• 한국식품과학회지
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• 제40권3호
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• pp.251-256
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• 2008

한국의 전통 한국의 전통적인 식품 중, 대표적인 장류로서 반가 식품에 해당하는 수조육류와 어패류를 첨가하여 제조한 어육장(규합총서의 방법)을 발효시키되, 2달 간격으로 발효기간에 따라 ${\alpha}$-amylase, esterase, ${\beta}$-glucosidase, lipase, lipoxygenase 및 protease의 활성을 각각 측정하여 경시적 변화를 관찰하였다. 어육장을 액체와 고체시료로 나누어 이상에서 열거한 효소들의 활성을 측정한 결과, lipase 및 lipoxygenase의 비활성도는 모두 0.05unit/mg protein 이하로서 효소 활성도가 낮은 수준이었으며, 1년동안의 발효·숙성기간 중 비활성 증감변화도 미미하였다. 반면,${\alpha}$-amylase, esterase, ${\beta}$-glucosidase 및 protease는 숙성기간에 따라 효소의 활성이 증가하는 것을 확인할 수 있었고, 특히 10개월째에는 액체시료의 경우 4종류 효소의 비활성이 급격히 증가하였다가 감소하는 것을 확인할 수 있었다. 전반적으로 고체시료의 단백질 함량은 액체시료보다 높았지만, 액체시료의 비활성이 고체시료보다 2-5배 이상 높은 결과를 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제24권7호
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• pp.925-935
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• 2014

A cold-adapted carbohydrate esterase, CEST, belonging to the carbohydrate esterase family 6, was cloned from Microbulbifer thermotolerans DAU221. CEST was composed of 307 amino acids with the first 22 serving as a secretion signal peptide. The calculated molecular mass and isoelectric point of the mature enzyme were 31,244 Da and pH 5.89, respectively. The catalytic triad consisted of residues Ser37, Glu192, and His281 in the conserved regions: GQSNMXG, QGEX(D/N), and DXXH. The three-dimensional structure of CEST revealed that CEST belongs to the ${\alpha}/{\beta}$-class of protein consisted of a central six-stranded ${\beta}$-sheet flanked by eight ${\alpha}$-helices. The recombinant CEST was purified by His-tag affinity chromatography and the characterization showed its optimal temperature and pH were $15^{\circ}C$ and 8.0, respectively. Specifically, CEST maintained up to 70% of its enzyme activity when preincubated at $50^{\circ}C$ or $60^{\circ}C$ for 6 h, and 89% of its enzyme activity when preincubated at $70^{\circ}C$ for 1 h. The results suggest CEST belongs to group 3 of the cold-adapted enzymes. The enzyme activity was increased by $Na^+$ and $Mg^{2+}$ ions but was strongly inhibited by $Cu^+$ and $Hg^{2+}$ ions, at all ion concentrations. Using p-nitrophenyl acetate as a substrate, the enzyme had a $K_m$ of 0.278 mM and a $k_{cat}$ of $1.9s^{-1}$. Site-directed mutagenesis indicated that the catalytic triad (Ser37, Glu192, and His281) and Asp278 were essential for the enzyme activity.

• 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.

• 대한수의학회지
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• 제37권1호
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• pp.129-135
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• 1997

Peripheral blood mononuclear cells(PBMNC) of Korean native cattle rosetted with Korean goat erythrocytes(KGRBC) and blood monocytes were evaluated for four cytochemical reactions such as acid phosphatase(ACP), alkaline phosphatase-anti-boby(ALP-Ab), ${\alpha}$-naphthyl butyrate esterase(${\alpha}$-NBE) and peroxidase. The results obtained were as follows; In rosetted cells, the positivities of ACP in E AET-DeX, EA and EAC were 70.3%, 22.4% and 25.2%, those of ${\alpha}$-NB were 27.4%, 44.2% and 79.8%, and those of ALP-Ab were 9.5%, 88.3% and 91.5%, respectively. Whereas, the positivity for Peroxidase in monocytes was 100%. In non-rosetted (remained) cells, the positivities of ACP in E AET+DeX. EA and EAC were 41.4%, 57.2% and 61.9%, those of ${\alpha}$-NB were 38.6%, 16.5% and 18.9% and those of ALP-Ab were 98.2%, 5.3% and 6.3%, in order.

