CHARACTERIZATION OF A 3RD PHASE-TRANSITION IN MULTILAMELLAR DIPALMITOYLLECITHIN LIPOSOMES
CHARACTERIZATION OF A 3RD PHASE-TRANSITION IN MULTILAMELLAR DIPALMITOYLLECITHIN LIPOSOMES
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DOI：
10.1021/bi00523a011
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发表时间：
1981-01-01
期刊：
影响因子：
2.9
通讯作者：
FULDNER, HH
中科院分区：
文献类型：
--
作者：
FULDNER, HH
材料和方法：在cm -纤维素（Comfurius & Zwaal, 1977）上进行层析，丙酮重结晶两次。通过薄层色谱、* H和31P核磁共振检测其纯度。脂肪酸的均匀性是通过切割它们和用气相色谱分析它们的甲酯衍生物来保证的（Eibl & Lands, 1970）。样品制备。在45℃双蒸馏水（约10 mg/mL）中培养1-2小时，制备多层脂质体。在培养时间内，在高温下旋转几次，约1 min。然后将脂质体在低重力（1000-15000#，10分钟，4℃）下离心，使颗粒中的脂质浓度在30%至60%（w/w）之间。量热法。差示扫描量热计（Perkin-Elmer DSC 2 with intraccooler I）用于量热测量。样品盘（不锈钢，密封）通常含有8-12毫克的脂质体颗粒；以适量的水为参照。每个样品在0.313 C/min的加热/冷却速率和1 mcal/s的灵敏度（满量程）下扫描几次。测量完成后，用重量法测定样品的脂质含量。此外，对样品盘的初始和最终总重量进行比较，确保没有发生水分损失。
Materials and MethodsCommercially available DPL (obtained from Fluka, Buchs, Switzerland) was chromatographed on CM-cellulose (Comfurius & Zwaal, 1977) and recrystallized twice from acetone. Its purity was checked by TLC and* H and 31P NMR. The homogeneity of the fatty acids was assured by cleavingthem and by analyzing their methyl ester derivatives with gas chromatography (Eibl & Lands, 1970). Sample Preparation. Multilamellar liposomes were prepared by incubating the dry lipid in doubly distilled water (ca. 10 mg/mL) at 45 C for 1-2 h. During the incubation time, the dispersion was vortexed several times for about 1 min at the elevated temperature. The liposomes were then centrifuged at low g forces (1000-15000#, 10 min, 4 C) to give lipid concentrations in the pellet between30% and 60%(w/w). Calorimetry. A differential scanning calorimeter (Perkin-Elmer DSC 2 with Intracooler I) was used for the calorimetric measurements. The sample pans (stainless steel, hermetically sealed) usually contained 8-12 mg of the liposomal pellet; an appropriate amount of water was taken as reference. Each sample was scanned several times at a heating/cooling rate of 0.313 C/min and at a sensitivity of 1 mcal/s (full scale). The lipid content of the samples was determined gravime-trically after completion of the measurements. Also, com-parison of the initial and final total weights of the sample pans ensured that no water loss had occurred.