Crosslinking Structure of Keratin: Number and Type of Crosslinks in Microstructures of Untreated and Potassium Cyanide Treated Human Hair

The study investigated the crosslinking structure of human hair, focusing on the effects of potassium cyanide (KCN) treatment. It was found that disulfide (SS) bonds in hair were converted to monosulfide (S) crosslinks when treated with 0.08M aqueous KCN. The treatment affected low-sulfur (LS) and high-sulfur (HS) proteins differently, with SS bond scission occurring faster in HS proteins. The study determined the percentage of different crosslinks in LS and HS proteins, with LS proteins having 27.0% intermolecular SS, 39.0% intermolecular X, and 34.0% intramolecular SS + X links, while HS proteins had 11.9% intermolecular SS and 88.1% intramolecular SS links. The total number of crosslinks in hair was 627 μmol/g, with LS and HS proteins contributing 13.8% and 86.2%, respectively.