Collins J M, Dominey R N, Grogan W M
Department of Biochemistry and Molecular Biophysics, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0614.
J Lipid Res. 1990 Feb;31(2):261-70.
The shape of the fluidity gradient of the outer hemi-leaflet of the plasma membrane of living HeLa cells was determined using a series of n-(9-anthroyloxy) fatty acid probes where n = 2, 3, 6, 7, 9, 10, 11, 12, and 16. Fluorescence uptake and steady-state anisotropy values were obtained with a flow cytometer capable of continuous recording over time of vertical and horizontal emission intensities, and of the output of these intensities as calculated anisotropy values. The fluorescence uptake of all of the membrane probes was rapid up to about 15 min. The magnitudes of the uptake of fluorescence were, for the n-(9-anthroyloxy) series, in the order 2 greater than 3 greater than 6 greater than 7 greater than 9 greater than 10 greater than 11 = 12 = 16. Anisotropy values were constant from 5 to 30 min after addition of the various probes, and the magnitudes were in the order 7 greater than 6 greater than 9 = 10 greater than 2 = 3 greater than 11 greater than 12 greater than 16, indicative of the shape of the fluidity gradient. No differences were noted between the values obtained with 12-(9-anthroyloxy) stearic acid and 12- (9-anthroyloxy) oleate. The kinetics of anisotropy exhibited by those probes with the anthroyloxy group in positions deeper than 9, where initially higher values declined until equilibrium was reached, were probably indicative of an energy barrier at the approximate depth sensed by 7 AS.
使用一系列n-(9-蒽氧基)脂肪酸探针（其中n = 2、3、6、7、9、10、11、12和16）测定了活HeLa细胞质膜外半层流动性梯度的形状。利用一台能够随时间连续记录垂直和水平发射强度以及这些强度计算出的各向异性值输出的流式细胞仪，获得了荧光摄取和稳态各向异性值。所有膜探针的荧光摄取在约15分钟内迅速发生。对于n-(9-蒽氧基)系列，荧光摄取量的大小顺序为2＞3＞6＞7＞9＞10＞11 = 12 = 16。添加各种探针后5至30分钟内各向异性值保持恒定，其大小顺序为7＞6＞9 = 10＞2 = 3＞11＞12＞16，这表明了流动性梯度的形状。12-(9-蒽氧基)硬脂酸和12-(9-蒽氧基)油酸获得的值之间未观察到差异。那些蒽氧基位于9位以上位置的探针所表现出的各向异性动力学，最初较高的值会下降直至达到平衡，这可能表明在7-AS所感知的近似深度处存在能量屏障。
