• 제목/요약/키워드: Acyl transfer

검색결과 40건 처리시간 0.023초

산국의 잎과 줄기에서 ACAT 저해활성을 가지는 Guaianolides의 분리 (Isolation of Guaianolides with ACAT Inhibitory Activity from the Leaves and Stems of Chrysanthemum boreale Makino)

  • 이종록;박문기
    • 한국환경과학회지
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    • 제26권11호
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    • pp.1275-1284
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    • 2017
  • Acyltransferase (AT) catalyzes the transfer of an acyl moiety from acyl-coenzyme A (acyl-CoA) to an acceptor. ATs play important roles in the maintenance of homeostasis in the human body and have been linked to various diseases; therefore, several ATs have been proposed as potential targets for the treatment or prevention of such diseases. The AT family includes acyl-CoA:cholesterol AT (ACAT), diacylglycerol AT, and monoacylglycerol AT for the metabolism of lipids. Furthermore, recent molecular biological studies revealed the existence of their isozymes with distinct functions in the body. ACAT plays a critical role in the formation of cholesteryl esters from cholesterol and fatty acids, and is a potential target for treating hypercholesterolemia. During an experiment designed to discover biologically active compounds from herbal medicines, we isolated two known guaianolide sesquiterpene lactones from Chrysanthemum boreale Makino (Compositae). The lactones were characterized from their spectroscopic data (NMR, IR, MASS). These compounds were subjected to ACAT inhibition assay. Here, we report the isolation and structural elucidation of the compounds 8-o-acetyl-2-methoxy-10-hydroxy-3,11(13)-guaiadiene-12,6-olide and 8-acetyl-3,10-hydroxy-4(15),11(13)-guaiadiene-12,6-olide. In the ACAT inhibition assay, compound 1 showed strong inhibitory activity, with an $IC_{50}$ value $45{\mu}g/mL$, whereas compound 2 did not exhibit significant inhibitory activity with an over $100{\mu}g/mL$.

Nucleophilic Substitution Reactions of Thiophenyl Phenylacetate with Benzylamines in Acetonitrile

  • 오혁근;김선경;이익춘
    • Bulletin of the Korean Chemical Society
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    • 제20권9호
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    • pp.1017-1020
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    • 1999
  • The aminolysis reactions of thiophenyl phenylacetates with benzylamines are investigated in acetonitrile at 55.0℃. Relatively large selectivity parameters, βx≒ 1.5, βz = -1.5~-1.8 and βxz = 0.92 together with the valid reactivity-selectivity principle are consistent with stepwise acyl transfer mechanism with rate limiting expulsion of the leaving group, thiophenolate anion, from the tetrahedral intermediate, T ± . The first order kinetics with respect to the benzylamine concentration and the realtively large secondary kinetic isotope effect (kH / kD = 1.2-1.7) involving deuterated benzylamine nucleophiles suggest a four center type transition state in which concurrent leaving group departure and proton transfer are involved.

Aminolysis of Aryl Thiol-2-furoates and Thiol-2-thiophenates in Acetonitrile

  • 오혁근;이준용;이익춘
    • Bulletin of the Korean Chemical Society
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    • 제19권11호
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    • pp.1198-1202
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    • 1998
  • Aminolysis of aryl thiol-2-furoates and thiol-2-thiophenates with benzylainines are investigated in acetonitrile at 50.0 ℃. Relatively large selectivity parameters, ρx(βx), ρz(βx) and ρxz (> 0) together with the valid reactivity-selectivity principle are consistent with a stepwise acyl transfer mechanism with rate-limiting expulsion of the leaving group, thiophenolate anion, from the tetrahedral intermediate, T±. The first-order kinetics with respect to the benzylamine concentration and the relatively large secondary kinetic isotope effect involving deuterated benzylamine nucleophiles suggest a four-center type transition state in which concurrent leaving group departure and proton transfer are involved.

키토산 유도체의 단분자막과 Langmuir-Blodgett Film (Monolayer and Langmuir-Blodgett Film of Chitosan Derivatives)

  • 신재섭
    • 멤브레인
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    • 제6권1호
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    • pp.32-36
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    • 1996
  • 키토산에 acylation을 하여 acylate된 키토산을 합성하였으며 이 acylate된 키토산을 trough 위에 spreading하여 $\pi-A$ curve를 얻었다. 이 $\pi-A$ curve로부터 glucose unit 당의 제한 면적을 계산할 수 있었으며 온도에 따른 $\pi-A$ curve의 변화도 측정하였다. 또한 유리판을 수평적으로 접하는 방법으로 이 단분자막을 유리판 위에 transfer할 수 있었다.

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In Silico Screening of a Novel Inhibitor of β-Ketoacyl Acyl Carrier Protein Synthase I

  • Lee, Jee-Young;Jeong, Ki-Woong;Lee, Ju-Un;Kang, Dong-Il;Kim, Yang-Mee
    • Bulletin of the Korean Chemical Society
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    • 제32권5호
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    • pp.1645-1649
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    • 2011
  • [ ${\beta}$ ]Ketoacyl acyl carrier protein synthase I (KAS I) is involved in the elongation of unsaturated fatty acids in bacterial fatty acid synthesis and a therapeutic target of designing novel antibiotics. In this study, we performed receptor-oriented pharmacophore-based in silico screening of E. coli KAS I (ecKAS I) with the aim of identifying novel inhibitors. We determined one pharmacophore map and selected 8 compounds as candidates ecKAS I inhibitors. We discovered one antimicrobial compound, YKAe1008, N-(3-pyridinyl) hexanamide, displaying minimal inhibitory concentration (MIC) values in the range of 128-256 ${\mu}g/mL$ against MRSA and VREF. YKAe1008 was subsequently assessed for binding to ecKAS I using saturation-transfer difference NMR spectroscopy. Further optimization of this compound will be carried out to improve its antimicrobial activity and membrane permeability against bacterial cell membrane.