• 한국미생물생명공학회:학술대회논문집
• /
• 한국미생물생명공학회 2001년도 Proceedings of 2001 International Symposium
• /
• pp.179-182
• /
• 2001

Two intracellular enzymes, cellobiose phosphorylase (CBP) and cellodextrin phosphorylase (CDP) are involved in the phosphorolytic pathway in cellulose degradation. Those enzymes are considered to be useful in syntheses of oligosaccharides because the reactions are reversible. CBP from Cellvibrio gilvus and CDP from Clostridium thermocellum YM-4 were cloned and over-expressed in Escharichia coli. Both the enzyme reactions showed ordered bi bi mechanism. Acceptor specificity of CBP in the reverse reaction was determined. Several $\beta$-l,4-glucosyl disaccharides were synthesized by using the reaction. A new substrate inhibition pattern, competitive substrate inhibition, was also found in the reverse reaction of CBP Cellobiose was produced from sucrose at a high yield by a combined action of three enzymes including CBP

• 한국약용작물학회:학술대회논문집
• /
• 한국약용작물학회 2011년도 추계학술발표회
• /
• pp.294-295
• /
• 2011

• 한국약용작물학회:학술대회논문집
• /
• 한국약용작물학회 2009년도 심포지엄 및 춘계학술발표회
• /
• pp.303-304
• /
• 2009

• 한국미생물·생명공학회지
• /
• 제1권1호
• /
• pp.37-42
• /
• 1973

본실험에서 얻어진 결과를 요약하면 다음과 같다. 1) Inulin을 분해하는 효소를 생산하는 Aspergillus속 1주를 선별하였다. 2) 선별된 묘주효소의 E.P차에 의한 침전은 pH8~5에서 효소단백질이 다량 회수되었다. 3) 선별된 묘주가 분비하는 Inulase활성최적 pH는 3.0부근이 었다. 4) 선별된 묘주의 Inulin 분해효소의 활성최적 온도는 $55^{\circ}C$였다. 5) 본 Sample효소의 열에 대한 안정성은 $50^{\circ}C$에서 10분간 열처리 하여도 안정하였다. 6) 본 Sample효소의 안정 pH는 2.5~4.5정도였다. 7) 본 Sample효소의 금속 ion에 대한 영향은 $Mg^{++}$는 Activator였으며 $Sb^{+++}$, $Bi^{+++}$.는 저농도에서는 inhibitor였으나 $10^{-4}$ M~$10^{-4}$ M 농도일때는 촉진시켰으며 더욱 금속 ion농도가 높아짐에 따라 inhibition하였으며 $Ag^{++}$, $Hg^{++}$의 경우에는 저농도($10^{-8}$ M)일 때는 Activation하였고 반면, 농도가 높아짐에 따라 저해효과가 더욱 컸으며 특히 $Hg^{++}$의 경우 $10^{-2}$ M 농도에서 약 80% 저해를 나타내었다.내었다.

• Journal of Microbiology and Biotechnology
• /
• 제24권1호
• /
• pp.19-25
• /
• 2014

An extracellular agarase was purified from Bacillus sp. BI-3, a thermophilic agar-degrading bacterium isolated from a hot spring in Indonesia. The purified agarase revealed a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with an apparent molecular mass of 58 kDa. The optimum pH and temperature of the agarase were 6.4 and $70^{\circ}C$, respectively. The activity of the agarase was stable at high temperatures, and more than 50% activity was retained at $80^{\circ}C$ for 15 min. Furthermore, the enzyme was stable in the pH range of 5.8-8.0, and more than 60% of the residual activity was retained. Significant activation of the agarase was observed in the presence of $K^+$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$, and $Sr^{2+}$; on the other hand, $Ba^{2+}$, $Zn^{2+}$, $Cu^{2+}$, $Mn^{2+}$, $Co^{2+}$, $Fe^{2+}$, and EDTA inhibited or inactivated the enzyme activity. The components of the hydrolytic product analyzed by thin-layer chromatography showed that the agarase mainly produced neoagarobiose. This study is the first to present evidence of agarolytic activity in aerobic thermophilic bacteria.

