What chemical substance is formed in the hair fiber due to hydrogen peroxide interacting with the disulfide bond?

The chemical substance formed in the hair fiber when hydrogen peroxide interacts with the disulfide bond is cysteic acid. This occurs when hydrogen peroxide, which is an oxidative agent, breaks the cystine bonds (disulfide bonds formed between the amino acid cysteine) in the hair structure. The reduction of these disulfide bonds results in the oxidation of cysteine to form cysteic acid, which is a product of this reaction.

Cysteic acid is characterized by the addition of a sulfonic acid group to the cysteine structure, which enhances its solubility in water and makes it a key player in the chemical processes involved in hair coloring and lightening. Understanding the role of cysteic acid is crucial for hair colorists, as this reaction can affect the overall integrity and texture of the hair following chemical treatments.

The other options mentioned—cystic acid, cystecic acid, and cystatin—do not accurately represent the product formed due to this specific chemical interaction. Cystic acid is not a standard term related to hair chemistry, cystecic acid does not exist in the context of hair treatment, and cystatin is a protein that plays a role in various biological functions but is not directly related to