Dual specificity phosphatase 18（DUSP18) belongs to the dual-specificity phosphatase（DSP) family， which catalyzes dephosphorylation of phosphotyrosine and phosphothreonine residues. DUSP18 has a preferential enzymatic activity for phosphorylated tyrosine residues over threonine residues， in addition DUSP18 dephosphorylates p-nitrophenyl phosphate（pNPP) in vitro. Furthermore， DUSP18 is inhibited by iodoarectic acid and is activated by manganese ions. DUSP18 is extensively expressed with the highest levels in the liver， brain， ovary and testis.
