• 대한화학회지
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• 제34권2호
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• pp.203-210
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• 1990

의약 전달체에 사용되는 생체분해성 고분자로서 L-lactic acid 와 L-glutamic acid가 각기 다른 조성비로 이루어진 공중합체를 합성하였다. Poly (L-lactide)는 zink oxide를 이용하여 합성하였으며, Poly (L-lactide) 말단에 3-Amino-l-propanol을 도입시킨 다음 이미 합성된 γ-benzyl-L-glutamate-N-carboxyanhydride (γ-BLG-NCA)를 개환중합시켜서 block copoly (L-lactide-γ-benzyl-L-glutamate)를 합성하였다. NMR로써 L-lactide와 γ-BLG-NCA가 서로 일정한 비율로 이루어진 공중합체가 합성되었음을 확인하였으며, 생성된 공중합체들의 열적성질은 시차주사열량계법 및 열무게 측정법으로 조사하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제1권6호
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• pp.699-705
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• 1997

Although it is known that neuronal cell death during development occurs by apoptosis, the mechanisms underlying excitatory amino acid-induced neuronal cell death remain poorly understood. In this study we have examined the mechanism by which L-glutamate, an excitatory amino acid neurotransmitter, induces cell death in PC12 cell lines. To characterize cell death, we employed sandwich enzyme-linked immunosorbent assay(ELISA) method for cellular DNA fragmentation, DNA agarose gel electrophoresis and chromatin staining by acridine orange and ethidium bromide after treating the PC12 cells with L-glutamate. L-Glutamate caused dose-dependent cell death with a maximum at 24 hrs after the treatment. These cellular fragmentation was blocked by pretreatment of MK-801, a noncompetitive N-methyl-D-aspartic acid(NMDA) receptor antagonist, and nerve growth factor(NGF). Analysis of DNA integrity from L-glutamate-treated cells revealed cleavage of DNA into regular sized fragments, a biochemical hallmark of apoptosis. The PC12 cells that were induced to die by L-glutamate treatment exhibited classical chromatin condensation under the light microscopy after acridine orange and ethidium bromide staining. These results suggest that apoptosis is one of the key features that are involved in L-glutamate-induced excitotoxic cell death in PC12 cells, and these cell death are mediated by NMDA receptor and depend on NGF.

• 한국버섯학회지
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• 제11권4호
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• pp.181-186
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• 2013

${\gamma}$-Aminobutyric acid(GABA) is a four carbon non-protein amino acid that has several well-known physiological functions, such as a postsynaptic inhibitory neurotransmitter in the brain and induction of hypotensive and tranquilizer effects. A lactic acid bacterium was isolated from button mushroom bed, which is showing high GABA productivity by TLC or HPLC analysis. The strain was identified as Lactobacillus hilgardii by analysis of 16S rDNA gene sequence. When the maximum production of GABA by L. hilgardii was investigated with various concentration of monosodium glutamate, the yield of GABA reached to be 53.65 mM at 1% mono sodium glutamate (MSG) in flask cultivation. A Glutamate decarboxylase (GAD) enzyme, which was known to convert MSG to GABA, was purified from a cell-free extract of L. hilgardii and the molecular weights of purified GAD was estimated to 60,000 by SDS-PAGE. The optimum pH and temperature of GAD were at pH4.6 and at $37^{\circ}C$, respectively. The GAD activity was increased by the addition of sulfate ions such as ammonium sulfate, sodium sulfate and magnesium sulfate, indicating that the increase of hydrophobic interaction causes the increase of GAD activity.

