• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.11a
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• pp.153-159
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• 1996

${\alpha}$-Melanotropin (Ac-Ser-Tyr- Ser-Met-Glu$\^$5/-His-Phe-Arg-Trp-Gly$\^$10/-Lys-Pro-Val-NH$_2$) is one of the first peptide hormones to be isolated and have its structure determined. It was early recognized to have essentially the same N-terminal tridecapeptide sequence as adrenocorticotropic hormone (ACTH) except that the N-terminal was acetylated in the case of ${\alpha}$-MSH but not in the case of ACTH, indicating that their biosyntheses were different (Figure 1). Subsequently it was discovered that ${\alpha}$-MSH and ACTH were derived from the same gene, currently referred to as proopiomelanocortin (POMC). Its original bioactivity was pigmentation, but it also was recognized that it may have activity in the central nervous system, though the precise nature of these central activities have been controversial. The recent cloning and expression of five melanocortin receptors, with the MC3 and MC4 receptors found primarily in the brain and the MC5 receptor (MC5-R) found throughout the body, has provided new impetus to understand the structure-activity relationships of ${\alpha}$-MSH at these receptors. The effects of ${\alpha}$-MSH on pigmentation are mediated by the MC1-R expressed specifically on the surface of melanocytes. Similarly the MC2-R is involved in the regulation of adrenal steroidogenesis by ACTH. However, given the complexity of expression of the MC3, MC4, and MC5 receptors, it has not been possible to identify any simple correlations between these receptors and the reported biological activities of the melanocortin peptides. Consequently, potent and receptor specific agonists and especially antagonists would be extremely valuable tools for the determination of the physiological roles of the MC3, MC4, and MC5 receptors. Though the extensive structure-activity relationships have provided much information on agonist activity related to pigmentary effects, only recently has it been possible to begin to systematically develop potent and selective antagonists.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.453-458
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• 1988

This research was carried out to investigate the effects of Maillard reaction products and nondialyzable melanoidins on the nitrite-scavenging. Nitrite-scavenging reactions were done at the different pH conditions(pH 1.2, 4.2 and 6.0). Maillard reaction products and nondialyzable melanoidins, produced from the glucose-amino acids(lys., gly., arg., his.)model systems, had a great of nitrite-scavenging effects. Nitrite-scavenging effects of Maillard reaction products and nondialyzable melanoidins were also pH dependent, being higher at pH 1.2 and lower at pH 6.0. By the treatment of Maillard reaction products and nondialyzable melanoidins with sodium borohydride, nitrite-scavenging effects were remarkably decreased at pH 1.2.

• Korean Journal of Agricultural Science
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• v.39 no.2
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• pp.255-261
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• 2012

A bacterium AB-55, isolated from waste mushroom bed of Agaricus bisporus in Sukseong-myeon, Buyeo-gun, Chungcheongnam-do, Korea, was screened onto xylan agar congo-red plate by the xylanolysis method and was used to produce an xylanase in shaker buffle flask cultures containing oat spelt xylans. The phylogenetic analysis using 16S rRNA gene sequence data showed that the strain AB-55 had the highest homology (99.0%) with Bacillus subtilis and it was named as Bacillus subtilis AB-55. A xylanase was purified by ammonium sulfate precipitation (50~80%), gel filtration on sephacryl S-300, and ion exchange chromatography on DEAE sepharose FF. The molecular weight of the xylanase was estimated as 44 kDa by SDS-PAGE. Optimal pH and temperature for the xylanase activity was pH 7 and $50^{\circ}C$, respectively. N-terminal amino acid sequence of the enzyme was identified as Ser-Ala-Val-Lys-His-Gly-Ala-Ile-Val-Phe. The substrate specificity of the enzyme exhibited that it hydrolyzed efficiently oat spelt xylan as well as beechwood xylan, but showed no activity against Avicel and carboxymethyl clellulose (CMC). The enzyme activity was enhanced by $Fe^{2+}$ and $Mn^{2+}$ whereas was entirely inhibited by $Hg^+$.

