• Journal of Microbiology
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• v.40 no.1
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• pp.33-37
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• 2002

An enzymatic reaction for the production of D-alanine from D-aspartic acid and pyruvate as substrates by a thermostable D-amino acid aminotransferase (D-AAT) was investigated at various conditions In the temperature range of 40-70$\^{C}$ and pH range of 6.0-9.5. The D-AAT was produced with recombinant E. coli BL21, which hosted the chimeric plasmid pTLK2 harboring the D-AAT from the novel thermophilic Bacillus sp. LK-2. The enzyme reaction was shown to follow the Ping Pong Bi Bi mechanism. The K$\_$m/ values for D-aspartic acid and pyruvate were 4.38 mar and 0.72 mM, respectively. It was observed that competitive inhibition by D-alanine, the product of this reaction, was evident with the inhibition constant K$\_$i/ value of 0.1 mM. A unique feature of this reaction scheme is that the decorboxylation of oxaloacetic acid, one of the products, spontaneously produces pyruvate. Therefore, only a catalytic amount of pyruvate is necessary for the enzyme conversion reaction to proceed. A typical time-course kinetic study skewed that D-alanine up to 88 mM could be produced from 100 mM of D-aspartic acid with a molar yield of 1.0.

• 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.

• Korean Journal of Clinical Laboratory Science
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• v.43 no.2
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• pp.57-67
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• 2011

In this study, we investigated the correlation between the administration of various antiviral agents and the alternation of specific biomarkers induced by the hepatitis B virus (HBV). Eligible subjects diagnosed with chronic hepatitis B were prescribed with antiviral drugs at the Gastroenterology Internal Medicine Department of E University Hospital in Daejeon between May 2004 and September 2009. Lamivudine was prescribed to 66 out of 100 patients. Of the 12 patients, 6 (50.0%) showed a change from being HBe-antigen-positive to being HBe-antigen-negative. Of the 39 patients, 23 (59.0%) showed higher than 40 IU/L alanine aminotransferase (ALT). Of the 65 patients, 41 (63.1%) showed HBV DNA decrease of 1 log, and were prescribed with Lamivudine. Adefovir was prescribed to 3 out of 100 patients. Of the 12 patients, 1 (8.3%) showed a change from being HBe-antigen-positive to being HBe-antigen-negative, and was prescribed with Adefovir. Entecavir was prescribed to 19 (19.0%) out of 100 patients. Of the 12 patients, 3 (25.0%) showed a change from being HBe-antigen-positive to being HBe-antigen-negative. Of the 12 patients, 3 (125.8%) showed higher than 40 IU/L ALT. Of the 65 patients, 14 (21.5%) showed HBV DNA decrease of 1 log, and were prescribed with Entecavir. Clavudine was prescribed to 7 out of 100 patients. Of the 12 patients, 1 (8.3%) showed a change from positive HBe antigen to negative HBe antigen. Of the 39 patients, 5 (12.8%) showed higher than 40 IU/L ALT. Of the 65 patients, 6 (9.2%) showed HBV decrease of 1 log, and were prescribed with Clavudine. These results do not show a statistically significant correlation between drugs and biomarkers. Data on combination therapy using Lamivudine and Adefovir show no statistically significant difference between drugs and biomarkers. Medications for periodic inspection was not correlated to HBe-antigen-negative conversion, ALT, and HBV DNA. HBV DNA was significantly reduced in patients with high levels of AST(aspartic acid aminotransferase) and ALT before treatment. In addition, the decrease of HBV DNA after 12 months of treatment was less frequently observed in patients treated with Lamivudine compared with other drugs. This result is associated with Lamivudine resistance. Although the association of drugs with diagnostic markers and the correct choice of treatment is difficult to determine, these results may be useful for further research on diagnosis and treatment of the hepatitis B virus.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.4
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• pp.263-270
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• 2019

