Microscopy of keratin filaments inside cells.

Keratin (n/[1][2]) 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.[3][4] The only other biological matter known to approximate the toughness of keratinized tissue is chitin.[5][6][7]


Keratin derives from Greek κερατίνη keratíni[citation needed] from κέρας keras (genitive κέρατος keratos) meaning "horn" originating from the Proto-Indo-European *ḱer- of the same meaning.[8] It is composed of "horn like", i.e., kerato,[9][citation needed] to which the chemical suffix -in is appended.[10][citation needed] The Greek keras is used in many animal names, e.g. Rhinoceros, meaning "nose with a horn".

Other Languages
አማርኛ: ኬራቲን
العربية: كيراتين
български: Кератин
bosanski: Keratin
català: Ceratina
čeština: Keratin
dansk: Keratin
Deutsch: Keratine
eesti: Sarvaine
español: Queratina
Esperanto: Keratino
euskara: Keratina
français: Kératine
Gaeilge: Ceiritin
galego: Queratina
한국어: 케라틴
հայերեն: Կերատիններ
hrvatski: Keratin
Bahasa Indonesia: Keratin
italiano: Cheratina
עברית: קרטין
Kreyòl ayisyen: Keratin
lietuvių: Keratinas
magyar: Szaru
Bahasa Melayu: Keratin
မြန်မာဘာသာ: ကီရာတင်
Nederlands: Keratine
日本語: ケラチン
norsk: Keratin
norsk nynorsk: Keratin
occitan: Queratina
oʻzbekcha/ўзбекча: Muguzlanish
polski: Keratyny
português: Queratina
русский: Кератины
Scots: Keratin
Simple English: Keratin
slovenčina: Keratín
slovenščina: Keratin
کوردی: کێراتین
srpskohrvatski / српскохрватски: Keratin
Basa Sunda: Keratin
suomi: Keratiini
svenska: Keratin
தமிழ்: நகமியம்
Türkçe: Keratin
українська: Кератини
اردو: قرنین
Tiếng Việt: Keratin
粵語: 角蛋白
中文: 角蛋白