• Parasites, Hosts and Diseases
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• v.46 no.3
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• pp.183-186
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• 2008

Helminthic cysteine proteases are well known to play critical roles in tissue invasion, nutrient uptake, and immune evasion of the parasites. In the same manner, the sparganum, the plerocercoid of Spirometra mansoni, is also known to secrete a large amount of cysteine proteases. However, cysteine protease inhibitors regulating the proteolytic activities of the cysteine protease are poorly illustrated. In this regard, we partially purified an endogenous cysteine protease inhibitor from spargana and characterized its biochemical properties. The cysteine protease inhibitor was purified by sequential chromatographies using Resource Q anion exchanger and Superdex 200 HR gel filtration from crude extracts of spargana. The molecular weight of the purified protein was estimated to be about 11 kD on SDS-PAGE. It was able to inhibit papain and 27 kDa cysteine protease of spargana with the ratio of 25.7% and 49.1%, respectively, while did not inhibit chymotrypsin. This finding suggests that the cysteine protease inhibitor of spargana may be involved in regulation of endogenous cysteine proteases of the parasite, rather than interact with cysteine proteases from their hosts.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.11
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• pp.32-38
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• 1998

For the purpose of monitoring the abnormal state in proportion to cutting in automatic production process, the 3 kinds of specimens different from mechanical properties by austempering through temperature variation were manufactured, and the effects of tool wear on thrust and AE RMS was analyzed with sequential drilling in in-process. When the ADI specimens were drilled, the relationship of thrust and AE RMS with flank wear was studied through experiments, and it is confirmed that the reliable wear state is able to be monitored by using these signals. It was shown that thrust and AE RMS increased slowly till flank wear reached to V$_{B}$ = 0.25mm, and they increased steeply over the value. The effective tool exchange time was able to be pre-estimated by using this fact. It was validated that the tool breakage was able to be detected on the real time by monitoring in in-process.s.

• Journal of the Korean Magnetic Resonance Society
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• v.16 no.2
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• pp.172-184
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• 2012

The prokaryotic molecular chaperone Hsp33 achieves its holdase activity upon response to oxidative stress particularly at elevated temperature. Despite many structural studies of Hsp33, which were conducted mainly by X-ray crystallography, the actual structures of the Hsp33 in solution remains controversial. Thus, we have initiated NMR study of the reduced, inactive Hsp33 monomer and backbone NMR assignments were obtained in the present study. Based on a series of triple resonance spectra measured on a triply isotope-[$^2H/^{13}C/^{15}N$]-labeled protein, sequence-specific assignments of the backbone amide signals observed in the 2D-[$^1H/^{15}N$]TROSY spectrum could be completed up to more than 96%. However, even considering the small portion of non-assigned resonances due to the lack of sequential connectivity, we confirmed that the total number of observed signals was quite smaller than that expected from the number of amino acid residues in Hsp33. Thus, it is postulated that peculiar dynamic properties would be involved in the solution structure of the inactive Hsp33 monomer. We expect that the present assignment data would eventually provide the most fundamental and important data for the progressing studies on the 3-dimensional structure and molecular dynamics of Hsp33, which are critical for understanding its activation process.

• Bulletin of the Korean Chemical Society
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• v.16 no.5
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• pp.401-406
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• 1995

