模型細胞膜(含有相同碳鏈的PC/PE)存在或缺乏固醇類的物理性質; The Physical Properties of Model Membranes Composed of PC and PE with Identical Acyl Chain in the Presence and Absence of Sterol.

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/7531

Title:	模型細胞膜(含有相同碳鏈的PC/PE)存在或缺乏固醇類的物理性質;The Physical Properties of Model Membranes Composed of PC and PE with Identical Acyl Chain in the Presence and Absence of Sterol.
Authors:	何愛玲;Ai-ling Ho
Contributors:	物理研究所
Keywords:	氘核磁共振;示差掃描量熱儀;麥角酯醇;膽固醇;cholesterol;ergosterol;POPC;POPE;phospholipid;sterol;2H-NMR;DSC
Date:	2008-07-09
Issue Date:	2009-09-22 10:59:28 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	我們的研究分為兩部分：(I)兩種成分的細胞膜：POPC、POPE；(II)三種成分的細胞膜：POPC、POPE、sterol。利用2H-NMR和DSC，測得POPC/POPE細胞膜的相行為會隨著POPE濃度及溫度而改變。在2H-NMR中，我們以氘取代POPC及POPE sn-1鏈上的氫，來量測POPC及POPE的行為。我們是第一位提出POPE濃度從0到60mol%對溫度的相圖。在相圖上發現一個大範圍的膠態(gel-phase)及液晶態(lc-phase)之兩態共存區。且發現在低於十七度時，POPC及POPE並不是混合得相當均勻，只有在超過十七度時，才有較均勻的混合。利用POPC及POPE上的氘，2H-NMR測得POPC/POPE細胞膜出現固醇類時(1:1:1 POPC/POPE/ergosterol及1:1:1 POPC/POPE/cholesterol) 的相行為會隨著POPE濃度及溫度而改變。實驗中發現，這兩種固醇，在膠態會降低POPC/POPE (1:1)膜的有序程度，但在液晶態卻能增加POPC/POPE (1:1)膜的有序程度，且麥角酯醇的效應低於膽固醇。在沒有固醇類的情況下，POPC及POPE只能在某些溫度下混合均勻，而混合不均勻的溫度區域，在加入麥角酯醇及膽固醇後，有助於POPC及POPE的混合。此外，對於麥角酯醇幫助POPC/POPE膜均勻混合的能力而言，其作用的溫度範圍明顯小於膽固醇。 We investigate two-component membranes composed of POPE and POPC, and three-component membranes composed of POPE, POPC and sterol. The phase behavior of POPC/POPE membranes was studied as a function of POPE concentration and temperature by 2H-NMR and DSC. For 2H-NMR measurements, POPC and POPE were deuterium labeled alternatively such that the behavior of both POPC and POPE can be observed. We present the first temperature-composition diagram for POPE concentration range from 0 to 60 mol%. Coexistence of the gel and lc phases is observed over a wide temperature and composition range. It is found that POPC and POPE do not mix well in 1:1 POPC/POPE below17℃, but mix well above 17℃. To investigate the properties of POPC/POPE membranes in the presence of sterol, 1:1:1 POPC/POPE/ergosterol and 1:1:1 POPC/POPE/cholesterol were studied as a function of temperature by 2H-NMR, with POPC and POPE deuterium labeled alternatively. We show that the presence of ergosterol (or cholesterol) disorders gel-phase POPC/POPE (1:1) membranes, whereas orders lc-phase POPC /POPE (1:1) membranes. The effect of ergosterol is weaker than cholesterol. Furthermore, the presence of ergosterol (or cholesterol) modulates the mixing properties of POPC/POPE membranes. POPC and POPE mix well in some temperature range, where they are poorly mixed in the absence of sterol. The enhancement of mixing of of POPC/POPE membranes by ergosterol is observed in a temperature range narrower than that by cholesterol.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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