• The Korean Journal of Physiology
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• 제26권1호
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• pp.89-97
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• 1992

In hypoxic tissue conditions, pyruvate can not enter the Krebs cycle and lactic acid, produced from pyruvate, accumulates to induce lactic acidosis. Pyruvate, However, can also be converted to alanine by glutamate pyruvate transaminase, that could be enhanced by glutamate. Therefore, it would be a fundamental measure to treat the lactic acidosis in tissue hypoxic conditions when one can convert the accumulated lactic acid, through pyruvate, to alanine. To test the above hypothesis, we induced a lactic acidosis in cats and the effect of glutamate on recovery of acid base state and removal of the lactic acid from blood were assessed and the results were compared with those of bicarbonate administration, which is one of the most frequently used conventional measure for correction of the acid base state during lactic acidosis. The results were that glutamate and combined glutamate bicarbonate solutions not only restored the acid base status completely from the lactic acidosis in an hour or two, but also restored the blood level of lactate partially. We concluded that administration of glutamate solution to convert pyruvate into alanine is effective in preventing lactic acid accumulation and treating lactic acidosis.

• The Korean Journal of Physiology and Pharmacology
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• 제2권1호
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• pp.41-48
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• 1998

The present study was undertaken to characterize homocysteic acid (HCA)-and cysteic acid (CA)-mediated formation of inositol phosphates (InsP) in primary culture of rat cerebellar granule cells. HCA and CA stimulated InsP formation in a dose-dependent manner, which was prevented by the N-methyl-D-aspartate (NMDA) receptor antagonist D,L-2-amino-5-phosphopentanoic acid (APV). CA-, but not HCA-, mediated InsP formation was in part prevented by the metabotropic glutamate receptor antagonist ?${\alpha}$-methyl-4-carboxyphenylglycine ($({\pm})$-MCPG). Both HCA- and CA-mediated increases in intracellular calcium concentration were completely blocked by APV, but were not altered by $({\pm})$-MCPG. CA-mediated InsP formation was in part prevented by removal of endogenous glutamate. In contrast, the glutamate transport blocker L-aspartic acid-${\beta}$-hydroxamate synergistically increased CA responses. These data indicate that in cerebellar granule cells HCA mediates InsP formation wholly by activating NMDA receptor. In contrast, CA stimulates InsP formation by activating both NMDA receptor and metabotropic glutamate receptor, and in part by releasing endogenous glutamate into extracellular milieu.

• KSBB Journal
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• 제15권2호
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• pp.195-200
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• 2000

네 종류의 질소원 yeast extract, sodium glutamate, peptone, tryptone과 각 질소원의 농도 및 포도당의 초기 농도가 해양 미생물 Thraustochytrium aureum ATCC 34304의 linoleic acid 생산성에 미치는 영향을 규명하여 다음의 결과를 얻었다. 초기 당 농도를 10 g/L로 하고 질소원으로는 sodium glutamate를 사용하였을 때 균체 단위 질량에 대해 생성된 지질의 중량 분율이 최대값 0.302 mg/g를 나타내었으며, 균체에 대한 linoleic acid 중량 분율도 8%로 최대값을 나타내었다. Lino-leic acid의 생성속도는 질소원으로 peptone과 sodium gluta-mate를 사용하였을 경우 다른 질소원으로 peptone과 sodium gluta-mate를 사용하였을 경우 다른 질소원을 사용하였을 때 보다 2.5 배까지 높은 수치를 나타내었다. 초기 당 농도가 증가하면 linoleic acid의 생산성은 상승하나 당 농도 30 g/L 이상에서는 그 상승폭이 대단히 완만하였다. 초기 당 농도가 30 g/L 경우 질소원으로 peptone을 사용하였을 때는 linoleic acid의 생산량이 200 mg/L, sodium glutamate를 사용하였을 때는 130 mg/L를 나타내었다. 질소원의 농도가 증가하면 균체 내에 생성되는 지질의 양도 증가하는 경향을 나타내었다. 질소원이 sodium glutamate인 경우 농도 1 g/L까지는 지질의 함량이 뚜렷한 증가현상을 나타내었으나 농도 1.0 내지 2.0 g/L 이상에서는 질소원의 농도가 증가하면 지질의 생성량이 감소하였다.

• 대한화학회지
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• 제37권1호
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• pp.136-140
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• 1993

새로운 methotrexate 중간체인 diethyl N-[4-{[(2,4-diamino-6-yl)methyl]-amino}benzoyl]-L-glutamate(10)를 합성하기 위하여 p-nitrobenzoic acid를 chlorination한 다음 L-glutamic acid와 coupling하고 이를 esterification한 후, 환원과 methylation시켜 diethyl N-(4-methylaminobenzoyl)-L-glutamate(7)를 합성하였다. 이 화합물(7)을 DMF 존재하에서 NaH와 allyl chloride를 가하여 allylation한 다음 여기에 $IN_3$ addition 반응으로 diethyl-p-[N-(2-azido-3-iodopropyl)-N-methyl]aminobenzoyl-L-glutamate(9)를 합성하였다. 이 화합물(9)을 2,4,5,6-tetraaminopyrimidine hydrochloride와 cyclization시켜 methotrexate diethylester를 얻었다.

