• 한국환경과학회지
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• 제11권12호
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• pp.1315-1320
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• 2002

Since the enzymatic degradation of microbial poly[(R)-3-hydroxybutyrate-co-3-hydroxyvalerate] (P(3HB-co-3HV)) initially occurs by a surface erosion process, a degradation behavior could be controlled by the change of surface property. In order to control the rate of enzymatic degradation, plasma gas discharge and blending techniques were used to modify the surface of microbial P(3HB-co-3HV). The surface hydrophobic property of P(3HB-co-3HV) film was introduced by CF$_3$H plasma exposure. Also, the addition of small amount of polystyrene as a non-degradable polymer with lower surface energy to P(3HB-co-3HV) has been studied. The enzymatic degradation was carried out at 37 $^{\circ}C$ in 0.1 M potassium phosphate buffer (pH 7.4) in the presence of an extracellular PHB depolymerase purified from Alcaligenes facalis T1. Both results showed the significant retardation of enzymatic erosion due to the hydrophobicity and the enzyme inactivity of the fluorinated- and PS-enriched surface layers.

• Journal of Microbiology and Biotechnology
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• 제4권2호
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• pp.113-118
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• 1994

A bacterial strain NS-83 isolated from soil was able to produce an extracellular thermostable protease. The strain was identified as Pseudomonas aeruginosa based on its morphological and physiological characteristics. A thermostable protease from this strain has been purified to homogeneity as judged by SDS-PAGE and isoelectric focusing. The purification procedures included hydrophobic interaction, ion exchange, and gel filtration chromatography. The $M_r$ and the pl of the enzyme were 32,000 and 5.9, respectively. The optimal pH at 55$^{\circ}C$ and the optimal temperature at pH 7.0 were 8.0 and 60$^{\circ}C$, respectively. The D-values of the enzyme at 60, 65, and 70$^{\circ}C$ were 22, 2.1, and 0.75 hrs, respectively. The enzyme activity was significantly inhibited in the presence of 1 mM o-phenanthroline or EDTA, suggesting that the enzyme is metalloprotease. The $K_m$, and $V_{max}$ for Hammarsten casein were found to be 3.2 mg/ml and 0.918 unit/ml, respectively. These enzymatic properties were similar to those of elastase produced from P. aeruginosa IFO 3455, but the enzyme was clearly different from the reported elastase, in respect to $Ca^{++}$ effects on enzyme-thermostability. This property, together with amino acid composition analysis, confirmed that the enzyme differs from the known P. aeruginosa elastase.

• 한국식품영양학회지
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• 제36권1호
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• pp.42-49
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• 2023

To enhance the efficacy of Abeliophyllum distichum leaves, extracts were prepared using different solvents for hydrolytic enzyme-treated Abeliophyllum distichum leaves. Physicochemical quality and antioxidant activity were measured. Soluble solids, reducing sugar, ascorbic acid, flavonoids, and polyphenols contents showed the lowest values in the control without enzyme treatment. However, they showed high contents in ethanol extract. In the case of enzyme treatment, their values were higher than those of the control. In particular, verbascoside content increased about 220 times more than that of the control group when treated with enzymes and extracted with 50% ethanol. pH was lowered upon enzymatic treatment. Regarding DPPH radical scavenging activity, for enzyme-free, 25% ethanol extract showed the highest activity among extracts with different solvents. For cellulase and pectinase-treated leaves, water extract showed the highest DPPH radical scavenging activity among extracts with different solvents. For leaves treated with enzyme combination, 50% ethanol extract showed the highest DPPH radical scavenging activity among extracts with different solvents. Regarding ABTS radical scavenging activity, it was generally higher in the 50% ethanol extract than in the water extract and 25% ethanol extract. In particular, verbascoside content was increased when the extract was prepared by co-treatment with enzymes and 50% ethanol.

• 한국전기전자재료학회논문지
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• 제15권7호
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• pp.621-626
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• 2002

In the case of immobilizing of glucose oxidase (GOx) in polypyrrole (PPy) conducting polymer using electrosynthesis, the GOx obstructs charge transfer and mass transport during the film growth. This may lead to short chained polymer and/or make charge-coupling weak between the GOx and the backbone of the PPy. That is mainly due to insulating property and net chain of the GOx. Since being the case, it is useless to increase in amount of GOx mere than reasonable in the synthetic solution. We improved the amount of immobilized GOx into the PPy by adding a little ethanol in the synthetic solution without any more amount of GOx in the solution. We electrochemically analyzed an improvement in the immobilizing event. For the glucose sensing, when ethanol was added by 0.1 mol $dm^{-3}$ in the synthetic solution, the Michaelis constant of the resulting enzyme electrode was about 32 mmol $dm^{-3}$ and maximum current was about $146\mu A$.

• Journal of Life Science
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• 제9권2호
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• pp.44-48
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• 1999

The ionization of tyrosine residue is known to be involved in the stabilization of transition-state in catalysis of astacin based upon the astacin-transition state analog structure. Two tyrosine residues, Tyr-216 and Tyr-219, are conserved in all MMPs related with astacin family, We replaced Tyr-216 and Tyr-219 into phenylalanine, respectively and the zinc binding properties, kinetic parameters, and pH dependence of each mutant are determined in order to examine the role of tyrosine residue in matrilysin catalysis. Both mutants contain two zinc atoms per mol of enzyme, indicating that either tyrosime does not affect the zinc binding property of the enzyme. Y216F and Y219F mutants are highly active and the kcat/Km values are only decreased 1.1-1.5-fold compared to the wild-type enzyme. The decrease in the activity of the mutants is essentially due to the increase in Km value. The pH dependencies of the kcat/Km values for both mutants are similar to the corresponding dependencies obtained with the wild type enzyme. The pKa values at the alkaline side of both mutants are not changed. These kinetic and pH dependence results indicate that the ionization of active site tyrosine residue of matrilysin is not reflected in the kinetics of peptide hydrolysin as catalyzed by astacin.

