• 대한화학회지
• /
• 제45권2호
• /
• pp.138-160
• /
• 2001

이 연구에서 온도, pH, 효소, 그리고 염의 첨가에 따라 부식(산화)전위에 영향을 주 인자들을 알아보기위해 비수용액 poly(vinylchloride)(PVC)와 poly(carbonate)(PC) 의 산화전위와 전류밀도를 측정하였다. Tafel 기울기는 분극곡선의 Tafel polt으로부터 결정되어졌다. 전달게수 ${\alpha}$는 기울기 (1-${\alpha}$)nF/2.3RT에서 얻어질 수 있고 인식된 전극 반응은 모든 조건에서 비가역적으로 나타났다.

• 한국식품영양과학회지
• /
• 제15권4호
• /
• pp.32-39
• /
• 1986

토양에서 분리한 여러가지 곰팡이류 가운데 beta-galactosidase 생성력이 가장 좋은 Aspergillus niger CAD 1을 효소 생산 균주로 선정 하였다. 이 균주의 효소 생산 최적 배양조건은 밀기울에 0.5% 탈지 분유를 첨가한 배지를 $30{\circ}C$에서 72시간 정치배양하는 것이었다. 아세톤으로 침전시킨 조효소(crude enzyme)는 일차로 DEAE-cellulose, 2차로 Sephadex G-100 gel filtration에 의하여 1,387배로 정제되었고 이때의 수율은 6.2%이였다. 정제된 효소의 최적 온도는 $45{\circ}C$ 최적 pH는 4.5이었으며, 기질로서 ONPG와 유당에 대한 Km값은 각각 $3.57{\times}10^3M$과 $83.3{\times}10^3M$, Vmax값은 각각 33.0 unit/mg protein과 15.38unit/mg protein이었다. 활성화 에너지는 9,900cal/mol이었으며 효소활성 및 안정제로 금속이온을 필요로 하지 않았다. 50ml의 탈지유, 4.8%유당 용액, 유청용액에 효소 5ml(182 unit/ml)를 침가하여 $45^{\circ}C$에서 10시간 반응시켰을 때의 유당 분해율은 각각 65%, 70%, 78%를 나타내었다.

• 농업과학연구
• /
• 제43권4호
• /
• pp.641-649
• /
• 2016

This study was conducted to evaluate the yield of bio-ethanol produced by separate hydrolysis and fermentation (SHF) with the pretreated rapeseed straw (RS) using crude enzyme of Cellulomonas flavigena and Saccharomyces cereviase. Crude enzyme of C. flavigena showed enzymatic activity of 14.02 U/mL for CMC 133.40 U/mL, for xylan 15.21 U/mL, for locust gum and 15.73 U/mL for rapeseed straw at pH 5.0 and $40^{\circ}C$, respectively. The hemicellulose contents of RS was estimated to compromise 36.62% of glucan, 43.20% of XMG (xylan + mannan + galactan), and 2.73% of arabinan by HPLC analysis. The recovering ratio of rapeseed straw were investigated to remain only glucan 75.2% after 1% $H_2SO_4$ pretreatment, glucan 45.44% and XMG 32.13% after NaOH, glucan 44.75% and XMG 5.47% after $NH_4OH$, and glucan 41.29% and XMG 41.04% after hot water. Glucan in the pretreatments of RS was saccharified to glucose of 45.42 - 64.81% by crude enzyme of C. flavigena while XMG was made into to xylose + mannose + galactose of 58.46 - 78.59%. Moreover, about 52.88 - 58.06 % of bio-ethanol were obtained from four kinds of saccharified solutions by SHF using S. cerevisiae. Furthermore, NaOH pretreatment was determined to show the highest mass balance, in which 21.22 g of bio-ethanol was produced from 100 g of RS. Conclusively, the utilization of NaOH pretreatment and crude enzyme of Cellulomonas flavigena was estimated to be the best efficient saccharification process for the production of bio-ethanol with rapeseed straw by SHF.