• Bulletin of the Korean Chemical Society
• /
• 제25권8호
• /
• pp.1195-1201
• /
• 2004

Tyrosinase was covalently immobilized on platinum electrode according to the method we developed for laccase (Bull. Korean Chem. Soc. 2002, 23(7), 385) and p-chlorophenol, p-cresol, and phenol could be detected with sensitivities of 334, 139 and 122 nA/ ${\mu}M$ and the detection limits of 1.0, 2.0, and 2.5 ${\mu}M$, respectively. The response time ($t_{90\%}$) is 3 seconds for p-chlorophenol, and 5 seconds for p-cresol and phenol. The optimal pHs of the sensor are in the range of 5.0- 6.0. This sensor can tolerate at least 500 times repeated injections of p-chlorophenol with retaining 80% of initial activity. In case of tyrosinase and laccase co immobilized platinum electrode, the sensitivities are 560 nA/ ${\mu}M$ for p-phenylenediamine (PPD) and 195 nA/ ${\mu}M$ for p-chlorophenol, respectively. The sensitivity of the bi-enzyme sensor for PPD increases 70% compared to that of only laccase immobilized one, but the sensitivity for p-chlorophenol decreases 40% compared to that of only tyrosinase immobilized one. The sensitivity increase for the bi-enzyme sensor for PPD can be ascribed to the additional catalytic function of the co-immobilized tyrosinase. The sensitivity decrease for p-chlorophenol can be explained by the “blocking effect” of the co-immobilized laccase, which hinders the mass transport through the immobilized layer. If PPD was detected with the electrode that had been used for p-chlorophenol, the sensitivity decreased 20% compared to that of the electrode that had been used only for PPD. Similarly, if p-chlorophenol was detected with PPD detected electrode, the sensitivity also decreased 20%. The substrate-induced conformation changes of the enzymes in a confined layer may be responsible for the phenomena.

• 한국약용작물학회지
• /
• 제18권4호
• /
• pp.255-265
• /
• 2010

The extent of growth L. plantarum (LP), L. delbrueckii subsp. bulgaricus (LD), L. fermentum (LF), S. thermophilus (ST), B. longum (BI) and S. cerevisiae (SA) was generally good with the lower concentration of the ginseng extract. Total sapogenin content was slightly different with kinds of a fermentation microorganism and the time of fermentation process, and generally reduced compare to before fermentation. The content of ginsenoside Rb1, Rb2, Rb3, Re and Rf were decreased with the fermentation but ginsenoside Rd was increased by the E, LF and SA fermented extract. The content of compound K increased in the order of not-fermented extrac < enzyme fermented extract < enzyme and microorganism fermented extract, and as the fermented time get longer, the content of compound K was sightly increased. Especially, the content of compound K of the SA fermented extract was the most increased, also it of the BI, LD and LF fermented extract was increased, so these extract were considered a high valuable. Polyphenol content of the BI, LD, LP and ST fermented extract indicated $9.18{\pm}0.39{\sim}15.68{\pm}0.54$ mg/10 g which was lower than it of a not-fermented extract ($11.92{\pm}0.26{\sim}28.41{\pm}0.39$ mg/10 g). Flavonoid content of a ginseng fermented extract indicated $26.93{\pm}0.17{\sim}156.45{\pm}1.29$ mg/10 g, it was higher than a not-fermented extract ($18.06{\pm}0.90$ mg/10 g). As the fermented time get longer, the flavonoid content tendency to increase. DPPH radical scavenging activity of a fermented ginseng extract was $24.11{\pm}1.41{\sim}55.62{\pm}0.33%$, it was slightly lower compared to a natural antioxidant, vitamin C. But it of the LF and ST fermented extract was similar to a natural antioxidant, vitamin C. It has not a concerned in a fermentation. Nitrite scavenging ability of a 24 hr fermented extract was above 80% at pH 2.5 and 4.2, it was similar to an artificial antioxidant, BHT ($84.76{\pm}0.13%$; pH2.5, $84.98{\pm}0.11%$; pH 4.2). It has not a concerned in a fermentation. SOD-like activity of a fermented extract was lower than that of a not-fermented extract ($19.22{\pm}0.51%$), but it of the E and LP-fermented extract was a very highly notable value. As the fermented time get longer, the SOD-like activity tendency to increase.

