• Title/Summary/Keyword: Transmethylation

Search Result 13, Processing Time 0.055 seconds

Effects of Carbon Tetrachloride-induced Hepatotoxicity on the Activities of Protein Methylases and SAM-Synthetase in Rat Liver (단백질 메틸화효소류 및 S-아데노실-L-메치오닌 연결효소의 활성도에 미치는 사염화탄소-유발 간독성의 영향)

  • Namkoong, Suck-Min;Yoo, Tae-Moo;Hong, Sung-Youl;Lee, Hyang-Woo
    • YAKHAK HOEJI
    • /
    • v.36 no.1
    • /
    • pp.66-72
    • /
    • 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.

  • PDF

Oligosaccharide-Linked Acyl Carrier Protein, a Novel Transmethylase Inhibitor, from Porcine Liver Inhibits Cell Growth

  • Seo, Dong-Wan;Kim, Yong-Kee;Cho, Eun-Jung;Han, Jeung-Whan;Lee, Hoi-Young;Hong, Sungyoul;Lee, Hyang-Woo
    • Archives of Pharmacal Research
    • /
    • v.25 no.4
    • /
    • pp.463-468
    • /
    • 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.

An Endogenous Proteinacious Inhibitor for S-Adenosyl-L-methionine-dependent Transmethylation Reactions; Identification of S-Adenosylhomocysteine as an Integral Part

  • Seo, Dong-Wan;Han, Jeung-Whan;Hong, Sung-Youl;Paik , Woon-Ki;Lee, Hyang-Woo
    • Archives of Pharmacal Research
    • /
    • v.22 no.3
    • /
    • pp.237-242
    • /
    • 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.

  • PDF

Transmethylation of Methylnaphthalene Over Beta, USY and Mordenite Zeolite Catalysts (제올라이트 Beta, USY, Mordenite 촉매를 이용한 Methylnaphthalene의 트랜스메틸화 반응)

  • Park, Jung-Nam;Park, Yong-Ki;Baeg, Jin-Ook;Hong, Suk-In;Lee, Chul Wee
    • Korean Chemical Engineering Research
    • /
    • v.43 no.5
    • /
    • pp.560-565
    • /
    • 2005
  • Catalytic performances of zeolite catalysts such as H-mordenite(HM), H-Beta$(H{\beta})$, H-USY(HUSY) for the transmethylation between 1-methylnaphthalene(1-MN) and 2-methylnaphthalene(2-MN) were investigated in a fixed-bed flow reactor. $H{\beta}$ showed higher and more stable conversion than others to exhibit a high and stable 2-MN/1-MN ratio of 2.3 and 2,6-DMN/2,7-DMN ratio of 1.3 at the $1^{st}$ hour of time on stream under the reaction conditions as follows: reaction temperature of $350^{\circ}C$, reaction pressure of 1.5 MPa, WHSV of $2.7g_{feed}/g_{cat}{\cdot}h$ and the molar ratio of 1-MN and 2-MN of 1:1. The catalytic behavior has been discussed in relation with the catalyst pore structure and acidity.

Development of Mechanism-based Irreversible Inhibitors of S-Adenosylhomocysteine Hydrolase as Borad-spectrum Antiviral Agents

  • Lee, Kang-Man;Moon, Hyung-Ryong;Choi, Won-Jun;Park, Jae-Gyu;Shin, Dae-Hong;Jeong, Lak-Shin
    • Proceedings of the PSK Conference
    • /
    • 2002.10a
    • /
    • pp.186-190
    • /
    • 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)

  • PDF

Metabolic, Osmoregulatory and Nutritional Functions of Betaine in Monogastric Animals

  • Ratriyanto, A.;Mosenthin, R.;Bauer, E.;Eklund, M.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.22 no.10
    • /
    • pp.1461-1476
    • /
    • 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.

Fatty Acid Composition Analysis of Major Oil Crops by One-Step Extraction/Methylation Method (일단계 추출 및 메칠화법에 의한 유료작물의 지방산 분석)

  • 김진경;김남희;방진기;이병규;박충범;이봉호
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.45 no.3
    • /
    • pp.211-215
    • /
    • 2000
  • Lipid extraction preceding fatty acid methyl esters preparation for gas-liquid chromatography is time-consuming and cumbersome. We performed one-step extraction/methylation method with a mixture of methanol-heptane-benzene-DMP-H$_2$SO$_4$ without prior fat extraction. The simultaneous digestion and lipid transmethylation takes place at 8$0^{\circ}C$ in a single phase. After cooling till room temperature, two phases are formed. The upper one of the phases contains the fatty acid methyl esters ready for GLC. The fatty acid composition of major industrial crops obtained by the one step extraction/methylation method (method 1 and 2) was almost identical with the fatty acid composition of the pure fats extracted with hexane by the Soxtec instrument (method 3). Due to its simplicity, speed, and reduced organic solvent the one-step extraction/methylation method (method 1 and 2) should be useful to determine overall fatty acid composition, especially in situations where many samples have to be analyzed.

  • PDF

Distribution of S-Adenosylmethionine Synthetase in the Pancreatic Tissues of Various Animals and Changes of S-Adenosylmethionine Synthetase Activities and S-Adenosylmethionine in the Developing Rat Organs (췌조직과 성장 발육에 따른 흰쥐 조직내 S-Adenosylmethionine Synthetase 활성도 및 S-Adenosyl-L-methionine의 분포)

  • Park, Seung-Hee;Yu, Tae-Moo;Hong, Sung-Youl;Lee, Hyang-Woo
    • YAKHAK HOEJI
    • /
    • v.38 no.4
    • /
    • pp.430-439
    • /
    • 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.

  • PDF