keratin

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Related to Cytokeratin: cytokeratin 18, cytokeratin 20, cytokeratin 7

keratin

(kĕr`ətĭn), any one of a class of fibrous proteinprotein,
any of the group of highly complex organic compounds found in all living cells and comprising the most abundant class of all biological molecules. Protein comprises approximately 50% of cellular dry weight.
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 molecules that serve as structural units for various living tissues. The keratins are the major protein components of hair, wool, nails, horn, hoofs, and the quills of feathers. These proteins generally contain large quantities of the sulfur-containing amino acidsamino acid
, any one of a class of simple organic compounds containing carbon, hydrogen, oxygen, nitrogen, and in certain cases sulfur. These compounds are the building blocks of proteins.
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, particulary cysteinecysteine
, organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer participates in the biosynthesis of mammalian protein.
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. The helical keratin molecules twist around each other to form elongated strands called intermediate filaments. The formation of a covalent chemical bondchemical bond,
mechanism whereby atoms combine to form molecules. There is a chemical bond between two atoms or groups of atoms when the forces acting between them are strong enough to lead to the formation of an aggregate with sufficient stability to be regarded as an
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 called a disulfide bridge between the sulfer atoms on two cysteins on separate polypeptide chains of keratin allows for the cross-linkage of these chains and results in a fairly rigid aggregate. This phenomenon is seen to be consistent with the physiological role of the keratins, which provide a tough, fibrous matrix for the tissues in which they are found. Human hair is approximately 14% cystine (cysteins cross-linked by disulfide bridges).

keratin

[′ker·əd·ən]
(biochemistry)
Any of various albuminoids characteristic of epidermal derivatives, such as nails and feathers, which are insoluble in protein solvents, have a high sulfur content, and generally contain cystine and arginine as the predominating amino acids.

keratin

A proteinaceous material used as a retarder for plaster.

keratin

, ceratin
a fibrous protein that occurs in the outer layer of the skin and in hair, nails, feathers, hooves, etc.
References in periodicals archive ?
Diffuse Cytokeratin 19 immunoreactivity was found in 93.
The markers used in the past include CK7, CK20, high-molecular-weight cytokeratin (HMWCK, 34[beta]E12), p63, and CK5/6.
Cytokeratin expression patterns for distinction of odontogenic keratocysts from dentigerous and radicular cysts.
Some of the curetted surfaces contain reactive urothelium (10X); (B) In most areas, the tumour had epithelioid cytologic features (10X); (C) Tumour with hemorrhagic changes (10X); (D) Tumour with spindle cell pattern (10X); (E) The immunostain for cytokeratin 7 is positive in the majority of the tumour cells (10X).
Intratumoral Expression Level of Epidermal Growth Factor Receptor and Cytokeratin 5/6 Is Significantly Associated With Nodal and Distant Metastasis in Patients With Basal-like Triple Negative Breast Carcinoma.
Additionally, immunohistochemistry is a useful tool in differentiating these tumors, since neoplastic cells in mesothelioma express epithelial cytokeratin and mesenchymal markers, such as Vimentin (9), whereas adenocarcinomas are specifically marked by cytokeratin.
ChRCC has been shown to be immunoreactive for CK7 (1,2,5-8), cytokeratin AE1/AE3, EMA, and to be negative for vimentin (1,2,5,7 8) as seen in these two cases with positive Hale's colloidal iron stain and negative PAS and PAS-D stain.
Extraskeletal myxoid chondrosarcoma consists of non-cohesive elongated tumor nests without ductal or tubular structures and the cells are cytokeratin negative [18].
Immunoexpression of HBME-1, high molecular weight cytokeratin, cytokeratin 19, thyroid transcription factor-1, and E-cadherin in thyroid carcinomas.
The researchers in Fleiszig's lab came upon cytokeratin 6A in their efforts to solve the mystery behind the eye's remarkable resilience to infection.
Low- molecular-weight cytokeratin stains cytokeratin 7 (CK7) and anti-cytokeratin (CAM 5.
Ampullary carcinoid cells express chromogranin in 92% of cases and neuron specific enolase, synaptophysin and cytokeratin in 100%; somatostatin is found in 58 to 67% of cases.