Chapter 1 23 group of proteins with high and ultra-high cystine sulphur content but of low α-helix content were identified as arising from the KAPs of the keratin composite or from the cystine-rich components of the fiber cuticle. Another group of proteins of high helix content but low in cystine were identified as arising from the KIFs of the keratin composite. The latter were divided into two groups according to charge with type I group being acidic and type II group neutral/ basic. Type I and type II were always present in equal amount and, given their charge complimentarily, it seemed possible they were the component parts of the two-stranded protein coiled-coils of the KIFs held together by electrostatic interaction. By dint of perseverance, and by purely chemical methods, the CSIRO group in Melbourne Australia in the 1980s obtained the complete amino acid sequence of a type-I IF protein from sheep’s wool.53 In the course of their work they discovered considerable sequence homology and common structural characteristics between the types I and II proteins that were also shared with a range of Figure 11. Schematic of the 2-D polyacrylamide separation of hair proteins.
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