• Journal of Microbiology and Biotechnology
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• v.2 no.4
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• pp.260-267
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• 1992

Pectate lyase from alkalitolerant Bacillus sp. YA-14 is an endo-type pectate lyase which acts randomly at the $\alpha$-1, 4-galacturonan linkage, and requires calcium or strontium ions for its activity. The enzyme is active on low methyl esterified pectin, but the activity toward a high methyl esterified substrate is reduced. The apparent Km's of the enzyme toward sodium polygalacturonic acid, polygalacturonic acid, and various pectins such as apple pectin, citrus pectin, and genu pectin are 0.826 mg/ml, 0.685 mg/ml, and 1.14 mg/ml, respectively. The enzyme activity is inhibited by SDS, urea, and sodium azide, but not by various reducing reagents, such as $\beta$-mercaptoethanol, Na-thiosulfate, Na-sulfate, cystein, and L-ascorbic acid. The enzyme is inactivated by N-bromosuccinimide, $I_2, H_2O_2$. PMSF, and iodoacetate. Judging from the results of their inhibition types, we speculate that tryptophan and serine residues are directly involved in enzyme activity, while tyrosine and methionine residues are indirectly involved in its activity.

• Korean Journal of Veterinary Research
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• v.43 no.3
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• pp.439-448
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• 2003

The VP2 gene of infectious bursal disease virus (IBDV) Chinju which was previously detected in Chinju, Korea was cloned and sequenced to establish the information for the development of genetically engineered vaccines and diagnostic reagents against IBDV. The nucleotide sequence of the entire Chinju VP2 gene consisted of 1,356 bases long encoding 452 amino acids in a single open reading frame (ORF). It consisted of 368 adenine (27.1%), 363 cytosine (26.8%), 339 guanine (25.0%) and 286 thymine (21.1%) residues. The predicted $M_r$ of the Chinju VP2 protein was 48 kDa, and the protein contained 13 phosphorylation sites by protein kinase C, casein kinase II or tyrosine kinase, whereas 3 asparagine-linked glycosylation sites were recognized. The nucleotide sequence of Chinju VP2 ORF had a very close phylogenetic relationship with 98-99% homology to that of the very virulent IBDVs (vvIBDVs) HK46, OKYM, D6948, UK661, UPM97/61 and BD3/99. Also, the Chinju VP2 protein revealed a very close phylogenetic relationship with 99-100% homology to that of these vvIBDVs. The Chinju VP2 protein had 100% amino acid identity in the variable region of residues 206-360 with that of the D6948, HK46, OKYM and UK661, as well as 100% identity in two hypervariable regions of residues 212-224 and 314-324 with those of the D6948, HK46, OKYM, UK661, UPM97/61 and BD3/99. The amino acid sequence of the chinju VP2 protein contained a serine-rich heptapeptide of SWSASGS as in these vvIBDVs.

• The Korean Journal of Zoology
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• v.33 no.4
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• pp.468-475
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• 1990

An In vitro protein sulfation in the soluble fraction of rat brain was charaderized further by an improved method of alkaline hydrolysis and thin layer ceflulose electrophoresis TLE) The protein sulfation was carried out in a reaction system containing [35 S] 3'-phosphoadenosine-5'-phosphosulfate (PAPS), Tris-maleate buffer (pH 8), MgCI$_2$, and soluble proteins from rat brain. The sulfated proteins were precipitated by acetone and alkaline hydrolysis was performed to obtain sulfated amino acids. The hydrolysate was separated further by TLE and the separated residues were identified by fluorography. The Iluorography of one-dimensional The showed at least nine sulfated residues including tryosine-O-sulfate. The other spots were not identified yet positively. General properties of protein sulfotransferases (PST) using this method were re-examined such as effects of concentrations of PAPS, pH, incubation temperature and $Mg^2$+. These results suggest a possible occurrence of several PST corresponding to each sulfated residue in rat brain and that the sulfation can occur not only in tyrosine but also in other residues as well.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.81-81
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• 1995

It is well known that Src Homology 2(SH2) domain in many intracellular signal transduction proteins is very important. The domain has about 100 amino acid residues and bind phosphotyrosine-containing peptide with high affinity and specificity. Lck SH2 domain is a Src-like, lymphocyte-specific tyrosine kinase. An 11-residue phosphopeptide derived from the hamster polvoma middle-T antigen, EPQp YEEIPIYL, binds with an 1 nM dissociation constant to Lck SH2 domain. And it is known that the phosphotyrosine and isoleucine residues of the peptide are tightly bound by two well-defined pockets on Lck SH2 domain's surface. To investigate the conformational changes during complexation of SH2 domain with phosphopeptide we have performed the molecular dynamics simulation for Lck SH2 domain with peptide and peptide-free form at look in aqueous solution. More than 3000 water molecules were incorporated to solvate Lck SH2 domain and peptide. Periodic boundary condition has been applied in molecular dynamics simulation. Data analysis with the results of that simulation shows that the phosphopeptide makes primary interaction with the Lck SH2 domain at six central residues, The comparison of the complexed and uncomplexed SH2 domain structures in solution has revealed only relatively small change. But the hydrophilic and hydrophobic pockets in the protein surface show the conformational changes in spite of the small structural difference between the complex and peptide-free forms.

