<p>Mandelate racemase <db_xref db="EC" dbkey="5.1.2.2"/> (MR) and muconate lactonising enzyme <db_xref db="EC" dbkey="5.5.1.1"/> (MLE) are two bacterial enzymes involved in aromatic acid catabolism. They catalyse mechanistically distinct reactions yet they are related at the level of their primary, quaternary (homooctamer) and tertiary structures [<cite idref="PUB00004081"/>, <cite idref="PUB00005404"/>].A number of other proteins also seem to be evolutionary related to these twoenzymes. These include, various plasmid-encoded chloromuconate cycloisomerases <db_xref db="EC" dbkey="5.5.1.7"/>, <taxon tax_id="562">Escherichia coli</taxon> protein rspA [<cite idref="PUB00005187"/>], E. coli bifunctional DGOA protein, E. coli hypothetical proteins ycjG, yfaW and yidU and a hypothetical protein from <taxon tax_id="1889">Streptomyces ambofaciens</taxon> [<cite idref="PUB00003121"/>].</p><p>This entry represents the C-terminal region of these proteins.</p>