• 생약학회지
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• 제30권3호
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• pp.306-313
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• 1999

Polyphenol Oxidase(PPO) was purified from an extract of Ginkgo biloba leaves by ammonium sulfate fractionation followed by sephadex G-150 column chromatography, which resulted in a 18-fold increase in specific activity. The enzyme was most active at pH 8.5 and the temperature optimum for the PPO catechol oxidation reaction was $45^{\circ}C$. Heat inactivation studies showed that heating for 7, 9 and 48 min, at 80, 70 and $60^{\circ}C$ respectively caused a 50% loss in enzymatic activity and that the enzyme was completely inactivated after heat treatment at $90^{\circ}C$ for 60 min. Km values of the PPO for catechol, hydroquinone and 4-methylcatechol derived from Lineweaver-Burk plots were $6.06\;{\times}\;10^{-4}M,\;1.02\;{\times}\;10^{-3}M,\;1.41\;{\times}\;10^{-3}M$ respectively. Of the substrates tested, 4-methylcatechol was oxidized most readily and the enzyme did not oxidize monophenols. The enzyme datalyzed browning reaction was completely inhibited in the presence of reducing reagents, namely ascorbic acid, cysteine, glutathione, 2-mercaptoethanol, potassium metabisulfite at 0.5 mM level. Sodium chloride showed very little inhibition effect on Ginkgo biloba leaves PPO. Lineweaver-Burk analysis of inhibition data revealed that the inhibition by cysteine, 2-mercaptoethanol, potassium cyanide was competitive with ki values of $1.1\;{\times}\;10^{-5}M,\;2.4\;{\times}\;10^{-5}M,\;8\;{\times}\;10^{-5}M$, respectively. Among the divalent cations, $Cu^{2+}ion$ was a strong activator on PPO and $Mn^{2+}ion$ was little or no effect on PPO activity $Ni^{2+}ion$ was an inhibitor on PPO.

• BMB Reports
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• 제32권4호
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• pp.385-392
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• 1999

The $NAD^+$-specific activity of a dual coenzyme-specific isocitrate dehydrogenase (IDH; EC 1.1.1.41) from the primitive fungus Pythium ultimum was investigated to elucidate the regulatory factors that may influence the intracellular distribution of carbon and the availability of intermediates, e.g. citrate, for fatty acid synthesis. Inhibition of $NAD^+$-IDH activity by diphospho- and triphosphonucleotides (ATP, ADP, and GTP) reflected the sensitivity of this enzyme to cellular energy charge even though monophosphonucleotides (AMP and GMP) had little effect on activity. NADPH, but not NADH, substantially inhibited $NAD^+$-IDH activity, showing noncompetitive inhibition with isocitrate. Oxalacetate and ${\alpha}$-ketoglutarate showed competitive inhibition with isocitrate, while citrate and cis-aconitate showed mixed-noncompetitive inhibition with isocitrate. Inhibition by these substances ranged from 29 to 46% at 10 mM. The inhibitory effect of oxalacetate was increased synergistically by glyoxylate, which alone caused 31% uncompetitive inhibition at 10 mM, and a mixture of the two substances at 1 mM each showed 98% inhibition of $NAD^+$-IDH activity. The regulation of $NAD^+$-IDH in Pythium ultimum seems to be a complex process involving mitochondrial metabolites. The addition of glyoxylate (3 mM) and oxalacetate (3 mM) to the culture medium resulted in the production of 49% more lipid by P. ultimum.

• Nutrition Research and Practice
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• 제5권2호
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• pp.93-100
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• 2011

Inhibition of angiotensin I-converting enzyme (ACE) activity is the most common mechanism underlying the lowering of blood pressure. In the present study, five organic extracts of a marine brown seaweed Ecklonia cava were prepared by using ethanol, ethyl acetate, chloroform, hexane, and diethyl ether as solvents, which were then tested for their potential ACE inhibitory activities. Ethanol extract showed the strongest ACE inhibitory activity with an $IC_{50}$ value of 0.96 mg/ml. Five kinds of phlorotannins, phloroglucinol, triphlorethol-A, eckol, dieckol, and eckstolonol, were isolated from ethanol extract of E. cava, which exhibited potential ACE inhibition. Dieckol was the most potent ACE inhibitor and was found to be a non-competitive inhibitor against ACE according to Lineweaver-Burk plots. Dieckol had an inducible effect on the production of NO in EAhy926 cells without having cytotoxic effect. The results of this study indicate that E. cava could be a potential source of phlorotalnnins with ACE inhibitory activity for utilization in production of functional foods.

