Further X-ray Evidence of Regularly Distributed Lysine in α-Keratin

Abstract

IT has recently been shown that in mohair fibres the fifth order of the 198 Å pseudo repeat (39 Å reflexion) is intensified when the ε-amino groups of lysine residues are acylated with 3,4,5-triiodobenzoic acid p-nitrophenylester¹. Particularly high yields of acylated ε-amino groups were obtained when dimethylsulphoxide was used as reaction medium. A sample of mohair which had been treated for 24 h at 40° C in this solvent, however, showed a somewhat diffuse X-ray pattern. We therefore looked for a reaction medium which did not cause structural distortion of the α-keratin and which gave high yields of acylated ε-amino groups.