• Bulletin of the Korean Chemical Society
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• v.10 no.5
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• pp.468-470
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• 1989

• Bulletin of the Korean Chemical Society
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• v.17 no.12
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• pp.1102-1104
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• 1996

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.766-771
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• 2004

Julong 601, a Gram-positive anaerobic bacterium strain capable of cleaving the C-ring of isoflavones daidzein and genistein, was isolated from human feces. BLAST search revealed that its complete 16S rDNA gene sequence has 99% similarity to Eubacterium ramulus. Metabolites of daidzein and genistein were determined as O-desmethylangolensin (O-Dma) and 2-(4-hydroxyphenyl) propionic acid (2-HPPA), respectively, based on UV, EI-MS, and $^1H$ and ^{13}C$ NMR spectral analyses. Enantiomers of O-Dma and 2-HPPA were isolated by chiral stationary-phase HPLC (CSP HPLC). Cleavage of the C-ring of daidzein and genistein by strain Julong 601 was highly enantioselective. Specific rotation ([$\alpha]_D$) and circular dichroism (CD) spectra of the enantiomers are reported here for the first time. Biotransformation kinetics of daidzein and genistein indicated that the C-ring of genistein has a higher susceptibility to bacterial degradation than that of daidzein.

• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.1921-1924
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• 2011

Nitrile-forming eliminations from $(E)-2,4,6-(NO_2)_3C_6H_2CH=NOC_6H_4-2-X-4-NO_2$ (1) promoted by $R_3NH/R_3NH^+$ in 70 mol % MeCN(aq) have been studied kinetically. When X = $NO_2$, the reactions exhibited second-order kinetics as well as Br$\"{o}$nsted ${\beta}$ = 0.63 and ${\mid}{\beta}_{lg}{\mid}$ = 0.34-0.46, and an E2 mechanism is evident. As the leaving group was made poorer (X = H, Cl, and $CF_3$), Br$\"{o}$nsted ${\beta}$ value increased from 0.63 to 0.85-0.89 without much change in the ${\mid}{\beta}_{lg}{\mid}$ value E2, indicating that structure of the transition state changed to an E1cb-like with extensive $C_{\beta}-H$ bond cleavage, significant negative charge development at the ${\beta}$-carbon, and limited $C_{\alpha}$-OAr bond cleavage.

• Journal of Life Science
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• v.14 no.4
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• pp.582-588
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• 2004

Eighty one bacterial strains of parathion degrading bacteria were isolated from soil samples that were contaminated with pesticide in Daejeon area. Among them, one bacterial strain was finally selected in media containing parathion as the sole source of carbon and energy, and this strain was identified as Pseudomonas rhodesiae H5 through physiological and biochemical tests, and analysis of its 16S rRNA sequence. Pseudomonas rhodesiae H5 was able to utilize various carbohydrates but did not utilize sorbose as sole carbon source. Pseudomonas rhodesiae H5 was resistance to ampicillin, spectinomycin, and mitomycin C but sensitive to kanamycin and chloramphenicol. And this strain showed high resistance up to several milligrams of heavy metals such as $BaCl_2$, LiCl, and $MnSO_4$. Optimal growth condition for temperature and pH of P. rhodesiae H5 was 3$0^{\circ}C$, and pH 7.0, respectively. It can be presumed that P. rhodesiae H5 hydrolyzed an organophosphate bond of parathion, forming p-nitrophenol, and then metabolized via ortho-ring cleavage mechanism.

• Journal of Microbiology
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• v.35 no.3
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• pp.188-192
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• 1997

The strain of S-47 degrading 4-chlorobenzoic acid (4CBA) was isolated from Ulsan chemical industrial complex by enrichment cultivation with 1 mM 4CBA. The strain was Gram-negative rod and grew optimally at 30.deg.C and pH 7 under aerobic condition, so that the organism was identified as a species of Pseudomonas. Pseudomonas sp. S-47 degraded 4-chlorobenzoic acid to produce a yellow-colored meta-cleavage product, which was confirmed to be 5-chloro-2-hydroxymuconic semialdehyde (5C-2HMS) by UV-visible spectrophotometry. 5C-3HMS was proved trometry. This means that Pseudomonas sp. S-47 degraded 4CBA via 4-chlorocatechol to 5C-2HMS by meta-cleavage reaction and then to 5C-2HMA by 5C-2HMS dehydrogenase.

