• 한국표면공학회지
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• 제36권5호
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• pp.364-372
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• 2003

In continuous galvanizing process, dissolution of iron into molten zinc results in a fairly great amount of dross. In order to decrease dross, the amount of dissolved iron of strip in molten zinc was investigated in the range of 0∼0.22%Al content, 440∼$470^{\circ}C$ strip temperature and 3∼60 sec dipping time. Uniform Fe-Al-Zn inhibition layer was formed in the coating layer/strip interface not only in the grain boundary but also in the grain of substrate with the increase of Al content in the zinc pot, while the amount of iron dissolution was decreased. Inhibition layer was unstable as the dipping time and strip temperature increased and the amount of iron dissolution increased.

• Bulletin of the Korean Chemical Society
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• 제3권3호
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• pp.122-129
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• 1982

In order to extend our understanding on the multiple inhibition enzyme kinetics, a general equation of an enzyme reaction in the presence of two different reversible inhibitors was derived by what we call "match-box mechanism" under the combined assumption of steady-state and quasi-equilibrium for inhibitor binding. Graphical methods were proposed to analyze the multiple inhibition of an enzyme by any given sets of different inhibitors, i.e., competitive, noncompetitive, and uncompetitive inhibitors. This method not only gives an interaction factor $({\alpha})$ between two inhibitors, but also discerns ${\alpha}_1$ and ${\alpha}_2$ with and without substrate binding, respectively. The factors involved in the dissociation constants of inhibitors can also be evaluated by the present plot. It is also shown that the present kinetic approach can be extended to other forms of activators or hydrogen ions with some modification.

• 대한약학회:학술대회논문집
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• 대한약학회 2000년도 NEW STRATEGY FOR DRUG DEVELOPMENT IN POST-GENOMIC ERA(대한약학회)
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• pp.136.3-137
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• 2000

• KSBB Journal
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• 제15권3호
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• pp.313-317
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• 2000

In this paper enantioselective production of levofloxacin by porcine liver esterase was investigated, To enhance the produc0-tivity various factors which affect the enzyme activity and the enantioselectivity were optimized, In terms of temperature and pH 45$^{\circ}C$ and 4.8 were found to be the best conditions for enzyme reaction. Addition of ofloxacin butyl ester the substrate at the concentration of 5 g/L was desirable to avoid the product inhibition and the activity of porcine liver esterase was maintained up to 72 hours.In addition to enhance the availability of substrate effect of solvent was also examined. It was found that the application of 5% (v/v) of acetone acetonitrile and dimethylsulfoxide did not increase the conversion of substrate and the presence of 5%(v/v) butanol inhibited the enzyme activity significantly.

• 상하수도학회지
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• 제13권4호
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• pp.35-44
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• 1999

In this study, it was attempted to remove nitrate and carbon in a single-stage reactor using acetate as substrate. Hybrid type upflow sludge baffled filter reactor was adopted using anaerobic sludge. Sludge bed in the bottom of reactor was intended to remove carbon and nitrate by denitrification and methanogenesis. And floating media in the upper part of reactor were intended to remove remaining carbon which was not removed due to the inhibition of nitrogen oxide on methane producing bacteria. The reactor removed over 96% of COD and most of nitrate with volumetric loading rate of $4.0kgCOD/m^3{\cdot}day$, hydraulic retention time of 24hr, 4,000mgCOD/L, and $266mgNO_3-N/L$. Nitrate in anaerobic sludge was converted to nitrogen gas(denitrification) or ammonia (ammonification) according to pH of influent, COD removal efficiency was easily affected by the change of volumetric loading rates and nitrate concentration. And when influent pH was about 4.7, most nitrate changed to ammonia while when influent pH was about 6.8~7.0, most nitrate denitrified independent of $COD/NO_3-N$ ratio. Most granules were gray and a few were black. In gray-colored granule, black inner side was covered with gray substance and SEM illustrated Methanoccoci type microorganisms which were compact spherical shape. Anaerobic filter removed residual COD effectively which was left in sludge bed due to the inhibition of nitrogen oxide.

• 미생물학회지
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• 제20권4호
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• pp.189-194
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• 1982

Acid protease produced from Aspergillus tubingensis was pruified by ethanol fractionation, dialysis, and DEAE cellulose column chromatography. As a result of purification its specific activity increased to 5.4 times, and percent recovery was 39. The kinetic constants of the enzyme were studied. Km and Vmax was $1.5{\times}10^{-7}M\;and\;0.11{\Delta}O.D/min$ , respectively, when casein was used as substrate. The order of Km value of several proteins is : casein

• BMB Reports
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• 제34권6호
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• pp.517-525
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• 2001

Six renaturable protein kinases that utilize the myelin basic protein (MBP) as a substrate were activated during prolonged exposure of cardiac myocytes to okadaic acid (OA). We characterized the substrate preference and activation of these kinases, with particular emphasis on 3 novel kinases-MBPK-55, MBPK-62 and MBPK-87. The transcription factors c-Jun, Elk, ATF2, and c-Fos that are used to assess mitogen-activated protein kinase activation were all poor substrates for these three kinases. MAPKAPK2 was also not phosphorylated. In contrast, Histone IIIS was phosphorylated by MBPK-55 and MBPK-62. These protein kinases were activated in cultured cardiac fibroblasts, H9c2 cardiac myoblasts, and Cos cells. High concentrations (0.5 to $1\;{\mu}M$) of OA were essential for the activation of the protein kinases in all of the cell types examined, whereas calyculin A [an inhibitor of protein phosphatase 1 (PP1) and PP2A], cyclosporin A (a PP2B inhibitor), and an inactive OA analog all failed to activate these kinases. The high dose of okadaic acid that is required for kinase activation was also required for phosphatase inhibition, as assessed by immunoblotting whole cell lysates with anti-phosphothreonine antibodies. A variety of chemical inhibitors, including PD98059 (MEK-specific), genistein (tyrosine kinase-specific) and Bisindolylmaleimide I (protein kinase C-specific), failed to inhibit the OA activation of these kinases. Thus, MBPK-55 and MBPK-62 are also Histone IIIS kinases that are widely expressed and specifically activated upon exposure to high OA concentrations.

