Keratin 19 analysis). Moreover, Ck-19 is widely applied as post-operative diagnostic marker of papillary thyroid carcinoma. Keratin 19 is often used together with keratin 8 and keratin 18 to differentiate cells of epithelial origin from hematopoietic cells in tests that enumerate circulating tumor cells in blood. Keratin 19 has been shown to interact with Pinin. Keratin 19 Keratin, type I cytoskeletal 19 also known as cytokeratin-19 (CK-19) or keratin-19 (K19) is a 40 kDa protein that in humans is encoded by the "KRT19" gene. Keratin 19 is a type I keratin. Keratin 19 is a member of the keratin family. The keratins
Collagen helix – this should not be confused with the right-handed alpha helix. These three left-handed helices are twisted together into a right-handed triple helix or "super helix", a cooperative quaternary structure stabilized by many hydrogen bonds. With type I collagen and possibly all fibrillar collagens, if not all collagens, each triple-helix associates into a right-handed super-super-coil referred to as the collagen microfibril. Each microfibril is interdigitated with its neighboring microfibrils to a degree that might suggest they are individually unstable, although within collagen fibrils, they are so well ordered as to be crystalline. A distinctive feature of collagen is the