• Korean Journal of Environment and Ecology
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• v.16 no.1
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• pp.46-54
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• 2002

This study was conducted to diagnose the health of street trees with physiological characters, and to figure out the relation of physiological characters and cambial electrical resistances. Ginkgo biloba, Prunes serrulata and Salix koreensis were chosen in the Cheonan City. Soils under trees were collected to analyze dehydrogenase activities, and chlorophyll content, nitrate reductase and superoxide dismutase activities were analyzed from leaves sampled at the edge of crown in July. Cambial electrical resistances were measured in May, July and September, Soils with low dehydrogenase activity reflected the level of pollution. Chlorophyll content was the lowest in the leaves of P. serrulata at the Dongseo-street. Nitrate reductase activity of Ginkgo biloba was higher than P. serruluta and Satix koreensis. Nitrate reductase activity showed higher activity in the city than control(Independence Hall and Yonam College), but superoxide dismutase activity in the city lower than control. P. serruzatu in the Dongseo-street that cambial electrical resistance increase continuously during the growing season, showed the loss of vitality Cambial electrical resistance was negatively or positively correlated with nitrate reductase($r^2$=-0.566) and superoxide dismutase activity($r^2$=0.579). It was concluded that cambial electrical resistance might be suitable for diagnosing the tree health.

• BMB Reports
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• v.32 no.3
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• pp.254-258
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• 1999

The NADPH-dependent succinic semialdehyde reductase is one of the key enzymes in the brain GABA shunt, and it catalyzes the formation of the neuromodulator $\gamma$-hydroxybutyrate from succinic semi aldehyde. This enzyme was inactivated by diethylpyrocarbonate (DEP) with the second-order rate constant of $1.1{\times}10^3\;M^{-1}min^{-1}$ at pH 7.0, $25^{\circ}C$, showing a concomitant increase in absorbance at 242 nm due to the formation of N-carbethoxyhistidyl derivatives. Complete inactivation of succinic semialdehyde reductase required the modification of five histidyl residues per molecule of enzyme. However, only one residue was calculated to be essential for enzyme activity by a statistical analysis of the residual enzyme activity. The inactivation of the enzyme by DEP was prevented by preincubation of the enzyme with the coenzyme NADPH but not with the substrate succinic semialdehyde. These results suggest that an essential histidyl residue involved in the catalytic activity is located at or near the coenzyme binding site of the brain succinic semialdehyde reductase.

• BMB Reports
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• v.43 no.4
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• pp.268-272
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• 2010

Aldo-keto reductase family 1 B10 (AKR1B10) is a member of the NADPH-dependent aldo-keto reductase (AKR) superfamily, and has been considered to be a potential cancer therapeutic target. Total extract from the bark of Rhus verniciflua (Toxicodendron vernicifluum (Stokes)) showed AKR1B10 inhibitory activity. To identify the active compounds from R. verniciflua responsible for AKR1B10 inhibition, nine compounds were isolated via bioactivity-guided isolation and tested for their effects against recombinant human AKR1B10 (rhAKR1B10). Results showed that butein, isolated from the ethyl acetate fraction, was most able to inhibit rhAKR1B10. The inhibitory rate of butein against rhAKR1B10 was 42.86% at $1\;{\mu}M$ with an IC50 value of $1.47\;{\mu}M$, and enzyme kinetic analysis revealed its inhibition mode to be uncompetitive.

• Parasites, Hosts and Diseases
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• v.28 no.2
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• pp.79-84
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• 1990

Metabolic inhibitors which act in the process of pyrimidine salvage influenced on the uracil incorporation into nucleic acids of Toxoplasma. Inhibitors of dihydrofolate reductase, pyrimethamine and methotrexate, and inhibitors of thymidylate synthase, fluoro-uridine, fluoro·dUMP and fluoro-uracil, diminished isotopic uracil uptake in dose-dependent manners. Azauridine which suppresses do novo pyrimidine biosynthesis did not affect the salvage even in a relatively high dose. These results suggested that the activation of uracil salvage should be closely related with the function of TMP biosynthetic enzymes. The pattern of thymidine uptake had no differences between control HL-60 cells and Toxoplasma infected cells, which did not reject the specific proliferation of Texoplasma. It can be exploited to characterize the elects of various compounds related with the proliferation of Toxoplasma, especially its DNA synthesis. Key words: Toxoplasma gondii, uracil salvage, dihydrofolate reductase, thymidylate synthase TMP biosynthesis.

• Korean Journal of Pharmacognosy
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• v.39 no.4
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• pp.324-329
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• 2008

Aldose reductase (AR), the key enzyme in the polyol pathway, plays an important role in the pathogenesis of diabetic complications such as cataract formation. AR inhibitors (ARI) can prevent or reverse early abnormalities in diabetic complications. However, none of ARI has achieved worldwide use because of limited efficacy or undesirable side effects. Therefore, evaluating natural sources for ARI potential may lead to the development of safer and more effective agents against diabetic complications. 49 Vietnam herbal medicines have been investigated with an in vitro evaluation system using aldose reductase inhibitory activities. Of these, 7 herbal medicines, Artemisia annua (leaf, stem), Duranta repens (leaf, stem), Excoecaria cochinchinensis (aerial part), Flueggea virosa (leaf, stem), Khaya senegalensis (leaf), Polygonum orientale (aerial part), Toxicodendron succedanea (leaf, stem) exhibited a significant inhibitory activity against aldose reductase. Particularly, Duranta repens (leaf, stem) and Toxicodendron succedanea (leaf, stem) showed two times more potent inhibitory activity than the positive control, 3.3-tetramethyleneglutaric acid (TMG).

