Dephosphorylates ptk. May be involved in the production and the transport of exopolysaccharides. H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Inhibited by ammonium molybdate, sodium orthovanadate, N-ethylmaleimide and iodoacetic acid. Glycan metabolism; exopolysaccharide biosynthesis. Belongs to the low molecular weight phosphotyrosine protein phosphatase family.