• 약학회지
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• 제53권2호
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• pp.74-77
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• 2009

Food deprivation decreases hepatic glutathione (GSH) levels, which is ascribed to alterations in availability of hepatic cysteine, a rate limiting factor for the GSH synthesis. The present study examines the effects of food deprivation on hepatic metabolism of sulfur amino acid in male rats. In rats fasted for 24 or 48 hours, hepatic GSH levels were decreased from $6.70{\pm}0.16{\mu}mol/g$ liver to $4.02{\pm}0.20$ or $4.06{\pm}0.07{\mu}mol/g$ liver, respectively. Hepatic S-adenosylmethionine levels were also decreased in fasted rats, but S-adenosylhomocysteine levels were increased. Hepatic methionine levels were not changed by food deprivation for 48 hours. On the other hand, hepatic cysteine or taurine levels were increased from $106.2{\pm}4.1$ to $130.0{\pm}2.7$ nmol/g liver or from $2.45{\pm}0.43$ to $5.07{\pm}0.78{\mu}mol/g$ liver, respectively, in 48-hour fasted rats. Activity of cystathionine beta-synthase catalyzed homocysteine to cystathionine, was markedly decreased, but activity of betaine homocysteine methyltransferase was increased in fasted rats, indicating that methylation of homocysteine to methionine is activated. Also activity of cysteine dioxygenase, involved in taurine synthesis, was increased. These results suggested that hepatic methionine levels were maintained in rats fasted for 48 hours through increase in homocysteine methylation, and hepatic GSH may serve as a cysteine supplier reservoir in fasting state.

• Asian-Australasian Journal of Animal Sciences
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• 제31권1호
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• pp.47-53
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• 2018

Objective: The objective of this experiment was to investigate the effects of heat stress on milk protein and blood amino acid profile in dairy cows. Methods: Twelve dairy cows with the similar parity, days in milk and milk yield were randomly divided into two groups with six cows raised in summer and others in autumn, respectively. Constant managerial conditions and diets were maintained during the experiment. Measurements and samples for heat stress and no heat stress were obtained according to the physical alterations of the temperature-humidity index. Results: Results showed that heat stress significantly reduced the milk protein content (p<0.05). Heat stress tended to decrease milk yield (p = 0.09). Furthermore, heat stress decreased dry matter intake, the concentration of blood glucose and insulin, and glutathione peroxidase activity, while increased levels of non-esterified fatty acid and malondialdehyde (p<0.05). Additionally, the concentrations of blood Thr involved in immune response were increased under heat stress (p<0.05). The concentration of blood Ala, Glu, Asp, and Gly, associated with gluconeogenesis, were also increased under heat stress (p<0.05). However, the concentration of blood Lys that promotes milk protein synthesis was decreased under heat stress (p<0.05). Conclusion: In conclusion, this study revealed that more amino acids were required for maintenance but not for milk protein synthesis under heat stress, and the decreased availability of amino acids for milk protein synthesis may be attributed to competition of immune response and gluconeogenesis.

• Toxicological Research
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• 제22권1호
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• pp.39-45
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• 2006

As the antioxidant and free radical scavenger, glutathione (GSH) participates in the preservation of cellular redox status and defense against reactive oxygen species and xenobiotics. Glutamate-cysteine ligase (GCL; also known as ${\gamma}$-glutamylcysteine synthetase, EC 6.3.2.2) is the rate limiting enzyme in GSH synthesis. In the present study, the accurate method for determination of GCL activity in crude liver extracts was developed by measuring both ${\gamma}$-glutamylcysteine and GSH from cysteine in the presence of glutamate, glycine and an ATP-generating system. We added glycine to promote the conversion of ${\gamma}$-glutamylcysteine to GSH, and to minimize the possibility of ${\gamma}$-glutamylcysteine metabolism to cysteine and oxoproline by ${\gamma}$-glutamylcyclotransferase. We established optimal conditions and substrate concentrations for the enzyme assay, and verified that inhibition of GCL by GSH did not interfere with this assay. Therefore, this assay of hepatic GCL under optimal conditions could provide a more accurate measurement of this enzyme activity in the crude liver extracts.

