• KSBB Journal
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• 제15권1호
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• pp.9-13
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• 2000

Cellulose 분해에 관련된 $\beta$-Glucosidase 효소 활성의 특성 파악을 위하여 송이균사(Tricholoma matsutake DGUM 26001)의 액체 배양시 세포외로 분비되는 $\beta$-Glucosidase 효소를 부분정제하여 그 특성을 조사하였다. 효소 활성에 미치는 적정 온도는 55-$70^{\circ}C$이었고 최적 온도는 $65^{\circ}C$이었다. 적정 효소활성에 영향을 주는 적정 pH는 3.0-5.0 범위였으며 최적 pH는 4.0이었다. Salicin을 기질로 최적 조건하에서 $\beta$-Glucosidase 효소의 비활성도는 18.7 unit/mg protein이었다. 열안정성은 $60^{\circ}C$이하의 온도에 60분간 열처리시 약 90%이상의 효소활성을 유지하였다. $Fe^{++}$이온은 효소활성을 촉진하였으나, $Hg^{++}$ 및 $Cu^{++}$이온은 효소활성을 매우 억제하였다. Salicin에 대한 효소활성을 100으로 하였을 때, cellobiose는 48.6%의 상대적 효소활성을 나타내었으며, cellobiose에 대한 Km값 및 Vmax값은 각각 0.12mM과 0.02umol/min었다.

• 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.

• 한국미생물·생명공학회지
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• 제25권1호
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• pp.56-61
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• 1997

An alkaline protease producing microorganism was isolated from korean traditional Meju and identified as Scopulariopsis brevicaulis. The optimum culture condition of Scopulariopsis brevicaulis for the production of alkaline protease was as follow: 2% soluble starch, 0.2$, tryptophan, 0.1% (NH$_{4}$) $_{2}$S$_{2}$O$_{8}$ 0.2% NaHPO$_{4}$, pH 7.5, 35$\CIRC $C. The optimum pH and temperature for the enzyme activity of alkaline protease producing Scopulariopsis brevicaulis were pH 9.0 and 50$\circ $C, respectively. The enzyme was relatively stable at pH 6.0~11.0 and at temperature below 40$\circ $C. The activity of the enzyme was inhibited by Hg$^{2+}$ whereas Cu$^{2+}$ gave rather activating effects on the enzyme activity. Phenylmethanesulfonyl fluoride inhibited the enzyme activity. This result indicates that serine is very important role in this enzyme. Km value for casein was 1.2410$^{4}$ M/L, V$_{max}$ value for casein was 25.99 $\mu $g/min. This enzyme hydrolyzed casein more rapidly than the hemoglobin.

• 대한약침학회지
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• 제14권2호
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• pp.5-14
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• 2011

Objectives: Fibrinolytic enzyme preparations were isolated from the snake venom of Macrovipera lebetica turanica in this study. Methods: The purity of the preparations was determined using SDS-PAGE and the enzymic characteristics of the purified fibrinolytic enzyme were determined. Results: 1. All of the two preparations with fibrinolytic activity obtained from the snake venom of M. l. turanicat contained the major polypeptide with the molecular weight of 27,500. One of the preparation showed purified fibrinolytic enzyme. 2. The purified fibrinolytic enzyme hydrolyzed ${\alpha}$-chain of fibrinogen faster than ${\beta}$-chain but not ${\gamma}$-chain. 3. The fibrinolytic activity was inhibited completely by EDTA, EGTA, 1,10-phenanthroline, and dithiothreitol. 4. The fibrinolytic activity was inhibited completely by calcium chloride, iron(III) chloride, mercuric chloride, and cobalt (II) chloride. 5. The fibrinolysis zone formed after addition of zinc sulfate was smaller but clearer than the control. Conclusions: These results suggested that the fibrinolytic enzyme purifed from the snake venom of M. l turanica was a metalloprotease containing dithiol group.

• 한국미생물·생명공학회지
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• 제23권5호
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• pp.573-579
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• 1995

A Bacillus strain capable of producing an extracellular malto-oligosaccharides forming $\alpha $-amylase was isolated from soil and designated as Bacillus sp. SUH4-2. The enzyme was purified by ammonium sulfate fractionation, DEAE-Toyopearl and Mono-Q HR 5/5 column chromatographies using a FPLC system. The specific activity of the enzyme was increased by 16.1-fold and the yield was 13.5%. The optimum temperature for the activity of $\alpha $-amylase was 60-65$\circ$C and more than 50% of initial activity was retained after the enzyme was incubated at 60$\circ$C for 40 min. The enzyme was stable over a broad pH range of 5.0-8.0 and the optimum pH was 5.0-6.0. The molecular weight of the enzyme was determined to be about 63.6 kD and isoelectric point was around 5.8. The enzyme activity was strongly inhibited by Mn$^{2+}$, Ni$^{2+}$, and Cu$^{2+}$ ; slightly by Ca$^{2+}$. The purified enzyme produced starch hydrolyzates containing mainly maltose and maltotriose from soluble starch. The starch hydrolyzates were composed of 11% glucose, 59% maltose, 25% maltotriose and 5% maltotetraose.

