PARP-1, a nuclear enzyme that synthesizes ADP-ribose polymers from NAD, specifically binds Zn2+ and DNA, and recognizes single-strand breaks in DNA. It is involved in base excision repair, both short-patch and long-patch, rejoining DNA strand breaks and plays a role in p53 expression and activation. A high level of basal neuronal DNA damage and PARP activity has been reported in rat brain tissue. PARP-1 was shown to be required for HIV-1 integration into DNA. If PARP-1 is deficient there is no productive HIV-1 infection.http://www.creative-enzymes.com/product/PARP1-From-Human-Recombinant_1336.html