• Asian-Australasian Journal of Animal Sciences
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• v.12 no.2
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• pp.233-243
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• 1999

Food safety or sanitation are terms broadly applicable to procedures designed to ensure that food quality is high and free of factors which may adversely affect human health. These factors include zoonotic diseases and acute and chronic effects of ingesting natural and human-made xenobiotics. Use of drugs in animal production for the treatment and control of animal diseases, to promote growth rate, and to improve feed conversion efficiency has expanded year by year, thus increasing the possibilities for occurrences in animal products of residues harmful to humans. Governmental agencies have made efforts to control or prevent residue problems. The Korean Food and Drug Administration (KFDA) is charged with the responsibility of establishing tolerances for veterinary drugs, pesticides, and mycotoxins and other non-pharmaceutical substances. The Department of Veterinary Service is responsible for establishing guidelines regarding withdrawal times of drugs, approval of drugs, their uses, and sanitation enforcement of livestock products. The authors describe the toxicological basis for the establishment of tolerance levels for xenobiotics and the pharmacokinetic basis for establishing withdrawal time for veterinary drugs. The regulatory tolerance levels of chemicals in pork and swine feed, Korean regulations on the use of feed additives, rapid residue test methods, the National Residue Program, and the Food Animal Residue Avoidance Databank are discussed. Rapid EIA methods that are under development for the screening of live animals are described These methods predict tissue residues from an examination of blood samples taken from pigs before they are slaughtered.

• YAKHAK HOEJI
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• v.49 no.3
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• pp.198-204
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• 2005

Human foamy virus (HFV) integrase mediates integration of viral c-DNA into cellular DNA. In this process, HFV integrase recognizes its own viral DNA specifically and catalyzes insertion of viral c-DNA. In order to study catalytic domains and residues, three deletion mutants and two point mutants of HFV integrase were constructed and analyzed with respect to enzymatic activities. The C-terminal deletion mutant showed decreased enzymatic activities while the N-terminal deletion mutant lost the activities completely, indicating that the N-terminal domain is more important than the C-terminal domain in enzymatic reaction. The point mutants, in which an aspartic acid at the 164th position or a glutamic acid at the 200th position of the HFV integrase protein was changed to an alanine, lost the enzymatic activities completely. However, they were well complemented with other defective deletion mutants to recover enzymatic activities partially. Therefore, these results suggest that the aspartic acid and glutamic acid at the respective 164th and 200th positions are catalytic residues for enzymatic reaction.

• YAKHAK HOEJI
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• v.33 no.6
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• pp.339-344
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• 1989

The alkaline protease produced by Sarcodon aspratus(Berk) S. Ito. was purified from its fruit bodies. The enzyme was purified by using ammonium sulfate fractionation, tris-acryl CM-cellulose column chromtography and chromatofocusing. The protease migrated as one major band with a molecular weight of about 29,000 dalton on sodium dodecylsulfate-polyacrylamide gel electrophoresis. The amino acid sequence of the N-terminal residues(21) of the enzyme was determined by automated sequence analysis. The sequence was Val-Thr-Thr-Lys-Gln-Thr-Asn-Ala-Pro-Trp-Gly-Leu-Gly-Asn-Ile-Ser-Thr-Thr-Asn-Lys-Leu. Comparison of this sequence with the N-terminal sequence of the p-roteinase K from Tritirachium album showed high similarity, i. e. 57.8% identical residues. The protease displayed a relatively high stability in sodium dodecyl sulfate.

• Journal of Ginseng Research
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• v.40 no.4
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• pp.351-358
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• 2016

