• Journal of Life Science
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• v.20 no.7
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• pp.1005-1011
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• 2010

$\gamma$-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system. GABA transporters (GATs) control extracellular GABA levels by reuptake of released GABA from the synaptic cleft. However, how GATs are regulated has not yet been elucidated. Here, we used the yeast two-hybrid system to identify the specific binding protein(s) that interacts with the carboxyl (C)-terminal region of GAT1, the major isoform in the brain and find a specific interaction with the ubiquitin-specific protease 14 (Usp14), a deubiquitinating enzyme. Usp14 protein bound to the tail region of GAT1 and GAT2 but not to other GAT members in the yeast two-hybrid assay. The C-terminal region of Usp14 is essential for interaction with GAT1. In addition, these proteins showed specific interactions in the glutathione S-transferase (GST) pull-down assay. An antibody to GAT1 specifically co-immunoprecipitated Usp14 from mouse brain extracts. These results suggest that Usp14 may regulate the number of GAT1 at the cell surface.

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.316-322
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• 2011

Lactobacillus sakei OPK2-59 isolated from kimchi was found to have ${\gamma}$-aminobutyric acid (GABA) producing ability and glutamate decarboxylase (GAD) activity. When the Lactobacillus sakei OPK2-59 was cultured in MRS broth with 59.13 mM and 177.40 mM monosodium glutamate (MSG), the optimum temperature range and pH for growth were $25-37^{\circ}C$ and pH 6.5, respectively. GABA conversion rates in MRS broth with 59.13 mM and 177.40 mM MSG were 99.58% and 31.00%, respectively at $25^{\circ}C$ and 48 h of cultivation. By using the cell free extract of Lactobacillus sakei OPK2-59, MSG was converted to GABA and the conversion rate was 78.51% at $30^{\circ}C$, pH 5. Conversion of MSG to GABA was enhanced by adding salts such as $CaCl_2$, $FeCl_3$, $MgCl_2$. These data suggest that the ability of Lactobacillus sakei OPK2-59 to produce GABA results from the activity of GAD in the cells and GABA conversion by the cell extract containing GAD can be enhanced by $CaCl_2$, $FeCl_3$, $MgCl_2$.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.1006-1010
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• 2007

This study investigated changes in the chemical and functional components of germinated rough rice for the development of functional foods. The chemical components that were determined for 'Ilpum', 'Goami2', 'Keunnun', and 'Heugkwang' rough rice cultivars included dietary fiber, free sugars, free amino acids, and functional components such as tocopherols and ${\gamma}$-oryzanol. The crude protein, fat, total dietary fiber, and free sugar contents of the rough rice increased significantly after germination. The essential amino acid content was particularly increased. After the germination of the 'Ilpum', 'Goami2', 'Keunnun', and 'Heugkwang' varieties, the following increases were found: ${\gamma}$-aminobutyric acid increased 2.4, 2.5, 6.1, and 3.4 times, respectively; ${\alpha}$-tocopherol, ${\alpha}$-tocotrienols, and ${\gamma}$-tocotrienols increased significantly; and ${\gamma}$-oryzanol content increased 0.8, 1.1, 1.5, and 1.2 times, respectively. Thus, germinated rough rice has the potential to be used as a healthy and functional food ingredient.

• Journal of Applied Biological Chemistry
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• v.56 no.2
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• pp.89-93
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• 2013

Gamma-aminobutyric acid (GABA) aminotransferase (gabT) and succinic semialdehyde dehydrogenase (gabD) genes from Pseudomonas fluorescens KCCM 12537 were cloned into a single pETDuet-1 vector and co-expressed in Escherichia coli BL21(DE3) simultaneously. The mixture of both enzymes, called GABase, is the key enzyme for the enzymatic analysis of GABA. The molecular mass of the GABA aminotransferase and succinic semialdehyde dehydrogenase were determined to be 52.8 and 46.7 kDa following computations performed with the pI/Mw program, respectively. The GABase activity between pH 6.0 and 9.0 for 24 h at $4^{\circ}C$ remained over 75%, but under pH 6.0 decreased rapidly. The GABase activity between 25 and $35^{\circ}C$ by the treatment at pH 8.6 for 30 min remained over 80%, but over $35^{\circ}C$ decreased rapidly. When the activity against GABA was defined as 100%, the purified GABase activity against 5-aminovaleric acid having a similar structure to GABA showed 47.7% and GABase activity against ${\beta}$-alanine, ${\varepsilon}$-amino-n-caproic acid, $_L$-ornithine, $_L$-lysine, and $_L$-aspartic acid showed between 0.3 to 2.3%. The GABA content was analyzed with this co-expressed GABase, compared with the other GABase which was available commercially. As a result, the content of GABA extracted from brown rice, dark brown rice, and black rice were $26.4{\pm}3.5$, $40.5{\pm}4.7$ and $94.7{\pm}9.3{\mu}g/g$, which were similar data of other GABase in the error ranges.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.8
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• pp.979-985
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• 2017

