• Journal of Applied Biological Chemistry
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• 제42권1호
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• pp.1-6
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• 1999

Poly-${\beta}$-hydroxybutyrate (PHB) and enzymes related PHB metabolism have been measured in nitrogen-fixing symbiosis of chickpea and cowpea plants. Bacteroids from chickpea and cowpea contained PHB to 0.8% and 43% of their dry weight, respectively, whereas the free-living cells CC 1192 and I 16 produced $285{\pm}55mg$ and $157{\pm}18mg$ of PHB g (dry weight)$^{-1}$. To further understand why chickpea bacteroids contained little PHB, the enzyme activities of PHB metabolism (3-ketothiolase, acetoacetyl-CoA reductase, PHB depolymerase, and 3-hydroxybutyrate dehydrogenase), the TCA cycle (malate dehydrogenase, citrate synthase, and isocitrate dehydrogenase), and related reactions (malic enzyme, pyruvate dehydrogenase, and glutamate:2-oxoglutarate transaminase) were compared in extracts from chickpea and cowpea bacteroids and the respective free-living bacteria. Significant differences were observed between chickpea and cowpea bacteroids and between the bacteroid and free-living forms of CC 1192, with respect to the capacity for some of these reactions. It is indicated that a greater potential for oxidizing malate to oxaloacetate in chickpea bacteroids could be a factor that favors the utilization of acetyl-CoA in TCA cycle rather than for PHB synthesis.

• Journal of Plant Biology
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• 제34권4호
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• pp.253-260
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• 1991

Spirodela polyrhiza and Lemna aequinoctialis often occurred at the sites of high ammonium concentration and at the sites of high nitrate concentration, respectively. We investigated the different distribution between two species in relation to the type of nitrogen sources and their concentrations. Our experiments showed that L. aequinoctialis grew faster than S. polyrhiza in nitrate media with lower than 15 mM concentration. The nitrate uptake was also faster in L. aequinoctialis than in S. polyrhiza. However, neither differences in growth nor in uptake patterns between these two species were observed in ammonium media. Glutamine synthetase (GS), glutamate dehydrogenase (GDH) and glutamate synthetase (GOGAT) activities were higher in L. aequinoctialis. In particular, nitrate reductase activity (NRA) in L. aequinoctialis was 12.1 times as high as that in S. polyrhiza. These results showed that the two species responded varyingly to the types of nitrogen sources and their concentrations. Therefore, the difference in geographic distribution between the two species appeared to reflect the interspecific differences in enzyme activities and, subsequently, nitrogen absorption abilities.

• Journal of Microbiology and Biotechnology
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• 제16권2호
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• pp.212-218
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• 2006

Three out of fourteen Microcystis-dominant cyanobacterial blooms in Central India were found to be toxic to mice ($LD_{50}$ ranging from 35-450 mg bloom dry mass/kg body weight). The liver architecture of the treated mice showed characteristic symptoms of hepatotoxicity relative to the untreated controls, with increased enzyme activities of serum lactate dehydrogenase (LDH), serum glutamate oxaloacetate transaminase (SGOT), alkaline phosphatase (ALP), and serum glutamate pyruvate transaminase (SGPT). RP-HPLC revealed the presence of microcystin-LR, microcystin-RR, and desmethyl microcystin-RR in the given region to maximum amounts of 390, 1,030, and $860{\mu}g/g$ bloom dry weight, respectively, corresponding to a maximum of 2.8 mg/l microcystin-LR in the lake water. Further confirmation of the microcystin variants was conducted using a MALDI-TOF MS analysis.

• 한국유기농업학회지
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• 제9권3호
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• pp.85-92
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• 2001

The effect of Dolichos lablab leave extract on enzyme activities in mice blood was investigated in this study to clarify the new useful application of the Plant leaves. There were not significant differences in the enzyme activities in mice blood among treatment fed with the leave extract and non fed control. The feeding treatment with the extract showed a tendency to activity compared to the nun fed control. The activities of glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and lactate dehydrogenase in mice blood at the treatment fed with lead and the leave extract were significantly low compared to their activities at the non fed treatment with the extract, respectively. The choline esterase activity was high at the leave extract feeding. The cadmium dietary treatment showed the same result as the lead treatment. In conclusion, the physiological function of the Jebikong leave was significantly in creased when the mice was stressed by the hear metal intake. Therefore, the plant leave extract would consider the reduction of heart metal effect.

• Archives of Pharmacal Research
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• 제20권2호
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• pp.103-109
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• 1997

The effects of ginseng total saponins (GTS) on hypoxic damage of primary cultures of astrocytes were studied. Hypoxia was created by placing cultures in an air tight chamber that was flushed with 95% $N_2/5%CO_2$ for 15 min before being sealed. Cultures showed evidence of significant cell injury after 24 h of hypoxia (increased lactate dehydrogenase (LDH) content in the culture medium, cell swelling and decreased glutamate uptake and protein content). Addition of GTS (0.1, 0.3 mg/ml) to the cultures during the exposure to hypoxic conditions produced dose-dependent inhibition of the LDH efflux. GTS (0.1, 0.3 mg/ml) also produced significant inhibition of the increased cell volume of astrocytes measured by $[^3H]$ O-methyl-D-glucose uptake under the hypoxic conditions. Decreased glutamate uptake and protein content was inhibited by GTS. These data suggest that GTS prevents astrocytic cell injury induced by severe hypoxia in vitro.

