ABSTRACT
This chapter discusses briefly the chemistry of keratin fibers needed to understand the nature of a wider spectrum of events within these fibers. Hair fibers form a major component of the outer covering for most mammals. They create a physical barrier between the animal and its environment, and have evolved as a result of their necessary exposure to harsh conditions and the need to be stable over long periods of time to quite severe treatment. All mammalian hairs, together with wools, horns, claws, nails, and quills, mainly consist of a protein material known as a-keratin. As a protein, alpha keratin is a biological polymer consisting of polypeptide chains formed by the condensation of amino acids. Hairs are produced completely within the hair follicle. Keratinization, the process of stabilization of the elongated cortical cells, occurs from the top of the bulb and is complete well before the fiber protrudes beyond the surface of the skin.
