Drenthe E H, Klompmakers A A, Bonting S L, Daemen F J
Biochim Biophys Acta. 1981 Mar 6;641(2):377-85. doi: 10.1016/0005-2736(81)90493-4.
The transverse distribution of the fatty acyl chains of the major phospholipids over the two faces of the photoreceptor membranes has been determined in bovine rod outer segment (stacked disk) preparations. For this purpose, the fatty acid composition of the phospholipids has been analyzed before and after treatment with trinitrobenzenesulfonic acid and phospholipase D. The latter agents are used under conditions in which they have been demonstrated to attack only the outer (cytoplasmic) face of the membrane. After treatment with trinitrobenzenesulfonic acid or phospholipase D, the fatty acid composition of the unreacted phospholipids is the same as that before treatment, regardless of the extent of modification or hydrolysis attained. The fatty acid composition of phosphatidic acid, resulting from phospholipase D action, also remains unchanged during progressive hydrolysis. These results indicate that the fatty acyl chains of the major phospholipids have the same composition on either side of the disk membrane. Together with our previously published evidence for the distribution of the major phospholipids in rod outer segment disk membranes, this means that both the phospholipids and their fatty acyl chains have a remarkably symmetrical distribution over the two membrane faces. On the basis of literature data it is concluded that this approximate symmetry reflects the high mobility of the entire phospholipid pool of disk membranes, thus including appreciable transbilayer movements of the phospholipids.
在牛视杆细胞外段（堆叠盘状）制剂中，已确定了主要磷脂的脂肪酰链在光感受器膜两个表面上的横向分布。为此，在用三硝基苯磺酸和磷脂酶D处理之前和之后，对磷脂的脂肪酸组成进行了分析。后两种试剂是在已证明它们仅攻击膜的外（细胞质）表面的条件下使用的。用三硝基苯磺酸或磷脂酶D处理后，无论达到的修饰或水解程度如何，未反应磷脂的脂肪酸组成与处理前相同。磷脂酶D作用产生的磷脂酸的脂肪酸组成在逐步水解过程中也保持不变。这些结果表明，主要磷脂的脂肪酰链在盘状膜的两侧具有相同的组成。连同我们先前发表的关于视杆细胞外段盘状膜中主要磷脂分布的证据，这意味着磷脂及其脂肪酰链在两个膜表面上都具有非常对称的分布。根据文献数据得出结论，这种近似对称性反映了盘状膜整个磷脂库的高流动性，因此包括磷脂明显的跨膜运动。
