Catalyzes auto- and hetero-ADP ribosylation and produces short oligomers by elongating the ADP-ribose chain (up to 6-mer). Binds DNA non-specifically but with high affinity. Forms very stable complexes with circular DNA wherein the circular DNA confers thermostability compared to linear DNA. NAD(+) + (ADP-D-ribosyl)n-acceptor = nicotinamide + (ADP-D-ribosyl)n+1-acceptor + H(+). Activity increases up to 5-6 times with Mg(2+) at 50 uM or higher ion concentration. 3-aminobenzamide (3-ABA) inhibits the activity by up to half and nicotinamide to a lesser extent. Zn(2+) inhibits the activity to half-maximal rate but at 500 uM concentration of the ion. Optimum pH is 6.5-10. Optimum temperature is 80 degrees Celsius. Activity decreases at 90-100 degrees Celsius.