• Molecules and Cells
• /
• v.19 no.1
• /
• pp.97-103
• /
• 2005

The role of residue C323 in catalysis by human glutamate dehydrogenase isozymes (hGDH1 and hGDH2) was examined by substituting Arg, Gly, Leu, Met, or Tyr at C323 by cassette mutagenesis using synthetic human GDH isozyme genes. As a result, the $K_m$ of the enzyme for NADH and ${\alpha}-ketoglutarate$ increased up to 1.6-fold and 1.1-fold, respectively. It seems likely that C323 is not responsible for substrate-binding or coenzyme-binding. The efficiency ($k_{cat}/K_m$) of the mutant enzymes was only 11-14% of that of the wild-type isozymes, mainly due to a decrease in $k_{cat}$ values. There was a linear relationship between incorporation of [$^{14}C$]p-chloromercuribenzoic acid and loss of enzyme activity that extrapolated to a stoichiometry of one mol of [$^{14}C$] incorporated per mol of monomer for wild type hGDHs. No incorporation of [$^{14}C$]p-chloromercuribenzoic acid was observed with the C323 mutants. ADP and GTP had no effect on the binding of p-chloromercuribenzoic acid, suggesting that C323 is not directly involved in allosteric regulation. There were no differences between the two hGDH isozymes in sensitivities to mutagenesis at C323. Our results suggest that C323 plays an important role in catalysis by human GDH isozymes.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.30 no.4
• /
• pp.405-411
• /
• 1985

The buffer soluble proteins were extracted from six cultivars of barley grains and analyzed by various electrophoresis; 7.5% polyacrylamide slab gel, 2-30% polyacrylamide porosity gradient tube gel, isoelectric focusing (pH4-9) and starch gel electrophoresis. The proteins, esterase, acid phosphatase, malate dehydrogenase, glutamate dehydrogenase and leucine aminopeptidase were investigated to find out the best method to differentiate barley cultivars. The result were that protein and esterase bands in 2-30% polyacrylamide porosity gradient tube gel electrophoresis and protein bands in 7.5% polyacrylamide slab gel electrophoresis showed typical varietal differences. Therefore, those methods were suitable for differentiation of barley cultivars. It was difficult to differentiate the cultivars by the other methodes and patterns of the other enzymes.

• Journal of Chest Surgery
• /
• v.31 no.5
• /
• pp.441-450
• /
• 1998

The medullospinal tract cells are known to play an important role in the control of the cardiovascular activities. To clarify the modes of action of the neurotransmitters on these cells, glutamate, GABA(${\gamma}$-aminobutyric acid) and bicuculline were applicated iontophoretically into the rostral ventrolateral medulla in adult cats anesthetised with ${\alpha}$-chloralose. Followings are the results obtained : 1. The spontaneous activities of the cardiac-related neurons in rostral ventrolateral medulla (RVLM) were increased by the glutamate and decreased by the GABA. 2. Bicuculline, an antagonist of GABA, alone didn't increase the frequency of the action potentials, but could reverse the cellular response to the GABA, simultaneously applicated. 3. GABA seemed to decrease the peak as well as the basal discharge of the neurons in RVLM, but hardly changed their periodicities. 4. The cellular responses of RVLM evoked by the peripheral nerve stimulation could be inhibited by the iontophoretically released GABA. In conclusion, GABA seemed to act as an inhibitory neurotransmitter on the cardiac- related neurons in RVLM of the cats anesthetized with ${\alpha}$-chloralose. But the maintenance of the periodicities of these cells after the application of bicuculline suggested that the afferent activity of the baroreceptor didn't play a key role in the spontaneous activities of the RVLM neurons.

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

• Journal of Embryo Transfer
• /
• v.13 no.3
• /
• pp.251-259
• /
• 1998

Concentrations of free amino acids in the BF of IVP bovine BL and HBL were examined in this study. The embryos derived from IVF oocytes were cultured in a SOFM containing BSA, EAA and NEAA. BF was aspirated from BL (180 h of age after insemination) and HBL (216 h of age after insemination), and introduced into drops of SOFM (30$\mu$l/drop) containing PVA through micromanipulation. The medium containing BF was then subjected to measurement of 20 amino acids by an automatic amino acid analyzer. The concentrations of isoleucine, leucine and methionine were higher (p〈0.05) in the BF from HBL than from BL, and no difference was found in aspartate or glutamate concentrations between BL and HBL, while threonine, alanine (p〈0.01) and the rest of the amino acids (p〈0.001) were significantly higher in the BF from HBL than from BL. Cystine was not found in either BL or HBL. A high concentration of glutamine was found in the BF from both BL and HBL, although it was not added to the culture medium. These results indicate that bovine BF contains several EAA (methionine in BL and isoleucine, leucine and methionine in HBL) and NEAA (alanine, glutamate, glycine, proline, serine and aspartate in BL, and glutamate and aspartate in HBL), and there is significant differences in the amino acid concentration in the BF between BL and HBL derived by WP.

