• Title/Summary/Keyword: L-Met

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Substitutions for Cys-472 and His-509 at the Active Site of $\beta$-Galactosidase from Lactococcus lactis ssp. lactis 7962 Cause Large Decreases in Enzyme Activity

  • Chung Hye-Young;Yang Eun-Ju;Chang Hae-Choon
    • Journal of Microbiology and Biotechnology
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    • v.16 no.8
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    • pp.1325-1329
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    • 2006
  • Structural modeling of $\beta$-galactosidase from L. lactis ssp. lactis 7962 has shown that the residues Cys-472 and His-509 are located in the wall of the active-site cavity. To examine the functions of Cys-472 and His-509, we generated five site-specific mutants: Cys-472-Ser, Cys-472-Thr, Cys-472-Met, His-509-Asn, and His-509-Phe. $\beta$-Galactosidase substituted at Cys-472 with Met or His-509 with Phe had <3% of the activity of the native enzyme when assayed using ONPG as substrate. The other mutants Cys-472-Ser, Cys-472-Thr, and His-509-Asn had ca. 10-15% of the native enzyme activity. The V$_max$ values of the five mutated enzymes were lower (60-7,000-fold) than that of native enzyme. These results show that the catalytic ability of $\beta$-galactosidase is significantly affected by mutations at Cys-472 or His-509.

Effects of Zn-L-Selenomethionine on Carcass Composition, Meat Characteristics, Fatty Acid Composition, Glutathione Peroxidase Activity, and Ribonucleotide Content in Broiler Chickens

  • Chaosap, Chanporn;Sivapirunthep, Panneepa;Takeungwongtrakul, Sirima;Zulkifli, Razauden Mohamed;Sazili, Awis Qurni
    • Food Science of Animal Resources
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    • v.40 no.3
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    • pp.338-349
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    • 2020
  • The effects of organic Zn-L-selenomethionine (Zn-L-SeMet) at 0.3 ppm on carcass composition, meat characteristics, fatty acid composition, glutathione peroxidase activity, and ribonucleotide content were compared against the commercial inorganic sodium selenite (Na-Se) and the combination of the two, in commercial broilers. A total of 540 one day-old chicks were assigned at random to 3 dietary treatments : i) commercial inorganic selenium as control or T1, ii) a 1:1 ratio of inorganic and organic selenium as T2, and iii) organic selenium as T3. Carcass composition, meat characteristics, cholesterol content, fatty acid composition, and ribonucleotide content were generally unaffected by treatments. However, discrepancy were significantly observed in glutathione peroxidase activity (GSH-Px) and water holding capacity, with organic selenium showing higher glutathione peroxidase activity (p<0.01) and lower shrinkage loss (p<0.05), respectively. These findings could be explained by the contribution of organic selenium in bioavailability of GSH-Px. However, having conducted in a commercial close house system with sufficient amount of nutritional supplementation, the present study demonstrated little or no effects of organic Zn-L-SeMet on meat characteristics, fatty acid composition, and ribonucleotide content (flavor characteristic) in broiler chickens.

Evaluation of the Patient Dose in Case of Standard Radiographic Examinations Using CR and DR (표준영상의학검사를 대상으로 한 CR과 DR에서의 환자선량평가)

  • Kim, Sang-Tae;Han, Beom-Hui
    • Journal of radiological science and technology
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    • v.33 no.3
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    • pp.173-178
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    • 2010
  • In projection radiography, two types of digital imaging systems are currently available, computed radiography (CR) and digital radiography (DR): a difference between them can be stated in terms of dose and image quality. In the Department of Radiology our hospital, a flat-panel DR equipment (Digital diagnost, Philips) and two CR systems (ADC Compact plus digitizer, AGFA) are employed. Eight standard radiographic examinations (Skull AP, Skull LAT, Chest PA, Chest LAT, Abdomen AP, L-spine AP, L-spine LAT, Pelvis AP) were considered: doses delivered to patients in terms of both entrance skin dose (ESD) were calculated and compared in order to study the dosimetric discrepancies between CR and DR. Assessment of image quality is undertaken by Consultant Radiologists to ensure that the quality criteria for diagnostic radiographic images of the European guidelines were met. Results showed that both ESD in DR are lower than that in CR; all images met the criteria in the European Guidelines for both modalities and were used for reporting by the radiologists. Since the operators are the same and the image quality is comparable in both modalities, this study shows that in the considered examinations, DR can perform better than CR from a dosimetric point of view.

