Study of cell-free protein synthesis in aqueous two-phase systems.

Protein synthesis in an aqueous two-phase system is reported here as a novel type of extractive bioconversion. Translation of BMV RNA was studied using either rabbit reticulocyte lysate or wheat-germ extract in aqueous dextran-PEG systems. Both polymers inhibited protein synthesis and the translation system partitioned into both phases. In the rabbit reticulocyte two-phase system, protein synthesis reached 30% of that in free solution, while in wheat-germ extract it was 60% of that in free solution. Protein was found mainly in the dextran (lower) phase but its partitioning was related to the polymer concentration, and molecular weight, as well as the ionic strength of the system. Protein synthesis was highly influenced by PEG concentration, potassium chloride concentration, and dextran molecular weight.