The P. fragi lipase overexpressed in E. coli as a fusion protein of 57 kilodalton (kDa) has been purified through glutathione-agarose affinity chromatography by elution with free glutathione. The general properties of the purified GST-fusion protein were characterized by observing absorbance of released p-nitrophenoxide at 400 nm which was hydrolyzed from the substrate p-nitrophenyl palmitate. The optimum condition was observed at 25 $^{\circ}C$, pH 7.8 with 0.4 ${\mu}g$ of protein and 1.0 mM substrate in 0.6% (v/v) TritonX-100 solution. Also the lipase was activated by Ca+2, Mg+2, Ba+2 and Na+ but it was inhibited by Co+2 and Ni+2. pGEX-2T containing P. fragi lipase gene as expression vector was named pGL191 and used as a template for the site-directed mutagenesis by sequential PCR steps. A Ser-His-Asp catalytic triad similar to that present in serine proteases may be present in Pseudomonas lipase. Therefore, the PCR fragments replacing Asp217 to Arg and His260 to Arg were synthesized, and substituted for original fragment in pGL19. The ligated products were transformed into E. coli NM522, and pGEX-2T harboring mutant lipase genes were screened through digestion with XbaI and StuI sites created by mutagenic primers, respectively. No activity of mutant lipases was observed on the plate containing tributyrin. The purified mutant lipases were not activated on the substrate and affected at pH variation. These results demonstrate that Asp217 and His260 are involved in the catalytic site of Pseudomonas lipase.

• Bulletin of the Korean Chemical Society
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• v.21 no.12
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• pp.1217-1221
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• 2000

L-alanine dehydrogenase from Bacillus subtilis exhibits allosteric kinetic properties in the presence of $ZN^{2+}$. $ZN^{2+}$ induces the binding of substrate (L-alanine) to be cooperative at pH 8.0. The effect of pH variation between pH 7.0 and pH 10.0 on the inhibition by $ZN^{2+}$ correlates with the pH effect on the $K_m$ values for L-alanine within these pH range indicating that $ZN^{2+}$ and substrate compete for the same site. No such cooperativity is induced by $ZN^{2+}$ when the reaction is carried out at pH 10. At this higher pH, $ZN^{2+}$ binds with the enzyme with lower affinity and noncompetitive with respect to L-alanine. Inhibition of L-alanine dehydrogenase by $ZN^{2+}$ depends on the ionic strength. Increase in KCI concentration reduced the inhibition, but allosteric property in $ZN^{2+}$ binding is conserved. A model for the regulatory mechanism of L-alanine dehydrogenase as a noncooperative substrate-cooperative cofactor allosteric enzyme, which is compatible in both concerted and the sequential allosteric mechanism, is proposed.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.4
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• pp.29-33
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• 2003

Material and electrical properties of copper-based ohmic contacts on n-type 4H-SiC were investigated for the effects of the post-annealing and the metal covering conditions. The ohmic contacts were prepared by sequential sputtering of Cu and Si layers on SiC substrate. The post-annealing treatment was performed using RTP (rapid thermal process) in vacuum and reduction ambient. The specific contact resistivity ($p_{c}$), sheet resistance ($R_{s}$), contact resistance ($R_{c}$), transfer length ($L_{T}$), were calculated from resistance (RT) versus contact spacing (d) measurements obtained from TLM (transmission line method) structure. The best result of the specific contact resistivity was obtained for the sample annealed in the reduction ambient as $p_{c}= 1.0 \times 10^{-6}\Omega \textrm{cm}^2$. The material properties of the copper contacts were also examined by using XRD. The results showed that copper silicide was formed on SiC as a result of intermixing Cu and Si layer.

• KSBB Journal
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• v.30 no.6
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• pp.291-295
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• 2015

The limited productivity of natural shell matrix proteins has hampered the investigation of their biochemical properties and practical applications, although biominerals in nature obtained by organic-inorganic assemblies have attractive mechanical and biological properties. Here, we prepared a vector for the expression of a fusion protein of a shell matrix protein from Pinctada fucata (named as GRP_BA) with the GRGDSP residue. The fusion protein of BA-RGD was simply produced in E. coli and purified through sequential steps including the treatment with $CaCl_2$ and EDTA solution for cell membrane washing, mechanical cell disruption and the application of non-ionic surfactant of Triton X-100 for BA-RGD inclusion body washing. The production yield was approximately 60 mg/L, any other protein band was not observed in SDS-PAGE and it was estimated that above 97% endotoxin was removed compared to the endotoxin level of whole cell. This study showed this simple and easy purification approach could be applied to the purification of BA-RGD fusion protein. It is expected that the protein could be utilized for the preparation of biominerals in practical aspects.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.2
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• pp.119-130
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• 2010

