• 한국미생물·생명공학회지
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• 제49권1호
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• pp.9-17
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• 2021

A γ-aminobutyric acid (GABA)-producing microorganism was isolated from galchi (hairtail fish, Trichiurus lepturus) jeotgal, a Korean salted and fermented seafood. The G144 isolate produced GABA excessively when incubated in MRS broth containing monosodium glutamate (MSG, 3%, w/v). G144 was identified as Lactobacillus brevis through 16S rRNA and recA gene sequencing. gadB and gadC encoding glutamate decarboxylase (GAD) and glutamate/GABA antiporter, respectively, were cloned and gadB was located downstream of gadC. The operon structure of gadCB was confirmed by reverse transcription (RT)-polymerase chain reaction. gadB was overexpressed in Escherichia coli and recombinant GAD was purified and its size was 54.4 kDa as evidenced by SDS-PAGE results. Maximum GAD activity was observed at pH 5.0 and 40℃ and the activity was dependent on pyridoxal 5'-phophate. The K_m and V_max of GAD were 8.6 mM and 0.01 mM/min, respectively.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1994년도 춘계학술대회 and 제3회 신약개발 연구발표회
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• pp.270-270
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• 1994

돼지 뇌조직으로부터 순수 분리 정제된 Glutamate decarboxylase (GAD)는 효소 dimer당 0.8mole 보조 인자인 pyridoxal-5-phosphate(PLP)가 강하게 binding되어 있었다. 이러한 부분적으로 resolved된 효소에 외부로부터 PLP를 넣어주면 효소의 활성도는 최대값으로 증가하였다. 정제된 GAD는 sulfydryl시약에 의한 화학변형에 의하여 효소의 활성도를 상실하였으며 환원제인 dithiothreitol이나 2-mercaptoethanol의 첨가에 의하여 효소의 활성도가 복구되는 것으로 보아 효소의 활성부위의 활성에 직접 관여하는 중요한 cysteinyl잔기가 존재하고 있는 것을 알 수 있다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1995년도 춘계학술대회
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• pp.73-73
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• 1995

We investigated the effect of derivatized phospholipid, P-pyridoxyl dipalmiuylphosphatidylethanolamine (P-pyr-DPPE), on the catalytic activity of purified porcine brain glutamate decarboxylase(GAD) which catalyzes the synthesis of GABA known as major inhibitory neurotransmitter in CNS. When the P-pyr-DPPE was incorporated into dipalmitdylphosphatidylcholine(DPPC) or phosphatidylserine(PS) vesicles, these vesicles enhanced the catalytic activity of GAD. P-pyr-DPPE also interacted with apoglutamate decarboxylase(apoGAD) and produced the free pyridoxal-5-phosphate(PLP) which is the natural cofactor of GAD. This result indicated that apoGAD catalyzed the cleavage reaction of the P-pyridoxyl moiety of the derivatized phopholipid to generate free PLP, and then free PLP bound to the apoGAD resulting in restroration of the catalytic activity of the enzyme.

• Preventive Nutrition and Food Science
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• 제9권4호
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• pp.324-329
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• 2004

In order to investigate the molecular mechanism of $\gamma$-aminobutyric acid (GABA) production in lactic acid bacteria, we cloned a glutamate decarboxylase (GAD) gene from Lactobacillus plantarum using polymerase chain reaction (PCR). One PCR product DNA was obtained and inserted into a TA cloning vector with a T7 promoter. The recombinant plasmid was used to transform E. coli. The insertion of the product was con­firmed by EcoRI digestion of the plasmid purified from the transformed E. coli. Nucleotide sequence analysis showed that the insert is a full-length Lactobacillus plantarum GAD and that the sequence is $100\%$ and $72\%$ identical to the regions of Lactobacillus plantarum GAD and Lactococcus lactis GAD sequences deposited in GenBank, accession nos: NP786643 and NP267446, respectively. The amino acid sequence deduced from the cloned Lactobacillus plantarum GAD gene showed $100\%$ and $68\%$ identities to the GAD sequences deduced from the genes of the NP786643 and NP267446, respectively. To express the GAD protein in E. coli, an expression vector with the GAD gene (pkk/GAD) was constructed and used to transform the UT481 E. coli strain and the expression was confirmed by analyzing the enzyme activity. The Lactobacillus plantarum GAD gene obtained may facilitate the study of the molecular mechanisms regulating GABA metabolism in lactic acid bacteria.

