Wertz P W
Dows Institute, University of Iowa, Iowa City 52242, USA.
EXS. 1997;78:227-37. doi: 10.1007/978-3-0348-9223-0_7.
Within the past 10 years, covalently bound lipids have been identified both in wool and hair and in epidermal stratum corneum. In hair, fatty acids, the most abundant of which is 18-methyleicosanoic acid, are attached via thioester linkages to protein at the outer surface of cuticle cells. This lipid layer, the fatty layer or F-layer, is thought to be of major significance in determining the surface properties of hair and wool. In epidermal stratum corneum, the covalently attached lipid has been identified as an omega-hydroxyceramide consisting of 30-through 34-carbon omega-hydroxyacids amide-linked to sphingosine bases. The hydroxyceramide molecules are attached to the outer surface of the cornified envelope through ester linkages, and provide a monolayer covering the outer surface of all corneocytes. This covalently bound lipid layer, or lipid envelope, interacts with free lipids and has a major influence on the organization of lipid lamellar structures in the intercellular space.
在过去10年里，共价结合脂质已在羊毛、毛发以及表皮角质层中被鉴定出来。在毛发中，脂肪酸（其中最丰富的是18-甲基二十烷酸）通过硫酯键连接在角质形成细胞外表面的蛋白质上。这个脂质层，即脂肪层或F层，被认为在决定毛发和羊毛的表面性质方面具有重要意义。在表皮角质层中，共价结合的脂质已被鉴定为一种ω-羟基神经酰胺，它由30至34个碳原子的ω-羟基酸与鞘氨醇碱基酰胺连接而成。羟基神经酰胺分子通过酯键连接在角化包膜的外表面，并形成覆盖所有角质形成细胞外表面的单分子层。这个共价结合的脂质层，即脂质包膜，与游离脂质相互作用，并对细胞间空间中脂质层状结构的组织有重大影响。
