The function of Ensembl gene identifier ENSG00000116863 (ADPRS, ADP-ribosylserine hydrolase) is as follows. ADP-ribosylhydrolase that preferentially hydrolyzes the scissile alpha-O-linkage attached to the anomeric C1'' position of ADP- ribose and acts on different substrates, such as proteins ADP- ribosylated on serine and threonine, free poly(ADP-ribose) and O- acetyl-ADP-D-ribose (PubMed:21498885, PubMed:29907568, PubMed:30045870, PubMed:30401461, PubMed:30830864, PubMed:33186521, PubMed:33769608, PubMed:33894202, PubMed:34019811, PubMed:34321462, PubMed:34479984, PubMed:34625544). Specifically acts as a serine mono-ADP- ribosylhydrolase by mediating the removal of mono-ADP-ribose attached to serine residues on proteins, thereby playing a key role in DNA damage response (PubMed:28650317, PubMed:29234005, PubMed:30045870, PubMed:33186521, PubMed:34019811, PubMed:34625544). Serine ADP- ribosylation of proteins constitutes the primary form of ADP- ribosylation of proteins in response to DNA damage (PubMed:29480802, PubMed:33186521, PubMed:34625544). Does not hydrolyze ADP-ribosyl- arginine, -cysteine, -diphthamide, or -asparagine bonds (PubMed:16278211, PubMed:33769608). Also able to degrade protein free poly(ADP-ribose), which is synthesized in response to DNA damage: free poly(ADP-ribose) acts as a potent cell death signal and its degradation by ADPRHL2 protects cells from poly(ADP-ribose)-dependent cell death, a process named parthanatos (PubMed:16278211). Also hydrolyzes free poly(ADP-ribose) in mitochondria (PubMed:22433848). Specifically digests O-acetyl-ADP-D-ribose, a product of deacetylation reactions catalyzed by sirtuins (PubMed:17075046, PubMed:21498885). Specifically degrades 1''-O-acetyl-ADP-D-ribose isomer, rather than 2''-O-acetyl- ADP-D-ribose or 3''-O-acetyl-ADP-D-ribose isomers (PubMed:21498885). {ECO:0000269|PubMed:16278211, ECO:0000269|PubMed:17075046, ECO:0000269|PubMed:21498885, ECO:0000269|PubMed:22433848, ECO:0000269|PubMed:28650317, ECO:0000269|PubMed:29234005, ECO:0000269|PubMed:29480802, ECO:0000269|PubMed:29907568, ECO:0000269|PubMed:30045870, ECO:0000269|PubMed:30401461, ECO:0000269|PubMed:30830864, ECO:0000269|PubMed:33186521, ECO:0000269|PubMed:33769608, ECO:0000269|PubMed:33894202, ECO:0000269|PubMed:34019811, ECO:0000269|PubMed:34321462, ECO:0000269|PubMed:34479984, ECO:0000269|PubMed:34625544}.