<p>Class A bacterial acid phosphatases (<db_xref db="EC" dbkey="3.1.3.2"/>) are a group of related proteins that catalyse the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate [<cite idref="PUB00002155"/>, <cite idref="PUB00003588"/>]. This reaction is non-specific and occurs in the periplasm. The enzyme is found as a homotetramer in <taxon tax_id="582">Morganella morganii</taxon> (Proteus morganii) [<cite idref="PUB00002155"/>] and possibly as a homodimer in <taxon tax_id="602">Salmonella typhimurium</taxon>, where it is regulated by a 2-component regulatory system formed by the products of the phoP and phoQ genes [<cite idref="PUB00003588"/>].</p>