Jones G R, Davey M W, Teisner B, Grudzinskas J G
Clin Chim Acta. 1981 Jul 18;114(1):75-82. doi: 10.1016/0009-8981(81)90230-8.
The affinity of placental protein 5 (PP5) for thrombin was examined by the application of placental homogenate, late pregnancy serum, plasma and amniotic fluid to thrombin-Sepharose column chromatography. A specific interaction between PP5 in these fluids and thrombin was seen, revealing heterogeneity of PP5 with respect to thrombin affinity. Placental homogenate contained non-binding (species I), interacting (species II) and strongly binding (species III) subpopulations of PP5. By contrast, serum contained predominantly the strongly binding form (species III) and a minor proportion of the non-binding form (species I). The interacting form (species II) was the major form in plasma and amniotic fluid. These observations imply that the interacting form (species II) is the dominant form produced by the placenta and secreted into the circulation, but is converted to species III, i.e. high affinity for thrombin during coagulation. These results suggest that PP5 may be involved locally in the regulation of the coagulation system during pregnancy.
通过将胎盘匀浆、妊娠晚期血清、血浆和羊水应用于凝血酶 - 琼脂糖柱色谱法，检测了胎盘蛋白5（PP5）对凝血酶的亲和力。观察到这些液体中的PP5与凝血酶之间存在特异性相互作用，揭示了PP5在凝血酶亲和力方面的异质性。胎盘匀浆含有PP5的非结合亚群（I型）、相互作用亚群（II型）和强结合亚群（III型）。相比之下，血清中主要是强结合形式（III型）和一小部分非结合形式（I型）。相互作用形式（II型）是血浆和羊水中的主要形式。这些观察结果表明，相互作用形式（II型）是由胎盘产生并分泌到循环系统中的主要形式，但在凝血过程中会转化为III型，即对凝血酶具有高亲和力。这些结果表明，PP5可能在妊娠期间局部参与凝血系统的调节。
