Type III collagen is the second most abundant collagen in human tissues and occurs particularly in tissues exhibiting elastic properties, such as skin, blood vessels and various internal organs. It is a homotrimer composed of three α1(III) chains and resembles other fibrillar collagens in its structure and function. Its elastic properties may be due to the disulphide bonds and the fact that there is no lysyl oxidase-dependent cross-link in the C-terminal end (Cheung et al. 1983). It is synthesized as procollagen similarly to type I collagen, but the N-terminal propeptide remains attached in the mature, fibrillar type III collagen more often than in type I. Mutations of type III collagen cause the most severe form of Ehlers-Danlos syndrome, EDS IV, which affect arteries, internal organs, joints and skin, and may cause sudden death when the large arteries rupture.