• 한국식품영양과학회지
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• 제19권4호
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• pp.342-348
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• 1990

Effects of various monosodium glutamate(MSG_ concentration (0-400mg%) on the quality of Korean cabbage kimchi during fermentation at 2$0^{\circ}C$ were investigated. The growth of lactic acid bacteria titratable acidity pH content of thiamine ascorbic acid $\beta$-carotene and sensory evaluation were observed in the presencve of MSG. Titratable acidity was increased in the kimchi contained MSG during the fermentation.l Wheeas the changes of pH in the kimchi contained MSG were similar to those in control, Maximum growth of lactic acid bacteria was observed after 49 hour of fermentation in kimchi contained with 200mg MSG. The might be due to the fact that MSG was given optimum pH for acid bacteria growth because of its buffering action. Therefore the periods of kimchi fermentation were reduced by addition of MSG, MSG also affected on the stability of ascorbic acid thiamine and $\beta$-carotene. According of MSG. MSG also affected on the stability of ascorbic acid thiamine and $\beta$-carotene. According to sensory evaluation MSG reduced sour taste in kimchi which increased edible periods.

• 대한약리학회지
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• 제31권2호
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• pp.141-144
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• 1995

뇌간의 세로트닌 신경계는 내재성 하행성 동통억제계(endogenous descending pain inhibitory system)에 있어서 중추적인 역할을 하고 있다. 뇌간의 세로토닌 신경세포에 대한 glutamate 수용체 중 N-methyl-D-aspartic acid-(NMDA-) 및 non-NMDA 수용체 효현제들의 작용을 알아보기 위하여, 쥐의 태자(태생 14일)로부터 뇌간을 분리하여 10일 동안 배양한 후 5-hydroxytryptamine(5-HT)의 분비에 대한 각 glutamate 수용체 효현제들이 영향을 연구하였다. Glutamate를 $10\;{\mu}M$에서 $1000\;{\mu}M$까지 농도를 변화하여 30분 동안 배지에 가한 후, 배지내에 분비되는 세로토닌을 측정한 결과, 농도 의존적으로 세로토닌의 분비가 증가되었다. Glutamate 수용체 중에서 NMDA 수용체 효현제인 NMDA를 $10\;{\mu}M$에서 $1000\;{\mu}M$까지 농도를 변화하여 30분 동안 배지에 가한 후, 배지내에 분비되는 세로토닌을 측정한 결과, 농도 의존적으로 세로토닌의 분비가 증가되었다. Non-NMDA 수용체 효현제인 kainate 및 AMPA를 $3\;{\mu}M$에서 $300\;{\mu}M$까지 농도를 변화하여 배지에 처리한 결과, 각 효현제에 의해 농도 의존적으로 세로토닌의 분비가 증가됨을 관찰하였다. 이상의 연구결과, 쥐의 태자(태생 14일)로부터 분리하여 10일동안 배양한 뇌간의 세로토닌 신경세포에 있어서 glutamate, NMDA, kainate 및 AMPA 모두 5-HT의 분비를 자극함으로써, NMDA- 및 non-NMDA 수용체 모두 5-HT의 분비에 관여하고 있음을 나타낸다.

• 한국미생물·생명공학회지
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• 제17권4호
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• pp.379-384
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• 1989

E. coli K-12 pgln 6가 지니는 glutamine synthetase와 반응계에 ATP 공급을 위하여 빵효모를 동시에 이용하여 glutamate로부터 glutamine의 생산이 수행되었다. Glutamine synthetase의 효소원으로서 E. coli K-12 pgln 6 생균체를 사용하였을 때, 18시간 배양 후에 11.8g/ι의 glutamine이 생산되었다(기질인 glutamate 기준으로 60%의 수율). 부분정제된 glutamine synthetase를 이용하여, 5시간 후에 19.8g/ι의 glutamine이 생산되었다. 이 양은 glutamate 기준으로 90% 수율에 해당되는 것이다.

• Animal cells and systems
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• 제1권3호
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• pp.467-473
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• 1997

Taurine (2-aminoethanesulfonic acid), one of bioactive amino acid in the mammalian brain, is known to exert inhibitory effects on neurons via GABA receptor. In the present study, we examined effects of taurine on glutamateinduced neurotoxicity on hippocampal neuron cell culture using cell counting method and lactate dehydrogenase (LDH) assay. After 10 d of culture, cells were stimulated with appropriate drugs. Only 43% of cultured neuronal cells survived at one day after stimulation with 500 uM L-glutamate for 10 min. Survival rate was enhanced by 82% in the presence of 10 mM taurine. LDH activity from the culture supernatant incubated with a combination of L-glutamate and taurine was less than half of that with L-glutamate alone. In the next series of experiments, interleukin-6 (IL-6) mRNA expression in cultured astrocytes was investigated using reverse tanscription-PCR (RT-PCR). IL-6 mRNA was detected in the astrocytes stimulated with L-glutamate in a dose-dependent manner, while not detected in the unstimulated control astrocytes. The expression of IL-6 mRNA caused by 10 mM glutamate was inhibited by taurine, but not by GABA. These findings demonstrated a neuroprotective action of taurine against glutamate-induced toxicity.

