• Title/Summary/Keyword: choline esters

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Hydrophobic Interaction Between the Acyl Moiety of Choline Esters and the Active Site of Acetylcholinesterase

  • Myung, Pyung-Keun;Sok, Dai-Eun
    • BMB Reports
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    • v.28 no.4
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    • pp.290-292
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    • 1995
  • Existence of a binding site for choline esters with an acyl chain of various sizes was examined by comparing the inhibitory potency of the respective compound. In contrast to acetylcholine, which showed a pure competitive pattern of inhibition, choline esters with an acyl chain of a long size ($C{\geq}5$) expressed a mixed type of inhibition. Binding of choline esters containing a long chain ($C_7-C_{12}$) to the hydrophobic region in the active site is deduced from a linear relationship between the $K_{iE}$ value and the size of acyl moiety, and a good hydrophobicity relationship. In addition, the non-competitive component in the inhibition of acetylcholinesterase seems to be due to the interaction of choline esters with both the hydrophobic site and the trimethylammonium-binding site in the active center of the acetylated acetylcholinesterase.

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Reaction Mechanism of Acetylcholinesterase Catalyzed Hydrolysis of Thiocholine Esters (아세틸콜린에스터라제 촉매에 의한 티오에스테르의 가수분해 반응 메카니즘 연구)

  • 정대일;최순규;이용균;박유미;곽문정;신영주;최병욱;이봉호;한정태
    • Journal of Life Science
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    • v.12 no.1
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    • pp.32-42
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    • 2002
  • It was researched to react horse serum-BChE with hefanoylthiocholine chosen among choline esters. According as number of carbon of acyl group in choline esters was increased, reactivity was decreased but strength of ES complex was increased (Km=0,140mM). The pH-V/K profile for BChE-catalyzed hydrolysis of hexanoylthiocholine yields a p $K_{a}$ =4.974$\pm$0.028. This value is equal to recent literature that shows systematic shift from dependence of activity on the basic form fo a residue that huts a p $K_{a}$ =6.2~6.4 to catalysis by a residue or residues that has a p $K_{a}$ =4.7~5.0. The resulting kinetic solvent isotope effect of hexanoylthiocholine is $^{D/V}$K=1.18. The magnitude of the isotope effect suggests that proton transfer is not an element of transition-state stabilization.n.

$pD_2$ Value of Choline Esters on Motility of Isolated Rabbit Jejunum Segment (토끼의 적출장관 운동에 대한 Choline Esters의 $pD_2$)

  • Park, Joon Hyoung;Kim, Young Whan;Kim, Kil Soo
    • Current Research on Agriculture and Life Sciences
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    • v.7
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    • pp.231-235
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    • 1989
  • The effects of choline and choline esters(acetylcholine, methacholine, carbachol, bethanechol) on motility of isolated rabbit jejunum segment were examined and $pD_2$ values of each drugs were compared. The results were as follows. In choline, there were revealed that maximum effective concentration was $10^{-2}M$, $ED_{50}$ was $2.4{\times}10^{-3}M$, and $pD_2$ value was 2.619. In acetylcholine, there were revealed that maximum effective concentration was $10^{-4}M$, effect was hardly showin in $10^{-9}M$ concentration, $ED_{50}$ was $0.5{\times}10^{-5}M$, and $pD_2$ value was 5.154. In methacholine, there were revealed that maximum effective concentration was $10^{-5}M$, effect was hardly shown in $10^{-9}M$ concentration, $ED_{50}$ was $9{\times}10^{-7}M$, and $pD_2$ value was 6.045. In carbachol, there were revealed that maximum effective concentration was $10^{-5}M$, effect was hardly shown in $10^{-11}M$ concentration, $ED_{50}$ was $5.7{\times}10^{-7}M$, and $pD_2$ value was 6.244. In bethanechol, there were revealed that maximum effective concentration was $10^{-4}M$, effect was hardly shown in $10^{-8}M$ concentration, $ED_{50}$ was $3.3{\times}10^{-6}M$, and $pD_2$ value was 5.480. Choline and choline esters caused contraction on motility of isolated rabbit jejunum segment. The order of $pD_2$ values of drugs was carbachol, methacholine, bethanechol, acetylcholine and choline (in the descending order of potency).

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Synthesis of Acylthiocholines (Acylthiocholine들의 합성)

  • 정대일;이용균
    • Journal of Life Science
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    • v.12 no.1
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    • pp.26-31
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    • 2002
  • Choline esters that are used with substrate of BChE-catalyzed hydrolyses were synthesized by two methods. First, 2-chloroethyl thiohexanoate, 2-chloroethyl thioheptanoate, and 2-chloroethyl thiooctanoate were synthesized by the treatment of hexanoyl chloride with ethylene sulfide. Hexanoyl thiocholine and octanoyl thiocholine were synthesized by using 2-chloroethyl thiohexanoate and 2-chloroethyl thiooctanoate with trimethyl amine. Second, after reaction of ethylene sulfide and dimethyl amine, followed by acylation with acid anhydride and then heptanonyl thiocholine, decanoyl thiocholine were synthesized by treatment of methyl iodide.

