• 제목/요약/키워드: K_{cat}/K_m$

검색결과 396건 처리시간 0.034초

Relationship Among Body Mass Index, Nutrient Intake and Antioxidant Enzyme Activity of Postmenopausal Women

  • Lee, Haeng-Shin;Lee, Da-Hong
    • Preventive Nutrition and Food Science
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    • 제12권2호
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    • pp.95-102
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    • 2007
  • To elucidate the relationship among body mass index, nutrient intake and blood antioxidant capacity in the postmenopausal period, 60 women residing in Iksan area were recruited. Body mass index (BMI) was calculated base on height and weight, and food and nutrient intakes were estimated by 24-hour recalls of 3 non-consecutive days. Parameters of antioxidant capacity including the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and total antioxidant capacity (TA) were measured in fasting blood samples from the subjects. The average age, height, weight and BMI of the subjects were 65 years, 151.1cm, 59.5 kg and 26.0 m/kg$^2$, respectively. The macronutrient intake rate of carbohydrate : protein : fat were 65:17.5:17.5; the mean intakes of energy and protein were 1532.7 kcal (86.3% of RDA) and 67.1 g (122.0% of RDA) respectively. The mean intakes of phosphorus, vitamin A, niacin and vitamin C were higher than Recommended Daily Allowance (RDA) for Koreans. On the other hand, calcium and riboflavin intakes were only 84.6% and 70.4% of RDA. Among the parameters of antioxidant capacity, SOD activity was significantly lower in lean subjects (BMI<20) than in the normal or overweight subjects (BMI${\geq}$20) (p<0.05). TAs of the subjects with the highest intakes of vegetables and fruits were significantly higher than those of subjects with lower intakes (p<0.05). Antioxidant capacity was compared among subjects according to 3 different nutrient intake levels according percentage of RDA for Koreans for selected nutrients with the following results: The high protein and niacin groups exhibited significantly lower TA status than those of the other intake groups (p<0.05). In conclusion, the low BMI was associated with lower SOD activity in postmenopausal women. Higher consumption of fruits and vegetables was associated with higher TA. When protein and niacin intakes were excessive, SOD activity and TA tended to be low. SOD and TA, among antioxidant indexes, seemed to be mostly influenced by other factors. Therefore, more studies on the effects of nutritional intake and the activity of antioxidant enzyme should be conducted.

Antitumor effect of Careya arborea against Ehrlich ascites carcinoma with reference to lipid peroxidation and enzymatic and non enzymatic antioxidant system in Swiss albino mice

  • Kumar, R Sambath;Sivakumar, T;Senthil, V;Murthy, N Venkateswara;Balasubramaniam, V;Sabi, R Kanaga;Sundram, R. Shanmuga;Perumal, P;Mazumder, U K;Gupta, M
    • Advances in Traditional Medicine
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    • 제8권2호
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    • pp.154-163
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    • 2008
  • The methanol extract of stem barks of Careya arborea Roxb. (MECA) (Family- Myrtaceae) was evaluated for antitumor activity and antioxidant status against Ehrlich's Ascites Carcinoma (EAC) bearing Swiss albino mice. After 24 h of tumor inoculation the MECA was administered at the doses of 50, 100 and 200 mg/kg body weight/mice/day for 14 days. After the last dose and 18 h fasting mice were sacrificed. The effect of MECA on the growth of transplantable murine tumor, life span of EAC bearing hosts, hematological profiles, serum and liver biochemical parameters were estimated. The MECA showed significant (P < 0.01) decrease in ascites volume, packed cell volume and viable cell count and prolonged the life span of EAC tumor bearing mice. Hematological profiles reverted to more or less normal levels in extract treated mice. The MECA also produced protective effect by decreasing the activity of serum enzymes, bilirubin and increase the protein and uric acid levels. MECA significantly (P < 0.05) decreased the levels of lipid peroxidation, while significantly (P < 0.05) increased the levels of glutathione content, vitamin C, vitamin E, superoxide dismutase and catalase CAT. The results indicate that MECA exhibited significant antitumor and antioxidant activity in EAC bearing mice.

