• Molecular & Cellular Toxicology
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• v.5 no.4
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• pp.310-316
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• 2009

Some environmental chemicals have been shown to cause liver-toxicity as the result of bioaccumulation. Particularly, fungicides have been shown to cause varying degrees of hepatictoxicity and to disrupt steroid hormone homeostasis in in vivo models. The principal objective of this study was to evaluate the liver-toxic responses of environmental chemicals-in this case selected fungicides and parasiticides-in order to determine whether or not this agent differentially affected its toxicogenomic activities in hepatic tumor cell lines. To determine the gene expression profiles of 3 fungicides (triadimefon, myclobutanil, vinclozolin) and 1 parasiticide (dibutyl phthalate), we utilized a modified HazChem human array V2. Additionally, in order to observe the differential alterations in its time-dependent activities, we conducted two time (3 hr, 48 hr) exposures to the respective IC20 values of four chemicals. As a result, we analyzed the expression profiles of a total of 1638 genes, and we identified 70 positive significant genes and 144 negative significant genes using four fungicidic and parasiticidic chemicals, using SAM (Significant Analysis of Microarray) methods (q-value<0.5%). These genes were analyzed and identified as being related to apoptosis, stress responses, germ cell development, cofactor metabolism, and lipid metabolism in GO functions and pathways. Additionally, we found 120 genes among those time-dependently differentially expressed genes, using 1-way ANOVA (P-value<0.05). These genes were related to protein metabolism, stress responses, and positive regulation of apoptosis. These data support the conclusion that the four tested chemicals have common toxicogenomic effects and evidence respectively differential expression profiles according to exposure time.

• Journal of the Korean Chemical Society
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• v.24 no.4
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• pp.315-321
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• 1980

A steady-state kinetic study on a dye-coupled cytoplasmic polyol dehydrogenase from G. melanogenus was carried by the initial velocity measurements in the direction of the polyol oxidation and the product inhibition by D-fructose. For the initial rate experiments, D-mannitol and D-sorbitol were employed as the specific polyol substrates and 2,6-dichlorophenolin-dophenol (DPIP) as the specific cofactor substrate for the enzyme. When the polyol and DPIP were examined by varying one of substrates and by fixing the second, the corresponding reciprocal plots showed the typical parallel pattern. This suggests that the enzyme from G. melanogenus proceeds by a Ping Pong Bi-Bi mechanism in which the polyol may account as the first reactant-in, and the ketose formed as the first product-out, respectively. The product inhibition patterns obtained by D-fructose (one no-inhibition, one non-competitive, and two competitive) may also provide an additional conformatory evidence for the above mechanism. Based on the kinetic parameters obtained, it was also suggested that the rate-limiting step in the direction of polyol oxidation is associated with the release of the ketose from the Enzyme${\cdot}$Polyol complex.

• Archives of Pharmacal Research
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• v.21 no.2
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• pp.128-134
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• 1998

Nitric oxide synthase, NOS (EC.1.14.13.39), was purified from bovine pancreas over 5,500-fold with a 7.6% yield using 30% ammonium sulfate precipitation, and $2^1$,$5^1$-ADP-agarose and calmodulin-agarose affinity chromatography. The purified bovine pancreatic NOS (bpNOS) showed a single band on SDS-PAGE corresponding to an apparent molecular mass of 160 kDa, whereas it was 320 kDa on non-denaturating gel-filtration. This indicated a homodimeric nature of the enzyme. The specific activity of the purified bpNOS was 31.67 nmol L-citrulline fored/mtn/mg protein and an apparent $K\textrm{m}$ for L-arginine was 15.72 $\mu\textrm{M}$, The enzyme activity was dependent on $Ca^{2+}$ and calmodulin, and to a lesser extent on NADPH, FAD and FMN. $H_4B$ was not required as a cofactor for the activity. In an inhibition experiment with L-arginine analogues, $N^G$-nitro-L-arginine (NNA) had the most potent inhibitory effect on bpNOS, and $N^{G}$, $N^{G1}$-dimethyl-L-arginine (symmetric; sDMA) did not have any inhibitory effect. Immunohistochemical analysis of the bovine pancreas using brain type NOS antibody (anti-bNOS antibody) revealed that acinar cells showed strong immunoreactivity against the antibody.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.2
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• pp.55-58
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• 2015

