Applied Cosmetic Science and Technology Applied Cosmetic Science and Technology

Various raw materials are used in the manufacture of cosmetics for hair repair. For instance, hair care ingredients comprising proteins, peptides, and free amino acids are used to enhance the texture of damaged hair resulting from repeated chemical treatments, such as perms and hair coloring. Hair repair methods that restore tensile strength have been shown to improve the mechanical properties of hair. However, the elucidation of the binding mechanisms of keratin proteins, the primary components of hair, to hair repair components is essential to understand the mechanism underlying hair repair. This is challenged by the lack of established methods for evaluating the binding of repair components to keratin proteins. We established an experimental system to evaluate the binding of hair repair components to hair proteins using two approaches. The first involved the synthesis of keratin-derived peptides with a high α-helical potential. The second approach involved detecting the above-mentioned interactions using high-performance liquid chromatography. This technique was successfully applied to the hair repair component S-carboxymethyl alanyl disulfide keratin, which was found to bind specifically to Type II-derived sequences.