Keratin

Keratin (/ˈkɛrətɪn/) is one of a family of fibrous structural proteins. Keratin is the protein that protects epithelial cells from damage or stress that has potential to kill the cell. It is the key structural material making up the outer layer of human skin. It is the key structural component of hair and nails, and it provides the necessary strength and toughness for masticatory organs, such as the tongue and the hard palate. Keratin monomers assemble into bundles to form intermediate filaments, which are tough and form strong unmineralized tissues found in reptiles, birds, amphibians, and mammals. The only other biological matter known to approximate the toughness of keratinized tissue is chitin.

Etymology

Keratin derives from Greek κερατίνη from Greek keras (κέρας) (genitive keratos, κέρατος) meaning "horn" originating from the Proto-Indo-European *ḱer- of the same meaning. It is composed of "horn like", i.e., kerato, to which the chemical suffix -in is appended.

Examples of uses