What is Collagen?
Collagen is a major constituent of the extracellular matrix and the predominate protein found in animals, making up approximately 30% of all protein mass. Collagens are glycoproteins characterised by possessing at least one domain of triple helix structure.
A collagen triple helix domain is formed by 3 polypeptide α-chains which contain repeating Gly-X- Y residues, with Gly always being Glycine, and X typically representing proline and Y representing hydroxyproline. Each polypeptide chain forms a left-handed polyproline II helix, which is in turn twisted into a right-handed triple helix. The triple helix is stabilised by bonds between adjacent proline residues and between each strand.
At least 28 different types of collagens have been identified with Type I collagen being the most prevalent form, particularly in ligaments, tendons, skin, and bone tissue. The biophysical properties of mature, insoluble collagen allow it to withstand high tensile forces as well as being resistant to stretch. These are essential properties that enable the locomotion of organisms. Collagen also exhibits biochemical properties, being involved in cell growth, proliferation, and differentiation (this 'biochemical' form of collagen is typically soluble in acid or acid-pepsin digestion and can be detected using the Sircol Soluble collagen assay)
How is collagen used?
Due to its various properties, extracted and purified collagen is used in many different industries. It is used in medicine for wound healing and has a continually expanding role in tissue engineering and cell culture for biomedical purposes. There is growing use in the cosmetic industry where it is used for skin rejuvenation and feedstock for chemical formulations and the food industry both as a functional food supplement and as a food additive.