• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.265-279
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• 1997

The purpose of this study was to do an epidemiological survey of the salivary reductase activity and dental caries prevalence of the large group of preschool children and analyze the validity of the salivary reductase activity test as a caries activity test. One thousand and forty-four preschool children were examined for caries experience and salivary reductase activity by dental survey and the Resazurin Disc Test. 39.8% of children showed low salivary reductase activity, 39.4% showed middle, and 20.8% showed high. Salivary reductase activity increased as age increased. All indexes of caries experience were high when salivary reductase activity was high. There was positive relation between salivary reductase activity and caries experience. The salivary reductase activity of children with no caries experience was lower than that of children with caries experience. The salivary reductase activity of children with low caries experience was lower than that of children with high caries experience. It seemed that the salivary reductase activity test had basic validity as a caries activity test. However, the test's ability to select the small risk group of high caries susceptibility should be enhanced.

• Journal of Plant Biology
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• v.34 no.4
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• pp.283-288
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• 1991

This work was carried out to determined the effect of 2,4-dinitrophenol(DNP) on in vivo nitrate reductase activity in the root of 6 day old rye (Secale cereale L.) seedlings. The nitrate reductase activity in the roots of 6 day old rye seedlings pretreated with 0.5 mM DNP was higher than that of the control group in all the experimental conditions. The optimal concentration of KNO3 for maximum nitrate reductase activity was 10 mM in both control and treated group. The nitrate reductase activity in the treatment of 10 mM KNO3 gradually increased for 4 h in both groups, and then maintained constantly. The nitrate reductase activity occurred per hour was highest at 1 h in both groups, while it was declined by large degrees as time goes on. The daily pattern of nitrate reductase activity was gradually decreased in both groups with the passage of day. The optimal pH for this experiment and a previous paper (Kwon et al., 1991), it was determined that the nitrate reductase activity in both roots and shoots of rye seedlings was increased by the treatment of 0.5 mM DNP, and particulary in both groups, the nitrate reductase activity in the roots of rye seedlings was higher than that in shoots of them.

• BMB Reports
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• v.28 no.6
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• pp.515-522
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• 1995

The effects of the thyroid hormone ($T_3$) on 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity were evaluated in a baby hamster kidney cell line, C100. The cells cultured in MEM were supplemented with 10% thyroid hormone-depleted fetal bovine serum (THDS-MEM) and had a 82.5% lower level of HMG-CoA reductase activity than the cells grown in a medium supplemented with fetal bovine serum (FBS-MEM). When $T_3$ was supplemented to THDS-MEM, the reduction of the reductase activity was blocked in a dose-dependent manner. In the cells grown in THDS-MEM containing $T_3$ at a concentration of $10^{-6}$ M, the level of HMG-CoA reductase activity was 91.8% relative to the cells grown in FBS-MEM. These changes in HMG-CoA reductase activity seemed to be at least partly due to the changes of HMG-CoA reductase mRNA levels. The level of HMG-CoA reductase mRNA in cells incubated in THDS-MEM decreased to 76.2% relative to the cells grown in FBS-MEM, while the level of reductase mRNA in cells incubated in THDS-MEM containing $T_3$ at a concentration of $10^{-6}$ M increased to 243.4% relative to the cells grown in FBS-MEM. The increase of HMG-CoA reductase mRNA level after $T_3$ treatment may have been due to the increased stability of reductase mRNA, because the transcriptional rate of the reductase gene did not change significantly in the presence or absence of $T_3$. These results indicate that $T_3$ stabilizes HMG-CoA reductase mRNA at the posttranscriptional level and regulates HMG-CoA reductase activity in a dose-dependent manner.

• Toxicological Research
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• v.12 no.2
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• pp.155-161
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• 1996

The enzymatic properties for NADPH-P450 reductase domain of a fusion protein between human cytochrome P450 1A1 and rat NADPH-P450 reductase expressed in Escherichia coli were investigated. The fusion plasmid pCW/1A1OR-expressed E. coli membrane showed high NADPH-cytochrome c reductase activity ($830.1\pm 85.8 nmol\cdot min^{-1}\cdot mg protein^{-1}$), while pCW control vector and P 450 1A1 expression vector pCW/1A1 showed relatively quite low activity ($4.35\pm 0.49, 3.27\pm 0.50 nmol\cdot min^{-1}\cdot mg protein^{-1}$, respectively). The kinetic curves for NADPH-cytochrome c reductase followed typical Michaelis-Menten kinetics. The $K_{max}$ and $V_{max}$ for NADPH-dependent reductase activity were $8.24\pm 2.61\mu $and $817.9\pm 60.8 nmol\cdot min^{-1}\cdot mg protein^{-1}$, respectively, whereas those for cytochrome c-dependent reductase activity were $19.97\pm 2.86\mu M$ and $1303.5\pm 67.1 nmol\cdot min^{-1}\cdot mg protein^{-1}$. The reductase activities were also compared with those of rat, porcine and human liver microsomes. The activity of pCW/ 1A1OR-expressed E. coli membrane was 15.2-fold higher than that of rat liver microsome. Treatment with benzo(a)pyrene, 7-ethoxyresorufin and $\alpha$-naphthofiavone which are known as specific substrates or inhibitor for human P450 1A1 increased NADPH-cytochrome c reductase activity of fusion protein in E. coli membrane dose-dependently. These results demonstrate that the membrane topology of fused enzyme may be important for activity of its NADPH-P450 reductase domain.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.224-229
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• 1998

