• 펄프종이기술
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• 제35권2호
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• pp.39-45
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• 2003

This study was performed to develop the new type enzyme immobilization sheet from carboxymethylated refiner mechanical pulp (CRMP) substrate. Enzyme immobilization was attempted to couple carboxyl groups of CRMP with amino groups of the enzyme, trypsin, through the reaction of carbodiimide reagent, 1-ethyl-3-(3-dimethyl aminopropyl)-carbodimide (EDC ). Immobilization carrier, water insoluble CRMP fraction (CRMP-IS), was successfully reacted with the enzyme, formed peptide linkage like -CONH- at 1680$cm^{-1}$ / and new ester linkage like -COO$CH_3$, methylester at 1735$cm^{-1}$ /, and produced enzyme immobilized substrate (CRMP-IST). The enzyme immobilized handsheet was prepared by mixing the above chelated enzyme immobilized substrate(CRMP-IST) with kraft pulp by paper sheet machine like papermaking process. The sheet weight and strength were increased with increasing dosage of CRMP-IST, and decreased at more than 10％ mixing of CRMP-IST, but higher than the controls. Concerning activities of immobilized trypsin(CRMP-IST) sheet by caseinolysis, the teared-off sheet with shaking was shown higher enzyme activities than sheet shape without shaking. In conclusion, this enzyme immobilized sheet would be expected easy handling for practical application and reutilization.

• 생약학회지
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• 제15권2호
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• pp.78-84
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• 1984

Polyphenol oxidase was purified from acetone powder extract of the root of Ixeris sonchifolia. The enzyme obtained by ammonium sulfate fractionation and sephadex G-200 gelfiltration gave 51-fold purification over the crude extract. The purified enzyme showed activity toward chlorogenic acid, caffeic acid and pyrocatechol. The kinetics of thermal inactivation of the enzyme followed first-order reaction. Potassium cyanide and cysteine were potent inhibitors.

• 한국식품영양학회지
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• 제5권2호
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• pp.132-136
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• 1992

Streptomyces sp. YB-88-20 was Isolated from soil and the properties of chitobiase were investigated. The optimal reaction condition for the enzyme was pH 5.5 and 4$0^{\circ}C$ , and was stable in the range of pH 4. 0 to 5.5 and temperature at 4$0^{\circ}C$, and 40 min, respectively The enzyme was inactivated by heating at 45$^{\circ}C$ for 1 hr. The enzyme was slightly activated by Mna+. Mg2+, but inhibited by Fea+. Km and activation energy was 1.5072 M and 8.314 kcal/mol.

• 한국식품영양학회지
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• 제7권1호
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• pp.23-28
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• 1994

Soybean $\beta$-amylase was purified by DEAE-cellulose ion exchange chromatography, Sephadex G-100 gel chromatography, CM Sephadex C-50 ion exchange chromatography and CM Sephadex C-50 ion exchange rechromatography The purified enzyme showed 1, 020 unit/mg of specific activity. The purified enzyme was identified as homogenious by disc PAGE and analysis of reaction product.

• 한국식품영양학회지
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• 제6권4호
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• pp.307-313
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• 1993

Bacillus cereus $\beta$-amylase was purified by Sephadex G-100 gel filtration, CM Sephadex C-50 ion exchange chromatography and CM Sephadex C-50 ion exchange rechromatography The purified enzyme showed 871 unit/mg of specific activity. The purified enzyme was identified as homogenious by disc PAGE, SDS-PAGE and analysis of reaction product. The purified enzyme showed optimum pH 7.0. optimum temperature 5$0^{\circ}C$, and was stable at 0~5$0^{\circ}C$ and at pH range of 6~10.

• Journal of Microbiology and Biotechnology
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• 제1권1호
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• pp.50-53
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• 1991

The reaction steps involved in the bioconversion of a chemically synthesized precursor, $D,L-2-amino-{\Delta}^2-thiazoline-4-carboxylic$ acid (D,L-ATC), to L-cysteine and the properties of the involved enzymes were investigated. It was found that the conversion consisted of two steps, i. e., D,L-ATC to S-carbamyl-L-cysteine (S-C-L-cysteine) and S-C-L-cysteine to L-cysteine, and the S-C-L-cysteine was an intermediate between them. While the enzymes involved in the reactions were induced by the addition of D,L-ATC as an inducer, S-C-L-cysteine induced only the enzyme involved in the latter step. The conversion of S-C-L-cysteine to L-cysteine could be also carried out in the presence of hydroxylamine and its rate was much faster than that by the corresponding enzyme. On the other hand, L-cysteine (or L-cystine) was decomposed to evolve $H_2S$ by the enzyme considered to be a kind of desulfhydrase. However, hydroxylamine was a perfect inhibitor for this enzyme.