Cloning and Characterization of a Novel Mannanase from Paenibacillus sp. BME-14

  • Fu, Xiaoyu;Huang, Xiaoluo;Liu, Pengfu;Lin, Ling;Wu, Gaobing;Li, Chanjuan;Feng, Chunfang;Hong, Yuzhi
    • Journal of Microbiology and Biotechnology
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    • 제20권3호
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    • pp.518-524
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    • 2010
  • A mannanase gene (man26B) was obtained from a sea bacterium, Paenibacillus sp. BME-14, through the constructed genomic library and inverse PCR. The gene of man26B had an open reading frame of 1,428 bp that encoded a peptide of 475- amino acid residues with a calculated molecular mass of 53 kDa. Man26B possessed two domains, a carbohydrate binding module (CBM) belonging to family 6 and a family 26 catalytic domain (CD) of glycosyl hydrolases, which showed the highest homology to Cel44C of P. polymyxa (60% identity). The optimum pH and temperature for enzymatic activity of Man26B were 4.5 and $60^{\circ}C$, respectively. The activity of Man26B was not affected by $Mg^{2+}$ and $Co^{2+}$, but was inhibited by $Hg^{2+},\;Ca^{2+},\;Cu^{2+},\;Mn^{2+},\;K^+,\;Na^+$, and $\beta$-mercaptoethanol, and slightly enhanced by $Pb^{2+}$ and $Zn^{2+}$. EDTA did not affect the activity of Man26B, which indicates that it does not require divalent ions to function. Man26B showed a high specific activity for LBG and konjac glucomannan, with $K_m,\;V_{max}$, and $k_{cat}$ values of 3.80 mg/ml, 91.70 ${\mu}mol$/min/mg protein, and 77.08/s, respectively, being observed when LBG was the substrate. Furthermore, deletion of the CBM6 domain increased the enzyme stability while enabling it to retain 80% and 60% of its initial activity after treatment at $80^{\circ}C$ and $90^{\circ}C$ for 30 min, respectively. This finding will be useful in industrial applications of Man26B, because of the harsh circumstances associated with such processes.

Novel Low-Temperature-Active Phytase from Erwinia carotovora var. carotovota ACCC 10276

  • Huang, Huoqing;Luo, Huiying;Wang, Yaru;Fu, Dawei;Shao, Na;Yang, Peilong;Meng, Kun;Yao, Bin
    • Journal of Microbiology and Biotechnology
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    • 제19권10호
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    • pp.1085-1091
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    • 2009
  • A phytase with high activity at low temperatures has great potential for feed applications, especially in aquaculture. Therefore, this study used a degenerate PCR and TAIL PCR to clone a phytase gene from Erwinia carotovora var. carotovota, the cause of soft rot of vegetables in the ground or during cold storage. The full-length 2.5-kb fragment included an open reading frame of 1,302 bp and encoded a putative phytase of 45.3 kDa with a 50% amino acid identity to the Klebsiella pneumoniae phytase. The phytase contained the active site RHGXRXP and HD sequence motifs that are typical of histidine acid phosphatases. The enzyme was expressed in Escherichia coli, purified, and displayed the following characteristics: a high catalytic activity at low temperatures (retaining over 24% activity at $5^{\circ}C$) and remarkably thermal lability (losing >96% activity after incubation at $60^{\circ}C$ for 2 min). The optimal phytase activity occurred at pH 5.5 and ${\sim}49^{\circ}C$, and the enzyme activity rapidly decreased above $40^{\circ}C$. When compared with mesophilic counterparts, the phytase not only exhibited a high activity at a low temperature, but also had a low $K_m$ and high $k_{cat}$. These temperature characteristics and kinetic parameters are consistent with low-temperature-active enzymes. To our knowledge, this would appear to be the first report of a low-temperature-active phytase and its heterogeneous expression.

