The function of ABHD17B (abhydrolase domain containing 17B, depalmitoylase, Ensembl gene identifier ENSG00000107362) is as follows. Hydrolyzes fatty acids from S-acylated cysteine residues in proteins (PubMed:26701913). Has depalmitoylating activity towards DLG4/PSD95 (PubMed:26701913). Has depalmitoylating activity towards GAP43 (By similarity). Has depalmitoylating activity towards MAP6 (By similarity). Has depalmitoylating activity towards NRAS (PubMed:26701913). {ECO:0000250|UniProtKB:Q7M759, ECO:0000269|PubMed:26701913}.