Studies on the Composition of Lipid Class and Fatty Acid of Korean Black Soybean (한국 재래 검점콩의 지방질 조성에 관한 연구)

  • Lee, Kyung-Im;Ryu, Jung-Hee;Rhee, Sook-Hee;Cheigh, Hong-Sik
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.17 no.3
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    • pp.262-268
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    • 1988
  • Total lipids of Korean black Soybean were extracted, purified and fractionated into three lipid classes (Neutral lipid, NL; glycolipid, GL;phospholipid, PL) and the composition of lipid class and fatty acid were studied. Total lipids of black soybean consisted of 88.5% NL, 2.5% GL and-9.0% PL. In the NL, triglycerides were predominant(80.4%) and also sterol esters, hydrocarbons, diglycerides, free fatty acids and sterols were identified. The major component of GL were monogalactosyl diglycerides and esterified steryl glycosides, and then cerebrosides, steryl glycosides, digalactosyl diglycerides were also found. As major component of the PL, phosphatidyl ethanolamine and phosphatidyl choline were observed, other compounds such as phosphatidyl inositol, phosphatidyl serine and lysophosphatidyl choline were also determined. The major fatty acids in the NL and GL were linoleic acid, oleic acid and palmitic acid, however, PL contained higher relative content of palmitic acid and lower level of oleic acid compared with those of NL and GL.

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Distribution of Lipids in Panax ginseng Root (인삼근의 지질 분포)

  • Kim, U-Gap;Lee, Chang-Seop;Jeong, Byeong-Gap
    • Journal of Ginseng Research
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    • v.12 no.2
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    • pp.93-103
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    • 1988
  • Diversities of lipid compositions according to the morphological differences of the Panax ginseng root were studied by means of column, thin layer, gas-liquid chromate-graphies and histochemical stainings. Purified lipids from various parts were 1.08-2.23% of dry weight, of which 64.2-73.5% were neutral lipids, 15.4-17.4% were glycolipids and 10.4-19.2% were phospholipids. Especially the contents of neutral lipids were highest in cortex, suggesting to be the presence of lipid ducts only in cortex. Triglycerides, sterol esters and hydrocarbons were abundant in the neutral lipid fractions. Twelve components were identified in the periderm and cortex, but unidentified II, IV and V components were not present in the medulla. The major components of glycolipid freactions were sterol glycoside, digalactosyl diglyceride and esterified sterol glucoside. Phosphatidyl glycerol, phosphatidyl choline and phosphatidyl ethanolamine were major components of phospholipid fractions, And phosphatidyl choline was extreamly much in the periderm and medulla, but phosphatidyl glycerol was largest in quantity in the cortex. Eighteen kinds of fatty acids were identified in the neutral lipid, glycolipid and phospholipid fractions. Linoleic, palmitic, oleic and linolnic acids were the main components of fatty acids. The contents of saturated fatty acids, unsaturated fatty acids and essential fatty acids of each three fractions were different one another regardless of the Periderm, cortex and medulla.

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Lipid Contents and Fatty Acid Composition of Three Lipid Classes in Korean Pinenut (잣지질 성분의 분획정량 및 각 획분의 지방산 조성)

  • Kim, Myung;Rhee, Sook-Hee;Cheigh, Hong-Sik
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.13 no.4
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    • pp.406-412
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    • 1984
  • Total lipids (TL) from Korean pinenut (Pinuskoraiensis S & Z) were extracted, purified and fractionated into three lipid classes (neutral lipid: NL, glycolipid; GL, phospholipid; PL). Lipid contents(constituent components) and fatty acid composition of three lipid classes were determined by thin layer chromatography and gas chromatography. TL ranged from 69.0% to 69.8% in fresh pinenut and consisted of 95.9% to 96.7% NL, 3.2% to2.5% GL and 0.9% to 0.8% PL. In the NL, triglycerides were predominant (80.8%) with the smaller amounts of sterol, diglycerides, free fatty acids, sterol esters and hydrocarbons. Monogalactosyl diglycerides and esterified steryl glycosides (23.5%) were the major components of GL, but cerebrosides, steryl glycosides and digalactosyl diglycerides were also found as minor components. Of the PL, phosphatidyl choline (40.2%) and phosphatidyl ethanolamine (19.4%) were the major components, comprising over 60% of this class. Phosphatidyl inositol, lysophosphatidyl choline were also present in the PL. The major fatty acids in the NL were linoleic acid (48.6%), oleic acid (28.8%) and arachidic acid(14.4%), The fatty acid composition in the GL was similar to the pattern in the NL, but PL contained a higher percentage of palmitic acid (17.7%) and stearic acid (6.0%) than other lipid classes.

