Mrs. Carlson left the Cote d\'Azur hair salon with a beautiful hairdo. Her hair

Question

Mrs. Carlson left the Cote d'Azur hair salon with a beautiful hairdo. Her hair had a much fuller body to it than when she first arrived. She was anxious to see her friends, as they were all scheduled to go out to dinner that night Case Background Hair is composed basically of wrapped layers of keratinized cells; the keratin protein of the hair cells is comprised of a great deal of sulfur-containing amino acids. By chemically manipulating the sulfur-to- sulfur (disulfide) chemical bonds of these amino acids, the three-dimensional structure of hair can be alfered. Hair can be permed into various three-dimensional structures by manipulation of disulfide bonds such as are found in keratin. The amino acid cysteine contains a free sulfhydryl -S-H) side group (Figure 1.1) Keratin protein contains about 28% cysteine and thus has a great deal of sulfhydryl side units available for chemical manipulation by hairdressers Consider a protein molecule with two cysteine residues of the protein brought into close proximity (Figure 1.2). Such a situation could occur during a perm. When hair curlers can physically bring new cysteine amino acids into close proximity on the same protein chain, a covalent bond termed a disulfide bond can be formed and a loop in the protein can result (Figure 1.4) During a perm, the disulfide bonds are first reduced (broken by using a chemical that will add hydrogen to the disulfide bonds (Figure 1.5). Disulfide bonds will be broken creating free sulfhydryl groups (-S-H). The three dimensional structure of the hair's keratin protein will then be amenable to structural manipulation by the hairdresser. The hair proteins can be put into new shapes with curlers and the disulfide bonds can be reformed to hold the proteins in the new three dimensional shapes. T o create new disulfide bonds, a strong base is often used to remove the hydrogen atoms from the free sulfhydryl groups. New disulfide bonds then form if hydrogens CH+) are removed from adjacent suifhydryl groups of 2 cysteine residues. This chemical reaction the that occurs is an oxidation reaction (Figure 1.3). Oxidation is a term in chemistry to denote loss of hydrogen during a chemical reaction. The 2 cysteine amino acids, after formation of the disulfide bond, are collectively termed cystine.

Explanation / Answer

Hair is an array of many alpha keratin filaments. While perming, at the molecular level, the alpha helixes in the alpha keratin of the hair are stretched and the disulphide bonds are reduced or oxidised between two adjacent alpha helix keratin resulting in the change in the tertiary structure of the protein.

Related Questions

Navigate

• Browse (All)
• Browse M
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.