Osteocalcin

Literature References: Abundant noncollagenous, calcium-binding protein of bone; constitutes ~1-2% of the total bone matrix. Also found in tooth dentin and cementum. Contains 46-50 amino acid residues (human: 49); mol wt ~5800 daltons. Amino acid sequence is highly conserved across species. Characterized by 3 residues of the vitamin K-dependent amino acid, g-carboxyglutamic acid (Gla), q.v. Synthesized by osteoblasts and odontoblasts; modulated by calcitriol, q.v. Detectable in serum as an indicator of bone metabolism. Identification in chicken bone: P. V. Hauschka et al., Proc. Natl. Acad. Sci. USA 72, 3925 (1975). Characterization of calf BGP: P. A. Price et al. ibid. 73, 1447 (1976). Biosynthesis in bone cell culture: S. K. Nishimoto, P. A. Price, J. Biol. Chem. 254, 437 (1979). RIA determn in plasma: P. A. Price et al., J. Clin. Invest. 66, 878 (1980). Review of isoln and characterization: C. M. Gundberg et al., Methods Enzymol. 107B, 516-544 (1984). Review of hydroxyapatite binding characteristics: P. V. Hauschka, F. H. Wians, Jr. Anat. Rec. 224, 180-188 (1989). Comprehensive review: P. V. Hauschka et al., Physiol. Rev. 69, 990-1047 (1989). Review of diagnostic methods and clinical applications: M. J. Power, P. F. Fottrell, Crit. Rev. Clin. Lab. Sci. 28, 287-335 (1991). Immunohistochemical study and potential role in bone mineralization and resorption: H. I. Roach, Cell Biol. Int. 18, 617-628 (1994).