• Advances in Traditional Medicine
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• 제10권3호
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• pp.141-149
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• 2010

A concern of safety issue for traditional herbal medicine is the possibility of some herbs containing heavy metals responsible for several cases of metal poisoning. In our previous study, the physiological levels of heavy metals, such as Cd, Cu, Hg and Pb, were examined to evaluate a potential risk in patients taking herbal medicine. In this study, the levels of 12 heavy metals, including non-metallic element, Se, were analyzed in hair and compared to the results from the previous study. In the previous study, the levels of Cd, Cu, Hg and Pb in hair showed a significantly lower odds ratio than 1. In this study, however, all metals did not show any significant odds ratio higher or lower than 1 even if 5 of 12 metals showed lower odds ratio than 1. In addition, the levels of metal concentrations, especially for Cu, Fe, Pb and Zn, exceeding the WHO reference values were observed in hair. However, any evidence for metal accumulation in hair caused by taking herbal medicines for long duration was not observed in analysis of multiple regression and odds ratio from case-control study. This result would show another possibility for a role of herbs as a non-enzymatic chelator inhibiting the gastrointestinal absorption of heavy metals.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1996년도 한국생물과학협회 국제학술대회
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• pp.86.1-86
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• 1996

No Abstract, See Full Text

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1586-1588
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• 2013

• Journal of Microbiology and Biotechnology
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• 제18권8호
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• pp.1357-1363
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• 2008

The $P_{entC}$ promoter of the entCERA operon encoding enzymes for enterobactin biosynthesis in Escherichia coli is tightly regulated by the availability of iron in the culture medium. In iron-rich conditions, the $P_{entC}$ promoter activity is strongly repressed by the global transcription regulator Fur (ferric uptake regulator), which complexes with ferrous ions and binds to the Fur box 19-bp inverted repeat. In this study, we have constructed the expression vector pOS2 containing the $P_{entC}$ promoter and characterized its repression, induction, and modulation by quantifying the expression of the lacZ reporter gene encoding $\beta$-galactosidase. $\beta$-Galactosidase activities of E. coli transformants harboring pOS2-lacZ were highly induced in the presence of divalent metal ion chelators such as 2,2'-dipyridyl and EDTA, and were strongly repressed in the presence of excess iron. It was also shown that the basal level $\beta$-galactosidase expression by the $P_{entC}$ promoter was drastically decreased by incorporating the fur gene into the expression vector. Since the newly developed iron chelator-inducible expression system is efficient and cost-effective, it has wide applications in recombinant protein production.

• Journal of Microbiology and Biotechnology
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• 제25권4호
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• pp.503-510
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• 2015

The iLOV protein belongs to a family of blue-light photoreceptor proteins containing a light-oxygen-voltage sensing domain with a noncovalently bound flavin mononucleotide (FMN) as its chromophore. Owing to advantages such as its small size, oxygen-independent nature, and pH stability, iLOV is an ideal candidate over other reporter fluorescent proteins such as GFP and DsRed. Here, for the first time, we describe the feasibility of applying LOV domain-based fluorescent iLOV as a metal sensor by measuring the fluorescence quenching of a protein with respect to the concentration of metal ions. In the present study, we demonstrated the inherent copper sensing property of the iLOV protein and identified the possible amino acids responsible for metal binding. The fluorescence quenching upon exposure to Cu²⁺ was highly sensitive and exhibited reversibility upon the addition of the metal chelator EDTA. The copper binding constant was found to be 4.72 ± 0.84 µM. In addition, Cu²⁺-bound iLOV showed high fluorescence quenching at near physiological pH. Further computational analysis yielded a better insight into understanding the possible amino acids responsible for Cu²⁺ binding with the iLOV protein.

• 한국환경과학회지
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• 제13권8호
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• pp.711-719
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• 2004

The effect of nickel (Ni) on growth and some tolerance strategies with regard to heavy metal tolerance mechanism was investigated in radish (Raphanus sativus) seedlings. The protective effect of histidine on nickel stress conditions was also monitored. The seedling growth decreased with an increase in metal concentrations. The inhibitory effect was more pronounced in the root elongation than in the shoot elongation. Increasing Ni supply showed a progressive increase of Ni concentrations in the roots and shoots. Ni content was higher in the shoots than in the roots. In the presence of nickel, radish exhibited an antioxidative defense mechanism, as evidenced by the elevated malondialdehyde(MDA), showing that nickel is an efficient inducer of lipid peroxidation. Exposure of radish to elevated concentrations of nickel was accompanied by an increase in the proline content. Supplemental histidine in the presence of Ni ameliorated metal-induced growth inhibition and lipid peroxidation. Combinations of Ni and histidine resulted in a significant decline in proline content compared with Ni stress alone, indicating that histidine may provide protection against the adverse effect of Ni stress. From the results it is suggested that histidine is an efficient chelator by complexing metal ion within the plant and may playa role in nickel tolerance implicated in metal detoxification.

