• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.05a
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• pp.480-481
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• 2002

• BMB Reports
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• v.30 no.5
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• pp.332-336
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• 1997

The stimulatory effects of leucine on the activities of two soluble forms of brain glutamate dehydrogenase isoproteins (GDH I and GDH II) have been studied at various conditions. There were significant differences between GDH I and GDH II in their sensitivities to the action of leucine. When the effects of varied leucine concentrations on GDH activities were studied in the direction of reductive amination of 2-oxoglutarate with NADPH as a coenzyme, a marked activation was observed for both isoproteins at leucine concentrations up to 10 mM, whereas both isoproteins showed activation to a lesser extent with NADH as a coenzyme. The stimulatory effects of leucine on GDH activities in the direction of the oxidative deamination of glutamate were also observed, but to a much lesser extent. Leucine relieved the inhibition of GDH I by GTP and this resulted in an increase in the apparent activation by leucine in the presence of GTP. 2-Oxoglutarate was found to give rise to high substrate inhibition and leucine significantly reduced the substrate inhibition in the presence of $200\;{\mu}M$ NADH. Thus, the effects of leucine might be composed of a direct effect on the enzyme together with a relief of high substrate inhibition.

• BMB Reports
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• v.34 no.3
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• pp.268-273
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• 2001

In addition to the recognition site for glutamate, the N-methyl-D-aspartate (NMDA)-preferring glutamate receptor subtype shows a binding site for glycine. In this paper, we present the effects of 3-(4,6-dichloro-2-carboxymethylamino-5,7-dichloroquinoline-2-carboxylic acid (MDL 29951), a potent inhibitor of glycine binding to the NMDA receptor, on glutamate dehydrogenase (GDH) from bovine brains. The incubation of GDH isoproteins from bovine brains with MDL 29951 resulted in a dose-dependent loss of enzyme activity Separately or together, 2-oxoglutarate and NADH did not give an efficient protection against the inhibition, indicating that GDH isoproteins saturated with NADH or 2-oxoglutarate are still open to attack by MDL 29951. MDL 29951 was an uncompetitive inhibitor with respect to both 2-oxoglutarate and NADH for GDH isoproteins. These results suggest that the binding site of MDL 29951 is not directly located at the catalytic site, and the inhibition of GDH isoproteins by MDL 29951 is probably due to a steric hindrance, or a conformational change altered upon the interaction of the enzyme with its inhibitor. The inhibitory effects of MDL 29951 on GDH isoproteins were significantly diminished in the presence of ADP. GDH I reacted more sensitively with ADP than GDH II on the inhibition by MDL 29951. Our results suggest a possibility that the two types of GDHs are differently regulated by MDL 29951, depending on the physiological concentrations of ADP.

• Biomolecules & Therapeutics
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• v.8 no.1
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• pp.38-43
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• 2000

Several studies have shown that the stomach has sufficient alcohol dehydrogenase (ADH) activity to metabolize some amount of orally administered alcohol and the sex-related differences in the first-pass metabolism of alcohol might be associated with differences in the activity of gastric ADH(GADH). The aim of this study was to asses the sex-related differences in GADH in 48 male and 48 female Sprague-Dawley rats aged 1, 4, 10, 15, 20, and 30 weeks which each aged group had same sex ratio. The GADH activity was determined spectrophotometrically at 37$^{\circ}C$. The formation of NADH was monitored at 340nm for 10 minutes in the 1 ml of reaction mixture (0.5 M of Tris-HCl, pH 7.2 + 1.5 M of ethanol + 2.8 mM of NAD + 30 $\mu$l gastric mucosal supernatant). The GADH activity (nM of NADH/min/mg of cytosolic protein) was calculated using molecular extinction coefficient of 6.22 $\textrm{cm}^2$/$\mu$M for NADH. The GADH activities were 2.94$\pm$0.82 (n=48) in female rats and 3.34$\pm$2.17 (n=48) in male rats and had not significant difference between sex. However, the GADH activities were significantly (p<0.01) higher in female (1.91$\pm$0.59 and 3.30$\pm$0.49) than in male (0.68$\pm$0.43 and 1.92$\pm$0.81) of 1 and 4 weeks rats. However, it was significantly (p<0.05) higher in male (6.48$\pm$1.81, 3.65$\pm$1.04 and 5.13$\pm$1.30) than in female (4.23$\pm$1.23, 2.18$\pm$0.77 and 2.56$\pm$0.93) of 10, 20 and 30 weeks rats, respectively. Therefore, the results suggested that sex-related differences of the GADH activities in same aged rats were existed by age.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.501-508
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• 2003

Artificial coupling of one enzyme with another can provide an efficient means for the production of industrially important chemicals. Xylose reductase has been recently discovered to be useful in the reductive production of xylitol. However, a limitation of its in vitro or in vivo use is the regeneration of the cofactor NAD(P)H in the enzyme activity. In the present study, an efficient process for the production of xylitol from D-xylose was established by coupling two enzymes. A NADH-dependent xylose reductase (XR) from Pichia stipitis catalyzed the reduction of xylose with a stoichiometric consumption of NADH, and the resulting cofactor $NAD^+$ was continuously re-reduced by formate dehydrogenase (FDH) for regeneration. Using simple kinetic analyses as tools for process optimization, suitable conditions for the performance and yield of the coupled reaction were established. The optimal reaction temperature and pH were determined to be about $30^{\circ}C$ and 7.0, respectively. Formate, as a substrate of FDH, affected the yield and cofactor regeneration, and was, therefore, adjusted to a concentration of 20 mM. When the total activity of FDH was about 1.8-fold higher than that of XR, the performance was better than that by any other activity ratios. As expected, there were no distinct differences in the conversion yields of reactions, when supplied with the oxidized form $NAD^+$ instead of the reduced form NADH, as a starting cofactor for regeneration. Under these conditions, a complete conversion (>99%) could be readily obtained from a small-scale batch reaction.

