Formation of the three-dimensional lattice of the matrix -type i collagen is responsible for the three-dimensional fiber structure of the matrix. it is synthesized by osteoblasts and accounts for 85 to 90% of total bone protein. the noncollagenous bone proteins are primarily synthesized by osteoblasts and constitute 10 to 15% of bone protein. some plasma proteins are preferentially absorbed by the bone matrix. the noncollagenous proteins include cytokines and growth factors, which are synthesized endogenously and become trapped in the matrix. also included in the category of noncollagenous proteins are the cell attachment proteins (fibronectin and osteopontin); proteoglycans (e.g., chondroitin 4-sulfate and chondroitin 6-sulfate), which appear to play a role in collagen fibrillogenesis; and the gla proteins, such as osteocalcin (containing -carboxyglutamic acid), which binds ca2+ and mineral components to the matrix.
