A comparative study of high-sulphur proteins from α-keratins

1. Mammalian and marsupial α-keratins contain proteins which are similar to the high-sulphur protein fraction of Merino wool. 2. Keratins differ in the amount of these proteins which they contain, the observed range being 7 per cent (rhinoceros horn) to 45 per cent (raccoon hair). 3. Although high-sulphur proteins share a common richness in cystinyl, seryl and prulyl residues, in most amino acid residues there are large differences between them. 4. All high-sulphur proteins are electrophoretically heterogeneous, wool proteins containing the most components and guinea-pig hair the least. 5. Electrophoretic analysis of high-sulphur proteins shows potential as a means of identifying α-keratins.