• 펄프종이기술
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• 제31권3호
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• pp.1-9
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• 1999

Effect of furnish on enzyme activity was investigated by using the three components (cellulose, enzyme, and cationic polyelectrolyte) model papermaking system. Avicel was used as a cellulose model compound to observe the effect of adsorption and desorption of enzyme with other component and the resultant change of particle size. As an experimental result, the enzyme loses considerably its apparent activity due to the adsorption onto cellulose and cationic polyelectrolyte. Activities of enzyme applied to the actual papermaking stocks having controlled fiber length showed different behavior in terms of pulp species UKP and KOCC stocks. That is, the enzyme activity in UKP was increased as fines content increased, however, vice versa in KOCC stock . This result can be considered to be the existence of various contaminants included in the fines of KOCC . The effect of possible contaminants such as inorganic materials, calcium ion, surfactant, and conductivity on enzyme activity were also investigated.

• Journal of Nutrition and Health
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• 제27권9호
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• pp.892-900
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• 1994

A variety of important roles for branched-chain amino acids in metabolic regulation has been suggested. Branched-chain $\alpha$-keto acid dehydrogenase(BCKAD) complex is a rate limiting enzyme in branched-chain amino acid metabolism. The purpose of this study was to examine the effects of exercise on the activity and activity state of branched-chain $\alpha$-keto acid dehydrogenase in rat hert and liver thssues. Forty-eight Sprague-Dawley rats were assigned into three experimental groups : sedentary control, exercised, or exercised-rested. Submaximal exercise(running) for two hours significantly increased basal activity without a change in total activity in both tissues, with a concomitiant increase in activity state of the enzyme complex. At 10 min post-exercise, heart enzyme activity significantly decreased, though not to the control level, while liver enzyme activity remained unchanged. These data suggested that the exercise-induced increase in branched-chain $\alpha$-keto acid decarboxylation in rat tissues may not be the result of enzyme synthesis, but rather is due to increased activity of the BCKAD.

• The Korean Journal of Physiology
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• 제16권2호
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• pp.111-117
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• 1982

Slices of rat corpora lutea(CL) incubated with. prostaglandin $F_{{2{\alpha}}}(PGF_{2{\alpha}})$ in Krebs-Hensenleit (K-H) Ringer solution showed a decrease in $Na^+-K^+$-ATPase activity after 60 min of incubation. However, $PGF_{2{\alpha}}$ in vitro did not alter $Na^+-K^+$-ATPase activity of isolated luteal membrane fractions. Following $PGF_{2{\alpha}}$ induced in vivo luteal regression, reduction of Vmax an elevation of the activation energy above transition temperature of the lipid phase of the membrane occurred without changes of Km, optimum pH and transition temperature. These results suggest that reduction of $Na^+-K^+$-ATPase activity after $PGF_{2{\alpha}}$ treatment may be due to the reduction of the number of enzyme molecules or to masking of the active site of the enzyme without any change in enzyme characteristics. In addition, a change in membrane bound enzyme activity may be an early step in $PGF_{2{\alpha}}$ induced luleolysis.

• 한국미생물·생명공학회지
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• 제6권1호
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• pp.33-40
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• 1978

Immobilization of alkaline protease was investigated by absorbing the enzyme on adsorbents. Alkaline protease was adsorbed on silica gel selected as a carrier to immobilize the enzyme. In this study, properties of the immobilized enzyme were compared with those of the soluble enzyme. 1) The optimum pH (10.0) of the enzyme was not changed, but the activity was increased at alkaline pH by immobilization. 2) The optimum temperature of the immobilized enzyme was shifted from 50$^{\circ}C$ to 45$^{\circ}C$, while the temperature-activity Profile became broader than those of the soluble enzyme. 3) The pH stability of the immobilized enzyme was significantely increased at pH 4.0, althouth it did not change in the neutral and alkaline pH region. 4) The heat stability of the enzyme was enhanced in the temperature range of 55$^{\circ}C$∼65$^{\circ}C$ by the immobilization. 5) The immobilized enzyme retained 40％ of its original activity after repetitive use for 6 times. 6) The enzyme stability was greately improved for a prolonged storage at 4$^{\circ}C$.

• 대한한의학회지
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• 제17권2호
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• pp.264-276
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• 1996

This study was carried out to evaluate the effect of Samhwasan on the Na-K-ATPase activity of heart muscle. The Na-K-ATPase activity was prepared from rabbit heart ventricles. Samhwasan markedly inhibited the Na- K - ATPase activity in a dose-dependent manner with an estimated $I_{50}$ of 0.56%. Hill coefficient was 1.70, indicating that the enzyme has more than one binding site for the Samhwasan. Inhibition of enzyme activity by Samhwasan increased as pretreatment time was prolonged. Inhibition by the drug was not affected by a change in enzyme protein concentration. Kinetic studies of substrate activation of the enzyme indicated classical noncompetitive inhibition, showing significant reduction in Vmax without a change in Km value. Inhibitory effect by Samhwasan was not altered by changes in concentration of $Mg^{2+}$, $Na^+$ or $K^+$, dithiothreitol. a sulfhydryl reducing reagent, did not protect the inhibition of Na-K-ATPase activity by Samhwasan combination of Samhwasan and ouabain showed a cumulative inhibition fashion. These results suggest that Samhwasan inhibits Na-K-ATPase activity of heart ventricles with an unique binding site different from that of ATP, $Mg^{2+}$, $Na^+$ or $K^+$ and ouabain.

