• 한국식품과학회지
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• 제18권6호
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• pp.450-457
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• 1986

대두(大豆)중에 존재하는 장내(腸內) 가스발생인자(發生因子)(flatulence factor)인 raffinose와 stachyose의 제거(除去)에 효소제(酵素劑)를 이용하기 위한 기초연구로서, 시판효소제(市販酵素劑)에 대한 ${\alpha}-Galactosidase$의 활성도(活性度)를 비교하고 그의 효소적(酵素的) 특성(特性)을 조사하였다. 시판(市販)되는 6종의 효소제(酵素劑)중 Aspergillus niger에서 얻은 pectinase 제제가 가장 강력하였다. 선정된 효소제(酵素劑)의 특성(特性)을 조사한 결과 작용최적(作用最適) pH는 4.0-4.5, 안정도최적(安定度最適) pH는 4-5, 작용최적(作用最適) 온도는 $45^{\circ}C$였다. 합성기질(合成基質)인 $p{\cdot}nitropheyl-{\alpha}-D{\cdot}galactoside$에 대한 Michaelis constant(Km)는 2.08mM, 최대반응속도(最大反應速度)(Vmax)는 435 ${\mid}{\mu}{\mid}$moles substrate/minute/g enzyme preparation 이었으며 조해제(阻害劑)의 실험 결과 SH기(基)를 필수로 하는 효소(酵素)로 밝혀졌다. 본(本) 효소제(酵素劑)는 3가지 기질(基質)인 raffinose, sucrose, $p-nitrophenyl-{\alpha}-D{\cdot}galactoside$를 거의 완전하게 가수분해(加水分解)하였으며, raffinose와 stachyose의 분해(分解)과정을 thin-layer chromatography로 조사한 결과 단당류의 Spot만이 나타났다. 따라서 대두식품(大豆食品)중의 장내(腸內) 가스발생인자(發生因子)는 ${\alpha}-Galactosidase$ 역가(力價)를 가지는 효소제(酵素劑)의 이용에 의하여 쉽게 제거될 수 있을 것이다.

• 한국미생물·생명공학회지
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• 제22권5호
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• pp.507-514
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• 1994

Acetyl xylan esterase was produced by E. coli HB101 harboring a recombinant plasmid pKMG6 which contained the estI gene of Bacillus stearothermophilus. The maximum production was observed when the E. coli strain was grown at 37$\circC for 12 hours in the medium containing 0.5% acetyl xylan, 1.0% tryptons, 1.0% sodium chloride, and 0.5% yeast extract. The esterase produced was purified to homogeneity using a combination of ammonium sulfate fractionation, DEAE Sepharose CL-6B ion exchange chromatography and Sephacryl S-200 gel filtration. The native enzyme had an apparent molecular mass of 60 kd and was composed of two identical subunits of 29 kd. The N-terminal amino acid sequence of the polypeptide was Ala-X-Leu-Gln- Ile-Gln-Phe-X-X-Gln. The acetyl esterase displayed a pH optimum of 6.5 and a temperature opti- mum of 45$\circC. The heavy metal ions such as Ag$^{++}$, Hg$^{++}$ and Cu$^{++}$ inhibited nearly completely the activity of the esterase, and no specific metal ion was found to be required for the enzyme activity. The enzyme readily cleaved MAS, $\beta$-D-glucose pentaacetate, $\alpha$-naphthyl acetate, $\rho$-nitrophenyl acetate as well as acetyl xylan, but had no activity on $\rho$-nitrophenyl propionate, $\beta$-nitrophenyl butyrate or $\beta$-nitrophenyl valerate. The Km and Vmax values for MAS were 2.87 mM and 11.55 $\mu$mole/min, respectively. Synergistic behavior was demonstrated with a combination of xylanase and esterase from B. stearothermophilus in hydrolyzing acetyl xylan.

• Journal of Microbiology and Biotechnology
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• 제3권1호
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• pp.31-38
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• 1993

A bacterial strain KY-l isolated from sewage was able to produce an extracellular agarase(agarose 4-glycanohydrolase. EC 3.2.1.81). The strain KY-1 was identified as Cytophaga fermentans subsp. agarovorans based on its morphological and physiological characteristics. The agarase was purified by ammonium sulfate precipitation followed by DEAE-Sephadex A-50. Bio-Gel P-100. and CM-Cellulose column chromatography. The molecular weight of the purified enzyme was 24 kDa by SDS-polyacrylamide gel electrophoresis. The optimum temperature and pH for the enzyme activity were 30^{circ}C and 7.5, respectively. The enzyme activity was significantly inhibited in the presence of 0.1 mM $HgCl_2$. whereas it was elevated 3 times by $MnSO_4$ at 1 mM concentration. The Km value and Vmax were 16.67 mg/ml and 3.77 unit/ml.min. The agarase gene was cloned into Escherichia coli MC1061 using the plasmid vector pBR322. A 1.4 Kb DNA fragment of PstI-digested chromosomal DNA of C. fermentans KY-l was inserted into the PstI site of pBR322. expressed in the E. coli. and up to 60% of the total enzyme was extracellularly secreted. Enzymatic properties of the extracellular agarases produced by both the transformant and the donor were very similar in terms of optimal pH and temperature.

