Enzymatic approach to analyze the effects of mercaptans on hair

Different mercaptans were used to prepare reduced hair and permed hair samples. The reduced hair showed much higher protease degradation than the permed hair; also, the protease degradability of permed hair increased with repetitive treatments. The degradability of reduced hair was closely related to its cystine content, and that of permed hair was nearly unaffected by its cystine content. The degradability of both the reduced and permed hair was related to the reduction power of each mercaptan used on the hair and increased in the following order: CYS-treated hair < CA-treated hair < TG-treated hair.