Lecerf J, Fouilland L, Gagniarre J
Biochim Biophys Acta. 1987 Mar 13;918(1):48-59. doi: 10.1016/0005-2760(87)90008-7.
Biosynthesis of sphingomyelin from ceramides was investigated in lung subcellular fractions by incubating a lyophilized mixture of albumin and subcellular fraction (0.1-0.2 mg of protein) coated with [acyl-14C]-ceramide and phosphatidyl[methyl-3H]choline in Tris-buffer. The lamellar-body-rich fraction exhibited the highest specific activity for sphingomyelin biosynthesis measured by 14C incorporation into sphingomyelins or by [3H]phosphocholine transfer from phosphatidylcholines. Plasma membranes formed the next most active fraction, followed by the 'smooth' and, then, the 'rough' endoplasmic reticulum. Sphingomyelin biosynthesis by lamellar bodies was optimum at pH 7.4 and was inhibited by sphingomyelins formed. Slight inhibitory effects were also observed with Mn2+, Ca2+ and lysophosphatidylcholine. Phosphocholine transfer from CDPcholine was not observed under the reaction conditions employed. Ceramide conversion and phosphocholine transfer increased with ceramide concentration to reach a maximum at about 0.06 mM. The highest conversion rate was observed when 18:1 ceramide was used as an acceptor. When 1-palmitoyl-2-oleoylphosphatidylcholine was the phosphocholine donor, the overall biosynthesis of sphingomyelin was much higher than when using dipalmitoylphosphatidylcholine. These results suggest the possible involvement of the studied reaction in the control of the degree of saturation of the surfactant phosphatidylcholine.
通过在Tris缓冲液中孵育包被有[酰基-14C]-神经酰胺和磷脂酰[甲基-3H]胆碱的白蛋白与亚细胞组分的冻干混合物（0.1 - 0.2mg蛋白质），研究了肺亚细胞组分中神经酰胺合成鞘磷脂的过程。富含板层体的组分在鞘磷脂生物合成方面表现出最高的比活性，这通过14C掺入鞘磷脂或通过磷脂酰胆碱的[3H]磷酸胆碱转移来测定。质膜形成下一个活性最高的组分，其次是“光滑”内质网，然后是“粗糙”内质网。板层体进行的鞘磷脂生物合成在pH 7.4时最佳，并且会受到所形成的鞘磷脂的抑制。Mn2 +、Ca2 +和溶血磷脂酰胆碱也观察到轻微的抑制作用。在所采用的反应条件下未观察到从CDP胆碱的磷酸胆碱转移。神经酰胺转化和磷酸胆碱转移随着神经酰胺浓度的增加而增加，在约0.06 mM时达到最大值。当使用18:1神经酰胺作为受体时观察到最高的转化率。当1-棕榈酰-2-油酰磷脂酰胆碱作为磷酸胆碱供体时，鞘磷脂的总体生物合成比使用二棕榈酰磷脂酰胆碱时高得多。这些结果表明所研究的反应可能参与了表面活性剂磷脂酰胆碱饱和度的控制。
