Proteomic analysis of hydroxyapatite interaction proteins in bone.

Biomineralization involves proteins and/or other macromolecules directly in controlling the mineral crystal nucleation/induction, growth, and maturation. To identify these proteins in bone, bovine bone EDTA/NaCl extract was passed through a hydroxyapatite column followed by washing with 0.5 M NaCl and the bound proteins were collected and analyzed by mass spectrometry. More than 30 proteins were identified. While as described previously, albumin, alpha2-HS glycoprotein, decorin, biglycan, osteoadherin, osteonectin, etc. were included, collagen alpha2 (I), matrix extracellular phosphoglycoprotein, secreted phosphoprotein 24, chondroadherin, lumican, perlecan, thrombospondin 1, nucleobindin, etc. were for the first time shown to directly interact with calcium phosphate mineral.