• Journal of Applied Biological Chemistry
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• v.52 no.4
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• pp.216-220
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• 2009

Aldo-keto reductase family 1 B10 (AKR1B10) has been considered as a potential cancer therapeutic target. Ethanol extracts prepared from 82 Korean local plants were examined for their antioxidant activity and inhibitory effects on recombinant human AKR1B10 (rhAKR1B10) in vitro. 21 extracts showed more than 80% of ABTS radical scavenging activity at $100\;{\mu}g/mL$ and 11 extracts inhibited more than 50% of rhAKR1B10 activity at $10\;{\mu}g/mL$. Especially, 9 extracts showed potent inhibition on rhAKR1B10 activity compared with positive control tetramethylene glutaric acid.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.407-412
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• 2015

We investigated the effect of ultra-high molecular weight poly-γ-glutamic acid (UHMW γ-PGA) on hair loss in vitro and in vivo. 5-Alpha reductase is an enzyme that metabolizes the male hormone testosterone into dihydrotestosterone. By performing an in vitro experiment to analyze the inhibitory effects of UHMW γ-PGA on 5-alpha reductase activity, we determined that UHMW γ-PGA did in fact inhibit 5-alpha reductase activity, indicating the use of UHMW γ-PGA as a potential 5-alpha reductase inhibitor in the treatment of men with androgenetic alopecia. To evaluate the promotion of hair growth in vivo, we topically applied UHMW γ-PGA and minoxidil on the shaved dorsal skin of telogenic C57BL/6 mice for 4 weeks. At 4 weeks, the groups treated with UHMW γ-PGA showed hair growth on more than 50% of the shaved skin, whereas the control group showed less hair growth. To investigate the progression of hair follicles in the hair cycle, hematoxylin and eosin staining was performed. Histological observations revealed that the appearance of hair follicles was earlier in the UHMW γ-PGA-treated group than in the control group. The number of hair follicles on the relative area of shaved skin in the UHMW γ-PGA-treated group was higher than that observed on the shaved skin in the control group. These results indicate that UHMW γ-PGA can promote hair growth by effectively inducing the anagen phase in telogenic C57BL/6 mice.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.495-499
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• 2016

In order to identify the biochemical characteristics of LuxG, the luxG gene from bioluminescence bacteria of Photobacterium leiognathi ATCC 25521 was isolated by PCR-Amplification and inserted into pQE30 vector containing the T5 promoter and 6X His-tag system. The resulting recombinant plasmid was transformed into Escherichia coli to over-express the luxG gene and purify the gene product. The purified LuxG protein demonstrated ferric iron reductase activity and the kinetic parameters of $K_m$ and $V_{max}$ for FMN as well as the NADPH substrates of ferric iron reductase were determined, respectively.

• Journal of agricultural medicine and community health
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• v.19 no.2
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• pp.107-118
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• 1994

Health effects of pesticide among vinylhouse workers in Sangjoo County, Kyungpook Province were assessed by measuring cholinesterase, glutathion reductase, and methemoglobin. Activities of cholinesterases among vinylhouse workers and general farmers were 3.89U and 3.98U in serum and 5.29U and 5.50U in red blood cells, respectively. While levels of methemoglobin between vinylhouse workers(0.16%) and general farmers(0.17%) were very similar, glutathione reductase among vinylhouse workers were 8% lower than that of general farmers. Inhibition of RBC cholinesterase among vinylhouse workers was two times greater than general farmers, suggesting a greater exposure of vinylhouse workers to the organophosphate pesticides. Methemoglobin level among vinylhouse workers with more than or equal to 10 vinylhouse units was 13% higher than that of the workers with less than 10 units. Vinylhouse workers using protective gears during pesticide spray showed higher level of reduced glutathione and lower level of methemoglobin, as compared to the non-users. This indicates that protective gears play an important role against pesticide exposure. Vinylhouse workers practicing good personal hygiene showed a higher level of reduced glutathione, as compared to those with poor personal hygiene, indicating that personal hygiene is also an important factor in reducing pesticide exposure. The present study represents a first attempt to analyze cholinesterase, methemoglobin and glutathione reductase activities among the vinylhouse workers. While neither vinylhouse workers nor general farmers showed abnormal findings among biochemical parameters used in the present study, increased level of methemoglobin and decrease of glutathione reductase activity among vinylhouse workers suggest that these workers have been subject to a higher exposure of pesticide than general farmers.

• Journal of Genetic Medicine
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• v.6 no.2
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• pp.170-174
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• 2009

Tetrahydrobiopterin ($BH_4$) deficiency is caused by mutations in genes encoding enzymes involved in the synthesis and regeneration of $BH_4$. The condition is usually accompanied by hyperphenylalaninemia (HPA) and deficiency of neurotransmitter precursors L-dopa and 5-hydroxytryptophan. $BH_4$ deficiency is much rarer than classical phenylketonuria. Dihydropteridine reductase (DHPR) deficiency, an autosomal recessive genetic disorder, is a cause of malignant hyperphenylalaninemia due to $BH_4$ deficiency. When left untreated, DHPR deficiency leads to neurologic deterioration at the age of 4 or 5 months, including psychomotor retardation, tonicity disorders, drowsiness, irritability, abnormal movements, hyperthermia, hypersalivation, and difficulty swallowing. Treatment of DHPR deficiency should be initiated as early as possible with $BH_4$ supplementation and replacement of the neurotransmitter precursors L-dopa and 5-hydroxytryptophan. We report the first case of DHPR deficiency in Korea, a child diagnosed at 9 years of age by genetic testing.