• KSBB Journal
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• 제9권5호
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• pp.499-505
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• 1994

Bacillus macerans cyclodextrin glucanotrans­f ferase(CGTase)를 전분흡착법과 DEAE--cellulose 칼럼 크로마토그래피로 정제하였다. 효소의 분자량 은 67,000이였고 monomer였다. 정제된 효소는 전 분을${\alpha}$-, ${\beta}$-, ${\gamma}$-CD 로 전환시켰으며, CD생성비율은 각각 1 : 1.68: 0.32였다. ${\alpha}$-CD와 D-glucose의 coupling반응 초기에는 maltohexose가 주로 생성되었고, 그 후에 다른 oligosaccharide들이 생성되었다 .. a­C CD의 가수분해반응 초기에는 주로 maltotetrose가 생성되였고 그 이후에는 소량의 다른 이Igosa­C ccharide들이 생성되었다. 정제된 효소의 좋은 기질인 maltotriose 로부터 maltosyl 이나 D-glucopy ranosyl group이 전이될 수 있는데, 본 연구에서는 D정lucosyl transfer가 우세하였다.

• Journal of Applied Biological Chemistry
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• 제43권4호
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• pp.230-234
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• 2000

A new method to assay the capsaicinoid synthetase (CS) activity was developed by utilizing NADHcoupled enzyme systems involving pyruvate kinase and lactate dehydrogenase. CS activities in Capsicum placenta, depending upon the kinetics of the NADH oxidation, revealed almost the same profile as compared with those shown using an HPLC-based method. When the substrates, 8-methyl nonanoic acid and vanillylamine, for the CS enzyme were employed separately or simultaneously, it appeared that the two-step reaction, acyl-CoA formation and condensation with vanillyla~ne, of the CS enzyme was a coupled reaction. Thus, this assay method of the CS enzyme can be considered as an alternative to the HPLC-based method, since it has the advantages of rapidity and simplicity as well as reliability when compared with the existing method.

• KSBB Journal
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• 제14권5호
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• pp.539-542
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• 1999

의 대량생산과 분리.정제 기술의 개발을 위해 Arthrobacter ureafaciens KCTC 3387 균주를 이용한 발효 및 분리정제된 효소반응을 통한 DFAIII의 생산과 회수에 대하여 조사하였다. 첫 번째 방법으로는 Arthrobacter ureafaciens 균주를 발효배양하여 DFAIII 양이 최고가 되는 시점에서 발효정지 시킨후 silica gel를 통해 gel filtration을 분리하였고, 두 번째 방법으로는 정제된 효소로 반응시킨 다음 silica gel을 통해 gel filtration을 하여 분리하였으며, 세 번째 방법으로는 발효배양상등액에 에탄올을 첨가하여 생산물을 침전시켜 DFAIII를 분리하였다. 25 g/L의 초기 inulin 농도로부터 각각 1.57, 4.40, 0.34 g/L 의 정제분말이 얻어져 각각 6.3, 17.6, 1.4%의 수율로 회수되었고, 81, 97, 87%의 순도를 각각 나타내었다. 효소반응을 통한 DFAIII 생산 및 회수가 가장 높은 수율과 순도로 회수되었으며, 발효배양을 통한 DFAIII의 생산은 초기기질농도 25 g/L의 50%에 해당하는 DFAIII가 생산되었으나 효소반응에 의한 생산보다는 낮은 수율로 회수되었고 순도는 세 가지 방법 중 가장 낮았으며, 에탄올 침전반응은 가장 낮은 수율을 나타내었다.

• BMB Reports
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• 제31권5호
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• pp.444-452
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• 1998

The visible spectra of soybean ferric leghemoglobin reductase exhibited a charge transfer band at 530 nm under aerobic condition. Spectra of the oxidized enzyme show a flavin peak at 454 nm and the enzyme has three redox states associated with the active site of the enzyme. The enzyme has an active disulfide bridge and two-electron transfer may dominate in the ferric state of leghemoglobin reduction. The midpoint potentials of the enzyme were determined by spectrotitration to be -0.294 V for disulfide/dithiol and -0.318 V for FAD/$FADH_2$. Since the midpoint potentials for $NAD^+$/NADH and the ferrous/ferric states of leghemoglobin are -0.32 V and +0.22 V, respectively, it is proposed that two electrons are transferred sequentially from NADH to FAD, to the disulfide group, and then to the ferric state of leghemoglobin in the enzyme reaction.