• 한국식품영양과학회지
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• 제31권3호
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• pp.465-468
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• 2002

Affinity chromatography법에 의해 해바라기씨 유래 $\alpha$-galactosidase정제를 수행하여 locust bean gum 증점 대체자원의 개발을 위한 기초연구로서 정제효소처리된 guar gum 과 locust bean gum의 구성당인 galactose와 mannose의 구성비율을 비교 검토하였다. 정제효소처리된 guar gum의 중점효과는 galactose와 mannose비율이 1 : 3.2일 때 가장 증가하였다. 이와같은 비율은 효소적 처리시간을 24시간으로 하였을 때 나타내었다. 해바라기씨 유래 $\alpha$-galactosidase처리에 의한 guar gum으로부터의 galactose의 유리가 증점효과에 영향을 미치는 것으로 사료된다. Xanthan gum과 guar gum의 혼합, xanthan gum과 guar gum 및 정제효소처리된 천연 유래 copra meal과의 혼합물에 대한 증점효과도 비교하였다.

• 한국식품영양과학회지
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• 제26권6호
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• pp.1116-1121
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• 1997

Effects of gamma irradiation onf the activity and the properties(amino acid compositions, in vitro digestibility and SDS-PAGE pattern) of proteolytic enzymes were investigated. The proteolytic activity of soluble human serine protease, enzyme in kiwi and pineapple decreased 10% and 30~65% by 5 kGy and 30 kGy, respectively. In dried pancreatin and lysozyme, the proteolytic and antimicrobial activities decreased 6~14% and 10~20% by 5kGy and 40kGy, respectively. The analysis of above 10kGy-irradiated soluble human serine protease by SDS-PAGE revealed radiolysis of the enzyme into protein or peptides of lower molecular weights. The irradiation of skim milk, hammastein casein, and lysozyme up to 40kGy had no deleterious effect on either the in vitro digestibility or amino acid compositions.

• 공업화학
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• 제10권5호
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• pp.635-638
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• 1999

구두용 나피(裸皮)의 물성에 가장 큰 영향을 주는 탈모 공정에 단백질 분해 효소가 미치는 영향을 연구하였다. 나피의 물성을 기존의 방법 대신 전자 현미경을 이용하여 측정하는 새로운 방법을 제시하였다. 단백질 분해 효소를 이용한 바이오-테크 처리가 화학적 처리보다 탈모율에서 약간 저하되나 나피의 물성과 환경 측면에서 우수한 것으로 나타났다. 특히, 화학적 처리시 발생하는 유해 가스인 $H_{2}S$가 전혀 발생치 않았으며, 탈모 공정의 폐수 처리시 COD 및 BOD 값이 각각 939 mg/L와 5268 mg/L로 상당량 감소하여 기존의 처리 방법들보다 환경 친화적인 방법임을 확인할 수 있었다. 따라서, 탈모 공정은 $29{\sim}30^{\circ}C$의 온도 범위에서 단백질 분해 효소인 0.4~0.5% Lupin LE-10을 첨가하여 20시간 처리하는 것이 적합하였다.

• BMB Reports
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• 제29권2호
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• pp.111-115
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• 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 $45^{\circ}C$.

• 한국식품영양과학회지
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• 제25권4호
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• pp.687-694
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• 1996

한국산 겨자에서 myrosinase를 분리 및 정제하고, 이들의 효소학적 특성을 조사한 결과는 다음과 같다. 겨자 myrosinase를 DEAE-cellulose, Concanavalin A-Sepharose 및 FPLC Soporose 6 칼럼을 이용하여 분리 및 정제하였을 때 적어도 3개의 이성효소가 존재하는 것으로 나타났으며, Myrosinase II-2의 최종 비활성도는 57.lunits/mg, 정제도는 약 248배였다. SDS-PAGE상에서 myrosinase(II-2)의 단일밴드를 확인한 결과, 그 분자량은 약 67KD로 추정 되었다. 최적 pH는 phosphate 및 Tris-HCI 완충액에서 7.0이 가장 활성이 높았고, 그 효소는 pH 7.0에서 안정하였으며, 최적 활성을 나타내는 온도는 $37^{\circ}C$ 부근이었고, $40^{\circ}C$ 이상에서는 비교적 불안정하게 나타났다. Ascorbic acid의 영향은 1mM에서 가장 안정하였으며, 그 이상의 농도에서는 변화가 없었다. 망간과 마그네슘 및 나트륨은 효소활성을 촉진시키는 것으로 나타났으며 구리, 수은 및 철 이온은 약간 저해하였다. Ascorbic acid analogue 중 dehydroascorbic acid는 효소 활성을 저해하였으며, 나머지 것들은 거의 영향을 미치지 않았다. 2-Mer-captoethanol과 dithiothreitol과 같은 환원제는 효소활성을 억제하였으나 이들과 ascorbic acid를 함께 첨가 하였을 때는 활성이 다소 증가하였다.