• Journal of Microbiology and Biotechnology
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• 제2권4호
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• pp.260-267
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• 1992

Pectate lyase from alkalitolerant Bacillus sp. YA-14 is an endo-type pectate lyase which acts randomly at the $\alpha$-1, 4-galacturonan linkage, and requires calcium or strontium ions for its activity. The enzyme is active on low methyl esterified pectin, but the activity toward a high methyl esterified substrate is reduced. The apparent Km's of the enzyme toward sodium polygalacturonic acid, polygalacturonic acid, and various pectins such as apple pectin, citrus pectin, and genu pectin are 0.826 mg/ml, 0.685 mg/ml, and 1.14 mg/ml, respectively. The enzyme activity is inhibited by SDS, urea, and sodium azide, but not by various reducing reagents, such as $\beta$-mercaptoethanol, Na-thiosulfate, Na-sulfate, cystein, and L-ascorbic acid. The enzyme is inactivated by N-bromosuccinimide, $I_2, H_2O_2$. PMSF, and iodoacetate. Judging from the results of their inhibition types, we speculate that tryptophan and serine residues are directly involved in enzyme activity, while tyrosine and methionine residues are indirectly involved in its activity.

• 대한의생명과학회지
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• 제15권2호
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• pp.153-160
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• 2009

Photodynamic therapy(PDT) is a treatment utilizing the generation of singlet oxygen and other reactive oxygen species(ROS), which selectively accumulate in target cells. The aim of present work is to investigate the photodynamic therapy mechanism of 9-HpbD-a-mediated PDT in HeLa cell lines. We studied the general reactive oxygen species(G-ROS) activation after 9-HpbD-a PDT using fluorescence stain with $H_2DCF-DA$. G-ROS activation observed after 9-HpbD-a PDT and higher activation condition was 1 hour after PDT at 0.5 ${\mu}g/ml$ 9-HpbD-a concentration. Sodium azide and reduced glutathione(the singlet oxygen quencher) could protect HeLa cells from cell death induced by 9-HpbD-a PDT. But D-mannitol(the hydroxyl radical scavenger) could not protect cell death. Singlet oxygen played a decisive role in 9-HpbD-a PDT induced HeLa cell death. Type II reaction was the main type of ROS formation at 9-HpbD-a PDT.

• 한국동물학회지
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• 제7권1호
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• pp.33-38
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• 1964

한국산 도롱뇽 (Hynobius leechi BOULENGER) 발생배의 질소화합물의 대사를 연구하고져 발생단계에 따른 단백질구성(아미노) 산의 촉진(아미노) 산의 정성적 분석과 질소 배설물(ammonia, urea, uric acid, creatine and/or creatinine, total nitrogen)의 정량분석을 미수정란, 란할배, 포배, 양배, 신경배 및 부화직전의 배에 대하여 행하였다. 1. 발생단계에 따른 발생배내 단백질구성 (아미노산)은 전 단계를 통하여 일양하게 18종씩 검출되어TRh 유리 (아미노산) 은 17 내지 23 종 검출되었으며, 전체적으로 유리(아미노산) 분포상에 큰 변화가 없었다. 2. 발생단계에 따른 질소배설물 분석의 결과는 다음과같다. Ammonia 와 urea 의 배내 함량은 미수정란에서부터 양배까지 점차 감소하여 양배 이후 부화직전배까지 급격히 증가한다. Uric acid의 함량은 전 단계를 통해 미소하였으며 creating and/or creatininie 은 본 실험에서는 검출되지 않았다. 3. 발생단계에 따른 발생배내 ammonia 함량에 대한 sodium azide의 영향은 농도에 따라 이원적인 특이성을 가지고 있었다.

• 한국식품조리과학회지
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• 제10권4호
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• pp.339-345
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• 1994

Polyphenol oxidase in Yam was partially purified through ammonium sulfate fractionation, DEAE-cellulose column chromatography. The specific activity of purified PPO was 138.22 unit/mg protein. The optimum pH and temperature of purified PPO were respectively 7.0 and 30$^{\circ}C$. The heat treatment at 80$^{\circ}C$ for 6 min, decreased PPO activity to 50%. The enzyme showed high substrate specificity toward catechol. The Km value for catechol was 5 mM. In the Ames test using S. typhimurium TA98 and TA100 catechol-YEBRP, pyrogallol-YEBRP, chlorogenic-YEBRP showed strong antimutagenicity on sodium azide and MECF excepting hydroquinone-YEBRP showed killing effect on both strains.

• The Korean Journal of Physiology and Pharmacology
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• 제5권2호
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• pp.157-163
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• 2001

The effects of dimethyl sulfoxide (DMSO) were studied in two groups of Xenopus oocytes, one expressing ATP sensitive $K^+\;(K_{ATP})$ channel comprised of sulfonylurea receptor SUR1 and inwardly rectifying $K^+$ channel subunit Kir6.2, and the other expressing renal $K_{ATP}$ channel ROMK2. At concentrations of $0.3{\sim}10%$ (vol/vol) DMSO inhibited whole cell Kir6.2/SUR1 currents elicited by bath application of sodium azide (3 mM) in a concentration-dependent manner. The inhibition constant and Hill coefficient were 2.93% and 1.62, respectively. ROMK2 currents, however, was not affected significantly by DMSO. The results support the idea that DMSO inhibits $K_{ATP}$ channel expressed in Xenopus oocyte through a protein-specific mechanism(s) that remains to be further elucidated.

