Dephosphorylates the phosphotyrosine-containing proteins. H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Inhibited by N-ethylmaleimide and sodium orthovanadate. Optimum pH is 5.7-6.5. Optimum temperature is about 40 degrees Celsius. Belongs to the low molecular weight phosphotyrosine protein phosphatase family.