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 th e Escherichia coli MG1655 chromosome was identified as encoding the cl ass B acid phosphatase of this species on the basis of cloning and exp ression 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-f actor for activity. Similarly to other bacterial class B acid phosphat ases, it is able to dephosphorylate several organic phosphomonoesters as well as to catalyze the transfer of low-energy phosphate groups fro m phosphomonoesters to hydroxyl groups of various organic compounds.