This study was carried out to investigate the production of ${\gamma}$-aminobutyric acid (GABA) by lactic acid bacteria and to manufacture GABA using rice bran extract-based optimum medium. Electrostatic spraying technology was used to add GABA into the cereals. The isolated Lactobacillus brevis CFM11 produced the highest GABA production up to a concentration of $2,002.93{\mu}g/mL$ when cultivated in MRS broth containing 0.8% monosodium glutamate (MSG). The production level of GABA was $585.80{\mu}g/mL$ in rice bran extract containing 0.4% MSG, 2% sucrose, 1% skim milk, and 0.2% magnesium sulfate. After electrostatic spraying of the cultured suspension onto rice, GABA concentration reached $228.10{\mu}g/g$ while untreated rice reached $32.23{\mu}g/g$. These results demonstrate that rice bran extract can be an economic commercial medium for GABA production as a substitute for MRS broth. This study demonstrates the novel application of electrostatic spraying of GABA into cereal products for the first time.

• Korean Journal of Organic Agriculture
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• v.25 no.1
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• pp.171-185
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• 2017

${\gamma}$-aminobutyric acid (GABA) is a non-proteinogenic amino acid biosynthesized through decarboxylation of L-glutamic acid by glutamic acid decarboxylase. GABA is believed to play a role in defense against stress in plants. In humans, it is known as one of the major inhibitory neurotransmitters in the central nervous system, exerting anti-hypertensive and anti-diabetic effects. In this report, we wanted to enhance the GABA production from the barley leaf and corn silk by culturing them with lactic acid bacteria (LAB). The barley leaf and corn silk were mixed with various weight combinations and were fermented with Lactobacillus plantarum in an incubator at $30^{\circ}C$ for 48 h. After extracting the fermented mixture with hot water, we evaluated the GABA production by thin layer chromatography and GABase assay. We found that the fermented mixture of the barley leaf and corn silk in a nine to one ratio contained a higher level of GABA than other ratios, meaning that the intermixture and fermentation technique was effective in increasing the GABA content. We also tested several biological activities of the fermented extracts and found that the extracts of the fermented mixture showed improved antioxidant activities than the non-fermented extracts and no indication of cytotoxicity. These results suggest that our approach on combining the barley leaf and corn silk and its fermentation with LAB could lead to the possibility of the development of functional foods with high levels of GABA content and improved biological activities.

• KSBB Journal
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• v.16 no.1
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• pp.36-40
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• 2001

In order to study the molecular mechanism of $\gamma$-aminobutyric acid (GABA) production in plants, we cloned and sequenced a partial glutamate decarboxylase (GAD) cDNA from the Arabidopsis thaliana cDNA library, using primers targeted at highly conserved sequences of the petunia GAD gene. The cDNA fragment was inserted into TA cloning vector with T7 promoter and the recombinant plasmid obtained was used to transform E. coli. The plasmid DNA purified from the transformed E. coli was digested with EcoRI and the presence of the insert was confirmed. Nucleotide sequence analysis showed that the fragment is a partial Arabidopsis thaliana GAD gene and that the sequence showed 98% and 78% identity to the region of the putative Arabidopsis thaliana GAD sequences deposited in GenBank, Accession nos: U46665 and U10034, respectively. The amino acid sequence deduced from the partial Arabidopsis thaliana GAD gene showed 99% and 91% identities to the GAD sequences deduced from the genes of the U46665 and U10034, respectively. The partial cDNA sequence determined may facilitate the study of the molecular mechanism of GABA metabolism in plants.