• 미생물학회지
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• 제54권2호
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• pp.126-135
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• 2018

여러 종류의 mannanase를 생산하는 Cellulosimicrobium sp. YB-43으로부터 mannanase B를 암호하는 manB 유전자와 효소의 특성이 보고된 바 있다. Mannanase C (ManC)로 명명한 효소의 유전자가 manB 유전자의 하류에 위치한 것으로 예상되어 이를 중합효소 연쇄반응으로 클로닝하여 manC 유전자의 염기서열을 결정하였다. ManC는 448 아미노산 잔기로 구성된 것으로 확인되었으며 glycosyl hydrolase family 5에 속하는 mannanase와 상동성이 높은 활성영역과 탄수화물 결합영역(CBM2)이 존재하였다. ManC의 활성영역은 Streptomyces sp. SirexAA-E (55.8%; 4FK9_A) 및 S. thermoluteus (57.6%; BAM62868)의 mannanase와 아미노산 배열의 상동성이 55% 이상으로 가장 높았다. Signal peptide 영역이 제거되고 카르복실 말단에 hexahistidine이 연결되도록 제조한 His-tagged ManC (HtManC)의 유전자를 재조합 대장균에서 발현하여 균체 파쇄액으로부터 HtManC를 정제하였다. HtManC은 $65^{\circ}C$와 pH 7.5에서 최대 활성을 보였으며 pH 7.5~10범위에서 활성에 큰 변화가 없었다. HtManC는 locust bean gum (LBG)과 konjac에 대한 분해 활성이 guar gum과 ivory nut mannan (ivory nut)에 비해 높았다. 최적 반응조건에서 LBG를 기질로 하여 반응 동력학적 계수를 측정한 결과 Vmax와 Km이 68 U/mg과 0.45 mg/ml로 나타났다. HtManC에 의한 만노올리고당(MOS)과 mannan의 분해산물을 TLC로 관찰한 결과 mannobiose 보다 중합도가 큰MOS로부터 mannobiose와 mannotriose가 주된 분해산물로 생성되었다. 또한 LBG, konjac과 ivory nut의 분해산물로 mannobiose와 소량이 mannose가 공통적으로 관찰되었다.

• 약학회지
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• 제34권2호
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• pp.112-116
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• 1990

8-Acyl-2-hydroxyphenzaine -5, 10-dioxides and 8-acyl-2-aminophenazine-5, 10-dioxides bearing n-butanoyl, n-hexanoyl and n-octanoyl groups were synthesized. It was attempted to observe the effect of phenazine dioxide derivatives on the hepatic xanthine oxidase activity in this study. As the activity of xanthine oxidase, the key enzyme in the generation of superoxide anion radical ($O_2$), was measured in the presence of phenazine dioxide derivatives, the action of 8-acyl-2-hydroxyphenazine-5,10-dioxide derivatives inhibited with increase of numbers of carbon atom bearing 8-acyl group. Moreover, when plotted on double reciprocal form, the Vmax value decrease as increase of numbers of carbon atom bearing acyl groups without affecting the Km value. However, the hepatic xanthine oxidase activity was not changed by 8-acyl-2-aminophenazine-5,10-dioxide derivatives.

• 대한의생명과학회지
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• 제10권2호
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• pp.99-105
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• 2004

Liver and serum rhodanese activities were determined in acute ethanol intoxicated rats with extrahepatic cholestasis induced by common bile duct ligation (CBD) to manifest the biochemical background of alcohol drinking hazard under the hepatobiliary disease. Liver cytosolic and microsomal rhodanese activities and these Vmax values in CBD ligated rats with acute ethanol intoxication were found to be decreased much more than that in CBD ligation alone. However, the difference of Km value on above hepatic enzyme was not found between the experimental groups. On the other hand, serum rhodanese activity in CBD ligated rats with acute ethanol intoxication was greater increased more than that in CBD ligation alone. These results indicate that the biosynthesis of the hepatic rhodanese decreases and the serum rhodanese activity increases in cholestasis combined with acute ethanol intoxication, reflecting damage of aggravated hapatocytic membrane. Accordingly, the resulting data supported the fact that alcoholic drinks were enzymologically harmful to the hepatobiliary disease.