• 대한본초학회지
• /
• 제21권2호
• /
• pp.135-142
• /
• 2006

Objectives : On-Bi-Tang(OB) has been prescribed Chinese traditional medicine for the treatment of inflammatory disease such as chronic renal failure. In this study, we investigated the anti-inflammatory effect of OB extract in the BV2 murine microglial cells. Methods : After the water extract of OB was treated in BV2 cells, murine microglial line, the cell viability was measured by MTT assay. The production of nitric oxide (NO) and $TNF-{\alpha}$ was determined based on Griess reagent and enzyme linked immunosorbant assay (ELISA). mRNA expression of inducible nitric oxide synthase (iNOS) and $TNF-{\alpha}$ was analyzed by RT-PCR. Results : OB extract significantly inhibited the LPS-induced production of NO and TNF-a in BV2 cells. OB extract also suppressed the mRNA expression of iNOS and $TNF-{\alpha}$ in BV2 cells activated with LPS. Conclusion : These data suggests that OB extract may have the anti-inflammatory effect through the modulation of NO production and inflammatory cytokine such as $TNF-{\alpha}$.

• Journal of Microbiology and Biotechnology
• /
• 제21권8호
• /
• pp.838-845
• /
• 2011

The present work describes the identification, purification, and characterization of bile salt hydrolase (BSH) from Bifidobacterium animalis subsp. lactis. The enzyme was purified to electrophoretic homogeneity by hydrophobic chromatography, ion-exchange chromatography and ultrafiltration. SDS-PAGE analysis of putative BSH and gel filtration revealed that the analyzed protein is presumably a tetramer composed of four monomers each of about 35 kDa. The purified enzyme was analyzed by liquid chromatography coupled to LTQ FT ICR mass spectrometry and unambiguously identified as a bile salt hydrolase from B. animalis. The isoelectric point of the studied protein was estimated to be around pH 4.9. The pH optimum of the purified BSH is between 4.7 to 6.5, and the temperature optimum is around 50oC. The BSH of B. animalis could deconjugate all tested bile salts, with clear preference for glycine-conjugated bile salts over taurine-conjugated forms. Genetic analysis of the bsh showed high similarity to the previously sequenced bsh gene from B. animalis and confirmed the usefulness of bile salt hydrolase as a genetic marker for B. animalis identification.

• 공업화학
• /
• 제25권2호
• /
• pp.152-156
• /
• 2014

Isoquercitrin (IQ)은 폴리페놀의 일종인 quercetin (QU)의 3번 위치에 glucose가 하나 결합해 있는 배당체로서, 천연에는 미량만이 존재하고 있다. 최근 QU의 2배당체인 rutin (RU)을 기질로 사용하여 효소에 의한 부분 가수분해에 의해 IQ를 합성할 수 있다는 것이 알려졌다. 본 논문에서는, $Pecinex^{TM}$ 계열의 복합 효소를 사용하여 RU의 선택적 가수분해에 의해 IQ를 합성하는 반응에서 최적 효소를 선정하고, 효소량 및 반응물의 농도 등의 변수에 따른 반응성을 검토하였다. 그 결과, $50^{\circ}C$에서 1%의 반응물 농도로 RU 1 g 대비 8 mL의 Ultra Clear를 사용하는 것이 반응 속도 및 IQ의 선택성 측면에서 최적인 것으로 나타났다.