• 한국미생물·생명공학회지
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• 제47권1호
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• pp.139-147
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• 2019

Glutamate decarboxylase catalyzes the conversion of glutamate to gamma-aminobutyric acid (GABA), contributing to pH homeostasis through proton consumption. The reaction is the first step toward the GABA shunt. To date, the enzymes involved in the glutamate metabolism of Photobacterium damselae subsp. piscicida have not been elucidated. In this study, an open reading frame of P. damselae subsp. piscicida, showing homology to the glutamate decarboxylase or putative pyridoxal-dependent aspartate 1-decarboxylase genes, was isolated and cloned into an expression vector to produce the recombinant enzyme. Preliminary gas chromatography-mass spectrometry characterization of the purified recombinant enzyme revealed that it catalyzed not only the decarboxylation of glutamate but also the transamination of GABA. This enzyme of P. damselae subsp. piscicida could be bifunctional, combining decarboxylase and transaminase activities in a single polypeptide chain.

• Applied Biological Chemistry
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• 제51권1호
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• pp.79-83
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• 2008

본 연구에서는 신경독소일 뿐만 아니라 흥분성 신경전달물질로 잘 알려져 있는 glutamate 세포독성이 산화적 손상과 관련하고 있고, 여기에 방어효과를 보이는 제비꽃 추출물에 관하여 연구하였다. MTT reduction assay를 통하여 glutamate의 세포독성을 확인하였고 ascorbic acid와 같은 대표적인 항산화제를 처리한 후 광학 현미경을 이용한 형태학적 변화를 관찰하였다. N18-RE-105 세포주에 최종 농도 20mM의 glutamate를 처리 하면 40.8% 의 생존율을 보이는데 반하여 ascorbic acid 500 ${\mu}M$ 최종농도로 처리하였을 때 85.3%의 세포 생존율을 확인할 수 있었다. 그리고 신경세포 보호효과를 가지는 제비꽃을 methanol, ethanol, acetone 추출한 뒤 MTT reduction assay를 이용하여 활성을 확인하였으며 그 중 acetone 추출물을 최종농도 50, 100 ${\mu}g/ml$를 처리 시 76.8%, 79.4%로 가장 높은 세포 생존율을 확인할 수 있었다. 이 결과는 N18-RE-105 세포주의 형태학적 변화와 LDH release assey에서도 일치하는 결과를 확인하였다.

• 유기물자원화
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• 제5권1호
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• pp.25-32
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• 1997

토양에서 분리한 광합성 세균인 Rhodospirillum rubrum N-1 균주에 의한 ${\delta}$-aminolevulinic acid (ALA) 생산에 있어서 levulinic acid (LA) 및 ALA 생합성 경로의 첨가효과를 검토하였다. Glutamate를 제외한 Lascelles의 기본배지에 LA를 배양초기에 10mM, 이후 대수기 중기에 30 mM을 첨가한 결과 균체외의 ALA 생산성은 최고 45 mg/l 도달, LA 미첨가 대비 23배 증가하였다. ALA 생합성의 전구물질인 glycine-succinate ($C_4$) 및 glutamate ($C_5$)의 feeding 효과는 배양초기/대수기 중기에 LA 10/30 mM을, glutamate 30 mM/30 mM을 각각 첨가하는 한편, 대수기 중기에 10 mM 농도의 $C_4$ 전구물질을 별도로 첨가배양함으로써 미첨가 대비의 ALA 생산성이 약 40배 (75 mg/l) 증가하였다.