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 '
Flora and fauna of the Outer Hebrides there occasionally, but are more common off the West Beach. The grey seal now breeds on Hirta but did not do so before the 1930 evacuation. The beach at Village Bay in St Kilda is unusual in that its short stretch of summer sand recedes in winter, exposing the large boulders on which it rests. A survey of the beach in 1953 found only a single resident species, the crustacean isopod "Eurydice pulchra". Amongst the more exotic species found off the Outer Hebrides, is the giant squid ("Architeuthis") - specimens are occasionally washed up on the islands. There are only