35 Amino acids are joined in a protein by the formation of a peptide bond + H 3 N C C N C C O - + H 2 O H R 1 H R 2 O O H + H 3 N C C O - + + H 3 N C C O-H R 1 H R 2 O O Peptide (amide) bond Dipeptide â contains two amino acid residues planar. 36 20 amino acids can form 20 2 or 400 dipeptides.
Hydroxylapatite, also called hydroxyapatite (HA), is a naturally occurring mineral form of calcium apatite with the formula Ca 5 (PO 4) 3 (OH), but is usually written Ca 10 (PO 4) 6 (OH) 2 to denote that the crystal unit cell comprises two entities.Hydroxylapatite is the hydroxyl endmember of the complex apatite group.The OH â ion can be replaced by fluoride, chloride or carbonate, producing fluorapatite or chlorapatite. It crystallizes in the hexagonal crystal system.ydroxylapatite is the hydroxyl endmember of the complex apatite group. The OH â ion can be replaced by fluoride, chloride or carbonate, producing fluorapatite or chlorapatite. It crystallizes in the hexagonal crystal system.
Apatite is the defining mineral for 5 on the Mohs scale. Hydroxyapatite, also known as hydroxylapatite, is the major component of tooth enamel and bone mineral.A relatively rare form of apatite in which most of the OH groups are absent and containing many carbonate and acid phosphate substitutions is a large component of bone material.hosphorite is a phosphate-rich sedimentary rock, that contains between 18% and 40% P 2 O 5. The apatite in phosphorite is present as cryptocrystalline masses referred to as collophane.