Characterization of Nonkeratinous Proteins Extracted from Human Hair by Permanent Wave Lotion

This study characterized nonkeratinous and keratinous proteins extracted from human hair using permanent wave lotion I (PWL-I). It was found that PWL-I could extract proteins accounting for about 1% of the hair's total mass, with extraction efficiency increasing with pH. The molecular weights of these proteins ranged from 5,000 to 65,000. The amino acid composition of the extracts was similar to collagenous proteins, suggesting they were eluted from the δ layer among cortical cells. Additionally, keratinous proteins were extracted from hair damaged by repeated PWL treatments or bleaching, likely from the matrix in cortical cells composed of high sulfur content keratin. These findings contributed to understanding the mechanisms of protein elution and hair damage from external treatments.