Keratin Keratin Keratin () is one of a family of fibrous structural proteins. It is the key structural material making up hair, horns, claws, hooves, and the outer layer of human skin. Keratin is also the protein that protects epithelial cells from damage or stress. Keratin is extremely insoluble in water and organic solvents. Keratin monomers assemble into bundles to form intermediate filaments, which are tough and form strong unmineralized epidermal appendages found in reptiles, birds, amphibians, and mammals. The only other biological matter known to approximate the toughness of keratinized tissue is chitin. Keratin derives from Greek ' from '
In the Zone (The Outer Limits) in the tank with the nerve matter, and disappears, his own body now presumably permanently sped up to the point of being imperceptible to normal humans. A cured but aged Tanner and Jessica look at the "explanation" Dr. Chen left to them - his driver's license, which shows that he should have been only thirty years old. They realize he had tested the procedure on himself, causing his body to speed up and age faster. In the Zone (The Outer Limits) "In the Zone" is an episode of "The Outer Limits" television show. It was first broadcast on February 20,