• Natural Product Sciences
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• 제13권4호
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• pp.289-294
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• 2007

Ethanolic extract (50% v/v) and alkaloid fraction of Tylophora indica leaves were examined for lysosomal enzyme inhibitory activity in adjuvant-induced arthritic rats. The alkaloid fraction showed statistically significant inhibition of arthritic lesions (p < 0.05) from day 18, (p < 0.025) from day 20 and (p < 0.001) from day 21 onwards in the adjuvant-induced arthritis, which was comparable to the response of standard drug Indomethacin. The ethanolic extract was less significant than the alkaloidal fraction in inhibition of arthritis. Alkaloid fraction showed significant (p < 0.001) inhibitory effect on the lysosomal enzyme activities in adjuvantinduced arthritic rats. It also significantly prevented decrease in collagen levels and synovial damage observed during arthritis and also inhibited increase in urinary excretion levels of collagen degradation products like hydroxyproline, hexosamine, hexuronic acid, etc. Both ethanolic extract as well as the alkaloid fraction, however, did not show any significant activity in normal nonarthritic rats. The ethanolic extract and the alkaloid fraction may thus be able to inhibit the progress of inflammation and inhibit the destructive activity of lysosomal enzymes on structural macromolecules like collagen etc. in the synovial capsule in joints during arthritic states. They may thus prevent synovial damage observed during arthritis.

• 한국식품조리과학회지
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• 제19권1호
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• pp.107-113
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• 2003

In a previous study, a dietary supplement was developed in our lab using natural herbal extracts against digest enzyme activity in GI tract for weight control. This natural herbal extracts could regulate absorption of glucose and lipid by the inhibition of digest enzyme activity. In this study, we screened the natural herbs that inhibit glucoamylase activity and developed an water extract of cinnamon. The cinnamon extract delayed and decreased the increment of carbohydrate degradation through the inhibition of glucoamylase activity in vitro. Fifty volunteers were subjected to the intake of the herbal extracts by taking twice a day for 60 days. As a result, the treated subjects lost 3 kg of body weight and 3.5 kg of body fat mass after the treatment. Furthermore, the body mass index and waist size were significantly decreased during the experimental period. Above results suggested that the administration of the dietary additives composed of cinnamon and natural herbal extract improves the obesity by the decrement of body weight and body fat mass.

• 한국미생물·생명공학회지
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• 제34권2호
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• pp.121-128
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• 2006

Bacillus alcalophilus AX2000으로부터 xylanase를 정제한 후 효소의 활성부위를 조사하기 위하여 여러 가지 화학수식제를 사용하여 효소활성의 저해도를 측정하였다. 여러 가지 화학 수식제 중에서 carbodiimide와 N-bromosuccinimide가 효소 활성을 완전히 저해시켜 glutamic acid또는 aspartic acid 잔기와 tryptophan 잔기가 효소의 활성부위에 관여하리라 추측되었다. 각각의 경우에 효소 실활은 수식제의 첨가농도에 따라 pseudo first-order kinetics 양식을 보여주었으며, carbodiimide와 N-bromosuccinimide는 각각 비경쟁적 저해와 경쟁적 저해방식을 나타내었다. 기질첨가에 의한 효소활성 보호실험을 통하여 tryptophan 잔기가 기질결합부위라 판단 되었다. 효소 실활속도의 분석에 의해 효소활성에는 2개의 glutamic acid 또는 aspartic acid 잔기와 1개의 tryptophan 잔기가 관여하는 것으로 나타났다.

• 생명과학회지
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• 제15권4호
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• pp.633-640
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• 2005

Bacillus pumilus TX703으로부터 xylanase를 정제한 후 효소의 활성부위를 조사하기 위하여 여러 가지 화학수식제를 사용하여 효소활성의 저해도를 측정하였다. 여러 가지 화학수식제 중에서 carbodiimide와 N-bromosuccinimide가 효소활성을 완전히 저 해시 켜 glutamic acid 또는 aspartic acid 잔기와 tryptophan 잔기가 효소의 활성부위에 관여하리라 추측되었다. 각각의 경우에 효소 실활은 수식제의 첨가농도에 따라 pseudo first-order kinetics 양식을 보여주었으며, car-bodiimide와 N-bromosuccinimide는 각각 비경쟁적 저해와 경쟁적 저해방식을 나타내었다. 기질첨가에 의한 효소활성 보호실험을 통하여 tryptophan 잔기가 기질결합부위라 판단되었다. 효소실활속도의 분석에 의해 효소활성에는 2개의 glutamic acid 또는 aspartic acid 잔기와 1개의 tryptophan 잔기가 관여하는 것으로 나타났다.