• The Korea Journal of Herbology
• /
• v.20 no.4
• /
• pp.121-132
• /
• 2005

Objectives : Siegesbeckiae Herba's effect on the protection of nerve cells was tested, and the effects were compared between Siegesbeckia glabrescens Makino, the state of which is spica imported from China, and original Korean leaves of it. Methods : After damaging nerve cells by exposing them on NMDA (N-methyl-D-aspartic acid) and KA(kainic acid), Siegesbeckiae Herba's effect on cell death, inhibition rate, glutamate separation, and ROS(reactive oxygen species) production were examined. Results : 1. Siegesbeckiae Herba inhibited the cell death exposed to NMDA. 2. Siegesbeckiae Herba inhibited the amount of glutamate separated from nerve cells exposed to NMDA. 3. Siegesbeckiae Herba inhibited the production of ROS induced by NMDA. 4. Siegesbeckiae Herba did not inhibit the cell death exposed to KA. 5. Chinese Siegesbeckiae Spica had no inhibition effect on cell death. Conclusions : Siegesbeckiae Herba was effective in inhibiting the death of nerve cells exposed to NMDA, and in protecting nerve cells from various damages in nerve cell diseases. Because Chinese Siegesbeckiae Spica did not show such effects, it is necessary to closely examine those effects according to the used parts.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.4
• /
• pp.763-766
• /
• 2010

An efficient and simple fermentation process was developed for the production of ${\gamma}$-aminobutyric acid (GABA) by Lactobacillus sakei B2-16. When the L. sakei B2-16 was cultivated in the rice bran extracts medium containing 4% sucrose, 1% yeast extract, and 12% monosodium glutamate, the maximum GABA concentration reached 660.0 mM with 100% conversion yield, showing the 2.4- fold higher GABA concentration compared with the modified MRS medium without the rice bran extracts. The GABA production was scaled-up from a laboratory scale (5 l) to a pilot (300 l) and a plant (5,000 l) scale to investigate the application possibility of GABA production to industrial fields. The production yields at the pilot and plant scales were similar to the laboratory scale using rice bran extracts medium, which could be effective for the low-cost production of GABA.

• Preventive Nutrition and Food Science
• /
• v.13 no.4
• /
• pp.354-361
• /
• 2008

A novel bacterium isolated from Cheonggukjang was identified as a glutamate-dependent Bacillus subtilis HA with 98.3% similarity to Bacillus subtilis Z99104. Optimization of poly-$\gamma$-glutamic acid ($\gamma$-PGA) production by modulating fermentation factors including carbon sources, nitrogen sources, inorganic salts and fermentation time was investigated. Optimum culture broth for $\gamma$-PGA production consisted of 3% glutamate, 3% glucose and various salts, resulting in the PGA production of 22.5 g/L by shaking culture for 72 hr at $37^{\circ}C$. Average molecular weight of $\gamma$-PGA was determined to be 1,220 kDa through MALLS analysis. The $\gamma$-PGA solution showed a typical pseudoplastic flow behavior, and a great decrease in consistency below pH 6.0 regardless of the same molecular weight of $\gamma$-PGA. The molecular weights of isolated $\gamma$-PGA were drastically decreased by heat treatment in various acidic conditions, resulting in different hydrolysis of $\gamma$-PGA. The consistency of $\gamma$-PGA solution was greatly decreased with increase heating time in acidic conditions.

• Korean Journal of Microbiology
• /
• v.32 no.3
• /
• pp.232-237
• /
• 1994

Microorganism producing glutaryl 7-aminodeacetoxycephalosporanic acid (GL-7-ADCA) acylase was screened from soil. The microorganism was identified as Alcaligenes sp. J-421 by its morphology and biochemical properties. Cultural conditions of Alcaligenes sp. J-421 were investigated for the production of GL-7-ADCA acylase. Optimum medium composition was 1% glucose, 1% beef extract, 0.5% yeast extract, 0.2% monosodium L-glutamate, 0.1% glutaric acid, 0.2% NaCl, 0.5% $K_2$ $HPO_4$, and 0.05% $CuSO _4{\cdot}5H_2O$. Optimum cultivation conditions for the production of the enzyme in 5 l jar fermentor were $37^{\circ}C$, tip speed 300 rpm, aeration 1 vvm. Optimum reaction pH of the enzyme was 8.0 and the enzyme was stable at pH7.0-11.0.

• The Korean Journal of Zoology
• /
• v.7 no.2
• /
• pp.25-36
• /
• 1964

The present paper deals with the comparative study on phylogenic difference in the patterns of energy metabolism of brain slices of several vertebrate species by measuring oxygen consumptionwith glucose-6-phosphate, glucose-1-phosphate, glyceraldehyde-3-phosphate or glutamate as respiratory substrate employing Warburg's manometric method, by determination of the utilization rate of glucose using glucose-1-C14 by analyzing patterns of free amino acid distribution , and by histochemical determination using glucose-1-C14 by analyzing patterns of free amino acid distribution acid distribution , and by histochemical determination of glycogen contents. 1. Glucose enhances the oxygen consumption of brain slices of animals belinging to reptile, aves and mammalia while it shows a tendency to decrease that of animals belonging to pisces and amphibia. 2. Glucose-6--phosphate increase oxygen consumption more than glucose in every species examined, while glucose-1-phosphate and glyceraldehyde-3-phosphate increase that of Rana nigromaculata only . In general m, it appears that phosphosugars are more effective as a respiratory substrate to those species which have less endogenous respiration than to those having larger endogenous respiration. 3. Similar patterns of free amino acid distribution and the relative amount are found among the species and in every species examined glutamic acid is detected in the larges amount . ${\gamma}$-Amino butyric acid, glycine, alanine and aspartic acid are found in every species. 4. Ophicephalus showed less oxygen consumption than endogenous respiration when glutamate was added to the medium. When sodium fluoride was added, the oxygen consumption was some what increased . Such phenomenon wasnot found in the frog. 5. The result of histochemcial analysis of the brain showed that glycogen was abundantly present in the fish , amphibia , and especially in the reptile and that no distinctive grains of glycogen were found in the bird and mammal . From these facts, it may be supposed that anaerobic glycolysis as energy source dominates in fish and amphibia and aerobic respiration through the oxidation of glucose dominates in bird and mamal , the reptile occupying transitional position between these two categories. The way of obtaining energy for brain activity by the oxidation of glucose supplied from the circulating blood is seemed to be first acquired by reptile and the function is completed both in aves and mammal.