• BMB Reports
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• v.35 no.2
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• pp.165-171
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• 2002

A serine collagenolytic protease was purified from the internal organs of filefish Novoden modestrus, by ammonium sulfate, ion-exchange chromatography on a DEAE-Sephadex A-50, ion-exchange rechromatography on a DEAE-Sephadex A-50, and gel filtration on a Sephadex G-150 column. The molecular mass of the filefish serine collagenase was estimated to be 27.0 kDa by gel filtration and SDS-PAGE. The purified collagenase was optimally active at pH 7.0-8.0 and $55^{\circ}C$. The purified enzyme was rich in Ala, Ser, Leu, and Ile, but poor in Trp, Pro, Tyr, and Met. In addition, the purified collagenolytic enzyme was strongly inhibited by N-P-toluenesulfonyl-L-lysine chloromethyl ketone (TLCK), diisopropylfluorophosphate (DFP), and soybean trypsin inhibitor.

• Journal of Genetic Medicine
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• v.19 no.2
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• pp.100-104
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• 2022

The gene encoding solute carrier family 9 member 6 (SLC9A6) on Xq26.3 is associated with Christianson syndrome (CS) mimicking Angelman syndrome. In CS, developmental and epileptic encephalopathy (DEE) appears in about 20%, and DEE with spike-and-wave activation in sleep (SWAS) is reported only in several cases. A 10-year-old boy with DEE showed multidrug resistant focal seizures from 6 months of age. He had progressive microcephaly, regression, global developmental delay without speech, hyperkinesia, and truncal ataxia; he had a long thin face, esotropia, and happy demeanor. Brain magnetic resonance imaging demonstrated cerebellar atrophy. Electroencephalogram at 7.5 years of age showed nearly continuous diffuse paroxysms in slow wave sleep. The seizures were responsive to corticosteroids for a while. Trio whole exome sequencing exhibited a likely pathogenic variant of SLC9A6 in the proband and his asymptomatic mother: c.1194dup (p.Leu399AlafsTer12). This is a rare case report of CS with DEE-SWAS in a Korean patient.

• Journal of Electrical Engineering and Technology
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• v.7 no.4
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• pp.513-523
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• 2012

For precisely regulating the speed of a permanent magnet synchronous motor system with unknown load torque disturbance and disturbance inputs, an LMI-based sliding mode control scheme is proposed in this paper. After a brief review of the PMSM mathematical model, the sliding mode control law is designed in terms of linear matrix inequalities (LMIs). By adding an extended observer which estimates the unknown load torque, the proposed speed tracking controller can guarantee a good control performance. The stability of the proposed control system is proven through the reachability condition and an approximate method to implement the chattering reduction is also presented. The proposed control algorithm is implemented by using a digital signal processor (DSP) TMS320F28335. The simulation and experimental results verify that the proposed methodology achieves a more robust performance and a faster dynamic response than the conventional linear PI control method in the presence of PMSM parameter uncertainties and unknown external noises.

• Journal of Marine Bioscience and Biotechnology
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• v.7 no.1
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• pp.19-27
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• 2015

The objective of the current study was to evaluate the inhibitory and antioxidant activities of powdered katsuobushi (dried bonito) protein hydrolysates and their corresponding fractions. The powdered katsuobushi (dried bonito) hydrolysates were obtained by enzymatic hydrolysis using Alcalase, ${\alpha}$-chymotrypsin, Neutrase, pepsin, papain, and trypsin. The antioxidant efficacy of the respective hydrolysates were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, superoxide, and alkyl radical-scavenging activities. Among the hydrolysates, the peptic-derived hydrolysate exhibited the highest antioxidant activity compared to other enzymatic hydrolysates. Therefore, the peptic-derived hydrolysate was further analyzed, and was found to contain an active peptide with an amino acid sequence identified as Pro-Met-Pro-Leu-Asn-Ser-Cys (756 Da). The purified peptides from powdered katsuobushi (dried bonito) had an $EC_{50}$ value of $105.82{\mu}M$, and exhibited an inhibitory effect against DNA oxidation induced by hydroxyl radicals. Taken together, these results suggests that powdered katsuobushi (dried bonito) could be used as a natural antioxidant in functional foods and prevent oxidation reactions in food processing.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.478-484
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• 1996

Recombinant human epidermal growth factor (rhEGF) was produced by E. coli BL21 harboring a plasmid pYHB101. The maximum production was 68.7 mg/l when the E. coli strain was cultured at 25$\circ$C for 48 hours in the modified MBL medium containing 10 g/l glucose with 1 mM IPTG induction at 2 hours after inoculation. The rhEGF was purified upto 267 folds by Amberlite XAD- 7 chromatography, ultrafiltration, and DEAE Sepharose fast flow ion exchange chromatography with an overall yield of 66.6%. The purified rhEGF was further separated into two fractions by HPLC. The N-terminal amino acid sequence of the second fraction was Asn-Ser-Asp-Ser-Glu-Cys-Pro-Leu-Ser-His. The effect of rhEGF on the DNA synthesis was examined using in vitro biological assay based on the incorporation of 5'-bromo-2'- deoxy-uridine (BrdU). The purified rhEGF shows no difference with natural human epidermal growth factor (nhEGF) in N-terminal amino acids residues and biological activity. From the results, we concluded that rhEGF produced from E. coli harboring the plasmid pYHB101 was apparently the same as nhEGF.

