Cell-free system for synthesis of proteins derived from cultured mammalian cells

A process for producing a desired protein in a cell-free protein synthesis system comprising adding to a cell-free extract prepared from a culture of mammalian cells an uncapped mRNA encoding the desired protein and a set of translation factors comprising each of the following;

• the eukaryotic translation initiation factor 2 (eIF2),
• the eukaryotic translation initiation factor 2B (eIF2B), and
• the eukaryotic translational regulator p97,
• and incubating the mixture thereof at 32° C. for at least one hour, whereby the yield of the desired protein is five-fold more when compared to the synthesis of the desired protein obtained by incubation in the absence of addition of the factors elF2 and eIF2B and p97.