Erhardt A, Leray C, Binaglia L, Roberti R, Dreyfus H, Massarelli R, Freysz L
Centre de Neurochimie du CNRS, Strasbourg, France.
Biochim Biophys Acta. 1990 Jan 29;1021(2):126-32. doi: 10.1016/0005-2736(90)90024-i.
The transbilayer fatty acid distribution of diacylglycerophosphoethanolamine and the translocation of newly synthesized phosphatidylethanolamine molecules labelled with different fatty acids has been investigated in chick brain microsomes using trinitrobenzensulfonic acid. The determination of the fatty acid composition of diacylglycerophosphoethanolamine in both the outer and the inner leaflet of the microsomal vesicles revealed a similar distribution indicating that both leaflets share the same molecular species. The in vitro incorporation of radioactive fatty acids (16:0, 18:1 and 20:4(n-6] into ethanolamine phospholipids, known to be catalyzed by the lyosphosphatidylethanolamine acyl transferase, showed that the radioactive diacylglycerophosphoethanolamine molecules appeared first in the outer leaflet and were thereafter transferred to the inner leaflet. The apparent rate of translocation of the newly synthesized ethanolamine phospholipid molecules was the highest for those labelled with 16:0 and the lowest for those labelled with 20:4(n-6). The results indicate that the active site of the acyl-CoA:lysophosphatidylethanolamine acyltransferases is located on the outer leaflet of the microsomal vesicles and that the different newly synthesized molecular species of diacylglycerophosphoethanolamine may be translocated from the outer to the inner leaflet at different rates.
利用三硝基苯磺酸，对鸡脑微粒体中二酰基甘油磷酸乙醇胺的跨膜脂肪酸分布以及用不同脂肪酸标记的新合成磷脂酰乙醇胺分子的转运进行了研究。对微粒体小泡外层和内层中二酰基甘油磷酸乙醇胺的脂肪酸组成测定显示出相似的分布，这表明两层共享相同的分子种类。已知由溶血磷脂酰乙醇胺酰基转移酶催化的放射性脂肪酸（16:0、18:1和20:4(n-6)）在体外掺入乙醇胺磷脂中，结果表明放射性二酰基甘油磷酸乙醇胺分子首先出现在外层，随后转移到内层。新合成的乙醇胺磷脂分子的表观转运速率对于标记为16:0的分子最高，而对于标记为20:4(n-6)的分子最低。结果表明，酰基辅酶A：溶血磷脂酰乙醇胺酰基转移酶的活性位点位于微粒体小泡的外层，并且不同新合成的二酰基甘油磷酸乙醇胺分子种类可能以不同速率从外层转运到内层。