• BMB Reports
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• v.40 no.6
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• pp.1090-1094
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• 2007

Melittin (ME), a linear 26-residue non-cell-selective antimicrobial peptide, displays strong lytic activity against bacterial and human red blood cells. To design ME analogue with improved cell selectivity, we synthesized a melittin diastereomer (ME-D) with D-amino acid in the leucine zipper sequence (Leu-6, Lue-13 and Ile-20). Compared to ME, ME-D exhibited the same or 2-fold higher antibacterial activity but 8-fold less hemolytic activity. Circular dichroism analysis revealed that ME-D has much less $\alpha$-helical content in $\alpha$-helical content in the presence of zwitterionic EYPC/cholesterol (10 : 1, w/w) liposomes compared to negatively charged EYPE/EYPG (7 : 3, w/w) liposomes. The blue shift of the fluorescence emission maximum of ME-D in zwitterionic EYPC/cholesterol (10 : 1, w/w) liposomes was much smaller than in negatively charged EYPE/EYPG (7 : 3, w/w) liposomes. These results suggested that the improvement in therapeutic index/cell selectivity of ME-D is correlated with its less permeability to zwitterionic membranes.

• Preventive Nutrition and Food Science
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• v.7 no.2
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• pp.123-127
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• 2002

Ninety nine extracts from Korean plants were screened for their inhibitory activities on human immunodeficiency virus (HIV) type 1 pretense by an HPLC method. The pretense inhibitory activities were determined by incubating the extracts in reaction mixtures containing pretense and substrate (His-Lys-Ala-Arg-Val-Leu-(p-NO$_2$- Phe)-Glu-Ala-Nle-Ser-NH$_2$) to perform proteolytic cleavage reactions. Of the extracts tested, the water extracts of Viburnum awabuki (stem and leaves) and Distylium racemosum (leaves) had the highest pretense inhibitory activities at a concentration of 100ug/mL. Activity-guided fractionation, revealed that the n-butanol fraction of the V. awabuki extract and the ethyl acetate fraction from the D. racemosum extract had the greatest inhibitory activity on HIV-1 pretense.

• Natural Product Sciences
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• v.20 no.3
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• pp.202-205
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• 2014

Three compounds including 7,7-bis(3-indolyl)-p-cresol (1), cyclo-(S-Pro-R-Leu) (2) and cyclo-(S-Pro-R-Val) (3) were isolated from the strain of Bacillus megaterium LC derived from the marine sponge Haliclona oculata. All the isolated compounds showed antimicrobial activity at MIC values ranging from 0.005 to $5{\mu}g/mL$ against Gram-negative bacteria Vibrio vulnificus and V. parahaemolyticus, gram-positive bacteria Bacillus cereus and Micrococcus luteus, and the dermatophyte Trichophyton mentagrophytes. The results suggested that these compounds might have potential to be developed as agents treating dermatosis and controlling vibriosis in aquaculture.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.4
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• pp.414-417
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• 1992

In order to study the addition effect of Leuconostoc mesenteroides and nisin on Escherichia coli and lactic acid bacteria during fermentation and storage of Kimchi, Kimchi was stored at 4$^{\circ}C$ for 7 days and then in-creased the temperature to $25^{\circ}C$. Lactic acid content on Kimchi fermentation at 4$^{\circ}C$ was maintained initial content which was increased upto 0.9% and lactic bacteria was also increased after switching to $25^{\circ}C$. E. coli, on the other hand, was a little decreased from the initial level, but a significant decrease was found for the those Kimchi of Leuconostoc muenteroides added and nisin treated group when the fermentation temperature was switched to $25^{\circ}C$.

• Applied Biological Chemistry
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• v.33 no.4
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• pp.325-329
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• 1990

This study was undertaken to determine thermodynamic characteristics of B. subtilis p-4 and B. licheniformis p-5 proteases isolated from fermented anchovy paste. $K_m$ values of two proteases for casein as a substrate were 0.38mM in p-4 protease and 0.18mM in p-5 protease, respectively. Denaturation constants($K_D$) of p-4 and p-5 proteases were $12.2{\times}10^{-5}/sec\;and\;19.0{\times}10^{-5}/sec\;at\;40^{\circ}C,\;and\;35.7{\times}10^{-5}/sec\;and\;46.3{\times}10^{-5}/sec\;at\;50^{\circ}C$, respectively. Activation energies($E_a$) of p-4 and p-S pmteases were 19.6 Kcal/mole and 15.2kcal/mole, respectively. Free energy of activation(${\Delta}G^*$), activation enthalpy(${\Delta}H^*$) and activation entropy(${\Delta}S^*$) at $40^{\circ}C$ were 23.21Kcal/mole, 18.98Kcal/mole and -13.50 eu, respectively for p-4 protease and 22.93Kcal/mo1e, 14.58Kcal/mole and -26.68 eu, respectively for p-5 protease. The major amino acids in p-4 protease(151 residues of amino acid) were Gly, Glu, Pro, Asp, Ser, Ala, Lys and Leu, while those in p-5 protease(247 residues of amino acid) were Gly, Glu, Asp, Ala and Leu. It may be concluded that heat denaturation of two proteases showed liner regression curve and p-5 protease was more sensitive to heat than p-4 protease.