Moore D J, Rerek M E, Mendelsohn R
International Specialty Products, Skin R&D, Wayne, New Jersey 07470, USA.
Biochem Biophys Res Commun. 1997 Feb 24;231(3):797-801. doi: 10.1006/bbrc.1997.6189.
A three component model for the lipid barrier of the stratum corneum (SC) consisting of ceramide III, cholesterol, and perdeuterated palmitic acid, has been characterized by Fourier transform infrared spectroscopy. At physiological temperature the CD2 scissoring mode of the palmitic acid methylenes, and the CH2 rocking mode of the ceramide methylenes, are each split into two components. This indicates that both components exist in separate, conformationally ordered phases, probably with orthorhombic perpendicular subcells. The magnitude of the splitting indicates that the domains are at least 100 chains in size. The thermotropic behavior of the CD2 stretching vibrations demonstrates that conformational disordering of the palmitic acid commences at 42 degrees C with a transition midpoint of 50 degrees C. The CH2 stretching frequency indicates the ceramide chains remain ordered until 50 degrees C then disorder with a midpoint of 67 degrees C. The results provide a molecular characterization for the complex low temperature (10-40 degrees C) dynamic behavior suggested by recent 2H NMR experiments.
由神经酰胺III、胆固醇和全氘代棕榈酸组成的角质层脂质屏障的三组分模型，已通过傅里叶变换红外光谱进行了表征。在生理温度下，棕榈酸亚甲基的CD2剪式振动模式和神经酰胺亚甲基的CH2摇摆模式各自分裂为两个组分。这表明这两个组分存在于单独的、构象有序的相中，可能具有正交垂直亚晶胞。分裂的程度表明这些结构域的大小至少为100条链。CD2伸缩振动的热致行为表明，棕榈酸的构象无序在42℃开始，转变中点为50℃。CH2伸缩频率表明神经酰胺链在50℃之前保持有序，然后在67℃的中点发生无序。这些结果为最近的2H NMR实验所暗示的复杂低温（10 - 40℃）动态行为提供了分子表征。
