Tetzloff S U, Bizzozero O A
Biochemistry Dept. University of New Mexico-School of Medicine, Albuquerque 87131.
Biochem Biophys Res Commun. 1993 Jun 30;193(3):1304-10. doi: 10.1006/bbrc.1993.1767.
Proteolipid protein, the major protein component of central nervous system (CNS) myelin, is known to contain approximately 2% by weight of covalently bound fatty acids. Recently, this protein was also found, though at a lower concentration, in the peripheral nervous system (PNS). The present study was undertaken to determine whether PNS proteolipid protein, like its CNS counterpart, was fatty acylated. Myelin PLP and DM-20, the two proteins that constitute the proteolipid protein fraction, were isolated from bovine sciatic nerves by chromatography on a methylated Sephadex G-100 column. The identity of the isolated proteins was determined by (a) SDS-PAGE, (b) Western blot analysis, and (c) amino acid analysis, and fractions containing only PLP and DM-20 were subjected to acid-methanolysis. Gas-liquid chromatography of the released methyl esters revealed the presence of fatty acids (2.9% w/w) distributed as approximately 47% palmitic, 22% stearic, and 19% oleic acid. Similar results were obtained for bovine white matter proteolipid protein when isolated and analyzed in parallel with the peripheral nerve protein. These data unequivocally demonstrate that both PNS and CNS proteolipid protein are equally acylated.
蛋白脂质蛋白是中枢神经系统（CNS）髓磷脂的主要蛋白质成分，已知其共价结合脂肪酸的含量约为2%（重量）。最近，该蛋白也在周围神经系统（PNS）中被发现，尽管浓度较低。本研究旨在确定PNS中的蛋白脂质蛋白是否像其CNS对应物一样被脂肪酰化。构成蛋白脂质蛋白组分的两种蛋白质，即髓磷脂PLP和DM - 20，通过在甲基化葡聚糖凝胶G - 100柱上进行色谱分离，从牛坐骨神经中分离出来。通过（a）SDS - PAGE、（b）蛋白质印迹分析和（c）氨基酸分析确定分离出的蛋白质的身份，并且仅含有PLP和DM - 20的组分进行酸甲醇解。释放的甲酯的气相色谱分析显示存在脂肪酸（2.9% w/w），其分布约为47%棕榈酸、22%硬脂酸和19%油酸。当与周围神经蛋白平行分离和分析时，牛白质蛋白脂质蛋白也获得了类似的结果。这些数据明确表明，PNS和CNS的蛋白脂质蛋白都同样被酰化。
