<p>Orotidine 5'-phosphate decarboxylase (OMPdecase) [<cite idref="PUB00003724"/>, <cite idref="PUB00002768"/>] catalyses the last step in the <i>de novo</i> biosynthesis of pyrimidines, the decarboxylation of OMP into UMP. In higher eukaryotes OMPdecase is part, with orotate phosphoribosyltransferase, of a bifunctional enzyme, while the prokaryotic and fungal OMPdecases are monofunctional protein.</p><p>Some parts of the sequence of OMPdecase are well conserved across species. The best conserved region is located in the N-terminal half of OMPdecases and is centred around a lysine residue which is essential for the catalytic function of the enzyme.</p><p>This entry also includes enzymes such as 3-hexulose-6-phosphate synthase <db_xref db="EC" dbkey="4.1.2.43"/> and 3-keto-L-gulonate-6-phosphate decarboxylase <db_xref db="EC" dbkey="4.1.1.85"/>.</p> Orotidine 5'-phosphate decarboxylase domain