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Friday 13 December 2019


Definition :

Cytokeratins / KRTs is one of a family of fibrous structural proteins known as scleroproteins.It is a α-helix. It is reached in amino acids like alanine,valine,leucine,isoleucine,methionine,phenylealanine. Two strands of α-keratin are oriented in parallel and are wrapped to each other to form a super twisted coiled coil. In α-helix there is presence of hydrogen bond and inter chain S-S cross link.

It is the key structural material making up hair, nails, feathers, horns, claws, hooves, calluses, and the outer layer of skin among vertebrates. Keratin also 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 comes in two types, the primitive, softer forms found in all vertebrates and harder, derived forms found only among sauropsids (reptiles and birds).

Keratin resists digestion, which is why cats regurgitate hairballs.

Spider silk is classified as keratin, although production of the protein may have evolved separately from the same capacity in vertebrates.

See also

- KRTSs / cytokeratins
- keratinopathies