(ADP-ribosyl)hydrolase 1, also termed [Protein ADP-ribosylarginine] hydrolase and protein-N<sup>ÃÂ</sup>-(ADP-D-ribosyl)-L-arginine ADP-ribosylhydrolase (), is an enzyme that in humans is encoded by the ADPRH gene. This enzyme is a specific mono(ADP-ribosyl)hydrolase that catalyses the removal of an ADP-ribosyl modification from target arginine residues of protein substrates. The chemical reactions can formally be described as follows: