Adenosine 5′-diphosphoribose (ADP ribose) is composed of an adenine base attached to a ribose sugar, which is in turn linked to two phosphate groups. Adenosine 5′-diphosphoribose is a key molecule involved in a variety of cellular processes, particularly in the response to DNA damage and the regulation of gene expression.
References:
[1]. Gibson BA, et al., New insights into the molecular and cellular functions of poly(ADP-ribose) and PARPs. Nat Rev Mol Cell Biol. 2012 Jun 20;13(7):411-24.