A Novel Purification Procedure for Keratin-Associated Proteins and Keratin from Human Hair

The study developed a novel purification procedure for keratin-associated proteins (KAPs) and keratin from human hair using alcohols in the Shindai solution, which enhanced KAPs extraction while suppressing keratin extraction. The procedure, particularly with ethanol, allowed for the selective purification of KAPs and keratin, identifying six KAPs polypeptides and two keratin polypeptides. The amino acid compositions matched literature values, with recovery rates of approximately 10% for KAPs and 50% for keratin. Scanning electron microscopy revealed that KAPs may support keratin fibers by surrounding fibrous structures in the hair cortex, which disappeared upon keratin extraction.