Cloning and characterization of the NapA acid phosphatase phosphotransferase of Morganella morganii: identification of a new family of bacterial acid-phosphatase-encoding genes

The gene coding for the Morganella morganii phosphate-irrepressible acid phosphatase (NapA) is an acid phosphatase that has four polypeptide subunits of 27 kDa each. The enzyme has a transphosphorylating potential from organic phosphoric acid esters to nucleoside and other free hydroxyl group-containing compounds. Inorganic phosphate, EDTA, Ca2+ and nucleosides prevent enzyme activity while Co2+, Hg2+ and Zn2+ and Zn2+ promote the same. The NapA enzyme does not exhibit sequence similarity with any sequenced bacterial phosphatase but is similar to the proteins encoded by sequenced regions in the open reading frames of Escherichia coli and Proteus mirabilis genomes. It is proposed that NapA is a member of the new class B-family bacterial acid phosphatases.