collagen (kŏl`əjən), any of a group of proteins found in skin, ligaments, tendons, bone and cartilage, and other connective tissue connective tissue, supportive tissue widely distributed in the body, characterized by large amounts of intercellular substance and relatively few cells. The intercellular material, or matrix, is produced by the cells and gives the tissue its particular character.
..... Click the link for more information. . Cells called fibroblasts form the various fibers in connective tissue in the body. The fibroblasts produce three types of fibers to form the ground substance: collagen, elatin, and the reticulum. Collagen consists of groups of white inelastic fibers with great tensile strength. These fibers include fine fibrils, which are composed of even finer filaments, visible only through the electron microscope. Collagen protein contains an unusually high percentage of the amino acids proline proline (prō`lēn), organic compound, one of the 20 amino acids commonly found in animal proteins.
..... Click the link for more information. and hydroxyproline. X-ray diffraction studies provide evidence that the protein forms a wavy band, a coiled chain with periodic, i.e., repeating, arrangement of its amino acids. Cartilage is composed of fibrous collagen in an amorphous gel. The organic (nonmineral) content of bone is made up largely of collagen fibers with calcium salt crystals lying adjacent to each segment of the fiber; the fibers and salt crystals combined form a structure with compressional and tensile strength comparable to that of reinforced concrete. A group of diseases, often termed collagen, or connective tissue, diseases, involve a variety of alterations in the connective tissue fibers; rheumatoid arthritis, rheumatic fever, lupus, and scleroderma are included in this group. Some of these diseases may involve an autoimmune response, in which the immune mechanism injures or destroys the individual's own tissues (see immunity immunity, ability of an organism to resist disease by identifying and destroying foreign substances or organisms. Although all animals have some immune capabilities, little is known about nonmammalian immunity.
..... Click the link for more information. ). Collagen dissolved in boiling water becomes denatured to form gelatin gelatin or animal jelly, foodstuff obtained from connective tissue (found in hoofs, bones, tendons, ligaments, and cartilage) of vertebrate animals by the action of boiling water or dilute acid.
..... Click the link for more information. .

collagen

Any of a class of organic compounds, the most abundant proteins in the animal kingdom, occurring widely in tendons, ligaments, dentin (see tooth), cartilage, and other connective tissues. Their molecules share a triple-helix configuration. Collagens occur as whitish, inelastic fibres of great tensile strength and low solubility in water. Soluble when first synthesized (the form used in personal-care preparations), collagen changes to a more stable, insoluble form. Glue made from collagen in animal hides and skins is a widely used adhesive. Specially treated forms of collagen are used in medicine and surgery (including lip implants and other cosmetic surgery), in prostheses, and as sausage casings. Collagen is converted to gelatin by boiling it in water.

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collagen

collagen