Bone apatite extraction

Ninety five percent of the phosphorus on Earth belongs to the minerals of the apatite group. Apatites are inorganic constituents of bones and teeth of vertebrate and man, as well as a basis of many pathologic sohd formations. Minerals of the apatite group are the main raw materials in the production of phosphorus fertilizers, fodder and technical phosphates, elementary phosphorus, and phosphor-organic compounds. The mineral is sometimes substantially enriched in rare-earth elements (REE) making their extraction possible (Altshuller 1980). 

Phosphoproteins can be extracted from bone and dentine with EDTA. The phosphoproteins in dentine form about 10% of the total protein present, and have a very high serine and aspartine content with about half of the serine residues phosphorylated. Isolated dentine phosphoprotein has been shown to catalyse the formation of apatite from amorphous tricalcium phosphate, and it may act in this way in teeth (Chapter 11.1) [13]. 

In spite of considerable research no particular chemical structures have been found to have a clear-cut epitactic function for the nucleation of biological apatite crystals. A bone morphogenetic factor has been postulated but, although active extracts have been prepared from cultures of mineralizing bone, no specific substance has yet been isolated. 

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