The role of synthetic and bone extracted Ca-phospholipid-PO4 complexes in hydroxyapatite formation.
The calcium-phospholipid-phosphate (Ca-PL-PO4) complex isolated from young bone has been shown to initiate hydroxyapatite formation from a metastable calcium phosphate solution. The action of the complex was compared to that of the acidic phospholipids: phosphatidyl serine, phosphatidyl inositol and phosphatidic acid. These phospholipids first remove calcium, and a small amount of phosphate from the metastable solution forming a material similar to the complex isolated from bone, and then form hydroxyapatite. The rate of hydroxyapatite proliferation, once phosphatidyl serine and phosphatidyl inositol are converted to Ca-PL-PO4 complexes, is the same as the rate observed for comparable weights of the complex isolated from bone. It is suggested that the complex isolated from bone was formed in a manner similar to the complexes in our in vitro experiments. Finally, our evidence supports the possibility that a similar complex is responsible for the initial mineralization in matrix vesicles.
D001846:Bone Development; D002113:Calcification, Physiologic; D002118:Calcium / Q000378:metabolism*; D002474:Cell-Free System; D006882:Hydroxyapatites / Q000378:metabolism*; D007700:Kinetics; D010710:Phosphates / Q000378:metabolism*; D010712:Phosphatidic Acids / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D010718:Phosphatidylserines / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*
D006882:Hydroxyapatites; D010710:Phosphates; D010712:Phosphatidic Acids; D010716:Phosphatidylinositols; D010718:Phosphatidylserines; D010743:Phospholipids; D002118:Calcium