• Archives of Pharmacal Research
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• v.15 no.3
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• pp.229-233
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• 1992

The pKa value of histidine-51 residue was determined by the pH dependency of contents of NADH bound to the active site in the orse liver alcohol dehydrogenase and % inactivation with diethyl pyrocarbonate treatment of the enzyme. The pKa for His-51 was -7.15 in the ternary complex and -6.7 in the enzyme itself.

• Rapid Communication in Photoscience
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• v.2 no.2
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• pp.42-45
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• 2013

Natural photosynthesis utilizes solar energy to convert carbon dioxide and water to energy-rich carbohydrates. Substantial use of sunlight to meet world energy demands requires energy storage in useful fuels via chemical bonds because sunlight is intermittent. Artificial photosynthesis research focuses the fundamental natural process to design solar energy conversion systems. Nicotinamide adenine dinucleotide ($NAD^+$) and $NADP^+$ are ubiquitous as electron transporters in biological systems. Enzymatic, chemical, and electrochemical methods have been reported for NADH regeneration. As photochemical systems, visible light-driven catalytic activity of NADH regeneration was carried out using platinum nanoparticles, molecular rhodium and cobalt complexes in the presence of triethanolamine as a sacrificial electron donor. Pt nanoparticles showed photochemical NADH regeneration activity without additional visible light collector molecules, demonstrating that both photoactivating and catalytic activities exist together in Pt nanoparticles. The NADH regeneration of the Pt nanoparticle system was not interfered with the reduction of $O_2$. Molecular cobalt complexes containing dimethylglyoxime ligands also transfer their hydrides to $NAD^+$ with photoactivation of eosin Y in the presence of TEOA. In this photocatalytic reaction, the $NAD^+$ reduction process competed with a proton reduction.

• Fisheries and Aquatic Sciences
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• v.11 no.1
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• pp.36-40
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• 2008

We analyzed the nucleotide sequences of about 500 bp of the mitochondrial NADH dehydrogenase subunit 3 (ND3) gene to estimate the genetic variation of Korean masu salmon (Oncorhynchus masou) populations. DNA samples were collected from 104 river-only specimens and 52 anadromous specimens from three hatcheries and one river. There are no records of artificial release into the river. We amplified the ND3 gene by polymerase chain reaction, targeting areas that included parts of the cytochrome oxidase III gene and the NADH dehydrogenase subunit 4L gene, and defined 14 haplotypes based on 12 variable nucleotide sites in the examined region. Among the haplotypes, ten were specific to river-only specimens within hatchery populations. Haplotype diversity of river-only populations in hatcheries was higher than that of anadromous and wild populations. Pairwise population $F_{ST}$ estimates and neighbor-joining tree analyses inferred that anadromous and river-only populations were distinct. These results suggest that sequence polymorphism in the ND3 region may be a useful marker for analyzing the genetic variation and population structure of masu salmon.

• Journal of Life Science
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• v.8 no.2
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• pp.203-207
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• 1998

NAD4 as a gene encoding NADH dehydrogenase subunit 4 in the micodhondrion from maize has been cloned using RT-PCR and sequenced for examining RNA edited sites. Analysis of mt cDNA sequences showed the typical RNA editing patterns and unusual base changes as well;RNA editing from cDNA sequences occured base change from c to U in most cases, however transitions from t to g and G to A were also observed. Even though those editings appared to be occurred randomly, RNA edited sites showed mostly in exon 1 and exon 4 regions, when compared with NAD4 cDNA from wheat, locations of edited sites did not consistent with each other suggesting that the phenomenon of RNA editing occured randomly not site-specific manner.

• Journal of Applied Biological Chemistry
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• v.43 no.4
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• pp.230-234
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• 2000

A new method to assay the capsaicinoid synthetase (CS) activity was developed by utilizing NADHcoupled enzyme systems involving pyruvate kinase and lactate dehydrogenase. CS activities in Capsicum placenta, depending upon the kinetics of the NADH oxidation, revealed almost the same profile as compared with those shown using an HPLC-based method. When the substrates, 8-methyl nonanoic acid and vanillylamine, for the CS enzyme were employed separately or simultaneously, it appeared that the two-step reaction, acyl-CoA formation and condensation with vanillyla~ne, of the CS enzyme was a coupled reaction. Thus, this assay method of the CS enzyme can be considered as an alternative to the HPLC-based method, since it has the advantages of rapidity and simplicity as well as reliability when compared with the existing method.