EVIDENCE THAT THE CORNEOCYTE HAS A CHEMICALLY BOUND LIPID ENVELOPE
EVIDENCE THAT THE CORNEOCYTE HAS A CHEMICALLY BOUND LIPID ENVELOPE
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DOI：
10.1111/1523-1747.ep12470383
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发表时间：
1987-06-01
影响因子：
6.5
通讯作者：
DOWNING, DT
中科院分区：
文献类型：
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作者：
SWARTZENDRUBER, DC;WERTZ, PW;DOWNING, DT
哺乳动物表皮的角质层含有神经酰胺、游离脂肪酸、胆固醇和胆固醇硫酸盐的混合物，占组织干重的14%，可以通过氯仿/甲醇彻底提取来去除。随后的温和碱性水解释放出额外的脂质，其几乎完全由与鞘氨醇酰胺连接的C30-C34 Ω-羟基酸组成，相当于组织质量的2%。在本研究中，使用透射电子显微镜证明初始提取去除了构成表皮水屏障的细胞间薄片，但留下了被称为角质细胞质膜的透明带。随后的碱水解和脂质提取去除了透明带，因此该透明带必定含有Ω-羟基酰基鞘氨醇。从这些脂质的原位衍生化和分子模型构建的结果推断，结合的脂质与角质细胞包膜表面的蛋白质以酯键形式存在。因此，紧密堆积的羟基酰基鞘氨醇分子形成每个角质细胞的脂质包膜。
The stratum corneum of mammalian epidermis contains a mixture of ceramides, free fatty acids, cholesterol, and cholesteryl sulfate, amounting to 14% of the dry weight of the tissue, that can be removed by exhaustive extraction with chloroform/methanol. Subsequent mild alkaline hydrolysis liberates additional lipid, consisting almost exclusively of C30-C34 .omega.-hydroxyacids in amide linkage with sphingosine, equal to 2% of the tissue mass. In the present study, transmission electron microscopy was used to demonstrate that the initial extraction removes the intercellular lamellae that constitute the epidermal water barrier but leaves the lucent band that has been termed the corneocyte plasma membrane. The subsequent alkaline hydrolysis and lipid extraction remove the lucent band, which must therefore contain the .omega.-hydroxyacylsphingosines. From the results of in situ derivatization of these lipids and the construction of molecular models, it is inferred that the bound lipids exist in ester linkage with protein on the surface of the corneocyte envelope. The tightly packed hydroxyacylsphingosine molecules thus form a lipid envelope for each corneocyte.