• 약학회지
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• 제36권1호
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• pp.66-72
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• 1992

In order to test relationships between hepatotoxicity and transmethylation, activities of protein methylases and SAM (S-adenosyl-L-methionine)-synthetase were examined in liver tissues of rats treated with $CCl_4$. Also the concentrations of SAM and SAH were measured by HPLC in rat liver. The results are as follows. (1). Activities of protein methylases were not significantly changed in 24 hours after $CCl_4$ treatment. However, in 48 hours, activities of protein methylases were significantly increased in comparison with that of control. (2). Activity of SAM-synthetase was increased steadily in the time course after $CCl_4$ treatment. (3). S-adenosyl-L-methionine concentration of liver tissues in $CCl_4$-treated group was elevated in 24 hours, and then declined thereafter. But the SAH concentration was slightly decreased in the time course after $CCl_4$ treatment. These results indicate that SAM was very actively used in transmethylation reactions of $CCl_4$ damaged rat liver, suggesting the strong relationships between hepatotoxicity and transmethylation phenomena.

• Archives of Pharmacal Research
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• 제25권4호
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• pp.463-468
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• 2002

We have previously reported on the identification of the endogenous transmethylation inhibitor oligosaccharide-linked acyl carrier protein (O-ACP), In this study, the role of the transmethylation reaction on cell cycle progression was evaluated using various transmethylase inhibitors, including O-ACP. O-ACP significantly inhibited the growth of various cancer cell lines, including NIH3T3, ras-transformed NIH3T3, MDA-MB-231, HT-1376, and AGS. In addition, exposure of ras-transformed NIH3T3 to O-ACP caused cell cycle arrest at the $G_0/G_1$ phase, which led to a decrease in cells at the S phase, as determined by flow cytometry. In contrast, transmethylase inhibitors did not affect the expression of $p21^{WAF1/Cip1}$, a well known inhibitor of cyclin dependent kinase, indicating that the cell cycle arrest by transmethylase inhibitors might be mediated by a $p21^{WAF1/Cip1}$-independent mechanism. Therefore, O-ACP, a novel transmethylase inhibitor, could be a useful tool for elucidating the novel role of methylation in cell proliferation and cell cycle progression.

• Archives of Pharmacal Research
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• 제22권3호
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• pp.237-242
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• 1999

A proteinacious inhibitor with a molecular weight of 1,600 Da which inhibits S-adenosyl-L-methionine-dependent transmethylation reactions was purified from porcine liver to homogeneity by procedures including boiling, Sephadex G-25 column chromatography and repeated HPLC. Employing both Nuclear Magnetic Resonance (NMR) and Fast Atom Bombardment-Mass (FAB-Mass) spectroscopy, S-adenosylhomocysteine was conclusively identified as an integral part of the inhibitor. The purified S-adenosylhomocysteine was competitive with S-adenosyl-L-methionine with Ki value of $6.3{\times}10^{-6}$ M towards protein methylase II.

• Bulletin of the Korean Chemical Society
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• 제4권3호
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• pp.151-152
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• 1983

• Korean Chemical Engineering Research
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• 제43권5호
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• pp.560-565
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• 2005

1-methylnaphthalene(1-MN)과 2-methylnaphthalene(2-MN) 사이에서의 트랜스메틸화 반응을 제올라이트, H-mordenite(HM), H-Beta$(H{\beta})$, H-USY(HUSY) 촉매를 이용한 고정층 반응기에서 수행하였다. $H{\beta}_{25}(SiO_2/Al_2O_3=25)$ 촉매는 다음과 같은 조건, 반응온도 $350^{\circ}C$, 반응압력 1.5 Mpa, 전체 액상 반응물의 WHSV $2.7g_{feed}/g_{cat}{\cdot}h$, 반응물 1-MN과 2-MN의 몰비 1:1, 반응 1시간에서 2-MN/1-MN 비=2.3와 2,6-DMN/2,7-DMN 비=1.3을 보이면서 다른 촉매보다 높은 전환율과 안정성을 나타내었다. 촉매의 세공구조, 산성도와 관련하여 촉매성능을 해석하였다.

