Mechanims of stimulation of in vitro protein synthesis by some copolymers of styrene, vinyluracil, and vinyladenine with maleic acid and acrylic acid.

Copolymers of vinyl bases with acrylic acid and styrene or 1-vinyluracil with maleic acid were found to stimulate in vitro polyphenylalanine synthesis using a system extracted from Escherichia coli MRE600. Poly(styrene-maleic acid) was found to inhibit a ribosomal bound ribonuclease. Poly(1-vinyluracil, maleic acid), poly(1-vinyluracil, acrylic acid), and poly(9-vinyladenine, acrylic acid) were not inhibitors of the ribosome bound ribonuclease. The potent (up to fivefold) stimulation by these three polymers is due to the action of the polymers to interfere with ribosomal bound inhibitory protein. A protein, removed by washing ribosomes with 1 M ammonium chloride, characterized by M.J. Miller, A. Niveleau, and A.J. Wahba ((1974) J. Biol. Chem. 249, 3803) has been described as a potent inhibitor of in vitro poly(U)-coded protein synthesis using extracts of Escherichia coli MRE 600.