• Bulletin of the Korean Chemical Society
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• 제9권6호
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• pp.394-398
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• 1988

Unusually high reactivity was found in peptide bond formation between p-nitrobenzophenone oxime resin (I) ester and amino acid 4-(methylthio)phentyl (MTP) esters. A charge-transfer complex between the two phenyl rings of the oxime resin (I) and the incoming amino acid MTP esters was considered to be responsible to accelerate the aminolysis reaction of the peptide oxime resin ester. Several di-, tri-, and pentapeptide fragments for preparing enkephalin and glutathione oligomers were successfully prepared in short times.

• Journal of Microbiology and Biotechnology
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• 제31권1호
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• pp.33-42
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• 2021

Due to the potential of antioxidants to scavenge free radicals in human body, it is important to be able to prepare antioxidant peptides that meet the industrial requirements for cosmetics and food. Here, we determined in vivo/in vitro activities of antioxidant peptide from P. fucata (PFAOP) prepared by bio-fermentation method. The antioxidant property test results showed the DPPH, hydroxyl, superoxide radical-scavenging, and cellular antioxidant activity. EC50 values of PFAOPs were 0.018 ± 0.005, 0.126 ± 0.008, 0.168 ± 0.005, and 0.105 ± 0.005 mg/ml, respectively, exhibiting higher antioxidant activities than glutathione (p < 0.05). Moreover, anti-proliferation and cytotoxicity activity results illustrated PFAOP has a potent anti-proliferative activity against HepG2, Caco-2, and MCF-7 carcinoma cells with no cytotoxicity. Moreover, the protocols we developed in this work demonstrated several excellent advantages in PFAOP preparation compared to enzymatic hydrolysis or chemical synthesis methods and provide a theoretical foundation for higher-value application of marine-derived functional peptides.

• Journal of Dairy Science and Biotechnology
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• 제42권1호
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• pp.18-22
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• 2024

In this study, we performed whole-genome sequencing of Levilactobacillus brevis KL251 (KL251) isolated from kimchi. The KL251 genome, characterized by a circular chromosome spanning 2,345,062 base pairs with a GC content of 45.78%, was analyzed. KL251 contains 2,275 coding DNA sequences (CDSs), 56 transfer RNAs (tRNAs), and 4 ribosomal RNAs (rRNAs). Genes associated with gamma-aminobutyric acid (GABA) production and CRISPR-Cas systems were identified and could potentially be used for GABA synthesis and defense against foreign DNA. Additionally, the presence of functional genes involved in isoprenoid biosynthesis, glutathione generation, and redox sensing showed that cellular metabolism and stress responses were important characteristics of this genome. These genomic findings suggest that the KL251 strain could potentially have several applications, including food fermentation, probiotics, dairy product starters, and the development of health-enhancing products.

• 약학회지
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• 제42권3호
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• pp.336-344
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• 1998

Effects of ochratoxin A (OTA) on embryo development were studied in cultured whole embryos from 9.5 day gestation rat for 48 h. OTA (more than $0.5{\mu}g/ml$) induced microcephaly in the cultured rat whole embryos. Protein and DNA content, and DNA synthesis were significantly inhibited by OTA. We next examined whether the microcephaly seen in cultured whole embryo partially results from inhibition of differentiation of embryonic midbrain cells. Embryonic midbrain cells were extracted from 12 day gestation rat embryos, and cultured for 96 hr. OTA ibhibited cell differentiation about 50% over control. We also tested whether OTA-induced embryotoxicity would be associated with oxidative damages. We measured the ${\gamma}$-glutamyltranspeptidase (${\gamma}$-GT) and glutathione peroxidase (GPX) activities, and glutathione (GSH) content in both cultured whole embryos and embryonic midbrain cells. OTA decreased GSH content, whereas slightly increased ${\gamma}$-GT activity, but GPX activity was not significantly changed. These results show that OTA caused the microcephaly and its effect may be partially due to the inhibition of cell differentiation of embryonic midbrain cells, but the role of oxidative damages is not clear in embryotoxicity.