Cloning and Overexpression of a Paenibacillus ${\beta}-Glucanase$ in Pichia pastoris: Purification and Characterization of the Recombinant Enzyme

  • Yang, Peilong;Shi, Pengjun;Wang, Yaru;Bai, Yingguo;Meng, Kun;Luo, Huiying;Yuan, Tiezheng;Yao, Bin
    • Journal of Microbiology and Biotechnology
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    • 제17권1호
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    • pp.58-66
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    • 2007
  • Isolation, expression, and characterization of a novel $endo-{\beta}-1,3(4)-D-glucanase$ with high specific activity and homology to Bacillus lichenases is described. One clone was screened from a genomic library of Paenibacillus sp. F-40, using lichenan-containing plates. The nucleotide sequence of the clone contains an ORF consisting of 717 nucleotides, encoding a ${\beta}-glucanase$ protein of 238 amino acids and 26 residues of a putative signal peptide at its N-terminus. The amino acid sequence showed the highest similarity of 87% to other ${\beta}-1,3-1,4-glucanases$ of Bacillus. The gene fragment Bg1 containing the mature glucanase protein was expressed in Pichia pastoris at high expression level in a 3-1 high-cell-density fermenter. The purified recombinant enzyme Bg1 showed activity against barley ${\beta}-glucan$, lichenan, and laminarin. The gene encodes an $endo-{\beta}-1,3(4)-D-glucanase$ (E. C. 3.2.1.6). When lichenan was used as substrate, the optimal pH was 6.5, and the optimal temperature was $60^{\circ}C$. The $K_m,\;V_{max},\;and\;k_{cat}$ values for lichenan are 2.96mg/ml, $6,951{\mu}mol/min{\cdot}mg,\;and\;3,131s^{-1}$, respectively. For barley ${\beta}-glucan$ the values are 3.73mg/ml, $8,939{\mu}mol/min{\cdot}mg,\;and\;4,026s^{-1}$, respectively. The recombinant Bg1 had resistance to pepsin and trypsin. Other features of recombinant Bg1 including temperature and pH stability, and sensitivity to some metal ions and chemical reagents were also characterized.

고양이에서 상아질과민증 탈감작제에 의한 치수신경 활동성 변화 및 상아세관 폐쇄양상에 대한 연구 (CHANGES IN INTRADENTAL NERVE ACTIVITY AND OCCLUDING ASPECTS OF DENTINAL TUBULES BY CHEMICAL DESENSITIZING AGENTS APPLIED TO THE CAT DENTIN)

  • 오원만;손호현
    • Restorative Dentistry and Endodontics
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    • 제20권2호
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    • pp.508-526
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    • 1995
  • This experiment was performed to study mechanisms of desensitization by chemical desensitizing agents in hypersensitive dentin and compare effects of these agents by measuring the activity of intradental nerves and observing their occluding aspects on dentinal tubules with SEM over time after application of chemical desensitizing agents to the exposed dentinal surfaces. Canines of adult cats weighing 2-3 kg were cross-sectioned at 1.5 mm from incisal apex, and the smear layer of the exposed dentinal susface was removed by 32 % $H_3PO_4$ for 15 sec. Chemical desensitizing agents such as 10% $SrCl_2$, 5% $KNO_3$ and 30% $K_2C_2O_4$, were applied to the exposed dentin surfaces for 2 minutes. Intradental nerve activity was measured immediately after application of the agents, at 15 minutes and at 30 minutes by stimulating with 4M NaCl. To compare occluding ability of desensitizing agents on dentinal tubules in vivo and in vitro, the structures of the exposed dentinal surfaces of nonvital and vital teeth were morphologically observed by SEM. The results obtained were as follows : 1. Intradental nerve activity was decreased immediately after the application of 10 % $SrCl_2$, 5% $KNO_3$ and 30% $K_2C_2O_4$. (p<0.01), among which 30% $K_2C_2O_4$. showed the highest desensitizing effect(p<0.01). 2. The immediately decreased intradental nerve activity after application of 10 % $SrCl_2$ and 5% $KNO_3$ was increased over time. 10% $SrCl_2$ and 5% $KNO_3$ showed no desensitizing effect respectively at 30 minutes and at 15 minutes after application. 3. The immediately decreased intradental nerve activity after application of 30 % $K_2C_2O_4$ was persistently continued during the period of observation (p<0.01). 4. Precipitates of $SrCl_2$ and $KNO_3$ were not noted on the exposed dentinal surfaces and within dentinal tubules by SEM examination. On the other hand, 30 % $K_2C_2O_4$ produced precipitates on the exposed dentinal surfaces and openings of dentinal tubules without any formed preciptates within dentinal tubules. 5. Ten percent $SrCl_2$, 5 % $KNO_3$ and 30 % $K_2C_2O_4$ showed no differences in their occluding aspects on dentinal tubules either in vivo or in vitro studies and either immediately following application or at 30 minutes. These results suggest that the desensitizing effect of $SrCl_2$ and $KNO_3$ is resulted from their reducing effect on the intradental nerve activity rather than from their precipitates' occluding the dentinal tubules. However, desensitizing effect of 30 % $K_2C_2O_4$, is probably resulted from its precipitates' occluding the openings of the dentinal tubules as well as from it's reducing effect on the intradental nerve actibity.

