kollagen

Kollagen (collagen) is a family of structural proteins that form a major component of the extracellular matrix in animals. It provides tensile strength to connective tissues such as skin, bone, tendons, ligaments, and cartilage. Among its many isoforms, the fibrillar types I, II, and III are the most abundant in the body.

Molecularly, collagen molecules typically consist of three polypeptide chains wound into a triple helix. The chains are encoded by several COL genes (for example COL1A1 and COL1A2 for type I; COL2A1 for type II; COL3A1 for type III). Some collagen forms assemble into fibrils; others, such as type IV, form network-like sheets in basement membranes.

Biosynthesis begins inside cells with the synthesis of procollagen, which contains N- and C-terminal propeptides. Secreted procollagen is cleaved to form collagen molecules that self-assemble into fibrils and fibers in the extracellular space; cross-linking by the enzyme lysyl oxidase strengthens the network.

In tissues, collagen provides structural support and participates in wound healing and development. Type I is common in skin, bone, and tendon; type II in cartilage; type III in skin and vessels; type IV in basement membranes.

Nutrition and aging: vitamin C is required for post-translational modification of collagen; deficiency causes scurvy. Dietary collagen is digested to amino acids and peptides; collagen supplements contain hydrolyzed peptides, with evidence on skin or joint benefits varying.

Uses and health considerations: medical products include collagen-based wound dressings, scaffolds for tissue engineering, and dermal fillers. Sourcing can be bovine, porcine, or marine; allergy and disease-transmission risks exist, and regulatory status varies by country.