• Journal of Ginseng Research
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• 제13권1호
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• pp.5-7
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• 1989

The objective of this study was to investigate the preventive effect of ginseng on acetaldehyde-induced acute toxicity in mice . Compared to the control group, treatment with acetaldehyde inhibited the hepatic cytosolic xanthine oxidise activity with increase in dose. The inhibition of enzyme activity was not changed after dialysis. Pretreatment with ginseng butanol fraction prevented the inhibition of enzyme activity by acetaldehyde. In conjunction with the our previous results (Yakhak Hoeji, 29, 18 (1985)), these results suggest that the most likely mechanism for the observed preventive effects of ginseng against the acetaldehyde-induced acute toxicity may be the decrease hepatic acetaldehyde level.

• 한국식품영양학회지
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• 제31권6호
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• pp.926-932
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• 2018

This research was conducted to investigate the changes in quality characteristics of cheonggukjang fermented with the addition of hazelnut (10, 20, 30 and 40%) including; water content, pH, hydrophilic and lipophilic substances, color, viscosity and angiotensin converting enzyme inhibition activity. There was no significant change in pH with the addition of hazelnut. The water content significantly decreased with the addition of hazelnut. Hazelnut was also found to brighten the color of cheonggukjang. L-value and b-value increased with the addition of cheonggjuang. There was an insignificant change in the a-value. There was a slight decrease in the content of hydrophilic with addition of hazelnuts. Where there was more than 20% addition of hazelnut to soybean, the viscous substance content in cheonggukjang decreased significantly. Angiotensin converting enzyme inhibitory activity increased proportionally to the amount of hazelnut added. It was identified that the addition of 40% of hazelnut made its angiotensin converting enzyme inhibitory activity 10% point higher than that of control. These results suggests that the addition of hazelnut makes it possible to produce cheongkukjang of excellent angiotensin converting enzyme inhibitory activity.

• 한국식품영양과학회지
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• 제43권1호
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• pp.110-117
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• 2014

감국 phenolic compound의 추출을 위한 최적 추출조건은 70% ethanol로 6시간 추출이 최적이었다. 그때 추출수율은 물 추출물이 $7.12{\pm}1.61$ mg/g, ethanol 추출물이 $7.51{\pm}2.14$ mg/g이었고 초미세분쇄 했을 경우 물 추출물이 $8.63{\pm}1.15$ mg/g, ethanol 추출물이 $9.33{\pm}1.35$ mg/g이었다. 감국 추출물의 항산화력 측정에서 DPPH는 일반분쇄 추출물이 83.52%, 초미세분쇄 추출물이 92.37%이었다. ABTS radical cation decolorization의 경우 일반분쇄, 미세분쇄 및 초미세분쇄 추출물 모두 90% 이상이었다. Antixodant protection factor(PF)의 경우 초미세분쇄 한 감국의 물과 에탄올 추출물에서 1.82 PF와 2.16 PF의 높은 항산화력을 나타내었다. TBARS도 일반분쇄 및 미세분쇄에 비해 초미세분쇄 한 감국 추출물에서 더 낮은 TBARS값을 나타내었다. 감국 추출물의 xanthin oxidase 저해효과는 초미세분쇄 물 추출물이 67.53%, ethanol 추출물이 83.45%였다. Xanthin oxidase 저해는 물 추출물보다는 ethanol 추출물이, 초미세분쇄 추출물이 일반 추출물에 비해 효소억제효과가 더 우수한 결과를 나타내었다. Angiotensin converting enzyme 저해효과는 초미세분쇄 추출물의 경우 물 추출물에서 24% 이상의 억제효과를 나타내었고, ethanol 추출물은 34%의 억제효과를 나타내었다. 감국 추출물의 elastase 억제효과는 미세분쇄 추출물의 저해율 20.34%에 비하여 초미세분쇄 추출물의 억제율이 25.56%로 더 우수한 기능성을 나타내었다. Hyaluronidase의 경우 감국 물 추출물에서는 억제효과가 관찰되지 않았으며, ethanol 추출물에서만 35%정도의 염증억제효과를 보여주었다. 감국 추출물에 의해 대식세포에서 iNOS와 COX-2 단백질 발현억제 효과를 Western blot analysis로 측정한 결과 감국 에탄올 추출물에 의해 iNOS와 COX-2 단백질 발현이 100 ${\mu}g/mL$의 농도에서 각각 40%와 15%의 발현억제를 나타내었고, 농도 의존적으로 억제됨을 확인하였다. 본 연구결과 초미세분쇄에 의한 감국 추출물은 일반분쇄 추출물에 비해 고혈압과 통풍억제 효과가 확연히 높아짐을 알 수 있었다.