Huq N L, Tseng A, Chapman G E
Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia.
Biochem Int. 1987 Aug;15(2):271-7.
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.
骨钙素（OC）是脊椎动物骨骼中主要含γ-羧基谷氨酸（Gla）的蛋白质，已从鸸鹋（Dromaius novaehollandae）的骨骼中分离出来，并通过完整分子和蛋白水解片段的气相N端测序以及羧肽酶Y C端测序相结合的方法确定了其一级结构。通过对氚标记/热脱羧分子的N端测序部分中的氚放射性进行计数来定位Gla残基。鸸鹋OC由48个氨基酸残基组成，含有3个Gla残基和一个二硫键。其C端的29个残基与人类和绵羊OC序列的残基相同。将N端序列与其他OC的序列进行比对，发现与鸡OC的序列同源性高于与哺乳动物OC的序列同源性。