Background: This study was designed to investigate whether ginsenoside Rb1 (Rb1) and compound K (CK) ameliorated insulin resistance by suppressing endoplasmic reticulum (ER) stress-induced inflammation in adipose tissue. Methods: To induce ER stress, epididymal adipose tissue from mice or differentiated 3T3 adipocytes were exposed to high glucose. The effects of Rb1 and CK on reactive oxygen species production, ER stress, TXNIP/NLRP3 inflammasome activation, inflammation, insulin signaling activation, and glucose uptake were detected by western blot, emzyme-linked immunosorbent assay, or fluorometry. Results: Rb1 and CK suppressed ER stress by dephosphorylation of $IRE1{\alpha}$ and PERK, thereby reducing TXNIP-associated NLRP3 inflammasome activation in adipose tissue. As a result, Rb1 and CK inhibited IL-$1{\beta}$ maturation and downstream inflammatory factor IL-6 secretion. Inflammatory molecules induced insulin resistance by upregulating phosphorylation of insulin receptor substrate-1 at serine residues and impairing insulin PI3K/Akt signaling, leading to decreased glucose uptake by adipocytes. Rb1 and CK reversed these changes by inhibiting ER stress-induced inflammation and ameliorating insulin resistance, thereby improving the insulin IRS-1/PI3K/Akt-signaling pathway in adipose tissue. Conclusion: Rb1 and CK inhibited inflammation and improved insulin signaling in adipose tissue by suppressing ER stress-associated NLRP3 inflammation activation. These findings offered novel insight into the mechanism by which Rb1 and CK ameliorate insulin resistance in adipose tissue.

• Journal of Environmental Health Sciences
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• v.32 no.3
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• pp.227-234
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• 2006

There has been increasing concern in recent years about the occurrence, fate and toxicity of pharmaceutical products in aquatic environment. Although these compounds have been detected in a wide variety of environmental samples including sewage effluent, surface waters, ground water and drinking water, their concentrations generally range from the low ppt to ppb levels. It is therefore often thought to be unlikely that pharmaceuticals will have a detrimental effect on the environment. This study was conducted to determine the endocrine disruption effects of the several pharmaceutical residues in water using adult Japanese medaka (Oryzias latipes). The common antibiotics were used sulfa durgs (sulfamethoxazole and sulfamethazine) and tetracycline drugs (oxytetracycline and tetracycline). Positive control that was induced Vtg (vitellogenin) in male fish was used $17\beta$-estradiol. Vtg was qualified and quantified through Western blotting and ELISA. After SDS gel electrophoresis, the dominant protein band was identified to molecular weight approximately 205 kDa in whole body samples of vitellogenic female. In female medaka exposed to $17\beta$estradiol, there was no significant difference in total protein induction. In contrast, three to five day exposure of male fish to $17\beta$-estradiol resulted in more than 60.0% increase of total protein compared to that of control males (p<0.01). In case of antibiotics, female fish didn't show significant difference, but male fish was showed significant difference. In addition, Vtg induction in male fish was observed with all the test chemicals. On concentrations greater than 0.1 ppm of sulfamethoxazole, 1 ppm of sulfamethazine, 1 ppm of oxytetracycline and 20 ppm of tetracycline, Vtg induction was increased in a dose response manner. This study is one of the early reports suggesting potential endocrine disruption mechanism of antibiotic pharmaceutical products in aquatic ecosystem. Although the effect concentrations obtained from this study were high as unrealistically as in environments, it is endocrine disruption that we should be considered as one of the important consequences of pharmaceutical contamination at water environment, and warrants due attention in future researches.

• International Journal of Industrial Entomology and Biomaterials
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• v.17 no.1
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• pp.143-151
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• 2008

A muscle-specific lipase gene of the bumblebee Bombus ignitus was cloned and characterized. This gene, which we named Bi-Lipase, consists of seven exons encoding 317 amino acid residues. Bi-Lipase possesses all the features of lipases, including GXSXG consensus motif and Ser-Asp-His catalytic triad. Expressed as a 37-kDa polypeptide in baculovirus-infected insect Sf9 cells, recombinant Bi-Lipase showed an optimal pH of 9.0 and exhibited its highest catalytic activity at $40^{\circ}C$. Furthermore, through the addition of tunicamycin to the recombinant virus-infected Sf9 cells, recombinant Bi-Lipase was found to be N-glycosylated. Northern and western blot analyses indicated that Bi-Lipase was expressed in the wing, thorax, and leg muscles. These results show that Bi-Lipase is a muscle-specific lipase, suggesting a possible role of Bi-Lipase in the utilization of lipids for muscular activity in B. ignitus.

