Acts on tyrosine phosphorylated proteins, low-MW aryl phosphates and natural and synthetic acyl phosphates. H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate a phosphate monoester + H2O = an alcohol + phosphate Present with 3500 molecules/cell in log phase SD medium. Belongs to the low molecular weight phosphotyrosine protein phosphatase family.