• 한국균학회지
• /
• 제18권1호
• /
• pp.7-12
• /
• 1990

사과푸른곰팡이병균 Penicillium expansum의 benomyl 저항성균주(抵抗性菌株) 중(中) 병원성이 약화된 균주를 선발하여 pectin질(質) 분해효소(分解酵素)의 활성과 병원성(病原性)간의 관계를 알아보았다. 인공배지에서는 병원성이 높은 $S_2$균주와 병원성이 낮은 $R_2$균주가 endo-polymethylgalacturonase, endo-polygalacturonase, pectin methyl-trans-eliminase, polygalacturonate-trans-eliminase를 생산하였으며 두균주간의 효소활성에 있어서 현저한 차이는 없었다. 사과배지에서는 위의 4개의 효소가 모두 생산되었으나 endo-polymethylgalacturonsae, endo-polygalacturonase의 활성은 병원성이 높은 $S_1$균주가 병원성이 낮은 $R_2$균주보다 6배 이상 높은 활성을 보였으나 pectin methyl-trans-eliminase와 polygalacturonate-trans-eliminase의 활성은 큰 차이가 없었다. Ammonium sulfate로 염석시켜 얻어진 조효소액(粗酵素液) 중(中) $80{\sim}90%$ fraction에서 endo-PMG와 endo-PG의 활성이 가장 높았으며 이 조효소액(粗酵素液)의 첨가(添加)에 따른 저항성균주(抵抗性菌株)의 병원성이 대조구에 비하여 증가하였다.

• 한국식품영양학회지
• /
• 제10권1호
• /
• pp.65-73
• /
• 1997

본 실험은 벌꿀이 흰쥐(Sprague Dawley, ♂)의 효소활성에 미치는 영향을 구명하고저 설탕, 아카시아, 붉나무 그리고 잡화벌꿀을 각각 10%와 20%의 수용액으로 만들어 7주간 섭취 한 후 벌꿀의 효과를 비교한 바 다음과 같은 결론을 얻었다. LDH활성은 대조군에 비하여 아카시아꿀, 붉나무꿀, 잡화꿀용액 섭취군에서 증가하였다. $\alpha$-HBDH활성은 설탕용액, 아카시아꿀, 붉나무꿀, 잡화꿀용액 섭취군이 대조군에 비하여 증가하였다. 벌꿀 섭취군 중 20% 아카시아꿀 용액만 GOT, GPT의 활성이 증가하였다. ICD활성은 붉나무꿀 용액에서 증가하였으나 아카시아 및 잡화꿀 용액에서 뚜렷하게 감소되었다. 벌꿀용액 섭취는 PHI, 전혈 G-6-P DH 활성을 감소시켰으나, aldolase역가를 증가시키는 경향이었다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제12권7호
• /
• pp.1063-1069
• /
• 1999

Wheat straw samples (3-4 cm) were sprayed with solutions of urea (U) alone or with a dry addition of garden soil (GS), midden soil (MS), soya bean meal (SM) or jack bean meal (JM) as crude urease sources and with a pure urease (UR) enzyme. Each of the urease sources was included at two levels: 30 and 60 g/kg except pure urease, which was added at a level of 2.5 & 5.0 g/kg treated straw dry matter. Untreated straw without urease source was used as a control. After treatment, samples were sealed in polythene bags and stored for 2, 7, 14, 21 and 35 days at $19{^{\circ}C}$. The urease sources, their levels and treatment time produced significant effects on ammonia production (p<0.01). The addition of urease offered more flexibility in hydrolyzing urea in the shortest possible time. Incorporation of soya bean and jack bean meal was effective in reducing the modified acid detergent fiber (MADF) content of straw and the same time increasing organic matter (OM) digestibility. Overall effect, addition of soya bean to urea at a ratio of 1:1 appeared to be the most satisfactory urease source for the treatment of urea and wheat straw.

