• Journal of Microbiology and Biotechnology
• /
• 제24권11호
• /
• pp.1484-1489
• /
• 2014

A novel esterase gene, est01, was successfully unearthed from a biogas digester microbiota metagenomic library. The 1,194 bp est01 gene encodes a protein of 44,804 Da (designated Est01). The amino acid sequence of Est01 shows only moderate (33%) identity to a lipase/esterase. Phylogenetic analysis and biochemical characterization confirmed that Est01 is a new member of family VIII esterases. The purified Est01 from recombinant Escherichia coli BL21 (DE3) showed high hydrolytic activity against short-chain fatty acid esters, suggesting that it is a typical carboxylesterase rather than a lipase. Furthermore, the Est01 was even active at $10^{\circ}C$ (43% activity remained), with the optimal temperature at $20^{\circ}C$, and had a broad pH range from 5.0 to 10.0, with the optimal pH of 8.0. These properties suggest that Est01 is a cold-adaptive esterase and could have good potential for low-temperature hydrolysis application.

• Journal of Microbiology and Biotechnology
• /
• 제24권9호
• /
• pp.1260-1268
• /
• 2014

Screening of a gene library from Paenibacillus sp. PBS-2 generated in Escherichia coli led to the identification of a clone with lipolytic activity. Sequence analysis showed an open reading frame encoding a polypeptide of 378 amino acid residues with a predicted molecular mass of 42 kDa. The esterase displayed 69% and 42% identity with the putative ${\beta}$-lactamases from Paenibacillus sp. JDR-2 and Clostridium sp. BNL1100, respectively. The esterase contained a Ser-x-x-Lys motif that is conserved among all ${\beta}$-lactamases found to date. The protein PBS-2 was produced in both soluble and insoluble forms when E. coli cells harboring the gene were cultured at $18^{\circ}C$. The enzyme is a serine protein and was active against p-nitrophenyl esters of $C_2$, $C_4$, $C_8$, and $C_{10}$. The optimum pH and temperature for enzyme activity were pH 9.0 and $30^{\circ}C$, respectively. Relative activity of 55% remained at up to $5^{\circ}C$ with an activation energy of 5.84 kcal/mol, which indicates that the enzyme is cold-adapted. Enzyme activity was inhibited by $Cd^{2+}$, $Cu^{2+}$, and $Hg^{2+}$ ions. As expected for a serine esterase, activity was inhibited by phenylmethylsulfonyl fluoride. The enzyme was remarkably active and stable in the presence of commercial detergents and organic solvents. This cold-adapted esterase has potential as a biocatalyst and detergent additive for use at low temperatures.

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

• Journal of Microbiology and Biotechnology
• /
• 제22권8호
• /
• pp.1044-1053
• /
• 2012

The gene encoding an esterase enzyme was cloned from a metagenomic library of cow rumen bacteria. The esterase gene (est5S) was 1,026 bp in length, encoding a protein of 366 amino acid residues with a calculated molecular mass of 40,168 Da. The molecular mass of the enzyme was estimated to be 40,000 Da. The Est5S protein contains the Gly-X-Ser-X-Gly motif found in most bacterial and eukaryotic serine hydrolases. However, the Asp or Glu necessary for the catalytic triad [Ser-Asp-(Glu)-His] was not present, indicating Est5S represents a novel member of the GHSQG family of esterolytic enzymes. BlastP in the NCBI database analysis of Est5S revealed homology to hypothetical proteins and it had no homology to previous known lipases and esterases. Est5S was optimally active at pH 7.0 and $40^{\circ}C$. Among the p-nitrophenyl acylesters tested, high enzymatic activities were observed on the short-chain p-nitrophenyl acylesters, such as p-nitrophenyl acetate, etc. The conserved serine residue ($Ser_{190}$) was shown to be important for Est5S activity. The primers that amplified the est5S gene did not show any relative band with 49 species of culturable rumen bacteria. This implies that a new group esterase gene, est5S, may have come from a noncultured cow rumen bacterium.

• 미생물학회지
• /
• 제55권2호
• /
• pp.143-148
• /
• 2019

라세믹체 형태의 전구물질 methyl DL-${\beta}$-acetylthioisobutyrate (DL-ester)로부터 captopril 합성과정의 중간물질로 알려져 있는 D-${\beta}$-acetylthioisobutyric acid (DAT)를 효율적으로 제조하기 위해 광학선택적 esterase활성을 가진 신규 미생물을 탐색하였고 활성이 우수한 균주 CJ-317과 균주 CJ-187을 선별하고 동정한 결과, 각각 Klebsiella pneumoniae와 Pseudomonas putida로 동정하였다. 두 균주가 생산하는 esterase의 최적 반응온도와 내열성을 조사한 결과, P. putida CJ-187와 K. pneumoniae CJ-317의 최적활성은 각각 $60^{\circ}C$와 $75^{\circ}C$이었으며 또한 P. putida CJ-187의 경우, $60^{\circ}C$까지 안정한 반면 K. pneumoniae CJ-317은 $80^{\circ}C$에서도 1시간 동안 안정된 내열성 효소의 특성을 보였다. DAT에 의한 최종 산물의 활성 저해도에 있어서도 P. putida CJ-187은 2.5%와 5%의 DAT에 대해 각각 55%와 80%의 저해활성을 보인 반면 K. pneumoniae CJ-317는 각각 35%와 44%의 낮은 저해활성을 보임으로서 K. pneumoniae CJ-317은 captopril 합성의 중간체인 DAT 제조과정에 유용하게 활용할 수 있는 우수한 내열성 광학선택적 esterase 활성을 가지는 신규 균주임을 확인하였다.

