Collagen Type I, human

Type I Collagen usually exists as a heterotrimer formed by alpha 1(I) and alpha 2(I) chains and is found in bone, cornea, skin and tendon. In foetal tissues also homotrimers of alpha-1(I) are found, but they are not constituents of normal adult tissues. Collagens consist of 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 consists of a triple-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. Human collagen type I, cross-reactivity with collagen type II and IV <0.1%, collagen type III and V <1.0%, human fibronectin and laminin <0.1%, mouse laminin <0.1% (RIA at a 1:500 dilution).