• 한국균학회지
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• 제13권2호
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• pp.111-114
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• 1985

The production of lac case by the funguson various media was studied. The characteristics of the enzyme were also studied regarding to the optimum pH, stability, Km value, and inactivation. The maximum activity of laccase reached the 40 days of incubation and the barley straw extract appeared to be a strong inducer for laccase. The enzyme showed stability at wide range of pH with optimum pH of 6.6. Temperature stability of the enzyme was high. Laccase was not inactivated by the organic solvents used for the precipitation. The enzyme, how­ever, was completely inactivated by trichloroacetic acid and sodium azide.

• 대한화학회지
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• 제11권4호
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• pp.170-172
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• 1967

2-Phenyl-5-substituted phenyltetrazole and 2-substituted phenyl-5-phenyltetrazole were prepared from the corresponding hydrazone and phenyl azide with 2-methoxyethanol and metallic sodium as reaction medium at 110~115 $^{\circ}C$. At this reaction condition, however, the preparation of 2-substituted phenyl-5-phenyltetrazoles with substituents of relatively high Hammett substituent constant was unsuccessful. Surprisingly it was found that the solvent molecule was exchanged with substituent during the reaction when tried to obtain 2-m-fluorophenyl-5-phenyltetrazole using benzaldehyde m-fluorophenylhydrazone as starting material. Also disscussed the effect of electronic nature of substituents on the formation of 2,5-diphenyltetrazole derivatives.

• Journal of Microbiology and Biotechnology
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• 제9권4호
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• pp.525-528
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• 1999

Mutagenic activities of extracts from the filtrate of the cultured broth (PI-I), mycelia (pI-II), and the fruiting bodies (PI-III) of Phellinus igniarius were examined by Ames/Salmonella tests. No mutagenic activity was found in Salmonella typhimurium strains TA98 and TA100, either with or without S9 activation. In contrast, PI-I, PI-II, and PI-III showed inhibitory effects on the mutagenic activities by the directly-acting mutagens, 4-nitro-ο-phenylenediamine(NPD) and sodium azide ($NaN_3$), and also by the indirectly-acting mutagens, 2-aminofluorene (2-AF) and benzo[a]pyrene (B[a]P). These results suggest that P. igniarius possesses some antimutagenic activity and may contain some chemopreventive agents.

• 대한화학회지
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• 제11권1호
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• pp.8-11
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• 1967

A method of determination of gold in ores has been established: Disolved ore solution is evaporated to dryness, redissolved with 0.1N HCl then chloroaurate formed is adsorbed on anion exchange resin, Dowex $1\;{\cdot}\;{\times}4$. The resin is ignited and the residue is dissolved with HCl-$HNO_3$. After evaporation of the acid, and then dilution with water, sodium azide is added. The gold is extracted with amyl alcohol from the solution buffered to pH 6. The gold is determined by measuring absorbancy of the alcohol layer spectrophotometricaly at $385m{\mu}$. Various factors, HCl concentration, amount of the resin rate, if adsorption, foreign ions, effecting to the method, have been examined. This method seems to be satisfactory for the determination of gold presented dawn to 1g per metric ton in ore.

• Bulletin of the Korean Chemical Society
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• 제24권8호
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• pp.1181-1187
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• 2003

Condensation of 4-cyano-5,6-dimethyl-3-pyridazinone 1 with aromatic aldehydes gave the novel styryl derivatives 2a-c. Refluxing of compound 2a with phosphorus oxychloride furnished 3-chloropyridazine derivative 3. Compound 3 was reacted with thiourea and produced pyridazine-3(2H)thione 4. Thieno[2,3-c]- pyridazines 5a-e were achieved by cycloalkylation of compound 4 with halocompounds in methanol under reflux and in the presence of sodium methoxide. Also, refluxing of compound 4 with N-substituted chloroacetamide in the presence of potassium carbonate afforded thienopyridazines 6a-e. Cyclization of compound 6 with some electrophilic reagents as carbon disulfide and triethyl orthoformate furnished the novel pyrimido[4',5':4,5]thieno[2,3-c]pyridazines 12 and 13a-c, respectively. Diazotisation of compound 6 with sodium nitrite in acetic acid produced the pyridazino[4',3':4,5]thieno[3,2-d][1,2,3]triazines 14a-c. Ternary condensation of compound 1, aromatic aldehydes and malononitrile in ethanol containing piperidine under reflux afforded the novel phthalazines 16a-c. Compound 3 was subjected to some nucleophilic substitution reactions with amines and sodium azide and formed the aminopyridazines 17a, b and tetrazolo[1,5-b]-pyridazine 19, respectively. The structures of the synthesized compounds were established by elemental and spectral analyses.