• Journal of Chest Surgery
• /
• 제25권2호
• /
• pp.131-136
• /
• 1992

The effect of temperature of cardioplegic solution on myocardial preservation was studied using isolated rat heart perfusion technique. Twenty Sprague-Dawley rats, weighing 120~140gm, were pretreated with intraperitoneal injection of heparin sodium[300u/kg] and then the hearts were excised after cervical herniation 30 minutes later. The hearts were perfused in isolated working heart apparatus with oxygenated modified Tyrode solution at 37oC. After 10 minutes of non working heart perfusion, the hearts were subjected to arrest for 30 minutes by administration of 5cc cardioplegic solution at the temperature of 4oC [Group I ], 15oC [Group II], 25oC [Group III], 37oC[Group IV]. At the same time, the topical cooling of heart was performed using ice saline. After arrest, the hearts were reperfused by non working heart perfusion for 1 hour with modified Tyrode solution at 37oC. The CPK, GOT and LDH in reperfusate were measured at 5,20,40,60 minutes after start of reperfusion. With the values of those, we compared the effect of temperature of cardioplegic solution on myocardial preservation. The results were as follows; 1. The enzyme values in reperfusate were highest at 5 minute and after then declined. 2. At 5 minutes after reperfusion, the enzyme values in Group I were lower than those in other Groups. These results suggest that the cardioplegic solutions using for cardiac arrest and myocardial protection can be working better at 4oC than at any other temperature.

• Journal of Microbiology and Biotechnology
• /
• 제23권4호
• /
• pp.467-472
• /
• 2013

Helicobacter pylori increased the ${\gamma}$-glutamyltranspeptidase (GGT) production under low-pH (maximal at pH 4) and appropriate $pCO_2$ conditions, while the production of GGT mRNA correlated with increased total enzyme activity. At pH 4, the bacterium augmented enzyme production in the presence of glutamine (~10 mM) in the medium, which predominantly occurred after a 6-min time-lag. Monovalent salts such as NaCl or $NH_4Cl$ facilitated enzymatic activation in acidic solutions of approximately pH 4.5. In addition, glutathione's ${\gamma}$-glutamyl moiety cysteinylglycine appeared to be taken up readily by the intact H. pylori, but not by the one pretreated with a potent GGT inhibitor, acivicin, suggesting that the GGT may partake in glutathione uptake by the cell.

• Preventive Nutrition and Food Science
• /
• 제19권4호
• /
• pp.274-280
• /
• 2014

The purpose of this study was to investigate the biological activities of cultivated Angelica gigas Nakai (CAG) and wild Angelica gigas Nakai (WAG) extracts prepared by extraction with water, 30% ethanol, 60% ethanol, or 90% ethanol. The electron donating ability of the WAG extracts was higher than that of the CAG extracts and 0.1% and 1.0% solutions of the comparative substance, L-ascorbic acid. The superoxide dismutase-like activity of the CAG extracts was higher than that of WAG extracts. Superoxide dismutase-like activity was highest (33.95%) in the CAG water extract. The total polyphenol content was highest in the 60% ethanol extracts of WAG. The nitrite scavenging ability of the CAG and WAG extracts was highest at a pH of 1.2. The tyrosinase inhibitory effect was highest (43.72%) in the water extract of WAG. The angiotensin converting enzyme inhibitory activity was highest (83.84%) in the 60% ethanol extract of WAG. The results of the present study will be useful for understanding the antioxidant and angiotensin-converting enzyme inhibitory activities of Angelica gigas Nakai extracts.

• Biomolecules & Therapeutics
• /
• 제7권3호
• /
• pp.263-270
• /
• 1999

The in vitro permeation of thyrotropin-releasing hormone (TRH) through rabbit nasal, rectal and duodenal mucosae was studied in the absence and presence of an enzyme inhibitor and permeation enhancer. TRH in the donor and receptor solutions was assayed by HPLC. When thimerosal (TM, 0.5 mM) was added to the donor cell as an inhibitor, the permeation rate of TRH (200 $\mu\textrm{g}$/ml) increased linearly as a function of time. Fluxes of TRH through the nasal, rectal and duodenal mucosae were found to be 33.3$\pm$5.9, 11.8$\pm$1.9 and 9.6$\pm$0.7 $\mu\textrm{g}$/$\textrm{Cm}^2$/hr, respectively. The addition of sodium glycocholate, glycyrrhizic acid ammonium salt, sodium taurodihydrofusidate or L-$\alpha$-lysophosphatidylcholine to the donor solution containing TM did not result in the significant increase of permeation flux except for the duodenal mucosa, comparing with that in the presence of TM alone. Consequently, it was suggested that the nasal route was advantageous for systemic delivery of TRH, and the addition of TM and/or an enhancer was necessary to maximize the transmucosal permeation of TRH.