Collagens consist in a family of highly specialized glycoproteins of which at least 16 genetically distinct types are known to date. The basal unit of a collagen molecule cosists in a tripel-helical structure formed by 3 alpha-chains. Predominant amino acids are glycine, proline and hydroxproline. Regularly also lysines and hydroxylysines occur, which are responsible for cross-linkage and glycosylation of the protein chains. Different composition of alpha-chains and different glycosylation contribute to the high variability of collagens in different tissues and organs. Type III collagen is an alpha1(III)-trimer, MW 95 kDa, which forms 67 nm cross-banded fibrils. Typically it can be observed in skin, cartilage and vitreous body.Synonyms: Collagen, Pro-Collagen