A Model for the Surface of Keratin Fibers

A model of the epicuticle membrane of keratin fibers shows that it is a heavily crosslinked protein containing approximately 25% by weight of fatty acid, predomi nantly 18-methyleicosanoic acid, acylated to the protein as a thioester. The conclusion that acylated fatty acids reside on the surface of and completely surround individual cuticle cells is supported by an analysis of the amount of fatty acid removed by alcoholic alkali against treatment time and the observed decreasing amount of bound fatty acid found as fiber diameters increase. Allworden sacs form only under acidic conditions, which also cleave bound fatty acids. Prior removal of bound fatty acids facilitates the rapid formation of Allworden sacs.