• 대한약학회:학술대회논문집
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• 대한약학회 2000년도 춘계총회 및 학술대회
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• pp.151.2-151.2
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• 2000

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.186-190
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• 2002

S- Adenosylhomocysteine hydrolase $(SAH)^1$ catalyzes the hydrolysis of S-adenosylhomocysteine to adenosine and L-homocysteine. Inhibition of this enzyme accumulates S-adenosylhomocysteine, which in turn inhibits S-adenosyl-L-methionine dependent transmethylation, resulting in no formation of the capped methylated structure at the 5'-terminus of viral mRNA. Thus, S-adenosylhomocysteine hydrolase has been an attractive target for the development of broad spectrum of antiviral agents. (omitted)

• Asian-Australasian Journal of Animal Sciences
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• 제22권10호
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• pp.1461-1476
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• 2009

This review focuses on the metabolic and osmoregulatory functions of betaine and its impact on nutrient digestibility and performance in pigs and poultry. Betaine is the trimethyl derivative of the amino acid glycine, and is present in plant and animal tissue. It has been shown to play an important role in osmoregulation of plants, bacteria and marine organisms. Due to its chemical structure, betaine exerts a number of functions both at the gastrointestinal and metabolic level. As a methyl group donor, betaine is involved in transmethylation reactions and donates its labile methyl group for the synthesis of several metabolically active substances such as creatine and carnitine. Therefore, supplementation of betaine may reduce the requirement for other methyl group donors such as methionine and choline. Beneficial effects on intestinal cells and intestinal microbes have been reported following betaine supplementation to diets for pigs and poultry, which have been attributed to the osmotic properties of betaine. Furthermore, betaine potentially enhances the digestibility of specific nutrients, in particular fiber and minerals. Moreover, at the metabolic level, betaine is involved in protein and energy metabolism. Growth trials revealed positive effects of supplemental betaine on growth performance in pigs and poultry, and there is evidence that betaine acts as a carcass modifier by reducing the carcass fat content. In conclusion, due to its various metabolic and osmoregulatory functions, betaine plays an important role in the nutrition of monogastric animals.

• 한국작물학회지
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• 제45권3호
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• pp.211-215
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• 2000

시료의 지방산 분석은 먼저 지방의 추출이 선행되어야 하는데 이때에는 시료량 및 시약이 많이 들고 또한 분석시간이 많이 소요되므로 지방 추출 및 지방산의 에스테르화를 한 단계에서 실시하는 One step extraction/methylation법(방법 1)에 따라 주요 유료작물의 지방산 조성을 살펴보았다 이 방법은 methanol-heptane-benzene-DMP-H$_2$SO$_4$ 혼합용매를 사용하여 지방 추출 및 지방산 에스테르화를 단일층에서 일어나게 한것으로 기존의 sodium methoxide를 촉매로 한 methanolysis 법에 의한 지방산 분석 결과와 유의적인 차이를 보이지 않았다. 또한 이 혼합시약으로 이미 추출된 지방을 대상으로 실험하였을 때에도(방법 2) 기존방법과 유의적인 차이가 없었다. 따라서 이 One step extraction/methylation법은 시료가 생체이든 추출된 지방이든 그 과정이 단순하고 시간과 노력이 훨씬 적게 소요되어 지방산 분석에 널리 이용될 수 있을 것이며, 특히 1회에 많은 시료를 처리하고자 할 때 더욱 분석효율이 높을 것으로 기대되었다

• 약학회지
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• 제38권4호
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• pp.430-439
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• 1994

S-Adenosyl-L-methionine synthetase (ATP: methionine S-Adenosyltransferase, EC 2.5.1.6; AdoMet synthetase) catalyzes the biosynthesis of S-Adenosyl-L-methionine(AdoMet) from methionine in the presence of ATP. To elucidate the role of transmethylation reaction in the pancreatic tissues, we examined AdoMet synthetase and isozyme activities, and AdoMet contents in the various tissues. The activities of AdoMet synthetase marked the highest in the kidney, and the lowest in the testis among the various tissues of rat. Considerable amounts of AdoMet synthetase activities were detected in the pancreatic tissues of various animals except for those of frog. The level of ${\alpha}$ and ${\gamma}$ isozyme activities were present in the pancreatic tissues of various animals, while ${\beta}$ isozyme activities were detected as trace. AdoMet synthetase activities of rat brain, liver, testis were decreased with growth. In the rat pancreatic tissues, AdoMet synthetase activities were increased during 16 days after birth and then decreased between 16 and 47 days of age. Levels of AdoMet contents of rat brain and testis were decreased with growth. However, AdoMet contents of rat pancreas were decreased until 26 days of age, and then increased thereafter. AdoMet synthetase isozyme patterns did not vary with growth in the pancreas and testis. But, in the liver, ${\beta}$ form is strikingly increased with growth.