• Journal of Genetic Medicine
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• v.15 no.1
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• pp.28-33
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• 2018

Fabry disease (FD) is a rare X-linked lysosomal storage disorder caused by the deficiency of ${\alpha}$-galactosidase A. Patients with classical FD present acroparesthesia, hypohidrosis, cornea verticillata, disseminated angiokeratoma, and microalbuminuria in childhood, and develop life-threatening renal, cardiac, and cerebrovascular complications typically after the fourth decade of life. To date, more than 700 mutations responsible for FD have been identified in the human GLA gene. Herein, we report a novel GLA mutation, c.1117_1141del25 (p.Gly373Profs*10), identified in an 11-year-old Korean boy with FD presenting early cardiac and neurologic manifestation and in other affected family members. The boy had acroparesthesia, hypohidrosis, cornea verticillata, and left ventricular hypertrophy. His mother and sister also had acroparesthesia. Two males on the mother's side had similar pain and died of unknown causes. The plasma ${\alpha}$-galactosidase A activity (4.1 nmol/hr/mg protein) of the patient was markedly lower than the mean value of the controls. The plasma level of globotriaosylsphingosine was elevated in the patient and all the carriers. We concluded the novel GLA mutation c.1117_1141del25 is a pathogenic mutation for FD, probably related to the early cardiac manifestation of FD.

• Journal of Microbiology and Biotechnology
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• v.24 no.7
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• pp.905-913
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• 2014

Lj-RGD3, an RGD (Arg-Gly-Asp) toxin protein from the salivary gland of Lampetra japonica, exhibits antifungal activity against Candida albicans. Lj-RGD3 has three RGD motifs and shows homology to histidine-rich glycoprotein. We synthesised two mutant derivatives of Lj-RGD3: Lj-26, which lacks all three RGD motifs and contains no His residues; and Lj-112, which lacks only the three RGD motifs. We investigated the effects of the wild-type and mutated toxins on a gram-positive bacterium (Escherichia coli), a gram-negative bacterium (Staphylococcus aureus), and a fungus (C. albicans). rLj-RGD3 and its mutants exhibited antifungal but not antibacterial activity, as measured by a radial diffusion assay. The C. albicans inhibition zone induced by rLj-112 was larger than that induced by the other proteins, and its inhibitory effect on C. albicans was dose-dependent. In viable-count assays, the rLj-112 MIC was $7.7{\mu}M$, whereas the MIC of the positive control (ketoconazole) was $15{\mu}M$. Time-kill kinetics demonstrated that rLj-112 effectively killed C. albicans at $1{\times}$ and $2{\times}$ MIC within 12 and 6 h, respectively. Electron microscopy analysis showed that rLj-RGD3 and rLj-112 induced C. albicans lysis. Our results demonstrate a novel anticandidal activity for rLj-RGD3 and its mutant derivatives.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.19 no.1
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• pp.76-81
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• 2016

Carnitine palmitoyltransferase 1A (CPT1A) is an enzyme functioning in mitochondrial fatty acid oxidation (FAO) of the liver. Patients with CPT1A deficiency have impaired mitochondrial FAO and display hypoketotic hypoglycemia and hepatic encephalopathy as typical manifestations. In this report, we present a case of CPT1A deficiency presenting jaundice as the first manifestation. A 1.9 years old boy showed jaundice and elevated levels of free and total carnitine were observed. From direct sequencing analysis of CPT1A, two novel mutations, c.1163+1G>A and c.1393G>A (p.Gly465Arg), were identified. At the age of 2.2 years, hypoglycemia, tachycardia, and altered mental status developed just after cranioplasty for craniosynostosis. High glucose infusion rate was required for recovery of his vital signs and mentality. Diet rich in high carbohydrate, low fat and inclusion of medium chain triglyceride oil resulted in improvement in cholestatic hepatitis and since then the boy has shown normal growth velocity and developmental milestones to date.

• Journal of Microbiology and Biotechnology
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• v.34 no.8
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• pp.1660-1670
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• 2024

The aim of this study was to modify phytase YiAPPA via protein surficial residue mutation to obtain phytase mutants with improved thermostability and activity, enhancing its application potential in the food industry. First, homology modeling of YiAPPA was performed. By adopting the strategy of protein surficial residue mutation, the lysine (Lys) and glycine (Gly) residues on the protein surface were selected for site-directed mutagenesis to construct single-site mutants. Thermostability screening was performed to obtain mutants (K189R and K216R) with significantly elevated thermostability. The combined mutant K189R/K216R was constructed via beneficial mutation site stacking and characterized. Compared with those of YiAPPA, the half-life of K189R/K216R at 80℃ was extended from 14.81 min to 23.35 min, half-inactivation temperature (T₅₀³⁰) was increased from 55.12℃ to 62.44℃, and T_m value was increased from 48.36℃ to 53.18℃. Meanwhile, the specific activity of K189R/K216R at 37℃ and pH 4.5 increased from 3960.81 to 4469.13 U/mg. Molecular structure modeling analysis and molecular dynamics simulation showed that new hydrogen bonds were introduced into K189R/K216R, improving the stability of certain structural units of the phytase and its thermostability. The enhanced activity was primarily attributed to reduced enzyme-substrate binding energy and shorter nucleophilic attack distance between the catalytic residue His28 and the phytate substrate. Additionally, the K189R/K216R mutant increased the hydrolysis efficiency of phytate in food ingredients by 1.73-2.36 times. This study established an effective method for the molecular modification of phytase thermostability and activity, providing the food industry with an efficient phytase for hydrolyzing phytate in food ingredients.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.17-25
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• 2013

