DNA-directed synthesis in vitro of T4 phage-specific enzymes

The synthesis of deoxynucleotide kinase (EC 2.7.4.2) in vitro by a preparation consisting of T4 bacteriophage DNA and a cell-free extract of Escherichia coli has been reported. A study of the role of monovalent cations in the synthesis of this enzyme as well as alpha-glucosyl transferase (EC 2.4.1.2) shows that potassium ions are required for maximal enzyme production. Examination of the RNA-directed system indicates that potassium ions are more effective than ammonium ion in the translation of messenger RNA for the formation of the biologically active proteins studied. From a comparison of the magnitude of the effect of ions on both the DNA- and RNA-directed systems, we conclude that potassium ions may also have a marked stimulatory effect on transcription of the deoxynucleotide kinase gene of T4 DNA. The time required for messenger initiation and completion and the size distribution of messenger RNA formed in vitro were also examined.