Price P A, Lothringer J W, Baukol S A, Reddi A H
J Biol Chem. 1981 Apr 25;256(8):3781-4.
Several mineralizing tissues have been analyzed for the vitamin K-dependent protein of bone (BGP) in order to establish the temporal relationship between initial mineral deposition and the appearance of BGP. These studies demonstrate that the appearance of BGP in developing bone is not dependent on birth, as had been suggested in earlier studies of rat development, but rather on the prior deposition of bone mineral. In fetal human bone, the level of BGP (grams of BGP/mol of bone PO4) rises from 5% of the adult level at 10 weeks gestational age to the adult level at 15 weeks. Thus, adult levels of BGP are reached in human bone shortly after the initial appearance of mineral and long before birth. In adolescent rats, which have overall levels of BGP in bone near the adult level, the appearance of BGP at the ends of growing bones and in bone induced by implantation of demineralized bone matrix follows mineral deposition by approximately 2 weeks. The relative absence of BGP in initially deposited bone mineral and its subsequent appearance several days later may be causally related to the maturation of bone mineral to hydroxyapatite, a structure which binds BGP. The implications of the timing of BGP appearance in mineralizing tissues to its possible function in bone are discussed.
为了确定初始矿物质沉积与骨钙素（BGP）出现之间的时间关系，已对几种矿化组织进行了骨维生素K依赖蛋白的分析。这些研究表明，发育中的骨骼中BGP的出现并不像早期大鼠发育研究所暗示的那样依赖于出生，而是依赖于骨矿物质的先前沉积。在胎儿人骨中，BGP水平（每摩尔骨磷酸根中BGP的克数）从妊娠10周时的成人水平的5%上升到15周时的成人水平。因此，在矿物质最初出现后不久且远在出生之前，人骨就达到了成人水平的BGP。在青春期大鼠中，其骨骼中BGP的总体水平接近成人水平，生长骨末端以及脱矿骨基质植入诱导的骨中BGP的出现大约在矿物质沉积后2周。最初沉积的骨矿物质中相对缺乏BGP，而几天后其随后出现，这可能与骨矿物质成熟为与BGP结合的羟基磷灰石结构有因果关系。本文讨论了矿化组织中BGP出现的时间对其在骨骼中可能功能的影响。
