Structural property and function of D-erythro asymmetric chain sphingomyelins as studied by microcalorimetry and electron microscopy
Structural property and function of D-erythro asymmetric chain sphingomyelins as studied by microcalorimetry and electron microscopy
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DOI：
10.1007/s10973-007-8968-9
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发表时间：
2008-06
影响因子：
4.4
通讯作者：
H. Aoki;S. Kosakabe;M. Inumaru;A. Kuboki;S. Ohira;M. Kodama
中科院分区：
文献类型：
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作者：
H. Aoki;S. Kosakabe;M. Inumaru;A. Kuboki;S. Ohira;M. Kodama
以鞘氨醇磷酸胆碱为起始原料合成了具有确定酰基链的D-赤型鞘磷脂（SM），并比较了对称链长SM（棕榈酰SM：C16-SM）和不对称链长SM（山嵛酰SM：C22-SM，二十四烷酰SM：C24-SM）的结构性质及其相关相变现象。此外，研究了在C22-SM/C16-SM和C24-SM/C16-SM的混合体系中增加不对称链SM含量的效果。目前的量热和电子显微镜研究表明，（1）不对称链SM的主转变焓比对称链SM的主转变焓小约3kJ mol − 1，虽然前者的酰基链长度比后者长;（2）相对较小的囊泡（100 - 200 nm直径）被一个或多个薄片包围的不对称链SM，与大的多层囊泡相比（1500 - 2500 nm直径）具有对称链SM的至少15个染色层，和（3）共存的不对称链SM导致对称链SM的MLV的尺寸和多重性降低，同时降低主转变焓。
D-erythrosphingomyelines (SM) having a defined acyl chain were synthesized with sphingosylphosphorylcholine as a starting material, and both a structural property and its relating phase transition phenomenon were compared between a symmetric chain length SM (palmitoyl-SM: C16-SM) and asymmetric chain length SMs (behenoyl-SM: C22-SM, lignoceryl-SM: C24-SM). Furthermore, effect of increasing a content of asymmetric chain SMs in the mixture systems of C22-SM/C16-SM, and C24-SM/C16-SM was investigated.The present calorimetric and electron microscopic studies revealed that (1) The main transition enthalpy is smaller for the asymmetric chain SMs than for the symmetric chain SM by about 3 kJ mol−1, although the acyl chain length is longer for the former than for latter; (2) Relatively small size vesicles (100∼200 nm diameters) surrounded by one or more lamellae are observed for the asymmetric chain SMs, in contrast to large multilamellar vesicles (1500∼2500 nm diameters) having at least fifteen stained lamellae for the symmetric chain SM and (3) The coexisting asymmetric chain SMs cause the decrease in size and multiplicity for the MLV of the symmetric chain SM, simultaneously with a decrease in the main transition enthalpy.