Tetrahydrobiopterin ($BH_4$) can normalize blood phenylalanine (Phe) levels in $BH_4$ deficiency, but typically not in phenylketonuria (PKU). In 1999, Kure et al. reported that some PKU patients showed decreased blood Phe levels after $BH_4$ loading, and thereafter, those PKU patients were identified by neonatal PKU screening. A natural cofactor for phenylalanine hydroxylase (PAH) is a 6R-isomer of $BH_4$, which is first synthesized in Japan as Sapropterin dihydrochloride (Biopten$^{(R)}$) in 1982. In Japan, Biopten$^{(R)}$ is first approved for the treatment of $BH_4$ deficiency in 1992, and then for $BH_4$-responsive PAH deficiency (BPKU) in 2008. The discovery of BPKU has vast clinical implications. After Biopten$^{(R)}$ (Kuvan$^{(R)}$) is available for the treatment of BPKU, the QOL of both patients and their families were improved very much, since the serum phenylalanine levels were controlled within 4 mg/dL by $BH_4$ mono-therapy with a normal diet or $BH_4$ combined use of mild phenylalanine-restricted diet. Biopten$^{(R)}$ therapy in patients with BPKU is highly efficacious (70%) at maintaining serum Phe levels within recommended control range and provides excellent safety at least average use period of 10 years (range, 1-17 years) with no unwarranted side effects in Japan. In addition it has been confirmed that sapropterin therapy initiated before 4 years of age was very effective to maintain plasma Phe levels within the favorable range and was safe in Japanese patients with BPKU.

• Journal of Microbiology and Biotechnology
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• v.22 no.1
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• pp.141-146
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• 2012

Malassezia globosa is a common pathogenic fungus that causes skin diseases including dandruff and seborrheic dermatitis in humans. Analysis of its genome identified a gene (MGL_1677) coding for a putative NADPH-P450 reductase (NPR) to support the fungal cytochrome P450 enzymes. The heterologously expressed recombinant M. globosa NPR protein was purified, and its functional features were characterized. The purified protein generated a single band on SDS-PAGE at 80.74 kDa and had an absorption maximum at 452 nm, indicating its possible function as an oxidized flavin cofactor. It evidenced NADPH-dependent reducing activity for cytochrome c or nitroblue tetrazolium. Human P450 1A2 and 2A6 were able to successfully catalyze the O-deethylation of 7-ethoxyresorufin and the 7-hydroxylation of coumarin, respectively, with the support of the purified NPR. These results demonstrate that purified NPR is an orthologous reductase protein that supports cytochrome P450 enzymes in M. globosa.

• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.65-71
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• 2009

Microbial oxidoreductive systems have been widely used in asymmetric syntheses of optically active alcohols. However, when reused in multi-batch reaction, the catalytic efficiency and sustainability of non-growing cells usually decreased because of continuous consumption of required cofactors during the reaction process. A novel method for NADPH regeneration in cells was proposed by using pentose metabolism in microorganisms. Addition of D-xylose, L-arabinose, or D-ribose to the reaction significantly improved the conversion efficiency of deracemization of racemic 1-phenyl-1,2-ethanediol to (S)-isomer by Candida parapsilosis cells already used once, which afforded the product with high optical purity over 97%e.e. in high yield over 85% under an increased substrate concentration of 15 g/l. Compared with reactions without xylose, xylose added to multi-batch reactions had no influence on the activity of the enzyme catalyzing the key step in deracemization, but performed a promoting effect on the recovery of the metabolic activity of the non-growing cells with its consumption in each batch. The detection of activities of xylose reductase and xylitol dehydrogenase from cell-free extract of C. parapsilosis made xylose metabolism feasible in cells, and the depression of the pentose phosphate pathway inhibitor to this reaction further indicated that xylose facilitated the NADPH-required deracemization through the pentose phosphate pathway in C. parapsilosis. moreover, by investigating the cofactor pool, the xylose addition in reaction batches giving more NADPH, compared with those without xylose, suggested that the higher catalytic efficiency and sustainability of C. parapsilosis non-growing cells had resulted from xylose metabolism recycling NADPH for the deracemization.

• Clinical and Experimental Pediatrics
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• v.50 no.10
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• pp.931-937
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• 2007

The hemolytic uremic syndrome (HUS) is a rare disease of microangiopathic hemolytic anemia, low platelet count and renal impairment. HUS usually occurs in young children after hemorrhagic colitis by shigatoxin-producing enterohemorrhagic E. coli (D+HUS). HUS is the most common cause of acute renal failure in infants and young children, and is a substantial cause of acute mortality and morbidity; however, renal function recovers in most of them. About 10% of children with HUS do not reveal preceding diarrheal illness, and is referred to as D- HUS or atypical HUS. Atypical HUS comprises a heterogeneous group of thrombomicroangiopathy (TMA) triggered by non-enteric infection, virus, drug, malignancies, transplantation, and other underlying medical condition. Emerging data indicate dysregulation of alternative complement pathway in atypical HUS, and genetic analyses have identified mutations of several regulatory genes; i.e. the fluid phase complement regulator Factor H (CFH), the integral membrane regulator membrane cofactor protein (MCP; CD46) and the serine protease Factor I (IF). The uncontrolled activation of the complement alternative pathway results in the excessive consumption of C3. Plasma exchange or plasma infusion is recommended for treatment of, and has dropped the mortality rate. However, overall prognosis is poor, and many patients succumb to end-stage renal disease. Clinical presentations, response to plasma therapy, and outcome after renal transplantation are influenced by the genotype of the complement regulators. Thrombotic thrombocytopenic purpura (TTP), another type of TMA, occurs mainly in adults as an acquired disease accompanied by fever, neurologic deficits and renal abnormalities. However, less frequent cases of congenital or hereditary TTP associated with ADAMTS-13 (a disintegrin and metalloprotease, with thrombospondin 1-like domains 13) gene mutations have been reported, also. Recent advances in molecular genetics better allow various HUS to be distinguished on the basis of their pathogenesis. The genetic analysis of HUS is important in defining the underlying etiology, predicting the genotype-related outcome and optimizing the management of the patients.