• Journal of Microbiology
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• 제44권3호
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• pp.301-310
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• 2006

Two pathways of ammonium assimilation and glutamate biosynthesis have been identified in microorganisms. One pathway involves the NADP-linked glutamate dehydrogenase, which catalyzes the amination of 2-oxoglutarate to form glutamate. An alternative pathway involves the combined activities of glutamine synthetase, which aminates glutamate to form glutamine, and glutamate synthase, which transfers the amide group of glutamine to 2-oxoglutarate to yield two molecules of glutamate. We have cloned the large subunit of the glutamate synthase (GOGAT) from Salmonella typhimurium by screening the expression of GOGAT and complementing the gene in E. coli GOGAT large subunit-deficient mutants. Three positive clones (named pUC19C12, pUC19C13 and pUC19C15) contained identical Sau3AI fragments, as determined by restriction mapping and Southern hybridization, and expressed GOGAT efficiently and constitutively using its own promoter in the heterologous host. The coding region expressed in Escherichia coli was about 170 kDa on SDS-PAGE. This gene spans 4,732 bases, contains an open reading frame of 4,458 nucleotides, and encodes a mature protein of 1,486 amino acid residues (Mr =166,208). The EMN-binding domain of GOGAT contains 12 glycine residues, and the 3Fe-4S cluster has 3 cysteine residues. The comparison of the translated amino acid sequence of the Salmonella GOGAT with sequences from other bacteria such as Escherichia coli, Salmonella enterica, Shigella flexneri, Yersinia pestis, Vibrio vulnificus and Pseudomonas aeruginosa shows sequence identity between 87 and 95%.

• BMB Reports
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• 제36권6호
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• pp.545-551
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• 2003

A cDNA of bovine brain glutamate dehydrogenase (GDH) was isolated from a cDNA library by recombinant PCR. The isolated cDNA has an open-reading frame of 1677 nucleotides, which codes for 559 amino acids. The expression of the recombinant bovine brain GDH enzyme was achieved in E. coli. BL21 (DE3) by using the pET-15b expression vector containing a T7 promoter. The recombinant GDH protein was also purified and characterized. The amino acid sequence was found 90% homologous to the human GDH. The molecular mass of the expressed GDH enzyme was estimated as 50 kDa by SDS-PAGE and Western blot using monoclonal antibodies against bovine brain GDH. The kinetic parameters of the expressed recombinant GDH enzymes were quite similar to those of the purified bovine brain GDH. The $K_m$ and $V_{max}$ values for $NAD^+$ were 0.1 mM and $1.08\;{\mu}mol/min/mg$, respectively. The catalytic activities of the recombinant GDH enzymes were inhibited by ATP in a concentration-dependent manner over the range of 10 - $100\;{\mu}M$, whereas, ADP increased the enzyme activity up to 2.3-fold. These results indicate that the recombinant-expressed bovine brain GDH that is produced has biochemical properties that are very similar to those of the purified GDH enzyme.

• Journal of Plant Biology
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• 제29권4호
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• pp.233-242
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• 1986

In order to pursue some physiological studies on organogenesis in ginseng tissue culture, ginseng root explants were cultured on a modified MS medium containing NAA and kinetin. The activities of peroxidase and some enzymes were investigated and their isoenzyme patterns were also observed. The activity of peroxidase decreased by 20% in one week's culture and increased thereafter by 80% in culturing for 7 weeks compared with the control group. Glucose-6-phosphate dehydrogenase activity increased by 400% after culturing for 5 weeks and increased during the days preceeding root formation. The activities of glutamate dehydrogenase and acid phosphatase also increased during the culture. After 3 weeks' culture, new peroxidase isozyme (pH 7.6) appeared and 7 weeks' culture, another new peroxidase isozyme (pH unidentified) appeared. These patterns were also identified by using FPLC. After 7 weeks' culture, a new esterase isozyme of pH 8.5 appeared and isozyme patterns of acid phosphatase were quite changed compared with the isozyme patterns of tissue cultured for 5 weeks. In so far as these new isoenzymes appear distinctively after 7 weeks' culture, root differentiation is supposed to be induced after 7 weeks' culture.

• 한국막학회:학술대회논문집
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• 한국막학회 1994년도 춘계 총회 및 학술발표회
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• pp.26-27
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• 1994

효소는 생체내의 합성, 분해, 산화, 환원 등 복잡한 화학반응이 상온, 상압, 중성부근에서 효율적으로 진행되게 하는 단백질이 주성분인 유기촉매이다. 현재 알려져 있는 효소의 종류는 수백만종 이상으로 추정되며 그 중 100여종 이상은 순수한 결정상태이며 약 600종 정도는 어느 정도 순수하게 징제되고 있다. 이들 효소의 분자량은 Ribonuclease의 12,700에서 부터 L-Glutamate dehydrogenase나 Carboxylase의 1,000,000 이상으로 광범위하다.

• Journal of Plant Biology
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• 제20권1호
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• pp.1-5
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• 1977

Horizontal starch gel electrophoresis in three buffers was used to compare the electrophoretic patterns in three cherry species, wild Prunus subhirtella, cultivated P. yedoensis and P. donarium. Electrophoretic patterns of glutamate oxaloacetate, transaminase-2(GOT-2), malate dehydrogenase-2(MDH-2), and phosphoglucose isomerase(PGI) in three species showed strong evidence that P. yedoensis might be originated by hybridization between P. subhirtella and P. donarium.