• International Journal of Industrial Entomology and Biomaterials
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• v.20 no.1
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• pp.25-28
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• 2010

Silk fibroin was conjugated with methoxypoly(ethylene glycol) derivatives to prepare silk nanoparicles. Conjugation of SF with PEG was examined with various instrumental analyses. Nuclear magnetic resonance spectrometry and amino acid analysis showed that serine and tyrosine residues in SF were reacted with PEG and resulted in increasing molecular weight. The sizes and shapes of SF nanoparticles observed by transmission electronmicroscope were ranged about 150-400 nm in diameter and spherical morphology. UV/VIS spectrometry showed SF nanoparticles might be outer PEG and inner SF structure.

• Biotechnology and Bioprocess Engineering:BBE
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• v.2 no.2
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• pp.86-89
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• 1997

Epidermal growth factor(EGF) known as a urgastrone is a powerful mitogen with a wide variety of possibilities for medical usages. A mature EGF coding region was isolated from human prepro-EGF sequence by a conventional PCR and cloned into pQE vector in which the gene product was supposed to be expressed with 6$\times$His tag for the subsequent purification. The recombinant mature EGF was expressed in M15[Rep4], an Escherichia coli host strain, in amount of 30-40% of total proteins pressent in E. coli extract by the addition of isopropylthio-$\beta$-galactopyranoside (IPTG). The recombinant EGF purified using a Ni2+-NTA affinity colume chromatography was active in its ability to induce phosphorylation on tyrosine residues of several substrate proteins when murine NH3T3 and human MRC-5 fibroblast cells were stimulated with it. This work may provide the basic technology and information for the production of recombinant EGF.

• Analytical Science and Technology
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• v.8 no.4
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• pp.881-886
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• 1995

Several forms of gangliosides have been separated from various types of biological matrices using cyclodextrin-modified capillary zone electrophoresis (CZE). Quantitative analysis of phospholipids from biological fluids was achieved by micellar electrokinetic capillary chromatography (MECC) using 35mM sodium dodecyl sulfate. Phosphorylation, one of the most important post-translational modifications of proteins at serine, threonine and tyrosine residues in small peptides were identified and quantitative analyses of phosphopeptides were performed. Seven different neuropeptides which are relative the pain reachanism in the vertebrate central nervons system were also separated by CZE.

• Journal of Integrative Natural Science
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• v.10 no.3
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• pp.137-140
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• 2017

Diabetes mellitus has become a major growing public health problem worldwide. More than 90% of all diabetes cases are classified as type 2 diabetes (T2D), which is also known as non-insulin dependent diabetes. Protein tyrosine phosphatase 1B (PTP1B) plays an important role in the negative regulation of insulin signal transduction pathway and has emerged as novel therapeutic strategy for the treatment of type 2 diabetes. PTP1B inhibitors enhance the sensibility of insulin receptor (IR) and have favorable curing effect for insulin resistance-related diseases. Recently twelve anti-diabetic xanthones were isolated from the bark of Garcinia xanthochymus. Hence, in the present study, molecular docking was carried out for these twelve xanthones. The objective of this work is to study the interaction of the newly isolated xanthones with PTP1B. The docking results showed that xanthones have good interactions and has better docking score with PTP1B and suggest LYS120 and ASP181 are the important residues involved in interaction between PTP1B enzyme and the xanthones.

• Mass Spectrometry Letters
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• v.10 no.1
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• pp.32-37
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• 2019

The ${\pi}-{\pi}$ interactions of the peptide-dimer and peptide-trimer complexes were investigated in the (VQIVYK + LYQLEN) and (VQIVYK + NNQQNY) mixing solutions. The results showed that tyrosine (Y) residues were critical in the formation of hetero peptide-dimers and -trimers during the early oligomerization process. We used collision-induced dissociation (CID) along with electrospray ionization mass spectroscopy (ESI-MS) to obtain the structural information of the hetero-dimers and -trimers. We chose three amyloidogenic peptides-VQIVYK, NNQQNY, and LYQLEN-from tau protein, yeast prion-like protein Sup35, and insulin chain A, respectively. Hetero-dimer, -trimer, -tetramer, and -pentamer complexes were observed in the mass spectra. The tandem mass spectrum of the hetero-dimer and hetero-trimer showed two different fragmentation patterns (covalent and non-covalent bond dissociation). Y-Y interaction structures were also proposed for the hetero-dimer and -trimer complexes.

• Microbiology and Biotechnology Letters
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• v.34 no.2
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• pp.129-135
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• 2006

A gene encoding for a putative microsomal epoxide hydrolase (mEH) of a zebrafish, Danio rerio, was cloned and characterized. The putative mEH protein of D. rerio exhibited sequence similarity with mammalian mEH and some other bacterial EHs. A structural model for the putative mEH was constructed using homology modeling based on the crystallographic templates, 1 qo7 and 1 ehy. The catalytic triad consisting of $Asp^{233}$, $Glu^{413}$, and $His^{440}$ was identified, and the characteristic features such as two tyrosine residues and oxyanion hole were found to be highly conserved. Based on bioinformatic analysis together with EH activity assay, the putative protein was annotated as mEH of D. rerio. Enantiopure styrene oxide with enantiopurity of 99%ee and yield of 33.5% was obtained from racemic styrene oxide by the enantioselective hydrolysis activity of recombinant mEH of D. rerio for 45 min.