Pulmonary toxicity of talc containing tremolite asbestos (TCT) has been studied in term sequential in Sprague-Dawely rats. UICC chrysotile(average diameter 0.03${\mu}m$, average length 2.93${\mu}m$) was applied as the positive control. TCT was analyzed for its physicochemical properties by transmission electron microscope equipped with energy dispersive X-ray spectrometer(TEM-EDS). The effects of 2mg TCT(talc average diameter 9.7${\pm}$8.4${\mu}m$; tremolite average diameter 1.6${\pm}$1.6${\mu}m$, average length 10.8${\pm}$7.0${\mu}m$) on pathological changes were evaluated after 1, 8 weeks instilled into rat lungs. 2mg Chrysotile continuously affected lung pathological changes. Inflammation and granuloma response broke out from 1 week after instilled with chrysotile and the pathological examination further showed increased legions of lung after 8 weeks. But TCT did not showed lung pathological changes. The biopersistence of TCT and chrysotile was evaluated by TEM- EDS. Whereas chrysotile continuously have retained to 8 weeks instilled into rat lungs, talc of TCT showed statistically significant decrease of diameter from 1 weeks and statistically significant change in Si atomic % compositions at 8 weeks instilled into rat lungs. Physicochemical properties of tremolite of TCT were not affected until 8 weeks instilled into rat lungs. This study showed that the durability of TCT in the lungs is much weaker than chrysotile.

• Journal of the Korean Geotechnical Society
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• v.18 no.1
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• pp.71-78
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• 2002

This paper presents a back-calculation technique leer the prediction of the behavior of earth wall inserted in multi-layered soil deposit. The soil properties are back-calculated from the measured displacement at each construction stage and the behavior of earth wall far the next construction stage is predicted using back-calculated soil properties. For multi-layered soil deposit, the back-calculation would be very difficult due to the increase in the number of variables. In this study, to solve this difficulty, the back-calculation was performed successively from the lowest layer to the upper layers. An efficient elasto-plastic beam-column analysis was used for forward analysis to minimize the computation time of iterative back-calculation procedure. The coefficients of subgrade reaction and lateral earth pressure necessary for the formation of p-y curve were selected as back calculation variables, and to minimize the effect of abnormal behavior of the wall which might be caused by any unexpected action during construction, the difference between measured displacement increment and computed displacement increment at each construction stages is used as the objective function of optimization. The constrained sequential linear programming was used for the optimization technique to found values of variables minimizing the objective function. The proposed method in this study was verified using numerically generated data and measured field data.

• Journal of Microbiology and Biotechnology
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• v.18 no.2
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• pp.248-254
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• 2008

Candida magnoliae, an osmotolerant and erythritol producing yeast, prefers D-fructose to D-glucose as carbon sources. For the investigation of the fructophilic characteristics with respect to sugar transportation, a sequential extraction method using various detergents and ultracentrifugation was developed to isolate cellular membrane proteins in C. magnoliae. Immunoblot analysis with the Pma1 antibody and two-dimensional electrophoresis analysis coupled with MS showed that the fraction II was enriched with membrane proteins. Eighteen proteins out of 36 spots were identified as membrane or membrane-associated proteins involved in sugar uptake, stress response, carbon metabolism, and so on. Among them, three proteins were significantly upregulated under the fructose supplying conditions. The hexose transporter was highly homologous to Ght6p in Schizosaccharomyces pombe, which was known as a predominant transporter for the fructose uptake of S. pombe because it exhibited higher affinity to D-fructose than D-glucose. The physicochemical properties of the ATP-binding cassette transporter and inorganic transporter explained their direct or indirect associations with the fructophilic behavior of C. magnoliae. The identification and characterization of membrane proteins involved in sugar uptake might contribute to the elucidation of the selective utilization of fructose to glucose by C. magnoliae at a molecular level.