Boime I, Boguslawski S
Proc Natl Acad Sci U S A. 1974 Apr;71(4):1322-5. doi: 10.1073/pnas.71.4.1322.
In a very active cell-free system containing polysomes derived from human placenta and a cell-sap fraction prepared from ascites tumor cells, the synthesis of the hormone human placental lactogen (HPL) was detected. The identification was based on the following: (a) The in vitro synthesized protein labeled with [(35)S]methionine migrated at the same rate as authentic HPL on sodium dodecyl sulfate-polyacrylamide gels and (b) tryptic fingerprint analysis of the labeled protein yielded peptides having the same mobilities as seen with the same analysis of purified HPL. The amount of HPL synthesized in a cell-free system containing polysomes derived from term placenta was about 10% of the total proteins synthesized and in a comparable system containing first trimester ribosomes the level of synthesis was about 5%. These data suggest the potential for quantitating the HPL mRNA activity as a function of the period of gestation and for isolating the mRNA itself.
在一个非常活跃的无细胞系统中，该系统含有源自人胎盘的多核糖体以及由腹水肿瘤细胞制备的细胞液部分，检测到了激素人胎盘催乳素（HPL）的合成。鉴定基于以下几点：（a）用[³⁵S]甲硫氨酸标记的体外合成蛋白质在十二烷基硫酸钠-聚丙烯酰胺凝胶上的迁移速率与天然HPL相同；（b）对标记蛋白质的胰蛋白酶指纹分析产生的肽段迁移率与对纯化HPL进行相同分析时观察到的迁移率相同。在含有足月胎盘来源多核糖体的无细胞系统中合成的HPL量约占合成蛋白质总量的10%，而在含有孕早期核糖体的类似系统中，合成水平约为5%。这些数据表明，有可能根据妊娠期来定量HPL mRNA活性，并分离出mRNA本身。