• 약학회지
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• 제29권4호
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• pp.165-175
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• 1985

It has been reported that clonidine is $\alpha_2$-adrenergic agonist, potnet new hypotensive drug in human with low dose. The change in blood pressure is implicated in the concentration, release, uptake and metabalism of catecholamine and activity of catecholamine synthesizing enzyme in specific brain areas. Thus the experiment was set up to investigate the effect on the enzyme activity of clonidine alone and that of clonidine pretreated with imipramine or tranylcypromine by measuring activity of the Dopa-forming enzyme, tyrosine hydroxylase (TH) and epinephrine forming enzyme, phenylethanolamine-N-methyl transferase (PNMT) in brain and adrenal gland. The TH activity in brainstem and substantia nigra is decreased by intraperitoneally administered clonidine 0.1mg/kg twice a day for 5 days, but increased in the rats pretreated with imipramine 10mg/kg intraperitoneally given 26 hrs and 5 hrs before decaptitation. However the TH activity in all regions of brain is increased in rats pretreated with tranylcypromine 10mg/kg intraperitoneally twice a day for 5 days. The effect of clonidine on TH activity is due to inhibition release of norepinephrine by activation of presynaptic $\alpha_2$-adrenoreceptor, axon terminal result in the decrease of TH activity in brain. The increasing of TH activity in brain results in attenuation of the role of clonidine by pretreated with imipramine or tranylcypromine in rats. The activity of PNMT was not significantly affected by clonidine, imipramine and tranylcypromine in adrenal gland.

• 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.

• Journal of Plant Biology
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• 제33권2호
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• pp.105-110
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• 1990

Physiological gradient of IAA-oxidizing enzyme activities was investigated in order to elucidate the mechanism of shoot differentiation in Cymbidium sp. (‘Jungfrau’) protocorms by using phenolic compounds (2, 4-dichlorophenol, catechol), auxin-inhibitors (PCIB, TIBA), and hormones (GA3, ABA, BA). The activity of IAA oxidase was decreased in protocorms treated with catechol decreased the catalytic activity of IAA oxidase or TIBA but this enzyme activity was increased after a temporary decrease at initial stages in the presence of 2, 4-dichlorophenol or PCIB. The activity of IAA oxidase in BA-treated protocorms (white and crown gall-like) was the highest of all. However, the catalytic activity of peroxidase increased after a temporary decrease at initial period. These results suggest that shoot differentiation and growth may be influenced by effective IAA levels in the protocorms causing IAA-oxidizing enzyme and phenolic compounds.

• 한국식품영양학회지
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• 제14권2호
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• pp.138-144
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• 2001

This study was performed to investigate the influence of Chlorella which effected the change of Pb contents, enzyme activity and lipid compounds on the rats fed the beverage involved Pb and the different contented Chlorella added-diets for 18weeks. The rat's weight of 200ppm Pb group was decreased 6.04% and the cause of that was Pb intake. But the rat's weight of Chlorella added-diets +200ppm Pb group was increased 4.02% (p<0.01). When feeding the different(0%, 2%, 5%, 10% ) Chlorella added-diets with the Pb contented beverage to the rats, we could know that the Pb contents accumulated on tissue were decreased to 20.70(0%), 12.88(2%), 14.83 (5%) and 19.56(10%), compared with the quantity of Pb taken in. Total-cholesterol, triglyceride, glucose content and AST, ALT, ALP, LDH enzyme activity in serum were the highest on 200ppm Pb group and those were decreased by the order of different(2%∼5% >10%) Chlorella contents + 200ppmPb group. A significance was recognized on the level of 1%. Therefore, when rats were exposed to Pb, it was thought that the amount of Chlorella intake was adequate on content 2∼5% for reducing the lead toxicity.

• 한국식품과학회지
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• 제30권1호
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• pp.206-212
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• 1998

본 연구는 식용으로 사용되는 어패류의 화학오염지표로서 glutathione S-transferase (GST)의 활성을 사용 할 수 있는 가를 검토하기 위하여 수행하였다 어류의 간췌장 및 패류의 소화선에서 기초적 GST 효소활성은 시험한 동물종에 따라 차이를 보였다. 시험한 어패류 중 큰이랑 피조개에서의 활성이 가장 높았으며 메기 및 홍합이 그 다음이었다. 백합 및 이스라엘 잉어에서는 낮은 기초적 활성을 보여 주었다. 큰이랑 피조개를 전형적인 PAH물질인 3-methylcholanthrene에 1주일간 노출 시켰을 경우 GST의 활성은 약 30% 감소하였으며 노출중단 2주경에는 회복되었다. 다른 대부분의 동물종에서는 GST의 활성이 3-MC에 의하여 증가하였다. 홍합의 경우 기초 활성의 약 200%수준으로 증가하여 노출중단 후에도 1주일간 지속되다가 서서히 감소하였다. 이스라엘 잉어에서도 홍합과 유사한 반응이 관찰되었다. Phenobarbital은 홍합 및 이스라엘 잉어에서 GST활성을 증가시켰다. Clobibrate, butylated hydroxyanisole 및 oxolinic acid 등은 효소활성의 변화를 유발하지 아니하였다. 한편 phenol은 이스라엘 잉어에서 활성을 감소시켰다. 이 결과를 종합하면 식용 어패류의 정상적 GST활성은 동물종에 따라 큰 차이가 나며 화학물질 오염에 따른 변화도 증가, 감소 및 불변으로 다양한 것으로 관찰되었다. 따라서 이 효소의 활성을 측정함으로서 PAH나 phenol과 같은 환경 오염물질에 의한 오염정도를 추정할 수 있는 지표로의 사용이 가능하리라고 본다.