Poly(ADP-ribose) polymerase-1 (PARP-1) is an enzyme involved in DNA repair and cell apoptosis, which catalyzes the addition of ADP-ribose to target proteins, forming poly(ADP-ribose) modifications. PARP-1 is primarily located in the cell nucleus and plays a role in biological processes such as DNA damage response, gene expression regulation, and cell death. It is expressed in various tissues, particularly at higher levels in rapidly dividing cells. Mutations or abnormal expression of the PARP-1 gene are associated with various diseases, including cancer, neurodegenerative disorders, and cardiovascular diseases.