Description_x000D_ General description_x000D_ In human, keratin is classified into type I and type II. About 54 genes encodes for the keratin protein. The keratin 1 (KRT1) gene is mapped to human chromosome 12q13.13._x000D_ Keratins are characteristic intermediate filament proteins of the epithelia. There are 54 functional keratin genes in humans. This diverse group of cytoskeletal scaffolding proteins form intermediate filament networks which provide structural support to keratinocytes that maintain the integrity of the skin. Expression of keratin genes is usually regulated by differentiation of the epidermal cells within the stratifying squamous epithelium.It is the primary component of hair, skin and nails_x000D_ Application_x000D_ Keratin from human epidermis has been used as a standard in enzyme linked immunosorbent assay (ELISA)._x000D_ Biochem/physiol Actions_x000D_ Keratins are important for the mechanical stability and integrity of epithelial cells and tissues. Some keratins also have regulatory functions and are involved in intracellular signaling pathways, e.g. protection from stress, wound healing, and apoptosis._x000D_ Physical form_x000D_ Solution in 8 M urea, 50 mM Tris, 0.1 M β-mercaptoethanol and 0.1% sodium azide, pH 8.4