Dentin phosphoprotein

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Dentin phosphoprotein, or phosphophoryn, is one of three proteins formed from dentin sialophosphoprotein and is important in the regulation of mineralization of dentin. [1]

Phosphophoryn is the most acidic protein ever discovered and has an isoelectric point of 1. This extreme acidity is achieved by its amino acid sequence. Many portions of its chain are repeating -D-S-S- (aspartic acid-serine-serine) sequences. In protein chemistry, net acidity equates to negative charge. Being highly negative, dentin phosphoprotein is able to attract large amounts of calcium. In vitro studies also indicate phosphophoryn can initiate hydroxyapatite formation. [2]

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Dentin sialophosphoprotein is a precursor protein for other proteins found in the teeth. It is produced by cells (odontoblasts) inside the teeth, and in smaller quantities by bone tissues. It is required for normal hardening (mineralisation) of teeth. During teeth development, it is broken down into three proteins such as dentin sialoprotein (DSP), dentin glycoprotein (DGP), and dentin phosphoprotein (DPP). These proteins become the major non-collagenous components of teeth. Their distribution in the collagen matrix of the forming dentin suggests these proteins play an important role in the regulation of mineral deposition. Additional evidence for this correlation is phenotypically manifested in patients with mutant forms of dentin sialophosphoprotein. Such patients suffer dental anomalies including type III dentinogenesis imperfecta.

Hard tissue is tissue which is mineralized and has a firm intercellular matrix. The hard tissues of humans are bone, tooth enamel, dentin, and cementum. The term is in contrast to soft tissue.

References

  1. Cohen, Stephen, and Kenneth M. Hargreaves, eds. Pathways of the Pulp. 9th ed. St. Louis, MO: Mosby Elsevier, 2006. Print.
  2. Nanci, Antonio. Ten Cate's Oral Histology: Development, Structure, and Function. 7th ed. St. Louis, MO: Mosby Elsevier, 2008. Print.