硬脂酰鞘磷脂双层膜中亚稳态的证据。

Evidence for metastability in stearoylsphingomyelin bilayers.

作者信息

Estep T N, Calhoun W I, Barenholz Y, Biltonen R L, Shipley G G, Thompson T E

出版信息

Biochemistry. 1980 Jan 8;19(1):20-4. doi: 10.1021/bi00542a004.

Abstract

The physical properties of aqueous stearoylsphingomyelin dispersions have been investigated by differential scanning calorimetry, fluorescence spectroscopy, and X-ray diffraction. These studies indicate that the thermodynamically most stable gel state of this sphingomyelin is more highly ordered than the corresponding form of other phospholipids. This gel undergoes a transition to a liquid-crystalline conformation at 57 degrees C which is not rapidly reversible. Instead, the liquid-crystalline sphingomyelin supercools below 57 degrees C until a metastable gel is formed at 44 degrees C. The metastable gel slowly converts to the more highly ordered gel phase in an exothermic process at room temperature. The presence of various lipophilic substances enhances the stability of the metastable gel relative to the highly ordered form.

摘要

通过差示扫描量热法、荧光光谱法和X射线衍射法对硬脂酰鞘磷脂水分散体的物理性质进行了研究。这些研究表明，这种鞘磷脂在热力学上最稳定的凝胶态比其他磷脂的相应形态具有更高的有序性。这种凝胶在57℃时会转变为液晶构象，且该转变不可逆。相反，液晶态鞘磷脂会过冷至57℃以下，直到在44℃形成亚稳凝胶。在室温下，亚稳凝胶会通过放热过程缓慢转变为更有序的凝胶相。各种亲脂性物质的存在相对于高度有序的形态提高了亚稳凝胶的稳定性。