• 한국응용곤충학회지
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• 제40권3호
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• pp.265-271
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• 2001

Imidacloprid에 저항성을 보이는 복숭아혹진딧물에 대해 몇가지 저항성 기작을 조사하였다. 복숭아혹진딧물에 약제를 처리한 후의 체벽잔류량은 처리 후 시간이 지남에 따라 서서히 감소되었으나 감수성계통과 저항성계통 간에 체벽침투력의 유의성은 없었다. 체내잔류량은 양 계통에서 시간이 지남에 따라 점차 증가되었으며 감수성에서 많았다. 배설량은 저항성계통이 감수성계통보다 많아 약제 대시가 빠르게 나타났다. Imidacloprid 저항성계통의 acetylcholine-sterase (AChE) 활성은 감수성계통 보다 약 1.4배 높았으며, imidacloprid는 AChE를 저해하지 않았다. 저항성계통에 대해 산화효소 저해제인 PBO(piperonyl butoxide)와 esterase 저해제인 IBP (iprobenfos)를 혼합하여 사용한 결과 Imidacloprid : PBO의 비율은 1 : 1과 1 : 5에서 각각 69.4, 250배의 독성을 보였으며, IBP와 혼합사용(1 : 1과 1 : 5)에서는 각각 227, 80.6배의 독성을 보였다. 감수성계통에 PBO와 IBP를 imidacloprid와 같은 비율로 혼합처리 하였을 경우 단독처리와 독성차이가 보이지 않았다. $\alpha$-naphtyl butyrate와 $\beta$-naphtyl acetate 기질을 사용하여 비특이적 esterase의 활성을 측정한 결과 저항성계통의 감수성 계통보다 esteraseghkf성이 높게 나타났다. 따라서 imidacloprid 저항성 복숭아혹진딧물의 저항성 기작에는 산화효소와 esterase가 관여되고 있음을 알 수 있었다.

• 식품기술
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• 제15권2호
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• pp.85-92
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• 2002

보리를 도정할 때 부산물로 생성되는 겨층인 대맥강으로부터 추출한 폴리페놀추출물(BPE)은 인체유래의 백혈병성 혈액암세포인 HL60 세포에서 세포분화의 지표가 되는nitro blue tetrazolin(NBT)을 환원시키는 활성과 $\alpha$-naphthyl butyrate esterase 활성을 유도하는 것으로 보고되었다. 본 논문에서는 보리의 폴리페놀추출물(BPE)에서 정제한 프로안토시아니딘이 HL60 세포주의 세포분화에 미치는 영향을 조사하였다. 프로델피니딘 B-3, T1, T2 및 T3는 26-40%의 NBT -환원활성을 유도하였고, 22-32%의 $\alpha$-naphthyl butyrate esterase 활성을 유도하는 것으로 나타났다. 프로안토시아니딘은 또한 HL 60 세포주에서 retinoic acid가 유발시킨 과립구 세포분화와 sodiumbutyrate가 유발시킨 단립구 세포분화를 더욱 촉진시키는 것으로 나타났다.

• International Journal of Industrial Entomology and Biomaterials
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• 제13권2호
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• pp.113-117
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• 2006

Heterosis was studied involving two multivoltine silkworm breeds viz, APM1 and SLKSPM through rearing and isozyme analysis. A positive significant heterotic effect was observed in fecundity, hatching % and survivability. The heterobeltiosis was observed only in fecundity and hatching %. Isozyme analysis of ${\alpha}-esterase$ showed variation in loci and allelic expression. The allele with heterozygosity $(Est-2^{12})$ was observed at the Est-2 locus in $F_1$ progeny. Est-3 was observed in $F_1$ progeny, whereas it was completely absent in both parental lines. The present study suggests that the markers ($Est-2^{12}$ and Est-3) targeted for introgression may be useful for the improvement of fecundity and survivability as the phenomenon of heterosis was observed only in $F_1$ progeny.

