THE EFFECTS OF ULTRAVIOLET-IRRADIATED POLYURIDYLIC ACID IN CELL-FREE PROTEIN SYNTHESIS IN E. COLI*†

The incorporation of U-C14-L-phenylalanine prepared from poiy-L- phenylaianine from Escherichia coli into acidinsoluble material and poly-L- phenylaianine following ultraviolet irradiation of poiyuridylic acid was examined. Irradiation of the polyuridylic acid with doses of ultraviolet light from 24 to 72 x 104 ergs/mm2 resulted in a marked depression in C14- phenyiaianine incorporation and was accompanied by an increase in C14- serine uptake into both acid-soluble material as well as polyphenylaianine.