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돼지난자의 체외성숙시 Catalase와 난구세포의 영향 (Effects of Catalase and Cumulus Cells during In Vitro Maturation in Porcine Oocytes)

  • 이상영;사수진;김광재;정희태;양부근;박춘근;김정익
    • 한국가축번식학회지
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    • 제23권3호
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    • pp.239-245
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    • 1999
  • 본 연구는 돼지난자의 체외성숙시 난구세포와 cat-alase의 영향을 검토하고저 수행되었다. 체외성숙율은 catalase의 첨가유무에 관계없이 유의적인 차이는 인정되지 않았으나, 난구세포가 부착된 난자가 제거된 난자에 비해 유의적으로 높은 성숙율을 나타냈다 (P<0.05). 또한 48시간 (57%) 동안 난구세포가 부착된 경우 단지 처음 24시간 (42%) 동안만 난구세포가 부착된 경우에 비하여 유의적으로 높은 성숙율을 나타냈다 (P<0.05). 한편, 난구세포가 부착 또는 제거된 난자의 성숙시 처음 24시간 동안보다는 후반기 24시간 동안 catalase를 첨가한 경우 유의적으로 높은 성숙율을 나타냈으며 (P<0.05), 난구세포를 제거한 경우 성숙배양 24시간에서 M-II기로 성숙된 난자가 관찰되었다. 그러나 난구세포가 부착된 난자를 72시간 성숙배양 했을 때, catalase 무첨가 (65%)보다는 첨가시(79%) 유의적으로 높은 성숙율을 나타냈다. 본 연구의 결과로부터 난구세포는 돼지난자의 체외성숙시 필수적인 것으로 인정되며, catalase는 첨가시기에 따라 난자의 성숙에 효과적으로 작용하였으며, 체외성숙시 난자의 노화를 방지할 수 가능성이 있는 것으로 추측된다.

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The Effect of Propofol on Hypoxic damaged-HaCaT Cells

  • Park, Chang-Hoon;Kwak, Jin-Won;Park, Bong-Soo;Kim, Yong-Ho;Kim, Yong-Deok;Yoon, Ji-Uk;Yoon, Ji-Young;Kim, Cheul-Hong
    • 대한치과마취과학회지
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    • 제14권1호
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    • pp.41-47
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    • 2014
  • Background: Autophagy is a self-eating process that is important for balancing sources of energy at critical times in development and in response stress. Autophagy also plays a protective role in removing clearing damaged intracellular organelles and aggregated proteins as well as eliminating intracellular pathogens. The purpose of the present study was to examine the protective effect of propofol against hypoxic damage using keratinocytes. Methods: Human keratinocytes (HaCaT cells) were obtained from the American Type Culture Collection. Propofol which were made by dissolving them in DMSO were kept frozen at $-4^{\circ}C$ until use. The stock was diluted to their concentration with DMEM when needed. Prior to propofol treatment cells were grown to about 80% confluence and then exposed to propofol at different concentrations (0, 25, 50, 75, $100{\mu}M$) for 2 h pretreatment. Cell viability was measured using a quantitative colorimetric assay with thiazolyl blue tetrazolium bromide (MTT assay), and fluorescence microscopy and western blot analysis were used for evaluation of autophagy processes. Results: The viability of propofol-treated HaCaT cells was increased in a dose-dependent manner. Propofol did not show any significant toxic effect on the HaCaT cells. The autophagy inhibitor, 3-methyladenine, reduced cell viability of hypoxia-injured HaCat cells. Fluorescence microscopy and western blot analysis showed propofol induce autophagy pathway signals. Conclusions: Propofol enhanced viability of hypoxia-injured HaCaT cells and we suggest propofol has cellular protective effects by autophagy signal pathway activation.