• 한국임상수의학회지
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• 제7권1호
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• pp.429-438
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• 1990

건강한 개의 혈액세포와 골수세포의 세포화학적 특성을 조사하였다. 이 실험에서 혈액과 골수 시료에 항응고제를 일체사용하지 않았으며 시료채취후 즉시 도말표본을 작성하여 30분 이내에 반응을 실시하였다. 이 실험의 결과는 아래와 같다. 1. alkaline phosphatase의 활성은 호산구계통과 간혹 전골수구에서 양성반응을 나타내었다. 2. acid phosphatase의 활성은 대부분의 계통의 세포에서 양성반응을 나타내지만 tartrate로 억제하면 호산구계만 양성반응을 나타내었다. 3. peroxidase 활성은 골수구계통의 모든 세포에서 양성반응을 나타내며 단구에서는 미약한 양성의 미세과립을 나타내었다. 4. naphthyl-AS-D-chloroacetate esterase활성은 호중구계 세포에서만 양성을 나타낸다. 5. $\alpha$-naphthyl acetate esterase활성은 단구와 일부의 임파구에서 양성을 나타낸다 6. Sudan black B 염색은 골수구계 세포와 단구계 세포에서 양성을 나타내었다. 7. $\beta$-glucuronidase 활성은 적혈구계를 제외한 모든 세포에서 양성반응을 나타내었다.

• Archives of Pharmacal Research
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• 제21권1호
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• pp.41-45
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• 1998

Hypericin, a photosensitizing plant pigment, was found to be a potent inducer of differentiation of human myeloid leukemia U-937 cells. At a concentration of $0.2{\mu}M$, hypericin exhibited 50% growth inhibition. An effect on cell differentiation by hypericin was assessed by its ability to induce phagocytosis of latex particles, and to reduce nitroblue tetrazolium (NBT). Approximately 51% of $0.2{\mu}M$ hypericin-treated cells were stained with NBT and 63% showed phagocytic activity. In order to establish whether hypericin induces differentiation of U-937 cells to macrophage or granulocyte, esterase activities and cell sizes were measured. When U-937 cells were treated with $0.2{\mu}M$ and $0.15{\mu}M$ of hypericin, the .alpha.-naphthyl acetate esterase activity was increased by 38.4% and 48.1%, respectively, but naphthol AS-D chloroacetate esterase activity was not influenced. The size of hypericin-treated cells in terms of cell mass was larger than that observed in untreated cells as determined by flow cytometry. Protein kinase C (PKC) inhibitor, NA-382, decreased the NBT reducing activity of hypericin, whereas a cAMP-dependent protein kinase A (PKA) inhibitor, H-89, did not show any influence on the differentiations. These results indicate that hypericin triggers differentiation toward monocyte/macrophage lineage by PKC stimulation.

• Journal of Microbiology and Biotechnology
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• 제24권6호
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• pp.771-780
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• 2014

A putative lipolytic enzyme gene, named as est9x, was obtained from a marine microbial metagenome of the South China Sea. Sequence analysis showed that Est9X shares lower than 27% sequence identities with the characterized lipolytic enzymes, but possesses a catalytic triad highly conserved in lipolytic enzymes of the ${\alpha}/{\beta}$ hydrolase superfamily. By phylogenetic tree construction, Est9X was grouped into a new lipase/esterase family. To understand Est9X protein in depth, it was recombinantly expressed, purified, and biochemically characterized. Within potential hydrolytic activities, only lipase/esterase activity was detected for Est9X, confirming its identity as a lipolytic enzyme. When using p-nitrophenol esters with varying lengths of fatty acid as substrates, Est9X exhibited the highest activity to the C2 substrate, indicating it is an esterase. The optimal activity of Est9X occurred at a temperature of $65^{\cric}C$, and Est9X was pretty stable below the optimum temperature. Distinguished from other salt-tolerant esterases, Est9X's activity was tolerant to and even promoted by as high as 4 M NaCl. Our results imply that Est9X is a unique esterase and could be a potential candidate for industrial application under extreme conditions.