The Chemical Composition of Wool XV. The Cell Membrane Complex

The cell membrane complex of wool has been examined by electron microscopy of stained. cross sections after immersion of the wool in formic acid. The cell membrane complex of the cortex is considerably modified by the treatment, but that of the cuticle appears unchanged. Resistant membranes from cuticle cells, cortical cells and wool have been prepared by treatment with performic acid-ammonia. Amino acid analyses show that the resistant membranes from the cuticle contain citrulline but those from cortical cells do not. It is concluded that the cell membrane complex of the cuticle differs from that of the cortex. Because of the high lysine content of the resistant membranes, their resistance to chemical attack, the hydrophobicity of epicuticle and the observation of a small amount of e-(y-glutamyl)lysine, it is postulated that the resistant membranes may contain an appreciable amount of e-(y-glutamyl)lysine cross links.