ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] When the protein is overexpressed. Autophosphorylated. Dephosphorylated by etp. Belongs to the etk/wzc family. Seems to be expressed only in enteropathogenic E.coli strains; in E.coli K12 / MG1655 and K12 / W3110 this operon is silenced by an IS1D insertion in the promoter region.