Hydrogen sulfide is well-known to exhibit anti-inflammatory and cytoprotective activities, and also has protective effects in the liver. This study aimed to examine the protective effect of hydrogen sulfide in rats with hepatic encephalopathy, which was induced by mild bile duct ligation. In this rat model, bile ducts were mildly ligated for 26 days. Rats were treated for the final 5 days with sodium hydrosulfide (NaHS). NaHS ($25{\mu}mol/kg$), 0.5% sodium carboxymethyl cellulose, or silymarin (100 mg/kg) was administered intraperitoneally once per day for 5 consecutive days. Mild bile duct ligation caused hepatotoxicity and inflammation in rats. Intraperitoneal NaHS administration reduced levels of aspartate aminotransferase and alanine aminotransferase, which are indicators of liver disease, compared to levels in the control mild bile duct ligation group. Levels of ammonia, a major causative factor of hepatic encephalopathy, were also significantly decreased. Malondialdehyde, myeloperoxidase, catalase, and tumor necrosis factor-${\alpha}$ levels were measured to confirm antioxidative and anti-inflammatory effects. N-Methyl-D-aspartic acid (NMDA) receptors with neurotoxic activity were assessed for subunit NMDA receptor subtype 2B. Based on these data, NaHS is suggested to exhibit hepatoprotective effects and guard against neurotoxicity through antioxidant and anti-inflammatory actions.

• Journal of Physiology & Pathology in Korean Medicine
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• v.36 no.6
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• pp.235-241
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• 2022

The purpose of this study was to investigate the immune activation effect of Sasamsaengmaek-san (SSSMS) consisted of a mixture of Adenophora triphylla var. japonica, Liriope platyphylla, Panax ginseng C. A. Meyer and Schisandra chinensis. in Balb/c mice. Measuring alanine aminotransferase (ALT) and aspartic acid transaminase (AST) levels in Balb/c mice was performed to analyze the cytotoxicity. Cytokines (IFN-γ, IL-2, IL-12) which regulate the immune activation in Balb/c mice were measured by enzyme-linked immunosorbent assay (ELISA). Activated T lymphocytes in peripheral blood mononuclear cell (PBMC), spleen, lymph nodes were analyzed by flow cytometry using percentages. All tests were compared with red ginseng 100 ㎍/mL (RG 100), which is the most used for immune activity. As a result, cytokine activity was significantly increased at SSSMS 300 group. Activated T lymphocytes in PBMC, spleen, lymph nodes were significantly increased at SSSMS 300 group. These results suggest that there is a possibility of SSSMS activating an immune system by activating the cytokines, and it is confirmed that SSSMS also effective for generation and differentiation of T, B lymphocytes which activate the immune response.

• Journal of Applied Biological Chemistry
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• v.54 no.3
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• pp.206-213
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• 2011

Hepatoprotective effects of Monascus pilosus mycelial ethanol extract (MPME) were examined in high-fat diet induced-obese rats. The rats were randomly divided into 2 groups; normal control (NC) and a high-fat and high cholesterol diet group (HFC). The HFC diet group was fed a 5L79 diet supplemented with 15% lard and 1% cholesterol for 3 weeks for induction of obesity. And then, the rats were divided into 4 groups (n=5); the NC, a HFC diet obesity control group (HF), 0.5% MPME supplemented HFC diet group (MPM), and 2% conjugated linoleic acid (CLA) supplemented HFC diet group for 7 weeks. Whereas the daily weight gain of NC and HFC groups were 3.48 g and 4.48 g, respectively, those of MPM and CLA were 3.09 g and 4.38 g, respectively. Furthermore, activity of serum alanine and aspartic aminotransferase in HF was markedly higher than those of NC group, but, the activity in MPM and CLA was significantly lower than HF. Hepatic reduced glutathione content in MPM and CLA was higher than HF. On the contrary, hepatic lipid peroxide content in MPM and CLA was significantly lower than HF. In conclusion, although the precise mechanisms of the hepatoprotective effects of the MPME in this study are unknown, our study provides experimental evidence that MPME may prevent obesity and hepatic damage by high-fat and high cholesterol diet via inhibition of lipid absorption and induction of reactive oxygen spices scavenging enzyme such as superoxide dismutase.