Identification of the gene (aphA) encoding the class B acid phosphatase/phosphotransferase of Escherichia coli MG1655 and characterization of its product.

An open reading frame located in the tyrB-uvrA intergenic region of the Escherichia coli MG1655 chromosome was identified as encoding the class B acid phosphatase of this species on the basis of cloning and expression experiments. A protocol for purification of the enzyme (named AphA) was developed, and its properties were analyzed. The enzyme is a 100-kDa homotetrameric protein which apparently requires a metal co-factor for activity. Similarly to other bacterial class B acid phosphatases, it is able to dephosphorylate several organic phosphomonoesters as well as to catalyze the transfer of low-energy phosphate groups from phosphomonoesters to hydroxyl groups of various organic compounds.