Plays a role during the calcification of cartilage and the transition of cartilage to bone. Found on some small banded collagen fibrils and meshworks. The C-terminal propeptide, also known as COLFI domain, have crucial roles in tissue growth and repair by controlling both the intracellular assembly of procollagen molecules and the extracellular assembly of collagen fibrils. It binds a calcium ion which is essential for its function (By similarity). Belongs to the fibrillar collagen family.