding interactions would facilitate expulsion of the leaving group. However, the enhanced leaving-group ability is not responsible for the ${\alpha}$-effect shown by hydrazine because expulsion of the leaving group occurs after RDS. Destabilization of the ground-state of hydrazine through the electronic repulsion between the nonbonding electron pairs is responsible for the ${\alpha}$-effect found in the current $S_NAr$ reaction.

• Food Science of Animal Resources
• /
• v.31 no.3
• /
• pp.420-427
• /
• 2011

The use of lactic-acid bacteria (LAB) is effective for preventing and curing immune disorders by activating the immune system in the digestive tract and the consequent immune response in the blood. In this study, LAB and mixed LABs were used in an atopic dermatitis (AD) mouse model. Alleviation of AD was observed based on the change in cytokine level and immunohistochemical staining. An ex vivo test showed that immunoglobulin-E and interleukin (IL)-4 levels were significantly lower in all groups treated with LAB than in the group treated with only 1-chloro-2,4-dinitrobenzene. Results of an in vivo test based on the ex vivo results showed that the scratch score decreased in all groups treated with the LAB and particularly decreased in the group treated with mixed LABs. Additionally, the T helper (Th) 1 cytokines interferon-gamma and IL-12p40 were upregulated by the LAB and mixed-LABs, whereas levels of the Th2 cytokine IL-4 were downregulated in a mouse model of AD-like skin lesions. Furthermore, hematoxylin & eosin and immunohistochemical staining of the dorsal area of the mice in each group showed that AD improved in the LAB-treated groups. These results suggest that LAB and mixed LABs inhibit the development of AD in NC/Nga mice by suppressing the Th2 cell response and increasing the Th1 cell response. Our results indicate that mixed LABs are better than LAB for treating AD-like skin lesions.

• Proceedings of the Korean Society of Developmental Biology Conference
• /
• 2005.10a
• /
• pp.112-112
• /
• 2005

• Proceedings of the Korean Society of Embryo Transfer Conference
• /
• 2005.10a
• /
• pp.112-112
• /
• 2005

• Bulletin of the Korean Chemical Society
• /
• v.35 no.8
• /
• pp.2438-2442
• /
• 2014

A kinetic study is reported for $S_NAr$ reaction of 1-fluoro-2,4-dinitrobenzene (5a) and 1-chloro-2,4-dinitrobenzene (5b) with alkali-metal ethoxides (EtOM, M = Li, Na, K and 18-crown-6-ether complexed K) in anhydrous ethanol. The second-order rate constant increases in the order $k_{EtOLi}$ < $k_{EtO^-}$ < $k_{EtONa}$ < $k_{EtOK}$ < $k_{EtOK/18C6}$ for the reaction of 5a and $k_{EtOLi}$ < $k_{EtONa}$ < $k_{EtO^-$ < $k_{EtOK}$ < $k_{EtOK/18C6}$ for that of 5b. This indicates that $M^+$ ion behaves as a catalyst or an inhibitor depending on the size of $M^+$ ion and the nature of the leaving group ($F^-$ vs. $Cl^-$). Substrate 5a is more reactive than 5b, although the $F^-$ in 5a is ca. $10pK_a$ units more basic than the $Cl^-$ in 5b, indicating that the reaction proceeds through a Meisenheimer complex in which expulsion of the leaving group occurs after the rate-determining step (RDS). $M^+$ ion would catalyze the reaction by increasing either the nucleofugality of the leaving group through a four-membered cyclic transition state or the electrophilicity of the reaction center through a ${\pi}$-complex. However, the enhanced nucleofugality would be ineffective for the current reaction, since expulsion of the leaving group occurs after the RDS. Thus, it has been concluded that $M^+$ ion catalyzes the reaction by increasing the electrophilicity of the reaction center through a ${\pi}$-complex between $M^+$ ion and the ${\pi}$-electrons in the benzene ring.