• 생약학회지
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• 제51권1호
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• pp.30-35
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• 2020

We previously reported that caffeic acid isolated from Lonicera japonica showed potent neuroprotective activities against glutamate injured neuronal cell death in primary cortical cells. In this study, we tried to confirm the neuroprotective activity in glutamate injured HT22 cells and elucidate mechanisms of neuroprotective action of caffeic acid. We used glutamate induced HT22 cell death as a bioassay system. The compound decreased reactive oxygen species increased by high concentration of glutamate treatment in HT22 cells. Also, Ca²⁺ concentration was decreased by this compound. This compound made mitochondrial membrane potential maintain to normal condition. This also affected anti-oxidative enzymes and glutathione contents. Treatment of this compound increased not only glutathione reductase and peroxidase to the control level and also amount of glutathione, an endogeneous antioxidant. These experimental results showed that caffeic acid isolated from L. japonica exerted potent neuroprotective activity through the anti-oxidative pathway.

• KSBB Journal
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• 제29권6호
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• pp.426-431
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• 2014

pH controlled batch reactor and bubble column reactors have been developed in this research. They were used to produce high concentration of GABA and to determine optimal pH for GABA production. Glutamate decarboxylase (GAD) was isolated from recombinant E. coli and used for GABA production from monosodium glutamate (MSG). pH control was inevitable because the pH increased with MSG consumption. GAD showed highest activity at acidic conditions at pH 5.5 but the optimal pH for GABA production was pH 6.0. When 1.5 mole of MSG was used as reactant, the 1.05 mole of GABA was produced after 10 hrs batch reaction. Using bubble column reactors, 80 % of MSG was converted to GABA for 6 hrs reaction and 1.2 mole of GABA was produced.

• Journal of Microbiology and Biotechnology
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• 제27권9호
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• pp.1664-1669
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• 2017

Gamma-aminobutyric acid is a precursor of nylon-4, which is a promising heat-resistant biopolymer. GABA can be produced from the decarboxylation of glutamate by glutamate decarboxylase. In this study, a synthetic scaffold complex strategy was employed involving the Neurospora crassa glutamate decarboxylase (GadB) and Escherichia coli GABA antiporter (GadC) to improve GABA production. To construct the complex, the SH3 domain was attached to the N. crassa GadB, and the SH3 ligand was attached to the N-terminus, middle, and C-terminus of E. coli GadC. In the C-terminus model, 5.8 g/l of GABA concentration was obtained from 10 g/l glutamate. When a competing pathway engineered strain was used, the final GABA concentration was further increased to 5.94 g/l, which corresponds to 97.5% of GABA yield. With the introduction of the scaffold complex, the GABA productivity increased by 2.9 folds during the initial culture period.

• 한국미생물·생명공학회지
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• 제43권3호
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• pp.300-305
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• 2015

효율적인 γ-aminobutyric acid (GABA)의 생산을 위해 Lactobacillus plantarum WCFS1로부터 글루탐산 탈탄산효소(glutamate decarboxylase, GAD)를 대장균에 발현, 정제 후 silica beads에 covalent coupling 방법을 이용하여 고정화하였다. 고정화된 효소의 특성을 고정화하지 않은 효소와 비교한 결과, 모든 pH의 범위(pH 3.5–6.0)에서 80% 이상의 활성을 나타내었으며 pH 안정성과 열 안정성 모두 증대되었다. 이 고정화 효소를 packed-bed reactor에 충진하여 GABA의 생산성을 확인한 결과 1리터당 1시간에 최대 41.7 g의 GABA 생산이 가능한 것으로 확인되었다.

• Journal of Microbiology and Biotechnology
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• 제29권11호
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• pp.1745-1748
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• 2019

Gamma-aminobutyric acid (GABA) plays important roles in host physiology. However, the effects of GABA are greatly restricted due to its low bioavailability in the human body. Here, a high acid-tolerance GABA-producing strain, Lactobacillus brevis Bmb5, was isolated from kimchi. Bmb5 converted glutamate to GABA (7.23 ± 0.68 ㎍/μl) at a rate of 72.3%. The expression of gadB gene, encoding the enzyme involved in the decarboxylation of glutamate to GABA, was decreased upon incubation. Our findings indicate GABA production in Bmb5 is not directly correlated with gadB gene expression, providing new insight into the mechanisms underlying GABA production in Lactobacillus.

• 한국미생물·생명공학회지
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• 제2권3호
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• pp.141-147
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• 1974

초산으로 부터의 글루타민산 발효생성을 목적으로 Brevibacterium flavum nov. sp. D2209B 균주를 이용한 발효조건에 관하여 시험 검토한 결과는 다음과 같다. 1. 초산농도는 배지 l 당 30g 하일 때 L-GA생성이 좋았다. 2. KH$_2$PO$_4$, MgSO$_4$, FeCl$_3$, MnC1$_2$ 및 NaCl 등의 무기염류의 침가는 L-GA 생성을 위하여 필수적이며 이들 무기염의 농도차에 의한 현저한 영향은 볼 수 없었다. 3. Biotin의 농도는 l당 0.3r 이하의 한정된 범위에서 L-GA 생성이 가장 좋았다. 4. L-GA 생성을 위한 최적온도는 3$0^{\circ}C$이며 최적 pH는 7.5~8.5 였다 5. Succinic acid와 malic acid의 첨가로 L-GA 생성은 증가되었다. 6. 배양도중에 있어서의 penicillin 첨가는 L-GA생성을 촉진하며 발효 16시간째 배지 l당 20 unit를 첨가하였을 때 가장 효과적이였다. 7. 전배양시간은 16~20시간 배양이 가장 적당하였다.