초고온 고세균 Thermococcus pacificus P-4로부터 내열성 β-glucosidase의 새로운 기질 특이성 (Novel substrate specificity of a thermostable β-glucosidase from the hyperthermophilic archaeon, Thermococcus pacificus P-4)

  • 김윤재;이재은;이현숙;권개경;강성균;이정현
    • 미생물학회지
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    • 제51권1호
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    • pp.68-74
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    • 2015
  • Thermococcus pacificus P-4의 유전체 서열 분석을 통하여 예측되는 GH1 ${\beta}$-glucosidase를 암호화하는 유전자를 동정하였다. 그 유전자는 487 아미노산들을 암호화하는 1,464 bp 나타내었으며, 그 아미노산 서열은 Pyrococcus furiosus ${\beta}$-glucosidase와 77% 상동성을 나타내었다. 그 유전자는 Escherichia coli 시스템 내에서 복제 및 발현하였다. 재조합 된 단백질은 금속 친화크로마토그래피를 통하여 정제하고 특성을 분석하였다. 정제된 단백질(Tpa-Glu)은 pH 7.5와 $75^{\circ}C$에서 최적활성을 나타내었으며, 열안정성은 $90^{\circ}C$에서 약 6시간의 반감기를 보였다. Tpa-Glu는 pNP-${\beta}$-glucopyranoside, pNP-${\beta}$-galactopyranoside, pNP-${\beta}$-mannopyranoside, 그리고 pNP-${\beta}$-xylopyranoside 순으로 우수한 $k_{cat}/K_m$ 값을 나타내었다. 또한, Tpa-Glu는 ${\beta}$-1,3-linked polysaccharide (laminarin) 그리고 ${\beta}$-1,3-와 ${\beta}$-1,4-linked oligosaccharides에 대하여 exo-hydrolyzing 활성을 보였다. 본 연구는 초고온 고세균으로터 ${\beta}$-glucosidase가 exohydrolyzing 활성을 처음 확인한 것으로 이 효소는 laminarin의 당화공정에 ${\beta}$-1,3-endoglucanase와 함께 적용할 수 있을 것으로 기대된다.

섬유아세포에서 민들레 추출물 함유제(AF-343)에 의한 제 1형 교원질 발현 증가 (Increased Expression of Type I Collagen in AF-343 Treated Human Skin Fibroblasts)

  • 조수묵;김재현;김종근;박기문;조호찬;김인수;김범준;천영진;조재위
    • 약학회지
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    • 제56권1호
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    • pp.9-13
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    • 2012
  • We previously reported that the extract of Taraxacum platycarpum (AF-343) had several biological properties such as skin hydration and anti-inflammatory effects, thereby AF-343 be a promising anti-atopic dermatitis agent. However, few studies have been conducted to evaluate its effect on modulation of extracellular matrix proteins in human skin fibroblasts. The purpose of this study was to investigate the expressions of type I collagen, MMP-1, Smad2/3, and TIMP-1 proteins in AF-343-treated human skin fibroblasts. Human skin fibroblasts were treated by various concentrations of AF-343 (0~2 mg/ml). The expressions of type I collagen, matrix metalloproteinase-1 (MMP-1), Smad2/3, and TIMP-1 proteins were analyzed by Western blot analysis. In addition, level of type I collagen mRNA was analyzed by CAT assay. Expression of type I collagen protein was increased in AF-343-treated human skin fibroblasts by dose and time-dependent manners. Consistent with this result, the expressions of phospho-Smad2/3 in skin fibroblasts were increased and MMP-1 expression was decreased by AF-343 treatment. TIMP-1 expression was not significantly changed in AF-343 treated skin fibroblasts. Extract of Taraxacum platycarpum (AF-343)-induced up-regulation of type I collagen expression was through increased expression of phospho-Smad2/3. These results were occurred combined with down-regulation of MMP-1 in skin fibroblasts. Taken together, this study indicated that AF-343 has property of the modulation of ECM in tissue as well as skin hydration and anti-inflammation.