• Journal of Applied Biological Chemistry
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• 제42권4호
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• pp.169-174
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• 1999

Arabidopsis AHL gene contains 4 exons encoding a putative protein highly homologous to the yeast salt-sensitive enzyme HAL2, a 3'(2'),5'-bisphosphate nucleotidase involving in reductive sulfate assimilation. AHL cDNA complemented yeast met22 (hal2) mutant. AHL fusion protein expressed in E. coli exhibited $Mg^{2+}$-dependent, 3'-phosphoadenosine 5'-phosphate (PAP)-specific phosphatase activity. $Li^+,\;Na^+,\;K^+$ and $Ca^{2+}$ ions inhibit the enzyme activity by competing with $Mg^{2+}$ for the active site of the enzyme. The enzyme activity was also sensitive to ${\mu}M$ concentrations of toxic heavy metal ions such as $Cd^{2+},\;Cu^{2+}$ and $Zn^{2+}$, but was not recovered by addition of more $Mg^{2+}$ ions, suggesting that these ions inactivate the enzyme with a mechanism other than competition with $Mg^{2+}$ ions. Inhibition of the AHL enzyme activity may result in accumulation of PAP, which is highly toxic to the cell. Thus, the AHL enzyme could be one of the intial targets of heavy metal toxicity in plants.

• 한국수산과학회지
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• 제54권3호
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• pp.280-286
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• 2021

This study was performed to screen the antimicrobial activities and proteolytic enzyme stability of the acidified extract of the Blue mussel Mytilus edulis. The acidified extract showed potent antimicrobial activities against Gram-positive bacteria, Bacillus subtilis, and Gram-negative bacteria, Escherichia coli D31, but had no activity against Candida albicans. Treatment of extract with trypsin completely abolished all or significant antibacterial activity against the tested bacteria, but slightly decreased antimicrobial activity against B. subtilis, and treatment of extract with chymotrypsin retained almost antibacterial activity against the tested bacteria except for E. coli D31. To confirm the additional enzyme stability of the extract, antimicrobial activity of the extract was tested after treated with several enzymes. Enzymes treated extract showed potent antimicrobial activity against B. subtilis and its activity was also retained for 5 h after trypsin treatments. Non-proteinaceous materials in the acidified extract also showed strong DNA-binding ability but did not show bacterial membrane permeabilizing ability. All our results indicate that mussel extract might contain the proteinaceous or non-proteinaceous antibacterial materials target not bacterial membrane but intracellular components. These results could be used to develop mussel extract as an additive for the improvement of stability or antimicrobial activity of antibiotics against specific bacteria.

• 분석과학
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• 제36권1호
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• pp.44-52
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• 2023

This protocol clarifies a simple and precise method for measuring the activity of xanthine oxidase (XO) enzyme inhibitor. XO enzyme, which accelerates oxidative stress-related disorders through its capacity to generate hydrogen peroxide and superoxide anion radicals (O₂^•-), has been found to be inhibited by several plant extracts. Enzyme samples were incubated with a suitable buffer containing adequate amounts of xanthine as a substrate to determine XO activity. The method depends on direct measurements of uric acid and hydrogen peroxide production to test XO with and without interference. The CUPRAC reagent (Cu(Nc)₂²⁺) was used to inhibit enzyme reaction after incubation was complete. The generated urate and peroxide reduced the Cu(II)-neocuproine complex (Cu(Nc)₂²⁺) to a brightly colored Cu(I)-neocuproine complex (Cu(Nc)₂⁺), which was assessed with a spectrophotometer at 450 nm. XO activity was found to be directly related to the increased absorbance of the colored Cu(I)-neocuproine complex (Cu(Nc)₂⁺). To eliminate catalase enzyme interference, the proposed method used sodium azide and was validated against XO activity using the UV method in matched samples with t-test analysis. The proposed assay can determine XO activity with high precision, as indicated by the correlation coefficient (R² = 0.9935) from comparison with the reference protocol.

• 펄프종이기술
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• 제36권3호
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• pp.1-8
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• 2004

It is very difficult to compare directly the research results of enzymatic process in pulp and paper industry because commercial enzymes have diversity in its property. The chemical and biological properties of commercial enzymes were Investigated to help comparison of various commercial enzymes each other. In most case, the solid content of liquid enzymes was about 20%. The higher protein content in enzyme product does not mean the higher enzyme activity. Enzymes for paper process should selected by basis of enzyme activity, not by price of enzyme products. The chemical composition of fiber was not so much change with enzyme treatment. The enzymatic hydrolysis of fiber might negligible in paper process.

• 미생물학회지
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• 제18권2호
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• pp.59-66
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• 1980

Two strains S-P and S-P-2, both Streptomyces sp., have been isolated and were found to have relatively high specific enzyme activity compared to other organisms reported. The specific activity of the enzyme produced from these two strains were 0.25 and 0.2 international units respectively. The productivity of the enzyme achieved was about 50 IU/l/hr. Glucose isomerase form these strains was found to be stable under the temperature of heat treatment (at $65^{\circ}C$) for fixation of enzyme inside the dell. This organism has an advantage in that it did not require toxic metalic ion for enzyme activity and could utilize xylan in leu of xylose as an inducer. The optimal temperature and pH of enzymatic reaction purpose of using these data for the optimal operation and designing of enzyme reactor system. The reaction mechanism was found to follow the single substrate reversible reaction kinetics. The kinetic constants determined experimentally are : $K_{mf}=0.33M,\;K_{mb}=1.0M,\;V_{mf}=0.88{\mu}mole\;per\;min.,\;V_{mb}= 2.96{\mu}mole\;per\;min.\;and\;K_{eq}=0.74.