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Changes of Lipid Composition of Korean Black Soybean before and after Soaking (수침과정 전후의 한국산 검정콩의 지질성분 변화에 관한 연구)

  • Oh, Me-Kyong;Rhee, Sook-Hee;Cheigh, Hong-Sik
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.21 no.1
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    • pp.29-35
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    • 1992
  • Total lipids of Korean black soybean (Glycine man Merr) during soaking in water were extracted, purified and fractionated into three lipid classes, and then lipid contents and their fatty acid compositions were investigated. The lipids of the beans consisted of 89.1% neutral lipids, 1.5% glycolipids and 9.4% phospholipids, and these fractions did not change significantly during the soaking period. The neutral lipid fraction of the beans contained 92.1% triglyceride, 3.0% sterol esters and hydrocarbons, 2.8% diglyceride, 1.5% free fatty acids, 0.3% free sterols and 0.3% monoglyceride, and no significant changes were found in the composition of neutral lipid fraction from the soaked beans. Major components of the glycolipid fraction were esterified steryl glycosides (43.6%), steryl glycosides (26.6%) and digalactosyl diglycerides (14.5%), and these fractions did not change significantly during the soaking period. On the other hand, phosphatidyl choline (41.6%) and phosphatidyl ethanolamine (39.5%) were most abundant components found in the phospholipid fraction, and the contents of phospholipids changed a little during the soaking period. Linoleic acid, oleic acid and palmitic acid were the major fatty acids found in total lipids, neutral lipids, glycolipids and phospholipids. A few changes in the major fatty acid compositions of phospholipids were observed during the soaking period.

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Studies on the Lipid Components of Fresh Ginseng, Red Ginseng and White Ginseng (수삼(水蔘), 홍삼(紅蔘) 및 백삼(白蔘)의 지방질성분(脂肪質成分)에 관한 연구(硏究))

  • Choi, Kang-Ju;Kim, Dong-Hoon
    • Korean Journal of Pharmacognosy
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    • v.16 no.3
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    • pp.141-150
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    • 1985
  • Lipid and fatty acid compositions of free lipids and bound lipids from fresh ginseng, red ginseng and white ginseng were studied by means of silicic acid column chromatography, thin-layer chromatography and gas-liquid chromatography. Free lipid and bound lipid contents in those three samples were 1.21 to 1.45% and 0.32 to 0.45%. Neutral lipid fractions in free lipids from the samples were 76.6 to 79.7%, while glycolipid and phospholipid fractions were 11.6 to 14.7% and 8.5 to 8.7%, respectively. The major lipids were triglycerides, sterol esters and hydrocarbons, diglycerides and free sterols in neutral lipids, sterol glucoside, monogalactosyl diglyceride, esterified steryl glycoside, digalactosyl diglyceride in glycolipids and phosphatidyl ethanolamine, phosphatidyl glycerol, phosphatidyl choline and phosphatidyl inositol in phospholipids. Fourteen kinds of even numbered and four kinds of odd numbered fatty acids were identified in the four lipid fractions (TL, NL, GL and PL) by GLC, and the main fatty acids were linoleic acid, palmitic acid, oleic acid and linolenic acid.

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Studies on the Lipid Components of Various Ginsengs 1. lipid and Fatty Acid Compositions of the Free Lipids (각국 인삼의 지방질성분에 관한 연구 제1보, 유리 지방질중의 지방질 및 지방산 조성)

  • Choe, Gang-Ju;Kim, Man-Uk;Kim, Dong-Hun
    • Journal of Ginseng Research
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    • v.9 no.2
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    • pp.193-203
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    • 1985
  • Lipid and fatty acid compositions of the free lipids in Panax ginseng (Korea, Japan and China), Panax quinquefolium (America, Canada) and Panax notoginseng (China) were studied by means of silicic acid column chromatography, thin-layer chromatography and gas-liquid chromatography. Free lipid contents were 1.13 to 1.24% in panax ginseng and 0.87 to 1.18% in Panax quinquefolium and 0.39% in panax notoginseng. Neutral lipid fractions were 81.2 to 84.4%, while glycolipid fractions 8.01% to 14.47% and phospholipid fractions 3.49 to 5.74% in free lipid contents. The major components were triglycerides, free sterols, diglyceride, free fatty acids and sterol esters in neutral lipid fractions, sterol glucoside, monogalactosyl diglyceride, digalactosyl diglyceride, esterified steryl glucoside in glycolipid fractions and phosphatidyl glycerol, phosphatide, ethanolamine, phosphatidyl choline in phospholipid fractions. The contents and compositions of neutral lipids and glyclipids were some different among various ginsengs, whereas phospholipids showed relatively similar compositions in the contents. Seventeen fatty acids were analyzed in the four free lipid fractions from the various ginsengs and the main fatty acids were linoleic acid, palmitic acid, oleic acid and linolenic acid. It was found that the amounts of some fatty acids were different among the various ginsengs, but the fatty acid patterns of these ginsengs were on the whole similar.

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