• Journal of Microbiology and Biotechnology
• /
• 제5권6호
• /
• pp.335-340
• /
• 1995

Two types of Rhizoctonia solani esterases induced by cutin hydrolysate were partially purified by ammonium sulfate precipitation and gel filtration. The esterase I with hydrolyzing activity toward both ${\rho}-ni-trophenyl$ butyrate and ${\rho}-nitrophenyl$ palmitate and the esterase II with hydrolyzing activity toward only ${\rho}-ni-trophenyl$ butyrate were inhibited by ebelactone B, an esterase inhibitor produced by actinomycetes with $IC_{50}$ values of 0.01 and $0.09{\;}\mu\textrm{g}/l$, respectively. Spraying on rice seedling with ebelactone B at a concentration of $30{\;}\mu\textrm{g}/ml$ completely suppressed infection by R. solani. Ebelactone B could not protect the wounded rice seedling and did not show any inhibitory effect on the mycelial growth at a concentration of 1 mg/ml. These results indicate that ebelactone B, an esterase inhibitor protects rice plants from infection with R. solani by inhibition of penetration, not through fungitoxic or fungicidal effect.

• KSBB Journal
• /
• 제5권1호
• /
• pp.19-23
• /
• 1990

콜레스테롤 에스테라아제를 생산하는 미생물 strain CES506 균주를 토양으로부터 분리하여 Aeromonas속의 한 세균으로 동정하였다. 이 균주는 배양액 1ml당 0.023 단위의 콜레스테롤 에스테라아제를 생산하였다. 이 균주가 생산하는 본 효소를 균주 배양액으로부터 약 370배, 24%의 수율로 균질한 상태의 단백질로 정제하였다. 본 효소의 분자량은 SDS-PAGE로 산출한 결과 64,000으로 계산되었다. 본 효소는 cholesteryl-palmitate에 대해 높은 기질 특이성을 나타내었으며 cholesterylpalmitate의 가수분해에 대한 Km값은 0.15mM이었다.

• 한국응용곤충학회지
• /
• 제26권3호
• /
• pp.165-170
• /
• 1987

본(本) 실험(實驗)은 벼멸구에 대한 반수치사약량(半數致死藥量)의 차이(差異)를 나타내는 저항성(抵抗性) 및 감수성계통(感受性系統)과 그들의 교잡종(交雜種) $F_1$에 대(對)한 생화학적(生化學的) 특성(特性)을 구명(究明)하고자 실시(實施)하였다. 살충제무처리(殺蟲劑無處理)의 esterase활성(活性)은 저항성계통(抵抗性系統)과 교잡종(交雜種) $F_1$이 감수성계통(感受性系統)에 비(比)하여 높았으며, diazinon, MEP, BPMC 처리후(處理後) esterase의 활성변화(活性變化)는 저항성계통(抵抗性系統)과 교잡종(交雜種) $F_1$에서는 별차이(別差異)가 없었으나 감수성계통(感受性系統)에서는 현저(顯著)히 떨어졌다. Esterase의 높은 활성(活性)은 저항성발달(抵抗性發達)과 관계(關係)가 있었으며 교잡종(交雜種) $F_1$에서 esterase 활성(活性)이 높게 나타난 것은 저항성계통(抵抗性系統)이 우성인자(優性因子)로 유전(遺傳)됨을 알 수 있었다.

• 한국식품영양학회지
• /
• 제17권4호
• /
• pp.347-355
• /
• 2004

초석잠 메탄올 추출물이 뇌신경전달물질과 관련이 있는 acetylcholine esterase, monoamine oxidase 및 xanthine oxidase의 활성억제효과에 대하여 실험하였다. 실험관내에서 초석잠 추출물을 각각 100 및 200mg/kg씩 첨가한 다음 실험한 결과 첨가농도가 증가할수록 과산화지질의 생성을 억제하여 용량 의존형으로 나타났다. 쥐를 대상으로 20일간 투여한 동물실험에서는 초석잠 추출물 100 mg/kg을 식이에 혼합하여 투여한 결과 지질 과산화의 생성을 억제하였다. Acetylcholine esterase의 활성의 경우 초석잠 추출물을 100 mg/kg 투여한 결과 대조군에 비하여 효소활성이 23.11%로 억제되었고, monoamine oxidase 및 xanthine oxidase 활성이 각각 21.93% 및 63.58%로 억제되었다. 그리고 초석잠 추출물을 100 mg/kg을 투여한 경우 xanthine dehydrogenase로부터 xanthine oxidase로의 형전환비율은 28%로 현저하게 억제되었다. 또한, Xanthine dehydrogenase로부터 oxidase로의 형전환비율을 실험한 결과 정상상태에 비하여 억제됨을 알 수 있었다.

• 한국식품위생안전성학회지
• /
• 제2권4호
• /
• pp.181-189
• /
• 1987

한국 토양균 중에서 esterase 저해제를 생산하는 균주인 Streptomyces strain DMC-498을 oatmeal yeast extract 배지에서 3일간 액내 배양하였을 때 최고의 저해작용을 나타내었으며 균사체의 메탄올 추출물로부터 저해제를 분리하였다. linoleic acid가 저해작용이 있음을 확인하였으며 50% 저해작용을 나타내는 linoleic acid의 양은 $0.045\;\mu\textrm{g}/ml$이었다. 활성이 보다 큰 compound A는 분자량이 500 이상이며 산소를 2개이상 함유하고 있는 환상구조의 지방족 화합물로 생각된다. 이것을 상경적 저해작용을 나타내었다. DMC-498 균주가 함유하는 지질의 주성분은 isostearic acid, isostearic acid methyl ester, linoleic acid methyl ester 및 oleic acid methyl ester이었다.