• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.145-148
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• 2006

A new functional lipolytic enzyme (AT4) has recently been found from Agrobacterium tumefaciens C58 Cereon using a genome-wide approach. The enzyme has some sequence similarity to E. coli acetyl hydrolase, Emericella nidulans lipase, Moraxella sp. lipase, Acinetobacter lwoffii esterase, and Streptomyces hygroscopicus acetyl hydrolase. However, the sequence similarities are very low (less than $25\%$), suggesting that it is a new lipase/esterase enzyme. ill the present study, intact cell of the A. tumefaciens strain was shown to have lipolytic activity on a tributyrin-LB plate. The AT4 gene was then expressed at a high level in E. coli BL21 (DE3) cells and the enzyme was purified simply by Ni-NTA column chromatography. The purified enzyme showed hydrolytic activity toward p-nitrophenyl caproate, but not toward olive oil, suggesting that the AT4 enzyme was a typical esterase rather than lipase. AT4 esterase had a maximum hydrolytic activity at $45^{\circ}C$ and pH 8.0, when p-nitrophenyl caproate was used as a substrate. It was relatively stable up to $40^{\circ}C$ and at pH 5.0-9.0. Calcium ion and EDT A did not affect the activity and thermal stability of the enzyme. As for substrate specificity, AT4 enzyme could rapidly hydrolyze acetyl and butyl groups from p-nitrophenyl esters and 1-naphthyl esters. In addition, it also released acetyl residues from acetylated glucose and xylose substrates. Therefore, this new esterase enzyme might be used as a biocatalyst in acetylation and deacetylation reactions performed in the fine chemical industry.

• Korean Journal of Microbiology
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• v.39 no.2
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• pp.83-88
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• 2003

We cloned a gene encoding acetyl xylan esterase(axeA) of Streptomyces coelicolor A3(2) and studied its expression pattern in Escherichia coli. The full sequence of axeA was amplified by PCR. Sequence analysis of the PCR product revealed an open reading frame of 1,008 nucleotides encoding a protein consisted of 335 amino acid residues, with a calculated molecular mass of about 38 kDa. The base sequence showed 98% homology to the same gene of Streptomyces lividans. Two different kinds of acetyl xylan esterases were produced in Escherichia coli(pLacI) by IPTG induction; their molecular weights were 38 kDa and 34 kDa, respectively. Of these, 38 kDa protein seemed to be a total protein holding N-terminal signal peptide region, whereas 34 kDa protein seemed to be a matured protein without signal peptide which was produced by peptide bond cleavage between two amino acid residues of alanine 41 and alanine 42.

• Korean journal of applied entomology
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• v.30 no.2
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• pp.117-123
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• 1991

Acetylcholinesterase(AChE) and esterase activities as mechanisms of resistance to fenobucarb, carbofuran and diazinon in the insecticide-selected brown planthopper strains were investigated. Although there was no significant difference in AChE activity from suscept tible and resistant strains, AChE insensitivity was highly increased in the carbam없e insecticide-selected strains. On the other hand, esterase activity was moderately increa잃d in all the s selected strains. It is concluded that the cross-resistance and the level of resistance in the b brown planthopper can be explained by the combination of altered AChE and high esterase a activity, although a possible involvement of other factor(s) can not be excluded.

• Microbiology and Biotechnology Letters
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• v.47 no.1
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• pp.87-95
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• 2019

Esterase produced by Acinetobacter sp. B1 (strain B1) was optimized by means of one-variable-at-a-time and response surface methodologies. Results of the one-variable-at-a-time experiment showed that Tween 80 significantly increased esterase production of strain B1. The addition of Tween 80 to the culture medium increased the biomass and esterase activity of strain B1, stimulated content of total extracellular protein, and enhanced the oleic acid (C18:1) composition in the cell membrane of strain B1. The influence of eight culture variables on esterase production was evaluated by Plackett-Burman design. Results showed that Tween 80, pH, and $K_2HPO_4$ significantly affected the esterase production of strain B1. Tween 80, pH, and $K_2HPO_4$ were further optimized by central composite design. Under the optimized conditions (w/v, soluble starch 2.5%, tryptone 1.5%, Tween 80 0.8%, $K_2HPO_4$ 0.5%, NaCl 0.5%, pH 8.0, inoculum size 1%, and inoculum age 24 h), the maximum esterase activity of strain B1 was 152.13 U/ml, which was 10-fold higher than that of non-optimization after 36 h cultivation.

• The Korean Journal of Mycology
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• v.25 no.2 s.81
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• pp.85-90
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• 1997

The Isozyme activities of Lentinula edodes were studied as a preliminary study for genetic analysis after protoplast fusion. The presence of peroxidase, esterase, superoxide dismutase, acid phosphatase, alkaline phosphatase, alcohol dehydrogenase and ${\alpha}-amylase$ was examined. An intracellular buffer-soluble protein from the mycelia was used for enzyme analysis on nondenaturing polyacrylamide gels. The auxotrophs of Lentinula edodes were positive for peroxidase, esterase, superoxide dismutase and acid phosphatase. However, alkaline phosphatase, alcohol dehydrogenase and ${\alpha}-amylase$ were not detected. The esterase and peroxidase were not affected by the various culture age. Isozyme identification may be a useful tool after protoplast fusion.

