• Applied Biological Chemistry
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• v.43 no.4
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• pp.231-235
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• 2000

The changes of calmodulin levels, calmodulin-binding proteins, and $Ca^{2+}$/calmodulin-dependent glutamate decarboxylase during the growth of tobacco suspension cells were investigated. Tobacco cells exhibited a typical growth curve, including an exponential growth phase between 3 and 5 days after inoculation, and an apparent stationary phase occurring after 5 day. Although slight changes were observed from sample to sample, calmodulin protein levels remained similar during the phases of culture growth. Several $Ca^{2+}-dependent$ calmodulin-binding proteins including 56, 46, 36, and 32-kDa proteins were detected in tobacco cell extracts. The 56-kDa protein was identified as glutamate decarboxylase by Western-blot analysis using an anti-GAD monoclonal antibody. The levels of GAD protein and the specific activity of GAD enzyme were highest during the middle exponential phase of the culture growth cycle. These data suggest that $Ca^{2+}$/calmodulin-dependent glutamate decarboxylase is modulated during the growth of tobacco suspension cells.

• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.192.2-192
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• 2003

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.300-305
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• 2015

The glutamate decarboxylase gene (gadB) from Lactobacillus plantarum WCFS1 was cloned and expressed as an N-terminal hexa-histidine-tagged fusion protein in Escherichia coli BL21 (DE3) as the host strain. Purified glutamate decarboxylase (GAD) was immobilized onto porous silica beads by covalent coupling. The pH dependence of activity and stability of the immobilized GAD was significantly altered, when compared to those of the free enzyme. Immobilized GAD was stable in the range of pH 3.5 to 6.0. The resulting packed-bed reactor produced 41.7 g of γ-aminobutyric acid/l·h at 45℃.

• KSBB Journal
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• v.15 no.6
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• pp.615-620
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• 2000

To obtain quality germinated brown rices containing high levels of ${\gamma}$-aminobutyric acid (GABA), chitosan was applied during the brown rice germination. The GABA contents in germinated brown rices (1,035 nmole/g fresh weight) and brown rices germinated by water (771 nmole/g fresh weight) or by lactiv acid (728 nmole/g fresh weight). In addition to the enhancement of GABA, germination in the chitosan solution increased alanine concentration and decreased glutamic acid, aspartic acid and serine concentrations in the brown rices. The activity of glutamate decarboxylase was also enhanced by the chitosan treatment. Furthermore, germination by chitosan reduced fungal contamination markdely, compared with germination by water or germination by lactic acid. These results suggest that quality germinated brown rices containing high levels of GABA can be obtained by chitosan application.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.65-68
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• 2000

To obtain quality germinated brown rices containing high levels of ${\gamma}-amonobutyric\;acid$(GABA), chitosan was appliec during the germination of brown rices. The GABA contents of germinated brown rices (1,035 umole/g fresh weight) with 100 ppm chitosan solution for 72 hr were higher than those of ungerminated brown rices (136 nmole/g fresh weight) and brown rices germinated with water (771 nmole/g fresh weight) or with lactic acid (728 nmole/g fresh weight). In addition to the enhancement of GABA, germination in the chitosan solution increased alanine and decreased glutamic acid, aspartic acid and serine in the brown rices. The activity of glutamate decarboxylase was also enhanced by the treatment of chitosan. Furthermore, the germination with chitosan reduced fungi contamination markedly compared with water germination or lactic acid germination. These results suggest that quality germinated brown rices containing high levels of GABA can be obtained by chitosan application.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.4
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• pp.398-405
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• 2014

We assessed the GABA accumulation and other components after the 'Nunkeunhukchal (BGE)', 'Josanghukchal (BR)', and 'Ilmibyeo (IB)' grain was soaked in water for 24, 36, 48, 60, 72 and 96 hr. The results showed a continuous accumulation of GABA in soaking treated brown rice of BGE and IB. Among the treated hours, 72 hours of soaking had the maximal accumulation of GABA (51.4 mg/100 g), amino acid, polyphenol and other components. The activities of glutamate decarboxylase (GAD) in brown rice and rice-bran were the same in BGE rice. However, the formation of GABA treated with L-glutamate as substrate showed dramatic increase of 354.6 (fourteen times higher than normal extraction) and 726.4 mg/100 g in BGE rice and rice-bran, respectively. These results suggested that the soaking and extraction with L-glutamate buffer could be better methods for the harvest of increased GABA.

• Microbiology and Biotechnology Letters
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• v.44 no.1
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• pp.26-33
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• 2016

Dominant lactic acid bacteria (LAB) strains were isolated from traditional fermented foods to obtain rare ${\gamma}$-aminobutyric acid (GABA)-producing LAB. Out of 147 isolates, 23 strains that could produce GABA with 1% (w/v) L-monosodium glutamate (MSG) were first isolated. After further screening of these rare GABA-producing LAB by analysis of the glutamate decarboxylase and 16S rRNA gene sequences, Enterococcus faecium JK29 was isolated, and 1.56 mM of GABA was produced after 48 h cultivation in basic de Man, Rogosa, and Sharpe (MRS) medium. To enhance GABA production by E. faecium JK29, the culture conditions were optimized. When E. faecium JK29 was cultivated in optimized MRS medium containing 0.5% (w/v) sucrose and 2% (w/v) yeast extract with 0.5% (w/v) MSG, GABA production reached 14.86 mM after 48 h cultivation at initial conditions of pH 7.5 and $30^{\circ}C$.