[The role of terminal DNA groups in the activation of (ADP-ribose)polymerase]

Some peculiarities of activation of (ADP-ribose) polymerase by DNA fragments were studied. DNA fragments were produced by the digestion of calf thymus DNA by micrococcal nuclease and with a subsequent enzymatic modification of their end groups by nuclease S1, polynucleotide kinase of phage T4 and alkaline phosphatase. The dependence of the activating effect of DNA on the chemical structure of its end groups was established. It was shown that the terminal phosphate groups are involved in the formation of a catalytically active complex of (ADP-ribose) polymerase with DNA.