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 ?
Metastatic basaloid carcinoma present in a lymph node of unknown primary (A, hematoxylin-eosin) lacks diffuse staining for BerEp4 (B), shows diffuse staining for cytokeratin 14 (C), except in zones of comedonecrosis, and shows patchy staining for cytokeratin 17 (D) in the metastatic epithelial component.
Tests showed that cytokeratin 6A-derived fragments could quickly kill bacteria in water and in a saline solution, showing that the salt contained in human tears would not dilute the protein's effectiveness.
Each of the above-mentioned studies considered the use of polymerase chain reaction amplification of extracted DNA with primers for cytokeratin (9, 27, 28).
Small numbers of cytokeratin 8/18-containing alveolar type II cells were observed in rats exposed to BNF alone (Figure 2E).
Desmoglein 3 + cytokeratin 5/napsin A cocktail immunostain; cytoplasmic desmoglein 3 + cytokeratin 5 staining of squamous cell carcinoma in surgical excision and fine-needle aspirate (inset) specimens (original magnifications X200 and X400 [inset]).
Although not evident in the current case, 20% of cases may show dot-like cytokeratin positivity (11).
For HCC biomarkers, alpha-fetoprotein (AFP, 19-fold), plasminogen activator inhibitor-1 (PAI-1, 9-fold), cytokeratin 8 (6-fold), cytokeratin 18 (3-fold) and cytokeratin 19 (11-fold), were dramatically increased in arsenic-induced HCC.
Identification of a novel cytokeratin 19 pseudogene that may interfere with reverse transcriptase polymerase chain reaction assays used to detect micrometastatic tumor cells.
D) Positive staining with cytokeratin 7 (x200) in papillary RCC (arrow), negative staining in oncocytoma (arrowhead).
These atypical glands were diffusely strongly positive for p63 in the secretory cells (ie, not in a basal cell distribution), negative for high-molecular-weight cytokeratin (HMWCK), and positive for [alpha]-methylacyl coenzyme A racemase (AMACR) (Figure 1, D).
Immunohistochemistry for vimentin (mouse monoclonal antibody, clone 3B4, Dako Corp, Carpinteria, CA, USA), smooth muscle actin (mouse monoclonal, clone 1A4, Dako), cytokeratin (mouse monoclonal, clones AEI/AE3, Dako), desmin (mouse monoclonal, clone D33, Dako), and von Willebrand factor (rabbit polyclonal, Dako) were also performed on sections of the mass with a streptavidin-biotin peroxidase complex method.
The cells stained positive for Chromogranin, Synaptophysin and Cytokeratin.