The Enzymatic Methylation of Ribonucleic Acid and Deoxyribonucleic Acid

Abstract Infection of Escherichia coli B with bacteriophages T1, T2, or T4 results in increase in the activity of deoxyribonucleic acid methylase assayed in crude extracts of the infected cells. The largest increase is observed after infection with T2 phage; T4 and T1 phages lead to smaller increases in that order of decreasing magnitude. After infection with T3, T5, or T6 phages, a decrease in activity was observed; T7 and λ phages had no effect. The kinetics of the increase in methylase activity after T2 infection is similar to those found with the early enzymes induced by T-even phages, and protein synthesis is necessary for the increase to occur. The properties of the methylase activity of phage T2-infected bacteria suggest that it is a new phage-directed enzyme.