Procollagen C-endopeptidase  Procollagen C-endopeptidase (, "procollagen C-terminal proteinase", "carboxyprocollagen peptidase", "procollagen C-terminal peptidase", "procollagen C-proteinase", "procollagen carboxypeptidase", "procollagen carboxy-terminal proteinase", "procollagen peptidase") is an enzyme. This enzyme catalyses the following chemical reaction  This endopeptidase belongs to the peptidase family M12 (astacin family).