title: Unfolded phosphopolypeptides enable soft and hard tissues to coexist in the same organism with relative ease.
abstract: Unfolded phosphopolypeptides that contain one or more multiply phosphorylated short sequences can sequester amorphous calcium phosphate to form stable complexes of constant average size and chemical composition. A biofluid containing such complexes is supersaturated with respect to the bone and tooth mineral, hydroxyapatite but is undersaturated with respect to the amorphous precursor phase. Thus, soft tissues permeated by the biofluid should not experience ectopic calcification and hard tissues should remain mineralised. Sequestration by caseins allows high concentrations of calcium and phosphate to be attained in milk while osteopontin, fetuin and other phosphopolypeptides may act in a similar way in blood, other biofluids, soft and hard tissues.
authors.affiliation: Institute of Molecular, Cell and Systems Biology, School of Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK. carl.holt@glasgow.ac.uk
authors.forename: Carl
authors.initials: C
authors.lastname: Holt
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001826:Body Fluids / Q000737:chemistry; D002113:Calcification, Physiologic; D002130:Calcium Phosphates / Q000737:chemistry* / Q000378:metabolism; D002364:Caseins / Q000737:chemistry; D017886:Durapatite / Q000737:chemistry / Q000378:metabolism; D008892:Milk / Q000737:chemistry*; D008969:Molecular Sequence Data; D010748:Phosphopeptides / Q000737:chemistry* / Q000378:metabolism; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002130:Calcium Phosphates; D002364:Caseins; D010748:Phosphopeptides; D011506:Proteins; C519480:amorphous calcium phosphate; D017886:Durapatite