• BMB Reports
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• 제46권3호
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• pp.151-156
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• 2013

Phylogenetic and amino acid sequence analysis indicated that rice allene oxide synthase-1 (OsAOS1) is CYP74, and is clearly distinct from CYP74B, C and D subfamilies. Regio- and stereo-chemical analysis revealed the dual substrate specificity of OsAOS1 for (cis,trans)-configurational isomers of 13(S)- and 9(S)-hydroperoxyoctadecadienoic acid. GC-MS analysis showed that OsAOS1 converts 13(S)- and 9(S)-hydroperoxyoctadecadi(tri)enoic acid into their corresponding allene oxide. UV-Visible spectral analysis of native OsAOS1 revealed a Soret maximum at 393 nm, which shifted to 424 nm with several clean isobestic points upon binding of OsAOS1 to imidazole. The spectral shift induced by imidazole correlated with inhibition of OsAOS1 activity, implying that imidazole may coordinate to ferric heme iron, triggering a heme-iron transition from high spin state to low spin state. The implications and significance of a putative type II ligand-induced spin state transition in OsAOS1 are discussed.

• Archives of Pharmacal Research
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• 제10권1호
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• pp.50-59
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• 1987

(E)-2-Phenylcyclopropylamine ((E)-TCP), (Z)-2-Phenylacyclopropylamine ((Z)-TCP), (E)-1-methyl-2-phenylcyclopropylamine ((E)-MTCP), and (Z)-1-methyl-2-phenylcyclopropylamine ((Z)-MTCP) were synthesized and used to determine to what extent 1-methylsubstitution and stereochemistry of 2-phenycyclopropylamines affect inhibition of monoamine oxidase (MAO). Inhibition of rat brain mitochondrial MAO-A and B by the compounds were measured using serotonin and benzylamine as the substrate, respectively and $IC_{50}$ values obtianed with 95% confidence limits by the method of computation. For the inhibition of MAO-A, (E)-MTPC ($IC_{50}$ = 6.2 * $10^{-8}$M) was found to be 37 times more potent than (Z)-MTCP ($IC_{50}$ = 7.8 * $10^{-8}$M), was 7 times more potent than (Z)-MTCP($IC_{50}$= 4.7 * $10^{-7}$M) and (E)-TCP($IC_{50}$ =7.8 * $10^{-8}$M),0.6 times as potent as (Z)- TCP ($IC_{50}$ = 4.4 * $10^{-8}$M). The results suggested that while without 1-methyl group, potency of a (Z)-isomer was comparable to that of (E)-isomer, the methyl group in its (Z)-position was very unfavorable to the inhibition of MAO and that in its (E)-position, the methyl group contributed positively to the potency as found by the fact that (E)-MTCP was 1-5 times more potent than (E)-TCP. In view of the selective inhibition of MAO-A- or B over MAO-A and 1-methyl substitution as well as the stereochemical factors did not significantly influence the selectivity.

• 한국식품저장유통학회지
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• 제12권3호
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• pp.275-281
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• 2005

우슬이 민간요법으로 관절염 치료에 우수한 한약재로 알려진 바 우슬 추출물이 cathepsin B 에 대한 저해력을 검토하기 위하여 각종 용매로 우슬 추출물을 순차 분획하고 분획 추출물에 대하여 cathepsin B에 대한 저해활성을 검토하였으며 우슬의 지표물질인 20-hydroxy ecdysone이 추출분획에 검출되는지 TLC 및 HPLC를 이용하여 분석하였으며 우슬의 지표물질이 cathepsin B에 대한 저해활성여부를 확인한바 다음과 같은 결과를 얻었다. 우슬 뿌리에 대해 methanol/water(4:1, v/v) 추출물을 ethyl acetate, chloroform, chloroform/methanol(3:1, v/v), methanol의 각 용매로 분획한 결과, 분획 F4(methanol 분획)에서 수율이 가장 높아 $8.27\%$를 나타내었다. 각 분획별에 따라 cathepsin B에 대한 저해활성을 측정한 결과 F4분획물에서 가장 저해활성이 높았으며 F1분획에서도 높은 저해활성을 나타내었다. F4분획물 중 우슬의 지표물질인 20-hydroxy ecdysone이 검출되었으며 우슬에 함유되어있는 함량은 $0.33\%$이었다. 20-hydroxy ecdysone에 대하여 cathepsin B저해활성을 보기 위하여 cathepsin B저해활성제로 알려진 leupeptin과 활성을 비교해본 결과 기질을 BANA로 사용하였을 경우 leupeptin은 저해율이 $92\%$인데 비하여 20- hydroxy ecdysone은 $88\%$이었으며 F4분획물은 $97\%$를 나타내었고 기질을 CLN으로 사용하였을 경우 leupeptin은 저해율이 $62\%$인데 비하여 20-hydroxy ecdysone은 $36\%$이었으며 F4추출물은 $67\%$를 나타내었다.