Wasmoen T L, McKean D J, Benirschke K, Coulam C B, Gleich G J
Department of Immunology, Mayo Clinic, Rochester, Minnesota 55905.
J Exp Med. 1989 Dec 1;170(6):2051-63. doi: 10.1084/jem.170.6.2051.
A protein immunochemically related to the eosinophil granule major basic protein (gMBP) is found in increased concentration in the plasma of pregnant women and has been localized to placental trophoblasts by immunofluorescence. Pregnancy MBP (pMBP) is indistinguishable from gMBP in its reactivity with polyclonal antisera and a panel of 14 mouse mAbs. We report the purification of pMBP from human placenta by: (a) affinity chromatography over mAb immobilized on Sepharose, (b) gel filtration in 6 M guanidine.HCl buffer, and (c) reversed-phase HPLC. Purified pMBP and gMBP are biochemically indistinguishable in that both: (a) bind to DNA, (b) polymerize and bind to carrier proteins via disulfide linkages, (c) have a molecular weight of 14,000, (d) have isoelectric points greater than 10.6, (e) comigrate in two-dimensional gels, (f) coelute during reversed-phase HPLC on C18 columns, (g) have identical peptide maps after three different digestions, and (h) have partial amino acid sequence identity. This physicochemical identity has important implications as to the role of pMBP in human placentation.
一种在免疫化学上与嗜酸性粒细胞颗粒主要碱性蛋白（gMBP）相关的蛋白质，在孕妇血浆中的浓度升高，并已通过免疫荧光定位到胎盘滋养层细胞。妊娠MBP（pMBP）在与多克隆抗血清和一组14种小鼠单克隆抗体的反应性方面与gMBP无法区分。我们报告了通过以下方法从人胎盘中纯化pMBP：（a）在固定于琼脂糖上的单克隆抗体上进行亲和层析，（b）在6 M盐酸胍缓冲液中进行凝胶过滤，以及（c）反相高效液相色谱法。纯化的pMBP和gMBP在生化性质上无法区分，具体表现为两者均：（a）与DNA结合，（b）通过二硫键聚合并与载体蛋白结合，（c）分子量为14,000，（d）等电点大于10.6，（e）在双向凝胶中迁移位置相同，（f）在C18柱上进行反相高效液相色谱时同时洗脱，（g）在三种不同消化后具有相同的肽图，以及（h）具有部分氨基酸序列同一性。这种物理化学同一性对于pMBP在人类胎盘形成中的作用具有重要意义。
