Collagen is a fibrous protein. It has many functions in the body, such as:

  • Form the structure of bones
  • Makes up cartilage and connective tissue
  • Prevents blood that is being pumped at high pressure from bursting the walls of arteries
  • Is the main component of tendons, which connect skeletal muscles to bones

Collagen consists of three polypeptide chains wound around each other. Each of the three chains is a coil itself. Hydrogen bonds form between these coils, which are around 1000 amino acids in length, which gives the structure strength. This is important given collagen’s role, as structural protein. This strength is increased by the fact that collagen molecules form further chains with other collagen molecules and form Covalent Cross Links with each other, which are staggered along the molecules to further increase stability. Collagen molecules wrapped around each other form Collagen Fibrils which themselves form Collagen Fibres.


Since it is a fibrous protein, collagen is insoluble in water.

Some facts about collagen worth remembering:

  • It has a greater tensile strength than steel
  • There are no prosthetic groups in collagen
  • 35% of the amino acids in collagen are glycine