• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.501-505
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• 1990

Streptomyces sp. KISl3 isolated from soil was found to produce low molecular weight thiol protease inhibitors. The protease inhibitor production was closely linked to the cell growth and regulated by growth condition. The inhibitor was purified from the culture broth through butanol extraction, silicagel 60 column chromatography, Sephadex LH-20 gel filtration and preparative HPLC. The inhibitor showed specific inhibitory activity to thiol protease such as papain, picin and bromelain. The mode of inhibition against papain to Hammersten casein as a substrate was non-competitive.

• BMB Reports
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• v.29 no.3
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• pp.210-214
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• 1996

The pH dependence of the kinetic parameters of mutant O-acetylserine sulfhydrylase (OASS) from Salmonella typhimurium LT-2 has been determined in order to obtain information on the chemical mechanism. The initial velocity pattern obtained by varying the concentrations of OAS at several fixed concentrations of TNB, shows an intersection on the left of the ordinate at pH 7.0, indicating that the kinetic mechanism is a sequential mechanism in which substrate inhibition by OAS is observed while the wild type enzyme showed a ping pong mechanism. The values of $V/E_t$, $V/K_{OAS}E_{t}$ and $V/K_{TNB}E_{t}$ decreased by about 68%, 14% and 16% as compared with the wild type enzyme. The $V/K_{OAS}E_{t}$ is a pK of 6.5 on the acid side of the pH profile, and the $V/K_{TNB}$ is pH independent. As compared with the wild type enzyme, the pKs in the V/K profiles are shifted, reflecting that binding of the cofactor in free E:OAS is less asymmetric.

• Microbiology and Biotechnology Letters
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• v.23 no.4
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• pp.416-424
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• 1995

Mechanism of the cyclodextrin (CD) production reaction by cyclodextrin glucanotransferase (CGTase) using swollen extrusion starch as substrate was investigated emphasizing the structural features of starch granule. The degree of gelatinization was identified to be the most representative structural characteristic of swollen starch. The most suitable degree of gelatinization of swollen starch for CD production was around 63.52%. The structural transformation of starch granule during enzyme reaction was also followed by measuring the changes of the degree of gelatinization, microcrystallinity, and accessible and inaccessible portion to CGTase action of residual swollen starch. The adsorption phenomenon of CGTase to swollen starch was also examined under various conditions. The inhibition mechanism of CGTase by various CDs was identified to be competitive, most severely by a-CD. The mechanism elucidated will be used for development of a kinetic model describes CD production reaction in heterogeneous enzyme reaction system utilizing swollen extrusion starch.

• Microbiology and Biotechnology Letters
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• v.23 no.4
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• pp.425-431
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• 1995

A kinetic model of the cyclodextrin formation in a heterogeneous enzyme reaction system using swollen extrusion starch as substrate was derived emphasing the structural features of extrusion starch. The degree of gelatinization, the ratio of accessible and inaccessible portion of extrusion starch, adsorption of CGTase on swollen starch, the structural transformation during reaction, and product inhibition caused by produced CDs were considered in deriving kinetic model. Various kinetic constants were also evaluated. The derived kinetic equation was numerically simulated, which result showed that the derived kinetic equations can be used to predict the experimental data reasonably well under the various experimental conditions. Kinetic model can be utilized for the optimization of enzyme reactor and the process development for CD production from swollen extrusion starch.

• Korean Journal of Materials Research
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• v.17 no.1
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• pp.56-59
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• 2007

Recently, requirement for the ultra thin copper foil increases with smaller and miniaturized electronic components. In this study, we evaluated the surface morphology, crystal phase ana surface roughness of the copper film electrodeposited by pulse method without using additives. Homogeneous and dense copper crystals were formed on the titanium substrate, and the optimum condition was 25% duty cycle. Moreover, the surface roughness(Ra), $0.295{\mu}m$, is the smallest value in this condition. It is thought that this copper foil is good for electromigration inhibition due to the preferential crystal growth of Cu (111)

• Korean Journal of Pharmacognosy
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• v.29 no.4
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• pp.271-276
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• 1998

The inhibitory effects of MeOH extracts of 100 medicinal herbs on monoamine oxidase (MAO) activity were investigated. MAO was purified from mouse brain and its activity was determined by fluorospectrophotomer using kynuramine as a substrate. Nine kinds of MeOH extracts of herbs including Artemisia iwayomogi showed a mild inhibitory effect with ${100}-{200}\;{\mu}/ml$ in their $IC_{50}$ values on MAO activity. Seventeen MeOH extracts including Juglans mandshurica exhibited a weak inhibition of MAO activity with ${200}-{300}\;{\mu}/ml$ in their $IC_{50}$ values.

• Journal of Nutrition and Health
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• v.4 no.4
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• pp.25-28
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• 1971

The effects of additives for food and drug upon the tryptic hydrolysis of casein an a Synthetic substrate, $N^{\alpha}-Benzoyl-L-arginine$ ethylester (BAEE) in vitro has been studied. The results of this study were summarized as follows 1) It was found that the action of inhibition became stronger in the following order: Methyl parabene>Rose Bengal> Phloxine> Sod. DHA> Erythrosine by the colorimetric method using BAEE. These results also showed that other additives had no effect on the activity of trypsin. 2) All samples tested showed respectively same tendency using casein in this method. But the activity by Erythrosine and Sod. DHA was slightly increased in this experiment.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1978.10a
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• pp.208.4-209
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• 1978

The Chitinase which hydrolyzes the chitin, $\beta-1,$ 4-polymer of N-acetyl glucosamine, was purified from the culture broth of Streptomyces sp. 115-5 strain. The homogeneity of enzyme was reveali by CM-Sephadex C-50 column chromatography and polyacrylamide gel electrophoresis. The purified enzyme hydrolyzed chitin and chitosan, but not cellulose. And with chitin as the substrate, a Km value of 3.6mg per ml and a Vmax of $100\mu$ mole per hr were found. The activation energy for the reaction was 3.66 Kcal per mole. The M. W. was estimated 56,000 daltons, and PI as 3.0. The chitinase was inhibited by the addition of glucose, glucuronic acid, sorbitol and xylose as product inhibitors and its inhibition pattern by glucose was estimated pure competitive type.

• Journal of Microbiology and Biotechnology
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• v.5 no.5
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• pp.274-279
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• 1995

Ethyl caproate, one of the major flavor compounds deciding the quality of sake (Japanese wine), is produced during the brewing by the action of alcohol acyltransferase and esterases of sake yeast and koji mold. Extracellular esterases of Aspergillus oryzae required for ethyl caproate synthesis were purified partially. The enzymes had different optimum pH and affinity toward substrates. Substrate preferences and inhibition features showed the three enzymes to be B-type esterases or carboxylesterases (EC 3.1.1.1).

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.499-500
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• 2003

To investigate the potency of some natural extracts as skin whitening agents, in this study, 25 natural plants were prepared from natural sources including medicinal plants, such as Angelica dahurica using methylene dichloride, ethyl acetate, n-butyl alcohol, and water as the extraction and/or the partitioning solvents. These natural extracts were subsequently subjected to in-vitro DOPA auto-oxidation test in the media containing human or mushroom tyrosinase as the oxidation promoting enzymes. Most of the extracts showed relatively higher enzyme inhibition(omitted)