The synthesis of human placental lactogen hormone (hPL) in a cell-free wheat germ system

Total polysomes from human term placenta were incubated in a wheat germ cell-free system during 1 hr at 25 degrees C. Human placental lactogen hormone was identified among the proteins synthesized in vitro by immune precipitation and subsequent sodium dodecylsulphate electrophoresis of the immunoprecipitate. The zone containing the radioactivity from the immunoprecipitate [3H]-labelled lactogen hormone comigrated exactly with the radioactivity zone from added [14C]-labelled marker hormone. This result indicates that the molecular weight of the synthesized product must be equal or very similar to that of the native protein hormone.