• Journal of Applied Biological Chemistry
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• v.62 no.1
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• pp.73-79
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• 2019

A novel esterase gene (est7S) was cloned from an enriched metagenomic library derived from an oil-spill area. The gene encoded a protein of 505 amino acids, and the molecular mass of the Est7S was estimated to be 54,512 Da with no signal peptide. Est7S showed the highest identity of 40% to an esterase from a sludge metagenome compared to the characterized enzymes with their properties, although it showed 99% identity to a carboxylesterase in the genome sequence of Alcanivorax borkumensis SK2. Est7S had catalytic triad residues, Ser183, Glu312, and His420, and the GESAG motif in most family VII lipolytic enzymes. Est7S was purified from the crude extract of clone SM7 using Sephacryl S-200 HR and HiTrap Q column chromatographies. The purified Est7S was optimally active at $50^{\circ}C$ and pH 10.0. Est7S showed a high specific activity of 366.7 U/mg protein. It preferred short length esters, particularly p-nitrophenyl acetate, efficiently hydrolyzed R- and S-enantiomers of methyl-3-hydroxy-2-methylpropionate, and glyceryl tributyrate. These properties of Est7S may provide potential merits in biotechnological applications such as detergent and paper processing under alkaline conditions.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.197-203
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• 2001

A fusion protein, consisting of human epidermal growth factor as a recognition domain and human angiogenin as a toxin domain, can be used as a targeted therapeutic against breast cancer cells among others. The fusion protein was expressed as inclusion body in recombinant E. coli, and when the conventional, solution-phase refolding process was used the refolding yield was very low due to severe aggregation, probably due to the opposite surface charge due to vastly different pI values of each domain. Solid-phase refolding process exploiting ionic interactions between the solid matrix and the protein was tried, but the ionic binding yield was very low regardless of the resins and pH conditions used. To provide higher affinity toward the solid matrix, six lysine residues were tagged to the N -terminus of the hEGF domain When the cation exchange resins such as heparin- or CM-Sepharose were used as the matrix, the adsorption capacity increased 2.5-3 times and the subsequent refolding yield increased nearly IS times compared to the conventional process.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2005.09a
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• pp.173-182
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• 2005

A three dimensional (3D) model for the catalytic region of Type II Pseudomonas sp. USM 4-55 PHA synthase 1 (PhaC1$_{P.sp\;USM\;4-55}$) from residue 267 to residue 484 was developed. Sequence analysis demonstrated that PhaC1$_{P.sp\;USM\;4-55}$ lacked homology with all known structural databases. PSI-BLAST and HMM Superfamily analyses demonstrated that this enzyme belongs to the ${\alpha}/{\beta}$ hydrolase fold family. Threading approach revealed that the most suitable template to use was the Human gastric lipase (1HLG). The superimposition of the predicted PhaC1$_{P.sp\;USM\;4-55}$ model with the 1HLG template structure covering 86.2% of the backbone atoms showed an RMSD of 1.15 ${\AA}$ The catalytic residues comprising of Cys296, Asp451, His452 and His479 were found to be conserved and were located adjacent to each other. We proposed that the catalytic mechanism involved the formation of two tetrahedral intermediates.

• Journal of Pharmaceutical Investigation
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• v.24 no.4
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• pp.217-225
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• 1994

With the purpose of improving the therapeutic index of $[^3H]$ acyclovir (ACV) in the treatment of chronic hepatitis B infection, asialofetuin (AF) which after selective interaction with Ashwell's receptor specifically enters into hepatocytes, was chosen as a carrier system for hepatic targeting. This drug was first converted to its monophosphate (ACVMP), which was subsequently activated by water soluble carbodiimide to conjugate with ${\varepsilon}-NH_2$ groups of Iysine residues of AF. The molar ratio of ACVMP to AF in the conjugate was 3.9. In rats, elimination of ACVMP-AF conjugate after i.v. injection showed two phase elimination kinetics. Initial apparent elimination rate constant in rats was $0.191\;min^{-1}$ which was greater than that of ACV. The elimination rate constant from terminal phase was $0.021\;min^{-1}$. Area under the total radioactivities versus time curve was found to be several times larger in liver than in other organs (spleen, intestine, lung and kidney) after i.v. administration of the conjugate labelled in the drug moiety. The above results suggested that ACVMP-AF conjugate was rapidly taken up by hepatocytes and could be a useful hepatic targeting system.