• 한국수산과학회지
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• 제16권3호
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• pp.225-230
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• 1983

본 연구는 단백질 분해성이 강한 세균을 분리하고 그 균의 특성과 균이 생성하는 효소의 성질을 알기 위하여 시판식품 즉 ground beef, cooked shrimp meat, perch fillet, oyster meat, beef with textured vegetable protein, fish digest 등에서 세균을 분리하였다. 분리된 740균주중에서 $30.8\%$에 해당하는 228균주가 단백질 분해성이 있었으며 이 중에서 단백질 분해성이 제일 강한 균주는 Streptococcus sp.였다. 본 균주는 배지에 $KH_{2}PO_4\;0.15\%,\;K_{2}HPO_4\;0.4\%$를 첨가하여 $37^{\circ}C$에서 6시간 배양했을 때 maximum growth에 도달하였고 균체외 단백질 분해효소의 활성은 배양 7시간경에 최고에 달하였다. 그리고 본 Streptococcus sp.가 생성한 균체외 단백분해효소는 EDTA나 o-phenanthroline에 강한 조해작용을 받고 phenylmethylsulfonylfluoride나 p-hydroxymercuribenzoate에 영향을 받지 않는 metal-chelator sensitive protease임을 알 수 있었다.

• 생명과학회지
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• 제7권3호
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• pp.228-233
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• 1997

Artemia franciscana의 cyst에서 protease를 정제하가 위해 세포를 파쇄하여 원심 분리한 후 상등액을 회수하였다. 그상등액에서 40-60% 황산암모늄을 첨가하여 침전시켜서 염을 제가한 후, Sphadex G-200 및 DEAE-Sephadex A-50 column chromatography를 하여 정제한 후 본 효소의 특성을 조사한바 그 특성은 아래와 같았다. 정제 과정을 거치는 동안, 비활성은 13.64배 증가하였고, 수율은 7%였다. 그리고 이효소는 pH 6에서는 안정하였으나, pH 8이상에서는 대부분의 활성이 실활 되었고, 최적 pH는 3.0이었다. 따라서 이 효소는 전형적인 산성 pro-tease로 판정되었다. 본 효소는 60$^{\circ}$C이상의 온도에서 대부분 실활 되었고, 최적 활성 반응 온도는 35$^{\circ}$C였다. 금속 이온의 영향을 알아본 결과, $Cu^{++}$, Z$Zn^{++}$, $Fe^{++}$가 효소의 활성을 저해하였고, 중금속 chelator인 EDTA는 반대로 효소 활성을 증가시켰다. 단백질분해효소에 특이적인저해제를 첨가하여 실험한 결과 thiol protease ingibitor인 antipain, chymostatin, leupeptin, E-64, iodoacetate등에 효과적으로 효소활성이 저해받으므로 본 효소는 acid thiol protease라 판정했다.

• 대한예방한의학회지
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• 제13권1호
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• pp.93-103
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• 2009

Evidences from various countries suggest that toxic heavy metals in herbal medicine may constitute a serious health problem. In order to evaluate whether the toxic heavy metals caused by herbal medicine intake, blood samples collected from 222 patients taking herbal medicine were analyzed. In average levels of analyzed metals, $0.4{\sim}33.9%$ of total samples for 8 metals such as Cd, Co, Cu, Hg, Mn, Ni, Pb and Zn except Cr and Fe exceeded the upper limit for WHO reference value. In analysis of regression coefficients indicating the levels of metals increased or decreased after taking herbal medicine for one month, however, there were different aspects by intake types for herbal medicine. For example, the metals increased by taking decoction in blood samples were as follows; Cd and Pb whether Mn, Ni and Pb as increased metals were identified in the group taking pill and decoction(combined intake group). The odds ratio showing values higher than 1 indicating that people who take herbal medicine would have possibility higher for metal accumulation in blood than that from people who do not take herbal medicine. The metals showing the odds ratio higher than 1 were Hg and Ni in decoction group, and Cd and Hg in combined intake group. However, eight of the total, 10 metals showed the odds ratios lower than 1 by taking herbal medicine. Thus, this may explain the possible role of herbal medicine as a chelator for heavy metals in body.

• 한국수산과학회지
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• 제21권2호
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• pp.71-79
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• 1988

미생물에 의해 속성 저식염젓갈을 제조할 목적으로 저식염멸치젓(식염 $4\%$, KCl $4\%$, lactic acid $0.5\%$, 솔비톨 $6\%$ 및 고추가루 알코올추출물 $4\%$)에서 단백질분해력이 강한 미생물을 분리하여 그 특성을 조사한 결과는 다음과 같다. 숙성 40일경의 시료를 취하여 skim milk배지상에서 HC ratio 2.5이상인 단백질 분해력이 강한 균주를 선별하여 동정한 결과 A. anaeregenes, B. subtilis, S. saprophyticus 3균주이었으며 모두 pH 7.0, $30^{\circ}C$에서 균증식 및 효소활성이 양호하였다. 이들 균 중 B. subtilisrbs이 비증식속도는 $0.95hr^{-1}$, 12시간 배양후 $89\mu{g}-Tyr/hr.ml$의 효소환성을 나타내어 분리된 균주 중 활성이 가장 좋았으며 산업적 응용성이 기대되었다. 그리고 gel여과법으로 정제한 B. subtilis 프로테아제의 특성은 pH 7.0, $35^{\circ}C$에서 활성이 가장 우수하였으며 분자량은 23,000으로 추정되었다. 또 카제인을 기질로 하여 효소반응 속도를 측정한 결과 Km값이 $0.73\%$이었다. 효소저해제의 효과에서는 EDTA, o-phenanthroline에 의하여 거의 실활되었으며, 금속 이온으로는 $Fe^{2+},\;Ni^{2+},\;Cu^{2+}$ 이온등에 의해 강하게 저해되는 것으로 보아 metal chelator sensitive neutral protease로 추정되었다.