• 대한한방내과학회지
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• 제19권1호
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• pp.3-21
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• 1998

This study was to investigate the effects of Gibangganbang on the liver injury induced dimethylnitrosamine, CCl4, ethanol and partial hepatectomy. Hydroxyproline, hepatic fibrosis, hepatic inflammatory cell infiltration, fatty value, lipidoperoxide levels, glutathione levels, mitotic index, contents of protein in the serum and liver tissues were measured and observed. The results obtained were as follows. 1. The increasing level of hydroxyproline volume induced by dimethylnitrosamine in mice was decreased by the oral administration of Gibangganbang. 2. The degree of hitological fibrosis and hepatic inflammatory cell infiltration induced by $CCl_4$ was decreased by the oral administration of Gibangganbang. 3. The degree of fatty value and the increasing level of lipidoperoxide in liver tissues was decreased by the oral administration of Gibangganbang. 4. The level of glutathione in liver tissues was increasing by the oral administration of Gibangganbang. 5. The increasing level of microsomal lipidoperoxide in vitro assay was decreasing by the oral administration of Gibangganbang. 6. The increasing level of the mitotic index, weight of liver, contents of protein, RNA and DNA synthesis of the liver tissues after partial hepatectomy was activated by the oral administration of Gibangganbang. These results suggest that Gibangganbang not only inhibits liver cirrhotic change and ethanol-induced fatty change but also activates antioxidant enzymes and regeneration ability ocf liver.

• 대한의생명과학회지
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• 제11권3호
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• pp.319-326
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• 2005

It is well known that oxidative stress of reactive oxygen species (ROS) may be a causative factor in the pathenogenesis of bone disorder on osteoblast or osteoclast. The purpose of this study was to evaluate the cytotoxicity of oxidative stress, protective effect of glutamate receptor antagoinst against ROS-induced osteotoxicity, secretion of tumor necrosis factor $(TNF)-\alpha$ and the expression of c-fos gene in the cultured rat osteoblasts and osteoclasts. Cell viability by MTS assay or !NT assay, activity of glutathione peroxidase (GPx), lipid peroxidation (LPO) activity, protein synthesis by sulforhodamine B (SRB) assay, alkaline phosphatase (ALP) activity, lactate dehydrogenase (LDH) activity, MTS assay for NMDA (N-methyl-D-aspartate) receptor antagonist or AMPA/kainate receptor antagonist, measurement for $TNF-\alpha$, and c-fos gene expression were performed after these cells were treated with or without various cocentrations of xanthine oxidase (XO), hypoxanthine (HX), D-2-amino-5-phosphonovaleric acid (APV), 7-chlorokynurenic acid (CKA), 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and 6,7-dinitroquinoxaline-2,3-dione (DNQX), respectively. In this study, XO/HX showed decreased cell viability and glutathione peroxidase (GPx) activity, but it showed increased LPO activity, $TNF-\alpha$ secretion and c-fos expression. APV and CKA incresed protein sythesis and ALP activity. While, CNQX or DNQX did not show any protective effect in LDH activity or cell viability. From these results, XO/HX showed cytotoxic effect in cultured rat osteoblast or osteoclast, and also NMDA receptor antagonist such as APV or CKA was effective in blocking XO/HX-induced osteotoxicity in these cultures.

• 한국유가공학회:학술대회논문집
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• 한국유가공기술과학회 2005년도 창립 30주년 기념 국제심포지움 - 웰빙시대의 우유.유제품의 새로운 발견
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• pp.13-35
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• 2005

노인 인구 증가는 유럽과 미국에 걸쳐 몇 년간 관찰되어 왔지만, 일본과 한국과 같은 개발도상국에서도 증가 추세가 현저히 나타나고 있다. 개발도상국에서는 2000년, 65세 이상 노인의 인구비율이 1960년에 비해 약 5배 정도 증가했으며, 2050년에는 전체 인구의 40% 정도를 차지할 것으로 예상되고 있다. 이런 급격한 인구 변화는 이들이 특정 권리와 구매력을 지니는 새로운 사회경제적 집단으로 성장하게 하는 계기가 되었다. 노화가 일어나면, 식이요법으로 어느 정도 조절할 수 있는 인체의 변화가 다양하게 일어난다. 그 중 대표적인 것은 글루타치온 합성과 이용의 균형에 변화가 생기는 것이다. 글루타치온은 인체에서 가장 중요한 항산화 물질이고, 식이 내 시스테인 아미노산에 의해 체내 함량이 결정될 수 있다. 시스테인이 풍부한 펩티드 제품이 기능성 식품 및 식품원료로 개발되었다. 소비자 조사 결과, 이 제품은 숙면과 활력을 제공하는 등 장점이 있음이 밝혀졌다. 동물 임상 실험 결과를 통해 특별히 노인 인구를 대상으로 하여 시스테인 펩타이드의 생리 활성과 대사 과정을 소개하고자 한다.