• Toxicological Research
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• v.8 no.2
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• pp.191-203
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• 1992

The immunosuppressive effects of safrole were studied in female BALB/c mouse. Mice were given 100,200and 400mg safrole/kg daily for 14days and evaluated on day 15. The day 4 immunogloblin-M antibody response to T-dependent antigen, sheep red blood cells (SRBC) was inhibited dose-dependently in all doses studied. In vitro antibody response to polyclonal antigen, lipopolysaccharide (LPS) by spleen cell suspensions from safrole-treated mice were also significantly inhibited. When safrole was treated for 14days to mice, and mitogen-induced proliferation of splenocytes were assayed on day 15, there were significant suppression of responses to B-cell mitogen, LPS and T-cell mitogen concanavalin A(Con A) at a dose of 400mg safrole/kg. Direct addition of safrole on the splenocyte culture also produced a dose dependent suppression on in vitro antibody response to LPS, and mitogen-induced lymphoproliferatin at doses of 100,200,400 and 800${\mu}M$ safrole. The role of metabolic activation in safrole-induced suppression of in vitro antibody response was studied using splenocyte-hepatocyte coculture system. The suppression of in vitro antibody respose to LPS by safrole was not altered when safrole were incubated in the splenocyte-hepatocyte system for 4hr as compared with direct addition of safrole in splenocytes culture. Neither the addition of salicylamide, sulfotransferase inhibitor, nor the addation of inorganic sulfate, sulfation cofactor to the splenocyte-hepatocyte coculture, altered the suppression of antibody response by safrole. These results suggest that the immunosuppression by safrole may not by produced by the reactive metabolites which are mediated in carcinogenesis of safrole.

• Journal of Life Science
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• v.24 no.1
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• pp.98-103
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• 2014

NAD(P)H quinone oxidoreductase 1 (NQO1) is a flavoprotein that catalyzes the two electron reduction of diverse substrates, including quinones. It uses NADH or NADPH as a cofactor for enzymatic machinery. In the metabolism of quinones, NQO1 has two conflicting functions because of the different stability of converted hydroquinones. The stable form of hydroquinone is excreted from cells by conjugation with glutathione or glucuronic acid. The unstable form of hydroquinone induces cell death by induction of oxidative stress and DNA damage. Certain quinones known as bio-reductive agents have a cytotoxic function following reduction by NQO1. Bio-reductive agents, such as ${\beta}$-lapachone or mitomycin C, induce the depletion of NAD(P)H and the generation of oxidative stress in an NQO1-dependent manner. NQO1 is highly expressed in several cancer tissues. Therefore, NQO1 is a good therapeutic target for cancer treatment with bio-reductive agents.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2387-2392
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• 2009

A composite film of multi-walled carbon nanotube (MWCNT)/sol-gel-derived zinc oxide(ZnO)/Nafion has been utilized as an efficient immobilization matrix for the construction of a highly sensitive and stable tris(2,2'-bipyridyl) ruthenium(II) (Ru(${bpy)_3}^{2+})$ electrogenerated chemiluminescence (ECL) sensor. The electrochemical and ECL behaviors of Ru(${bpy)_3}^{2+})$ ion-exchanged into the composite film were strongly dependent upon the sol-gel preparation condition, the amount of MWCNT incorporated into the ZnO/Nafion composite film, and the buffer solution pH. The synergistic effect of MWCNTs and ZnO in the composite films increased not only the sensitivity but also the long-term stability of the ECL sensor. The present ECL sensor based on the MWCNT/ZnO/Nafion gave a linear response ($R^2$ = 0.999) for tripropylamine concentration from 500 nM to 1.0 mM with a remarkable detection limit (S/N = 3) of 15 nM. The present ECL sensor showed outstanding long-term stability (94% initial signal retained for 5 weeks). Since the present ECL sensor exhibits large response towards NADH, it could be applied as a transduction platform for the ECL biosensor in which the NADH is produced from the dehydrogenase-based enzymatic reaction in the presence of NA$D^+$ cofactor.