• Bulletin of the Korean Chemical Society
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• v.10 no.6
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• pp.600-604
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• 1989

In order to find the rational methods for improving the thermal stability of subtilisin Carlsberg, the mechanisms of irreversible thermoinactivation of the enzyme were studied at $90^{\circ}C.$ At pH 4, the main process was hydrolysis of peptide bond. This process followed first order kinetics, yielding a rate constant of $1.26\;{\times}\;10^{-1}h^{-1}$. Hydrolysis of peptide bond of PMS-subtilisin occurred at various sites, which produced new distinct fragments of molecular weights of 27.2 KD, 25.9 KD, 25.0 KD, 22.3 KD, 19.0 KD, 17.6 KD, 16.5 KD, 15.7 KD, 15.0 KD, 13.7 KD, and 12.7 KD. Most of the new fragments originated from the acidic hydrolysis at the C-side of aspartic acid residues. However 25.0 KD, 15.7 KD, and 13.7 KD which could not be removed in purification steps stemmed from the autolytic cleavage of subtilisin. The minor process at pH 4 was deamidation at asparagine and/or glutamine residues and some extend of aggregation was also observed. However, the aggregation was main process at pH 7 with a first order kinetic constant of $16 h^{-1}.$ At pH 9, the main process seemed to be combination of deamidation and cleavage of peptide bond.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.5
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• pp.1374-1381
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• 2004

The water extract of Dohongsamul-tang(DHSMT)has been traditionally used for treatment of ischemic heart in oriental medicine. However, little is known about the mechanism by which the water extract of DHSMT rescues cells from these damages. Therefore, this study was designed to evaluate the protective effects of DHSMT on zinc-mediated cytotoxicity in H9c2 cardiomyoblast cells. This study demonstrates that treatment of H9c2 cells with zinc caused a decrease in cell viability in a dose dependent manner and a chromatin condensation. Zinc induced the cleavage of poly(ADP-ribose) polymerase (PARP). In addition, zinc induced the decrease of Bcl-2, as well as increase of Bak expression and mitochondrial dysfunction. Zinc-induced H9c2 cell death was remarkably prevented by the pretreatment of DHSMT with consistent suppression of the cleavage of poly(ADP-ribose) polymerase (PARP), mitochondrial dysfunction and the expression of Bak and Bcl-2. Taken together, the results suggest that zinc induced severe cell death in H9c2 cardiomyoblast cells via intracellular GSH(reduced glutathione) depletion and the protective effects of DHSMT against oxidative injuries may be achieved through modulation of mitochondrial dysfunction and scavenging of ROS(reactive oxygen species).

• Mass Spectrometry Letters
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• v.10 no.2
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• pp.50-55
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• 2019

The fragmentation statistics of ion trap CID (Collision-Induced Dissociation) spectra using 87,661 tandem mass spectra of doubly charged tryptic peptides are analyzed here. In contrast to the usual method of using intensity information, the frequency of occurrence of fragment ions, with respect to the position of the cleavage site and the residues at these sites is studied in this paper. The analysis shows that the frequency of occurrence of fragment ion peaks is more towards the middle of the peptide than its ends. It was noted that amino acid with an aromatic and basic side chain at N- & C- terminal end of the peptide stimulates more peaks at the lower end of the spectrum. The residue pair effect was shown when the amide bond occurs between acidic and basic residues. The fragmentation at these sites (D/E-H/R/K) stimulates the generation of the y-ion peak. Also, the cleavage site H-H/R/K stimulates the generation of b-ions. K-P environment in the peptide sequence has more tendency to generate y-ions than b-ions. Statistical analysis helps in the visualization of the CID fragmentation pattern. Cleavage pattern along the length of the peptide and the residue pair effects, enhance the knowledge of fragmentation behavior, which is useful for the better interpretation of tandem mass spectra.

• Journal of Pharmaceutical Investigation
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• v.24 no.4
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• pp.273-279
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• 1994

The stability of three oximes, Hl-6 [(4-carbamoyl-2'[(hydroxyimino)-methyl]- 1,1'-oxydimethylenedi-(pyridinium chloride)], Hl-CN [(4 cyano-2'-[(hydroxyimino)-methyl] -1,1'-oxydimethylene-di-(pyridinium chloride)], and 2-PAM [pralidoxime chloride] in aqueous solutions was evaluated by HPLC assay. The rate of degradation is dependent on the pH as well as the temperature at which the solution is stored. The optimum pH for the stability of these oximes was pH 2 to 3. The degradation rate constant for 2-PAM ($k\;at\;70^{\circ}C$, $2.07{\times}10^{-4}/hr;\;E_a\;value$, 27.2 kcal/mol) was smaller than those for bis-pyridiniumoximes, Hl-6 ($k\;at\;70^{\circ}C$, $3.38{\times}10^{-3}/hr$) and Hl-CN ($k\;at\;70^{\circ}C$, $8.66{\times}10^{-3}/hr;\;Ea\;value$, 20.7 kcal/mol). In mechanistic analyses, it was found that Hl-CN was decomposed through not only the hydrolysis of nitrile group but also the cleavage of methylene ether bridge, in contrast to Hl-6 which was degraded mainly through the cleavage of methylene ether bridge.