<p> This family describes the bacterial oxaloacetate decarboxylase alpha subunit and its equivalents in archaea [<cite idref="PUB00007893"/>]. The oxaloacetate decarboxylase Na+ pump is the paradigm of the family of Na+ transport decarboxylases that present in bacteria and archaea. It a multi subunit enzyme consisting of a peripheral alpha-subunit and integral membrane subunits beta and gamma. The energy released by the decarboxylation reaction of oxaloacetate is coupled to Na+ ion pumping across the membrane.</p>