• Investigative Magnetic Resonance Imaging
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• v.21 no.2
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• pp.102-105
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• 2017

In adolescents, sleep deprivation problem is getting worse, and increased caffeine consumption is considered to relieve the stress caused by sleep deprivation and academic burden. In this study, immediate neurologic effects of caffeine intake on adolescents were evaluated in three high school students using the ${\gamma}-aminobutyric$ acid (GABA)/creatine ratio on magnetic resonance spectroscopy (MRS). MEGA-PRESS MRS and TE 135 ms single voxel MRS were performed in the anterior cingulate cortex before and after drinking a cup of coffee, which contained 104 mg of caffeine. GABA and creatine were measured on LCModel 6.3, respectively. In all three students, GABA/creatine ratios were decreased after caffeine intake. The GABA/creatine ratios obtained before caffeine intake were decreased after caffeine intake in all the three adolescents. In this preliminary study, caffeine intake caused an immediate decrease in the GABA/creatine ratio in the brain and it may be related to the neurologic effects of caffeine on an adolescent's brain.

• The Journal of Korean Medicine
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• v.25 no.1
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• pp.188-197
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• 2004

Objective and Methods : This study was performed to evaluate the anticonvulsant, antioxidant effect of modified formulas Korean traditional medicine Cheongsinhwadam-Jeon(CSHDJ). The extract of CSHDJ was administered (p.o.) to mice for 14 days in anticonvulsant and antioxidant tests. Results : The pretreatment of CSHDJ extract prohibited pentylenetrazol (PTZ)-induced convulsion. In PTZ-induced convulsion, lowered level of brain ${\gamma}$-aminobutyric acid(GABA) was restored normal state by the pretreatment of CSHDJ. Increased level of brain glutamic acid was lowered to normal state by CSHDJ, and increased activity of brain ${\gamma}-aminobutyric$ acid transaminase(GABA-T) was reduced to normal state by CSHDJ. In PTZ-induced convulsion, increased level of brain lipid peroxide was lowered to normal state by the pretreatment of CSHDJ. Increased activity of brain xanthine oxidase(XOD) was lowered by CSHDJ, and increased activity of brain aldehyde oxidase lowered to normal state by CSHDJ. In PTZ-induced convulsion, increased activities of superoxide dismutase(SOD) and catalase in brain were lowered by the pretreatment of CSHDJ, whereas increased level of glutathione and increased activity of gluthathione peroxidase in brain were not changed significantly. Conclusions : Above results suggest that CSHDJ has anticonvulsant, antioxidant effect. That seems to be strongly related with the levels of GABA, glutamate, lipid peroxide and the activities of GABA-T, XOD, aldehyde oxidase, SOD, catalase in brain tissue. From these results, CSHDJ could be applied to various convulsive disorders.

• Food Science and Biotechnology
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• v.18 no.6
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• pp.1398-1403
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• 2009

Present study deals with variations of physicochemicals including $\gamma$-aminobutyric acid (GABA), $\gamma$-oryzanol, free sugar, lipoxygenase activity, fat acidity, and germination rate from Korean brown rice cultivars. With increase of storage time and temperature, GABA, $\gamma$-oryzanol, lipoxygenase activity, and fat acidity increased, whereas free sugar and germination rate was reduced. Among cultivars, 'Gopumbyeo' exhibited the highest contents in GABA and $\gamma$-oryzanol during 12 weeks storage at $25^{\circ}C$ (GABA: $28.6{\pm}5.6{\rightarrow}170.4{\pm}4.6\;mg/100\;g$, $\gamma$-oryzanol: $6.1{\pm}0.7{\rightarrow}6.7{\pm}0.4\;mg/g$) and 'Ilpumbyeo' significantly decreased in free sugar during 12 weeks storage at $10^{\circ}C$ ($1,423.7{\rightarrow}1,058.4\;mg/100\;g$). Moreover, 'Taebongbyeo' exhibited the highest quality owing to low lipoxygenase activity, low fat acidity, and high germination rate. In free sugar compositions, sucrose exhibited the highest content (>70%), followed by fructose (>7%), raffinose (>5%), glucose (>3%), and maltose (>2%) during storage. Based on our results, changes of physicochemicals in stored brown rice may be important information in processing food and functional properties.