Dephosphorylates several organic phosphate monoesters. Also has a phosphotransferase activity catalyzing the transfer of low-energy phosphate groups from organic phosphate monoesters to free hydroxyl groups of various organic compounds (By similarity). a phosphate monoester + H2O = an alcohol + phosphate Binds 1 Mg(2+) ion per subunit. Homotetramer. Belongs to the class B bacterial acid phosphatase family.