• 미생물학회지
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• 제47권4호
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• pp.316-322
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• 2011

김치로부터 분리한 유산균 Lactobacillus sakei OPK2-59는 ${\gamma}$-aminobutyric acid (GABA) 생성능력과 glutamate decarboxylase(GAD) 활성을 보유하고 있음이 확인되었다. Lactobacillus sakei OPK2-59를 59.13 mM과 177.40 mM monosodium glutamate (MSG)가 함유된 MRS 배지에서 배양하면 균주의 성장을 위한 최적 온도범위와 pH는 각각 $25-37^{\circ}C$와 6.5였다. 59.13 mM과 177.40 mM MSG 함유 MRS 배지에서 배양온도 $25^{\circ}C$ 조건에서, 48시간 배양하였을 경우 MSG의 GABA 전환율은 각각 99.58%와 31.00%였다. 또한 Lactobacillus sakei OPK2-59 세포추출액을 이용하여 MSG를 GABA로 전환할 수 있었으며, 추출물에 의한 GABA 전환율은 $30^{\circ}C$, pH 5 조건에서 78.51%로 가장 높았다. 세포추출액에 의한 MSG의 GABA 전환에 미치는 무기염의 영향을 조사한 결과 $CaCl_2$, $FeCl_3$, $MgCl_2$를 첨가한 반응액에서 염을 넣지 않고 반응한 control보다 GABA 전환율이 2-3배 증진되는 것으로 조사되었다. 이러한 결과들은 김치 유산균 Lactobacillus sakei OPK2-59의 GABA 생성능은 유산균 세포 내에 존재하는 GAD에 의한 것이며, GAD에 의한 GABA 전환율은 무기염에 의하여 증진될 수 있음을 제안해 주는 것이다.

• The Plant Pathology Journal
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• 제16권2호
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• pp.63-69
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• 2000

No Abstract.See Full-text

• 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.

• Journal of Microbiology and Biotechnology
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• 제27권7호
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• pp.1216-1222
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• 2017

To develop starters for the production of functional foods or materials, lactic acid bacteria producing ${\gamma}-aminobutyric$ acid (GABA) were screened from jeotgals, Korean fermented seafoods. One isolate producing a high amount of GABA from monosodium $\text\tiny{L}$-glutamate (MSG) was identified as Enterococcus avium by 16S rRNA gene sequencing. E. avium M5 produced $18.47{\pm}1.26mg/ml$ GABA when incubated for 48 h at $37^{\circ}C$ in MRS broth with MSG (3% (w/v)). A gadB gene encoding glutamate decarboxylase (GAD) was cloned and overexpressed in E. coli BL21 (DE3) using the pET26b (+) expression vector. Recombinant GAD was purified through a Ni-NTA column and the size was estimated to be 53 kDa by SDS-PAGE. Maximum GAD activity was observed at pH 4.5 and $55^{\circ}C$and the activity was dependent on pyridoxal 5'-phosphate. The $K_m$ and $V_{max}$ values of GAD were $3.26{\pm}0.21mM$ and $0.0120{\pm}0.0001mM/min$, respectively, when MSG was used as a substrate. Enterococcus avium M5 secretes a lot of GABA when grown on MRS with MSG, and the strain is useful for the production of fermented foods containing a high amount of GABA.

• 한국약용작물학회:학술대회논문집
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• 한국약용작물학회 2008년도 추계학술발표회
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• pp.259-260
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• 2008

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.639-640
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• 2005