keratin


keratin
/ker"euh tin/, n.
a scleroprotein or albuminoid substance, found in the dead outer skin layer, and in horn, hair, feathers, hoofs, nails, claws, bills, etc.
[1840-50; KERAT- + -IN2]

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Fibrous structural protein of hair, nails, hooves, wool, feathers, and skin.

A quarter of the amino acids in keratin are cystine, whose ability to form strong bridging (disulfide) bonds with other cystine units accounts for keratin's great stability. Keratin does not dissolve in cold or hot water and does not easily undergo proteolysis. Its fibres are 10–12% longer at maximum water content (about 16%) than when dry. The sulfurous smell of burning keratin is distinctive.

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      fibrous structural protein of hair, nails, horn, hoofs, wool, feathers, and of the epithelial cells in the outermost layers of the skin. The polypeptide chains of keratin are arranged in parallel sheets held together by hydrogen bonding.

      Of the amino acids in keratin, cystine may account for as much as 24 percent. The numerous disulfide bonds formed by cystine are responsible for the great stability of keratin: it is completely insoluble in hot or cold water and is not attacked by proteolytic enzymes (the enzymes that cleave protein molecules).

      The length of keratin fibres depends on their water content: complete hydration (approximately 16 percent water) increases their length by 10 to 12 percent.

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Universalium. 2010.

Look at other dictionaries:

  • Keratin 14 — Identifiers Symbols KRT14; CK14; EBS3; EBS4; K14; NFJ External IDs OMIM …   Wikipedia

  • Keratin 10 — Identifiers Symbols KRT10; BCIE; BIE; CK10; EHK; K10; KPP External IDs OM …   Wikipedia

  • Keratin 19 — Identifiers Symbols KRT19; CK19; K19; K1CS; MGC15366 External IDs OMIM …   Wikipedia

  • Keratin 18 — Identifiers Symbols KRT18; CYK18; K18 External IDs OMIM …   Wikipedia

  • Keratin 5 — is a keratin protein often paired with keratin 14. PBB Summary section title = summary text = The protein encoded by this gene is a member of the keratin gene family. The type II cytokeratins consist of basic or neutral proteins which are… …   Wikipedia

  • Keratin 8 — Identifiers Symbols KRT8; CARD2; CK8; CYK8; K2C8; K8; KO External IDs OMIM …   Wikipedia

  • Keratin 1 — is a member of the keratin family. It is specifically expressed in the spinous and granular layers of the epidermis with family member keratin 10. Mutations in this gene have been associated with the variants of bullous congenital ichthyosiform… …   Wikipedia

  • Keratin 7 — Identifiers Symbols KRT7; CK7; K2C7; K7; MGC129731; MGC3625; SCL External IDs …   Wikipedia

  • Keratin 17 — Keratin 17, also known as KRT17, is a human gene.cite web | title = Entrez Gene: KRT17 keratin 17| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene Cmd=ShowDetailView TermToSearch=3872| accessdate = ] Keratin 17 is a type I cytokeratin. It… …   Wikipedia

  • Keratin 4 — Identifiers Symbols KRT4; CK 4; CK4; CYK4; FLJ31692; K4 External IDs OMIM …   Wikipedia

  • Keratin 13 — Identifiers Symbols KRT13; CK13; K13; MGC161462; MGC3781 External IDs OMI …   Wikipedia


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