title: The amino acid sequence of Emu osteocalcin: gas phase sequencing of Gla-containing proteins.
abstract: Osteocalcin (OC), the major gamma carboxyglutamic acid (Gla)-containing protein of vertebrate bone, has been isolated from bones of the emu (Dromaius novaehollandae) and the primary structure determined by a combination of gas phase N-terminal sequencing of the intact molecule and a proteolytic fragment, and carboxypeptidase Y C-terminal sequencing. Gla residues were located by counting tritium radioactivity in fractions from the N-terminal sequencing of the tritiated/thermally decarboxylated molecule. Emu OC consists of 48 amino acid residues containing 3 Gla residues, and a single disulphide bond. The C-terminal 29 residues are identical to those of the human and sheep OC sequences. Alignment of the N-terminal sequence against those of other OCs reveals greater sequence homology with chicken OC than with mammalian OCs.
mesh_terms: D015055:1-Carboxyglutamic Acid / Q000032:analysis; D000595:Amino Acid Sequence; D000818:Animals; D001717:Birds / Q000378:metabolism*; D001842:Bone and Bones / Q000032:analysis*; D002135:Calcium-Binding Proteins / Q000302:isolation & purification; D006801:Humans; D008969:Molecular Sequence Data; D015675:Osteocalcin; D013045:Species Specificity
chemical_list: D002135:Calcium-Binding Proteins; D015675:Osteocalcin; D015055:1-Carboxyglutamic Acid