• Journal of Microbiology and Biotechnology
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• v.21 no.7
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• pp.667-674
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• 2011

The gene for esterase (rEst1) was isolated from a new species of genus Rheinheimera by functional screening of E. coli cells transformed with the pSMART/HaeIII genomic library. E. coli cells harboring the esterase gene insert could grow and produce clear halo zones on tributyrin agar. The rEst1 ORF consisted of 1,029 bp, corresponding to 342 amino acid residues with a molecular mass of 37 kDa. The signal P program 3.0 revealed the presence of a signal peptide of 25 amino acids. Esterase activity, however, was associated with a homotrimeric form of molecular mass 95 kDa and not with the monomeric form. The deduced amino acid sequence showed only 54% sequence identity with the closest lipase from Cellvibrio japonicus strain Ueda 107. Conserved domain search and multiple sequence alignment revealed the presence of an esterase/ lipase conserved domain consisting of a GXSXG motif, HGGG motif (oxyanion hole) and HGF motif, typical of the class IV hormone sensitive lipase family. On the basis of the sequence comparison with known esterases/ lipases, REst1 represents a new esterase belonging to the class IV family. The purified enzyme worked optimally at $50^{\circ}C$ and pH 8, utilized pNP esters of short chain lengths, and showed best catalytic activity with p-nitrophenyl butyrate ($C_4$), indicating that it was an esterase. The enzyme was completely inhibited by PMSF and DEPC and showed moderate organotolerance.

• The Korean Journal of Zoology
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• v.31 no.3
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• pp.225-235
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• 1988

This study was carried out to compare distribution and isozyme pattern of nonspecific esterase, acid phosphatase and alkaline phosphatase on developing sparganum and adult of Spinometra erinacei by using enzyme-histochemical method and electrophoresis The sparganum and adult were recovered from rats and cat that were infected by sparganum. The results obtained were as follows: Nonspecific esterase had a strong activity in the parenchymal musculature of sparganum and adult, but no detectable level in ihe tegument. A total of 7 and 8 nonspecific esterase bands were detectable in sparganum and adult, respectively. Of these bands, band 3 and 4 were major bands in sparganum and adult. Acid phosphatase had a strong activity in the tegument and the epidermal musculature of sparganum, but no detectable level in the parenchymal musculature. A total of 3 bands were detectable in sparganum and adult. Of these bands, band 3 was major band in sparganum and adult. Alkaline phosphatase had a strong activity in the tegument and the epidennal musculature of sparganum and of adult, but no detectable level in the parenchymal musculature. A total of 2 and 4 bands were detectable in sparganum and adult. Of these bands, band 2 was major band in sparganum and adult. Based on the present results isozyme band patterns showed qualitative and quantitative changes in each tissues of sparganum and of adult during the development.

• International Journal of Industrial Entomology and Biomaterials
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• v.9 no.1
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• pp.59-63
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• 2004

By using PAGE, a study was made on the nonspecific esterase spectra of female genital organs and eggs in Bombyx mori L. The expression of 11 esterase bands was detected during ontogenesis of races and inter-races hybrids kept in Bulgaria. The gene activity of 9 esterase loci was assumed. Esterases specific for the spectrum of diapausing eggs were observed. In two esterase zones, intra- and inter-breed polymorphism was found. Based on the same breed specific expression, the existence of correspondence between esterase bands from spectra of different silkworm tissues and organs was suggested. Stage-specific expression of esterases in female genital glands, indicative of differentiated gene activity during ontogenesis, was established.

• Journal of the Korean Graphic Arts Communication Society
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• v.26 no.1
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• pp.17-28
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• 2008

The wood-pulp is treated with the three enzymes; Endo-xylanase, exo-xylanase and acetyl-esterase. The maximum value of relative activity appeared 0.95 in acetyl-esterase at $40^{\circ}C$, 0.9 in exo-xylanase at $40^{\circ}C$, and 0.8 in endo-xylanase at $50^{\circ}C$, respectively. And it has measured 0.8 in endo-xylanase, 0.95 in acetyl-esterase at pH 6 and 0.9 in exo-xylanase at pH 5, while the maximum value of relative activity does not rely on reaction time for three enzymes treatment, and the value was about 0.9, respectively. We have watched that decreased Kappa number and increased brightness. And it turned out that the three enzyme produced a lot of reducing sugar with wood-pulp treatment.

• Microbiology and Biotechnology Letters
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• v.21 no.6
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• pp.542-548
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• 1993

Bacillus stearothermophilus was shown to express multiple xylanolytic enzymes including acetyl xylan esterase. Genomic DNA of the strain partially digested with HindIII was ligated into the HindIII site of pBR322, and expressed in E. coli HB101 cells in order to clone the gene for acetyl xylan esterase. One transformant among 4000 screened formed a clear zone around its colony on the LB agar supplemented with 1.0% tributyrin. The functional clone harbored the recombinant plasmid pKMG5 with an insert of 5.1kb.