Collagens (types I, II, III, IV and V) are synthesized as precursor molecules called procollagens. These contain propeptide sequences, at both the amino-terminal and the carboxy-terminal ends. The function of these propeptides is to facilitate the winding of procollagen molecules into a triple-helical conformation within the endoplasmic reticulum. The propeptides are cleaved off from the collagen triple helix molecule during its secretion. The triple helix collagens then polymerize into extracellular collagen fibrils.
Clones PC5-5 and PC8-7 recognize procollagen type I C-peptide. They are suitable for the detection of non-denatured antigen released in tissue culture media and for monitoring of collagen synthesis.