Кератин

keratin is a surface-protective agent with film-forming and moisturizing action. Keratin is often used in cosmetics for its moisture-retention and protective effect.

Any of a class of fibrous proteins found in hair, feathers,horn, and hooves. The keratins contain polypeptide chains linked by disulfide bonds between cystein amino acids.

The protein encoded by this gene is a member of the cyclin-dependent protein kinase (CDK) family. CDK family members are highly similar to the gene products of Saccharomyces cerevisiae cdc28, and Schizosaccharomyces pombe cdc2, and are known to be important regulators of cell cycle progression. This kinase and its regulatory subunit cyclin C are components of the RNA polymerase II holoenzyme complex, which phosphorylates the carboxy-terminal domain (CTD) of the largest subunit of RNA polymerase II. This kinase has also been shown to regulate transcription by targeting the CDK7/cyclin H subunits of the general transcription initiation factor IIH (TFIIH), thus providing a link between the ′Mediator-like′ protein complexes and the basal transcription machinery. (provided by RefSeq)

Fibrous proteins are generally insoluble in water and consist of long, coiled strands or flat sheets which have strength and elasticity. Keratin and collagen come in this category. Keratin is present in hair and wool. It is characterized by the high contents of several amino acids, especially cystine, arginine and serine. Keratins are generally harder than the fibrous collagen. Keratins are insoluble in organic solvents, but absorb and hold water.