A study was conducted to screen the inhibitory activity of 3-hydroxy-3-methylglutaryl coenzyme A(HMG-CoA) reductase, which is known to be rate-limiting enzyme in cholesterol bosynthesis, from the extracts of 80% methanol and 70% ethanol of cereals and regumes. The strongest inhibitory activity was shown in the ethanol extract of sorghum among the ethanol extracts. The inhibitory activity of HMG-CoA reductase of prosomillilet methanol extract was 73%, and highest among the methanol extracts. The inhibitory activity of 44.7% was observed in sorghum methanol extract. The methanol extracts of prosomillet and sorghum were further fractionated with hexane, chloroform, ethylacetate, butanol and water. HMG-CoA reductase inhibitory activity was shown in all fractions of prosomillet and sorghum methanol extracts. Hexan fraction of both prosomillet and sorghum had the strongest inhibitory activity among five fractions, and the inhibitory activity was increased compared to each crude extracts.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.2
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• pp.281-290
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• 1993

This experiment was designed to evaluate the effect of degree of unsaturation (Experiment 1) and the chain length of constituent fatty acids of dietary fats (Experiment 2) on-3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activities in the liver and small intestine of chicks. Chicks were fed experimental diets for 10 days and then killed for the determination of the HMG-CoA reductase activities in the intestinal epithelial cell and hepatic microsomes. The hepatic HMG-CoA reductase activity showed the highest value in chicks fed the tallow-containing diet. Chicks fed diets containing safflower or coconut oil resulted in a significantly lower intestinal HMG-CoA reductase activity in comparison with those fed the olive oil-containing diet. The hepatic HMG-CoA reductase activity was significantly higher when fat-free and trilaurin were fed than when any other triglycerides were fed. This activity showed the lowest value in the chicks fed the diet containing tristearin. The HMG-CoA reductase activities in the jejunum and ileum were significantly or tended to be higher when trilaurin was fed than when any other triglycerides were fed. Except when trilaurin was fed, the presence of saturated fat in the diet did not have a significant effect on the intestinal HMG-CoA reductase activity, unlike the effect shown when a highly unsaturated fat was added to the diet. There was no significant correlation between the HMG-CoA reductase activities of the liver and intestinal, and the HMG-CoA reductase activity and cholesterol content of the intestinal epithelial cells.

• Biomolecules & Therapeutics
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• v.10 no.2
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• pp.85-88
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• 2002

Systematic fractionation of Angelica gigas roots led to the isolation of linear coumarins such as decursinol angelate, decursin and nodakenin. These compounds were tested for their effects on rat lens aldose reductase. Nodakenin was demonstrated to exhibit significant inhibition of rat lens aldose reductase activity with $IC_{50}$ value of $7.33\Mu\textrm{M}$.

• Archives of Pharmacal Research
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• v.11 no.4
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• pp.312-314
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• 1988

Thirteen monoterpenes were examined for their effects on the bovine lens aldose reductase activity. the monoterpenes tested in this study showed mild inhibitory effects except 3-carene which did not show any significant effect. At the concentration of $10^{-3}$ M(+) Pulegon showed 42% inhibition on lens aldose reductase activity, which is the most otent effect among the tested substance.

• BMB Reports
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• v.41 no.6
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• pp.444-447
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• 2008

Trypanothione reductase is an important target enzyme for structure-based drug design against Leishmania. We used homology modeling to construct a three-dimensional structure of the trypanothione reductase (TR) of Leishmania infantum. The structure shows acceptable Ramachandran statistics and a remarkably different active site from glutathione reductase(GR). Thus, a specific inhibitor against TR can be designed without interfering with host (human) GR activity.

• Natural Product Sciences
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• v.22 no.2
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• pp.102-106
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• 2016

A methanolic extract of Corydalis ternata having aldose reductase inhibitory activity was examined as a possible aldose reductase (ALR2) inhibitor, a key enzyme involved in diabetic complications. Seven alkaloids, tetrahydrocoptisine (1), corydaline (2), tetrahydropalmatine (3), isocorybulbine (4), corybulbine (5), dehydrocorydaline (6), and N-methyltetrahydroberbinium (7) were isolated from $CHCl_3$ fraction of C. ternata methanol extract. Among them, compounds 1, 5, and 7 exhibited $5.04{\pm}1.97%$, $5.00{\pm}1.26%$, and $1.80{\pm}2.33%$ inhibitions, respectively at $40{\mu}M$. The activities of the single compounds were not comparable to that of the whole extract, suggesting that the whole combination of each single compound was responsible for the activity of the extract as shown in many cases of natural medicines. Even though this is the second report on aldose reductase inhibition activity of C. ternata, recombinant human aldose reductase was employed in this study unlike in the previous report. Furthermore, the aldose reductase inhibitory activities of isocorybulbine, corybulbine, and N-methyltetrahydroberbinium, to the best of our knowledge, were evaluated for the first time in this study. These results suggest a use of the extract of C. ternata for ameliorating diabetic complications.