The thermotolerant methylotrophic yeast Hansenula polymorpha is an attractive model organism for various fundamental studies, such as the genetic control of enzymes involved in methanol metabolism, peroxisome biogenesis, nitrate assimilation, and resistance to heavy metals and oxidative stresses. In addition, H. polymorpha has been highlighted as a promising recombinant protein expression host, especially due to the availability of strong and tightly regulatable promoters. In this study, we investigated the possibility of employing human serum albumin (HSA) as the fusion tag for the secretory expression of heterologous proteins in H. polymorpha. A set of four expression cassettes, which contained the methanol oxidase (MOX) promoter, translational HSA fusion tag, and the terminator of MOX, were constructed. The expression cassettes were also designed to contain sequences for accessory elements including His8-tag, $2{\times}(Gly_4Ser_1)$ linkers, tobacco etch virus protease recognition sites (Tev), multi-cloning sites, and strep-tags. To determine the effects of the size of the HSA fusion tag on the secretory expression of the target protein, each cassette contained the HSA gene fragment truncated at a specific position based on its domain structure. By using the Green fluorescence protein gene as the reporter, the properties of each expression cassette were compared in various conditions. Our results suggest that the translational HSA fusion tag is an efficient tool for the secretory expression of recombinant proteins in H. polymorpha.

• Journal of Periodontal and Implant Science
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• v.41 no.6
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• pp.293-301
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• 2011

Purpose: We have previously reported that tetra-cell adhesion molecule (T-CAM) markedly enhanced the differentiation of osteoblast-like cells grown on anorganic bone mineral (ABM). T-CAM comprises recombinant peptides containing the Arg- Gly-Asp (RGD) sequence in the tenth type III domain, Pro-His-Ser-Arg-Asn (PHSRN) sequence in the ninth type III domain of fibronectin (FN), and the Glu-Pro-Asp-Ilu-Met (EPDIM) and Tyr-His (YH) sequence in the fourth fas-1 domain of ${\beta}$ig-h3. Therefore, the purpose of this study was to evaluate the cellular activity of osteoblast-like cells and the new bone formation on ABM coated with T-CAM, while comparing the results with those of synthetic cell binding peptide (PepGen P-15). Methods: To analyze the cell viability, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed, andto analyze gene expression, northernblot was performed. Mineral nodule formations were evaluated using alizarin red stain. The new bone formations of each group were evaluated using histologic observation and histomorphometrc analysis. Results: Expression of alkaline phosphatase mRNA was similar in all groups on days 10 and 20. The highest expression of osteopontin mRNA was observed in the group cultured with ABM/P-15, followed by those with ABM/T-CAM and ABM on days 20 and 30. Little difference was seen in the level of expression of collagen type I mRNA on the ABM, ABM/T-CAM, and ABM/P-15 cultured on day 20. There were similar growth and proliferation patterns for the ABM/T-CAM and ABM/P-15. The halo of red stain consistent with $Ca^{2+}$ deposition was wider and denser around ABM/T-CAM and ABM/P-15 particles than around the ABM particles. The ABM/T-CAM group seemed to have bone forming bioactivity similar to that of ABM/P-15. A complete bony bridge was seen in two thirds of the defects in the ABM/T-CAM and ABM/P-15 groups. Conclusions: ABM/T-CAM, which seemed to have bone forming bioactivity similar to ABM/P-15, was considered to serve as effective tissue-engineered bone graft material.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.730-738
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• 2016

est19 is a gene from Bacillus sp. K91 that encodes a new esterase. A comparison of the amino acid sequence showed that Est19 has typical Ser-Gly-Asn-His (SGNH) family motifs and could be grouped into the SGNH hydrolase family. The Est19 protein was functionally cloned, and expressed and purified from Escherichia coli BL21(DE3). The enzyme activity was optimal at 60℃ and pH 9.0, and displayed esterase activity towards esters with short-chain acyl esters (C₂-C₆). A structural model of Est19 was constructed using phospholipase A1 from Streptomyces albidoflavus NA297 as a template. The structure showed an α/β-hydrolase fold and indicated the presence of the typical catalytic triad Ser49-Asp227-His230, which were further investigated by site-directed mutagenesis. To the best of our knowledge, Est19 is a new member of the SGNH hydrolase family identified from thermophiles, which may be applicable in the industrial production of semisynthetic β-lactam antibiotics after modification.