InterPro domain: IPR011778

Dihydropyrimidinase (DHPase) catalyses the second step of the reductive pyrimidine degradation, the reversible hydrolytic ring opening of dihydropyrimidines [ 1 ]. Primarily converts 5,6-dihydrouracil to N-carbamyl-beta-alanine (also called 3-ureidopropanoate) but also acts on dihydrothymine and hydantoin. The enzyme is a metalloenzyme [ 2 ].

This entry represents the hydantoinase/dihydropyrimidinase family, which also includes D-phenylhydantoinases. This enzyme catalyses the stereospecific hydrolysis of the cyclic amide bond of D-hydantoin derivatives with an aromatic side chains at the 5'-position, and has no activity on dihydropyrimidines [ 3 ].

Dihydropyrimidinase-related proteins (collapsin response mediatorproteins, CRMPs) share sequence similarity with liver DHPase. Although purified CRMP does not hydrolyse DHPase substrates, it is likely that a relatedactivity accounts for its participation in neuronal growth cone signaling [ 4 ]. CRMP3 has histone H4 deacetylase activity [ 5 ].

1. Dihydropyrimidine amidohydrolases and dihydroorotases share the same origin and several enzymatic properties. Nucleic Acids Res. 31, 1683-92
2. A thermostable hydantoinase of Bacillus stearothermophilus NS1122A: cloning, sequencing, and high expression of the enzyme gene, and some properties of the expressed enzyme. Biosci. Biotechnol. Biochem. 58, 1621-6
3. Functional expression and characterization of the two cyclic amidohydrolase enzymes, allantoinase and a novel phenylhydantoinase, from Escherichia coli. J. Bacteriol. 182, 7021-8
4. Brain CRMP forms heterotetramers similar to liver dihydropyrimidinase. J. Neurochem. 69, 2261-9
5. Collapsin response mediator protein 3 deacetylates histone H4 to mediate nuclear condensation and neuronal death. Sci Rep 3, 1350