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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