Enhancing the Physicochemical Properties of Sodium Iodide-based Root Canal Filling Material with Lanolin Incorporation

  • Hye Shin Park;Jongsoo Kim;Joonhaeng Lee;Jisun Shin;Mi Ran Han;Jongbin Kim;Yujin Kim;Junghwan Lee
    • Journal of the korean academy of Pediatric Dentistry
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    • v.51 no.2
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    • pp.140-148
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    • 2024
  • This study aimed to enhance the physicochemical properties of sodium iodide-based root filling materials, particularly solubility. In earlier developmental stages, the iodoform-containing paste exhibited high antibacterial efficacy but failed to meet only the solubility requirement among the ISO 6876 criteria. Therefore, this study focused on enhancing the physicochemical properties of the paste under development, particularly centering on reducing its solubility. Four experimental groups were established, including three control group. The previously developed D30 paste was named the Oil 33 group, and the control group was named the Vitapex® group. The Oil 50 group, in which the oil content was increased, and the Oil 45L group, in which lanolin was incorporated. The physical properties (solubility, pH, flowability, and film thickness) of the four pastes were evaluated according to the ISO 6876 standards. No significant differences were observed between the Oil 45L and Vitapex® groups in any of the physical property evaluations. While the Oil 33 and Oil 50 groups met the ISO 6876 standards for flowability and film thickness, the Oil 45L group met all the physical properties. However, reducing the overall oil content may be necessary to enhance the antimicrobial properties. The result of the physicochemical experiments showed that the Oil 45L group with the newly formulated composition and incorporated lanolin exhibited low solubility meeting the ISO 6876 standard of ≤ 3%. We were able to develop a paste with more stable solubility than previous iodide-based root-filling materials. Therefore, the oil content must be further adjusted to improve its antimicrobial properties. If other physical properties also meet the ISO 6876 standards and demonstrate excellent results in cytotoxicity tests, this root filling material could potentially replace existing options.

A Severe Hepatotoxicity by Antituberculosis Drug, and its Recovery in Oriental Hospital

  • Son, Chang-Gue
    • The Journal of Korean Medicine
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    • v.37 no.2
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    • pp.119-124
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    • 2016
  • Objectives: To demonstrate a clinical course and feature of a female patient with a severe liver injury (DILI) during antituberculosis treatment for her intestinal tuberculosis, whom traditional Korean medicine completely recovered. Methods: A female patient with diagnosed as DILI by antituberculosis drugs had been treated with herbal drugs; and then the clinical outcome and biochemical parameters had been monitored. Result: A 45-year old female had taken antituberculosis drugs for about 2 months, and complained severe abdominal discomfort and dyspepsia. The RUCAM score was 10, which met the criteria for DILI (AST 584 IU/L, ALT 1212 IU/L, ALP 100 IU/L, and GGT 161 IU/L, total bilirubin 0.9 mg/dL). She had been treated with herbal drugs and acupuncture as inpatient and outpatient, and then her symptoms had been completely recovered with normalization of hepatic enzymes. Conclusion: This report provides a clinical characteristic for a severe hepatotoxicity induced by antituberculosis drugs, and showed an example of TKM-based application.

Gamakamide-E, a Strongly Bitter Tasting Cyclic Peptide with a Hydantoin Structure from Cultured Oysters Crassostrea gigas

  • Lee, Jong-Soo;Satake, Masayuki;Horigome, Yoichi;Oshima, Yasukatsu;Yasumoto, Takeshi
    • Fisheries and Aquatic Sciences
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    • v.15 no.1
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    • pp.15-19
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    • 2012
  • A new cyclic peptide (six-membered amino acid), gamakamide-E (L-Leu-L-Met (SO)-L-Me-Phe-L-Leu-D-Lys-L-Phe), was isolated as a strongly bitter tasting compound from cultured oysters, Crassostrea gigas. The molecular formula of $C_{43}H_{61}N_7O_8S$ was deduced from high resolution fast atom bombardment mass spectrometry (HR FAB-MS) ($[M+H]^+$ m/z 836.4356 ${\Delta}$= -2.4 mmu). Its unique structure including a hydantoin structure was firstly elucidated by nuclear magnetic resonance (NMR) analysis. Stereochemistries of constituent amino acids were determined by chiral high performanced liquid chromatography analysis of natural and synthesized peptides.

Determination of Stability Constants for $\beta$-Blocker and Carboxymethyl-$\beta$-cyclodextrin Complexes by Capillary Electrophoresis (모세관 전기영동법을 이용한 베타차단제-시클로덱스트린 포접화합물의 안정도상수 결정)

  • 박경래;임환미;뉴엔티퐁;김경호;강종성
    • YAKHAK HOEJI
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    • v.47 no.4
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    • pp.200-205
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    • 2003
  • The stability constants for the inclusion complexes between carboxymethyl-$\beta$-cyclodextrin (CM-$\beta$-CD) and five $\beta$-blockers, such as atenolol (ATE), bisoprolol (BIS), metoprolol (MET), pindolol (PIN) and propranolol (PRO) were determined by capillary electrophoresis. The magnitude of stability was decreased as following order; PRO>MET>BIS>ATE>PIN. Among them PRO showed the highest affinity towards CM-$\beta$-CD with stability constants of 383 and 371 $M^{-l}$ for (R)- and (S)-enantiomer, respectively. PIN enantiomers showed the lowest stability towards CM-$\beta$-CD, while the selectivity between (R)- and (S)-enantiomer was higher than any other tested $\beta$-blocker.r.