• 대한의생명과학회지
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• 제10권1호
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• pp.35-42
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• 2004

Liver and serum $\beta$-D-mannosidase activities were determined in ethanol intoxicated rats with extrahepatic cholestasis induced by common bile duct ligation (CBD) to manifest the biochemical background of alcohol drinking hazard under the hepatobiliary disease. Liver $\beta$-D-mannosidase activity and its Vmax value in CBD ligated rats with chronic ethanol intoxication were found to be significantly decreased than that in CBD ligation alone. However, the difference of Km value on above hepatic enzyme was not found between the experimental groups. On the other hand, serum $\beta$-D-mannosidase activity in CBD ligated rats with chronic ethanol intoxication was increased more than that in CBD ligation alone. These results indicate that the biosynthesis of the hepatic $\beta$-D-mannosidase decreases and the serum $\beta$-D-mannosidase activity increases in cholestasis combined with chronic ehtanol intoxication, reflecting damage of aggravated hapatocytic membrane. Accordingly, the resulting data supported the fact that alcoholic drinks were enzymologically harmful to the hepatobiliary disease.

• 대한본초학회지
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• 제22권4호
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• pp.21-28
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• 2007

Objectives : Kyenegum has been popularly used long as the digestive. The purpose of this study was to investigate the purification and characteristics of protease obtained from Kyenegum crude enzyme. Methods : Kyenegum protease was purified by precipitation with ammonium sulfate followed by SP-Spharose ion exchange chromatography. The molecular weight of Kyenegum protease was estimated by SDS-PAGE electrophoresis. Results : Kyenegum protease was 3,087 units/mg protein specific activity, 14.5 purification fold and 9.8 % recovery. The molecular weight of protease was estimated to be 18 kDa. The isoelectric point was pI 8.97 and values of Km and Vmax of its were 48 mg/mL and 2 units/min, respectively. Conclusion : The result suggests that the protease obtained from Kyenegum has excellent stability of temperature, acid and collagen substrate specificity.

• 미생물학회지
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• 제24권3호
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• pp.302-307
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• 1986

내성 P.aeruginosa에 의해 생성되는 항생물질 파괴효소인 cephalosporinase는 cephaloridine을 기질로 하여 효소활성도는 $45^{\circ}C$와 pH 8.5에서 각기 최고의 활성도를 나타내었다. SDS. carbenicillin 빛 cephalosporin계 항생체에 의해 효소의 활성도는 현저하게 억제되었으며 효소의 cephaloridine에 대한 $V_{max}$ 값을 100으로 하였올때 cefo p perazone의 $V_{max}$ 값은 2.8로 나타났다. 측정된 효소의 분자량은 $37.500{\pm}3,000$이었다. 다른 Gram음성셰균이 분비하는 cephalosporinase와 비교해본 결과 균체 자체의 특성에 의해 cepha]osporinase는 서로 다름을 알 수 있였 으며 이로 인하여 각각의 균체가 cephalosporin계 항생제에 대한 내성의 차이를 나타내는 하나의 중요한 원인으로 판단되었다.

• 대한간호학회지
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• 제13권2호
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• pp.87-104
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• 1983

It has been well documented that animals exposed to cold show increased activity of thyroid gland. The calorigenic action of thyroid hormone has been demonstrated by a variety of in vivo and in vitro studies. According to Edelman et al., the thyroid thermogenesis is due to activation of energy consuming processes, especially the active sodium transport by the hormone in target tissues. If so, the increase in thyroid activity during cold exposure should induce increased capacity of sodium transport in target tissue and the change in tissue metabolism should be precisely correlated with the change in Na+_K+_ATPase activity of the tissue. This possibility was tested in the present study: in one series, changes in oxygen consumption and Na+_K+_-ATPase activity of liver preparations were measured in rats as a function of thyroid status, in order to establish the effect of thyroid hormone on the tissue respiration and enzyme system in another series, the effect of cold stimulus on the serum thyroid hormone level, hepatic tissue oxygen consumption and Na+_K+_ATPase activity in rats. The results obtained are as follows: 1. The Na+_dependent oxygen consumption of liver slices, the oxygen consumption of liver mitochondria and the Na+_K+_ATPase activity of liver preparations were significantly inhibited in hypothyroidism and activated in hyperthyroidism. Kinetic analysis indicated that the Vmax. of Na+_K+_ATPase was decreased in hypothyroidism and increased in hyperth)'roidism. 2. In cold exposed rats, the serum triiodothyronine (T₃) level increased rapidly during the initial one day of cold exposure, then declined slowly to the control level after two weeks. The serum thyroxine (T₄) level decreased gradually throughout the cold exposure. Accordingly the T₃/T₄ratio increased. The mitochondrial oxygen consumption and the Na+_dependent oxygen consumption of liver slices increased during the first two days and then remained unchanged thereafter The activity of the Na+_K+_ATPase in liver preparations increased during cold exposure with a time course similar to that of oxygen consumption. Kinetic analysis indicated that the Vmax. of Na+_K+_ATPase increased. 3. Once the animal was adapted to cold, induction of hypothyroidism did not significantly alter the hepatic oxygen consumption and Na+_K+_ATPase activity. These results indicate that: 1) thyroid hormone increases capacities of mitochondrial respiration and active sodium transport in target tissues such as liver; 2) the increased T₃level during the initial period of cold exposure facilitates biosynthesis of Na+_K+_ATPase and mitochondrial enzymes for oxidative phosphorylation, leading to enhanced production and utilization of ATP, hence heat production.