Studies on the Changes of Taste Compounds during Soy Paste Fermentation (III) (된장 숙성 중 정미 성분의 변화에 관한 연구(III))

  • 김미정;이혜수
    • Korean journal of food and cookery science
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    • v.9 no.4
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    • pp.261-265
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    • 1993
  • For the purpose of supplying the information to improve the acceptability of soy paste as the condi-ment, the changes of peptide were determined. The results were as follows; Average peptide length were decreased. It was 102 at 0 day, 15 at 10 day and 4.1 at 180 day. Peptide fraction were the same as in 60 day and 180 day. Low molecular weight peptide were not changed greatly during fermention. Peptide identified in 180 day fermentation were Ala-Ser, Gly-Glu, Glu-Ser, Asp-Glu, Asp- Tyr, Asp-Ala-Ser, Ala-Ser-Glu, Glu-Ser-Ala, and Ala-Lys-Met. In the characteristics of bitter peptide in 180 day fermentation, soy paste itself didn't show bitter taste', solvent extration fraction I'showed bitter taste. After gel chromatography, fraction I, fraction II and fraction III were obtained and fraction II were bitter peptide of low molecular weight. After gel chromatography', solvent extration fraction 2'(water extration) were divided into fraction IV, V, VI,VII and VIII. Fraction IV, V and VI showed bitter taste. Amino acids composition of the fractions showing bitter taste were like that; fr. 1: Glu- (Asp, Pro, Val, lie or Leu)-Met fr. II Pro-(Glu, Val, Phe)-lle or Leu fr. IV: Glu-(Asp, Ala, Tyr, Leu of lie)-Phe fr. V: Ala-(Met, Glu, Pro)-lle or Leu fr. VI: Asp-(Phe, Ser, fly)-Val.

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Evaluation of Biogas Production Rate by using Various Electrodes Materials in a Combined Anaerobic Digester and Microbial Electrochemical Technology (MET) (미생물 전기화학 기술이 적용된 단일 혐기성소화조에서 전극재질에 따른 바이오가스 생성 효율 평가)

  • Shin, Wonbeom;Park, Jungyu;Lee, Beom;Kim, Yonggeun;Jun, Hangbae
    • Journal of Korean Society of Environmental Engineers
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    • v.39 no.2
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    • pp.82-88
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    • 2017
  • MET (Microbial Electrochemical Technology), such as MFC (Microbial Fuel Cell) and MEC (Microbial Electrolysis Cell), is a promising technology for producing sustainable biogas from an anaerobic digester (AD). At current stage, however, the most likely limiting factors, large internal resistances, should be overcome for successful scale up of this technology. Various researchers reported that application of electrode materials containing high current density, increase of ion strength and conductivity, configuration of electrode are good methods for minimizing internal resistances. Recently, stainless steel is receiving great attention because of not only high performance and durability but also low cost. Therefore, in this study, we evaluate electrochemical characteristics and biogas production rate using various electrode materials and configuration (graphite carbon coated with catalysts ($GC-C_M$) or not (GC), stainless steel mesh (SUS-M) and plate (SUS-P)). As the results, current densities of $GC-C_M$, GC, SUS-P, SUS-M were 2.03, 1.36, 1.04, $1.13A/m^2$, respectively. Methane yields of $GC-C_M$, GC, SUS-P, SUS-M were 0.27, 0.14, 0.19, 0.21 $L-CH_4/g-COD_{rem}$., respectively. Stainless steel shows high current density and methane yield, which are similar as graphite carbon coated with catalysts.

Studies of separation and quantitation for selenium species in food (식품중의 셀레늄 화학종의 분리 및 정량연구)

  • Jang, Hee-Young;Min, Hyungsik;Lee, Jonghae;Pak, Yong-Nam
    • Analytical Science and Technology
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    • v.26 no.3
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    • pp.182-189
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    • 2013
  • The purpose of this research is to separate and quantitate selenium species in some food samples with HPLC-ICP-MS. Cation exchange chromatography showed efficient separation only for inorganic Se species while reversed phase ion pair chromatography showed good separation for both inorganic and organic Se species. $C_8$ column ($Symmetryshield^{TM}\;RP_8$, 3.5 ${\mu}m$, $4.6{\times}150$ mm) was used with optimum condition of 5% methanol mobile phase, 0.05% of nonafluorovaleric acid ion pairing reagent. Five standard Se species of Se(IV), Se(VI), SeCys(selenocystein), SeMet(selenomethionine) and Se-M-C(seleno methyl cystein) were separated successfully under the optimum condition (mobile phase; 5% methanol, ion-pairing reagent; 0.05% nonafluorovaleric acid, flow rate; 0.9 mL $min^{-1}$). To extract Se species, microwave assisted and enzyme-assisted extraction methods were studied. In enzyme-assisted extraction method, protease I for garlic, protease I plus trypsin for pork and mackerel, and protease XIV for tuna showed the best extraction efficiency. With the optimum condition for each sample, it was found that mostly inorganic Se, SeCys and SeMet are present in the sample studied ranging from few ${\mu}g$ $g^{-1}$ to few tens of ${\mu}g$ $g^{-1}$.